SEMINARS

FALL 2005

Thursday Sept 8
A158 LSRC
4:00 - 5:15

C and N cycling in grasslands of Argentina and Uruguay: livestock introduction and its consequences
Gervasio Piñeiro, Universidad de Buenos Aires, Argentina
project researchers:
Gervasio Piñeiro(1); J.M. Paruelo (1); M.O. Oesterheld (1); E.O. Jobbagy (2); R.B. Jackson (3)

1- IFEVA/FAUBA, Buenos Aires. 2- Conicet, San Luis. 3- Duke University.

Grazing by domestic herbivores at high stocking rates, can alter the structure and function of natural grasslands. We evaluated the effects of grazing on the “Rio de la Plata” grasslands of South America using CENTURY, a process based biogeochemical model and field experiments. Contrary to prior studies, our ecosystem level simulations of grazing impacts showed a reduction in SOC associated with a more open and leaky nitrogen cycle that constrains long-term organic matter formation. To evaluate these results, we selected 13 grazing-exclosure sites in the “Rio de la Plata” grasslands of Uruguay. We sampled soil and roots and measured carbon and nitrogen contents at six depths in two different soil size fractions: the particulate organic matter (POM) of rapid turnover and the mineral associated organic matter (MAOM) of low turnover. As CENTURY simulations, our field results showed that grazing reduces total SOC in deep soils, but field data showed opposite trends in shallow soils. Grazing severely altered the vertical distribution of C in POM, increasing this labile SOC fraction towards the surface while decreasing C and N contents in the MAOM fraction in depth. The higher root contents (and belowground C inputs) measured at the surface in the grazed areas could be explaining the raise of surface POM, while other mechanisms are discussed for the accumulation of N in deeper horizons under grazing exclosure.

Gervasio Piñeiro was born in Buenos Aires Argentina on April 1973. A few years later he moved to Montevideo in Uruguay, where he made his school studies all through to the University. He obtained an Agricultural Engineering title at the Universidad de la República, Uruguay in 1999 and in the same year initiated his MSc courses at the Universidad de Buenos Aires in Argentina. He is currently enrolled in a PhD program at this University funded by CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas) and is a teaching assistant in Ecology since 1999. His research is now focused in understanding livestock impacts on ecosystem structure and functioning, and developing sustainable managerial practices for grasslands of southern South America. (more info at www.ifeva.edu.ar/en/staff/pineiro.htm)

Thursday Oct 27
A158 LSRC
4:00 - 5:15

What are the most important factors for climate—carbon cycle coupling?
S. C. Wofsy, Dept. of Earth and Planetary Science, and Division of Engineering and Applied Science, Harvard University.
Contributors include: J. W. Munger, S. P. Urbanski1, C. C Barford2, L. Hutyra, S. R. Saleska3, and A. L. Dunn
Current addresses: 1USFS,Missoula, MT; 2U. Wisconsin, Madison WI; 3U. Arizona, Tucson AZ.

The mechanisms that drive changes in ecosystem carbon balance in response to climate change are evaluated using data from long-term measurements of CO2 fluxes, environmental parameters, and ecological factors in boreal, mid-latitude and tropical ecosystems. We find that most model parameterizations overestimate the temperature sensitivity of ecosystem respiration and underestimate the role of soil water balance in controlling respiration and flammability. We conclude that models of climate—carbon feedbacks must carefully simulate regional precipitation, evaporation, evapotranspiration, and water balance, including factors leading to fires (e.g. sources of ignition), in addition to assessing changes in temperature. Covariances among these drivers of ecosystem change, along with the severity and frequency of extreme events, may also be critically important for understanding coupling between ecosystems and climate.
click for extended abstract >

Professor Steve Wofsy is Abbott Lawrence Rotch Professor of Atmospheric and Environmental Science, and Associate Dean of the Faculty of Arts & Sciences (FAS). at Harvard University. Professor Wofsy and colleagues are studying CO2 and other important atmospheric gases at long-term measurement stations located from the subarctic to the equator, complemented by atmospheric measurement campaigns using aircraft such as the University of North Dakota Citation II and NASA's ER-2 and WB-57F. Analysis and modelling studies aim to extract quantitiative information about sources, sinks, transformations, and transport of atmospheric trace gases, to help understand the factors that regulate atmospheric composition and to help design programs to mitigate undesirable change. Wofsy received a B.S. in Chemistry at the University of Chicago (1966), an M.A.(1967) and Ph.D. (1971) in Chemistry from Harvard University. For more information on Professor Wofsy , a list of his publications, and projects, see his website, http://www.deas.harvard.edu/ourfaculty/profile/Steven_Wofsy; and also click on “Personal Link”.

Tuesday Nov 1
A158 LSRC
4:00 - 5:15

Interactive impacts of vegetation on hydrology and soil chemistry: The grassland afforestation experiment
Esteban Jobbágy, Grupo de Estudios Ambientales, Universidad Nacional de San Luis & CONICET, San Luis, Argentina

Vegetation changes, particularly those involving transitions between tree- and grass-dominated systems can have a strong influence on two central aspects of ecosystem functioning: evaporative water losses and base cation cycling. Existing tree plantations (fast growing pines and eucalypts) established on native grasslands are used as large scale experiments to evaluate the role of these plant-level contrasts shaping the hydrology and soil/water chemistry of whole ecosystems. A global synthesis of stream flow studies suggests higher evapotranspiration in afforested watersheds (an extra 15% of precipitation is evaporated) compared to adjacent grasslands. A similar synthesis for paired soil studies reveals a widespread soil acidification (a decline of 0.5 pH units) in afforested stands associated with exchangeable Ca reductions. This seminar considers connections between soil and hydrological alterations across a network of tree plantations in the grasslands of Argentina and Uruguay, and Vegetation to water to soil influences on flat landscapes of the Pampas, where tree plantations initiate a discharge regime in areas that functioned as recharge zones prior to tree establishment.

In these situations hydraulic alteration on the phreatic aquifer result in the discharge of shallow and young waters with high bicarbonate content in the edge of tree plantations and deeper and older waters with low bicarbonate content towards their core. These hydrochemical contrasts result in highly saline and alkaline soils in the borders of tree plantations and saline but neutral soils in their core. Vegetation ? soil ? water influences are illustrated with a series of small watersheds occupied by tree plantations and native grasslands in the hills of Cordoba and Lavalleja. There, the acidifying effect of tree plantations observed in soils globally seems to translate into stream acidification accompanied by declining concentrations of base cations and dissolved inorganic carbon and increasing concentrations of dissolved aluminum. These results highlight a) the important role of vegetation change shaping soils and water resources, b) the interactive nature of the biogeochemical and hydrological effects of vegetation. Besides being a valuable ecological experiment, tree plantations in grasslands are a major and accelerating “real world” land use change in Southern South America that poses multiple strains to local ecosystems and societies. The ecological and socioeconomic drivers of this land use are introduced and the role of science favoring its monitoring and sustainable implementation is discussed based on examples from the Pampas.

Esteban Jobbágy obtained his degree of Agronomist from University of Buenos Aires in 1993 and his Ph.D. in Biology from Duke University in 2002. He works as a Research Scientist (CONICET) in the University of San Luis, Argentina, and as Research Associate at Duke. His past work has involved the understanding of the patterns and controls of primary production in Patagonia and Southern South America using field and remote sensing observations, the analysis of ecological convergence in temperate zones at both sides of the the equator using floristic and biogeographical information, the synthesis of the vertical distribution of carbon and nutrients in based on global databases among other aspects of terrestrial ecosystem. In the last four years he has focused on the role of plants controlling soil and groundwater chemistry and hydrology, using man-induced vegetation changes as a study system, particularly tree plantation established in grassland ecosystems.

A complementary research line involves the design and development of alternative forestry systems for grassland regions. In 2004 he has founded “Grupo de Estudios Ambientales” in the University of San Luis. There, a team of Physicist, Biologists, and Agronomists are developing the fields of Biogeochemistry and Ecohydrology through research and education. From San Luis, Esteban is currently coordinating a network of global change scientist in the Plata Basin including institutions from Brazil, Uruguay, Paraguay, Argentina, and the US. This network is exploring the biophysical and human drivers and consequences of land use shifts in an attempt to generate basic understanding of global change processes as well as ecosystem management tools for the basin.

Thursday Nov 3
A158 LSRC
4:00 - 5:15

New insights into the carbon cycle of Amazonia from a forest plot network
Yadvinder Mahli,Oxford University Centre for the Environment, and Research Fellow at the Institute of Ecology and Resource Management, University of Edinburgh

The Amazon rainforest biome plays a major role in the global carbon cycle. Hitherto, much research into the carbon cycling of intact Amazon forests has focussed on a few intensive field sites in Brazilian Amazonia. Here I present results from a forest plot network, RAINFOR, that has compared tropical forest dynamics across seven Amazonian countries. Amongst our key discoveries have been:

1. There are large and coherent regional gradients in the wood productivity of lowland Amazonian forests, with forests in western Amazonia being two to three times more productive than those in the east. These gradients appear to be driven by soil quality rather than climate, with soils in western Amazonia being younger and less weathered.
2. These variations in productivity have an effect on forest structure, with the dynamic western forests being dominated by fast-growing, short-lived, low wood density species, and the slow eastern Amazonian forests being dominated by slow-growing, long-lived, high wood density species. These contrasts result in mean wood density being 10 % higher in eastern Amazonia.
3. The stem volume of Amazon forests shows no regional variation in moderately wet to very wet forests, but declines in seasonally dry forests at the fringes of Amazonia.
4. The biomass of Amazonian forests peaks in central Amazonia and the Guyanas. It declines on the dry fringes because of reduction in stem volume, and declines in western Amazonia because of the decline in wood density.
5. The tree diversity of lowland Amazonian forests is strongly limited by the length of the annual dry season.
6. The productivity and diversity of Amazonian forests are driven by different environmental factors, and there is no simple relationship between the two.
7. There is evidence that the dynamics of Amazonian forests have accelerated in recent decades, with the greatest acceleration on the already dynamic forests of western Amazonia. The cause of this accelation is not yet clear, but it is plausible that global atmospheric change plays a major role.

Dr Yadvinder Malhi’s research focuses on how the physiology, structure, biomass and dynamics of tropical forests are controlled by climate and soils, and how these features of the forest may respond to ongoing atmospheric change. He is co-founder of the RAINFOR project, which has conducted systematic research in tropical forests across South America and Africa, and coordinator of the EU-funded training programme PAN-AMAZONIA (Project for the Advancement of Networked Science in Amazonia), which aims to train students from across Amazonia in ecological field science techniques. Mahli is co-editor of the book Tropical Forests and Global Atmospheric Change (Y. Malhi and O.L. Phillips, Oxford University Press, published July 2004). He has an undergraduate degree in Natural Sciences from the University of Cambridge, and a PhD in Meteorology from the University of Reading. His research interest in tropical forests began as a post-doctoral researcher at the University of Edinburgh, and he has been a Royal Society University Research Fellow since 1999. He is currently based at the Oxford University Centre for the Environment, and he is also an Honorary Research Fellow at the University of Edinburgh

Monday, Nov 21
A158 LSRC
4:00 - 5:15

Aerosol effects on climate: Does strong aerosol cooling in the past imply a hotter future?
Meinrat Andreae, Max Planck Institute for Chemistry, Germany

Meinrat Andreae is director of the biogeochemistry department at the Max Plank Institute for Chemistry (MPIC), located in Mainz, Germany. As a child, Andreae enjoyed reading about chemistry and playing with chemistry sets. In college, he had planned to major in chemistry, but found its study too remote from direct applications to the Earth. Andreae instead switched his focus to geochemistry, and he earned a Vordiplom (B.S.) in Earth sciences from the University of Karlsruhe, Germany, in 1970. In 1974, Andreae went on to earn his Diploma (M.S.) in Earth sciences from Germany’s University of Göttingen. His thesis focused on the isotope and element geochemistry of rocks in southern Norway. Through this work, he became interested in biogeochemistry. “These were old, metamorphosed rocks, once exposed to extremely high temperatures and pressures deep in the Earth’s crust,” he recalled. “But there were signs that they formed by biological processes.” Building on these interests, Andreae earned his Ph.D. in 1978 from the Scripps Institution of Oceanography in San Diego, Calif., where he studied ocean and terrestrial biosphere interactions. After graduating, he served as a professor of oceanography at Florida State University, and, in 1987, became a professor at the MPIC. In 1988, Andreae received the World Meteorological Organization’s Gerbier-Mumm award for his discovery of a feedback loop between marine phytoplankton activity and global climate. In addition to studying the role of marine biota as a source of climatically important trace gases, Andreae is interested in the sources and characteristics of atmospheric aerosols and their effects on precipitation and climate, and the effect of vegetation fires on ecology and atmospheric pollution. Through his research, Andreae has traveled to the Amazon basin, the jungles of central Africa, and, most recently, Siberia and China, where he is investigating the effect of atmospheric pollutants on climate systems. Andreae was named the editor of the AGU’s journal Global Biogeochemical Cycles last year.
(excerpted from EOS, November 1, 2005 issue)

SPRING 2005

Thursday, February 17
A158, LSRC
4:00 - 5:15

Selective Logging in the Brazilian Amazon: Biogeochemical Effects and Quantitative Damage Estimation Using Satellite Remote Sensing.
Michael Keller, Project Scientist for the Large-scale Biosphere Atmosphere (LBA) Experiment in Amazonia; USDA Forest Service, Intn'l Inst. of Tropical Forestry; and Professor at University of New Hampshire

Selective logging is an extensive land use in the Brazilian Amazon. Current estimates from economic data suggest that logging annually effects between 10,000 to 20,000 km2. Logging results in extensive damage to forest structure leading to changes in the forest carbon cycle and productivity. Forest productivity and the sustainability of logging depend greatly on the logging techniques employed. For years it has been shown that logging areas can be identified through satellite remote sensing. However, only recently, we have shown that using Landsat data together with extensive and detailed ground based measurements, forest damage can be quantified by spectral un-mixing of remotely sensed images. The combination of in situ and remote sensing studies provides a path to quantify logging effects on the Amazon region carbon cycle.

Michael Keller studies tropical forest ecosystems and the effects of land use change and agricultural intensification in Central and South America on the function of ecosystems and the control of atmospheric chemistry and composition. Keller’s research ranges from the biological controls of trace gas emissions at the organismal level to the estimation and modeling of regional and global trace gas and carbon budgets. Over the past two decades, he has lived and worked in Brazil, Panama, Costa Rica, and Puerto Rico as well as in the United States. He currently serves as lead scientist for the NASA sponsored LBA-ECO component of the Brazilian led Large Scale Biosphere Atmosphere in Amazonia (LBA) and the Co-Chair of the LBA International Science Steering Committee. LBA-ECO is designed around the question “How do tropical forest conversion, re-growth, and selective logging influence carbon storage, nutrient dynamics, trace gas fluxes and the prospect for sustainable land use in the Amazon region?” To answer this question Keller and his colleagues in LBA-ECO combine in situ measurements with regional models and remotely sensed observations of biological and social systems in the Amazonian environment.

Michael Keller is currently employed as a Research Scientist at the USDA Forest Service International Institute of Tropical Forestry in San Juan, Puerto Rico. He is stationed at the University of New Hampshire in Durham, NH where he is also an Affiliate Professor. Keller earned his B.A. in Geology at Harvard University and his Ph.D. in Geological and Geophysical Sciences at Princeton University.

Thursday, March 24
113 BIOSCI 4:15 - 5:30 -- Note place and time

The role of terrestrial ecosystem processes in determining patterns of terrestrial carbon fluxes and atmospheric CO2 concentrations: Results from a regional-scale coupled atmosphere-ecosystem model
Paul Moorcroft, Dept. of Organismic & Evolutionary Biology, Harvard University

Inverse studies of the carbon cycle have traditionally relied on low-frequency flask measurements collected at remote stations specifically located to eliminate variance in CO2concentrations arising from terrestrial processes. The insensitivity of these observations to terrestrial CO2 fluxes makes it difficult to infer regional terrestrial carbon fluxes or to attribute large-scale fluxes to particular causes such as climate variability, land-use change or CO2 fertilization. We are addressing this issue by developing a constrained implementation of the Regional Atmospheric Modeling System-Ecosystem Demography Model Version 2 (RAMS- ED2) for the New England region. RAMS-ED2 is a new, coupled atmosphere-ecosystem model that naturally scales between the fast timescale responses of individual plants to the atmosphere and the long-term, regional-scale dynamics of heterogeneous ecosystems subject to land-use change and forest harvesting. The model is designed to predict carbon fluxes on spatial scales from hectares to thousands of square kilometers that are consistent with fast timescale flux-tower measurements of CO2 fluxes, seasonal measurements of canopy phenology from remote sensing data and decadal scale forest inventory measurements and land-use history forcing. The ecosystem state variables and environmental response functions of the optimized model provide a comprehensive description of short and long term factors regulating fluxes in the regional carbon cycle. The optimized model will provide a unique tool for quantifying the contributions of environmental forcing, ecosystem recovery from land-use change, forest harvesting and CO2 fertilization to current and future patterns of terrestrial carbon fluxes and resulting patterns of atmospheric CO2 concentrations in North America.

Paul Moorcroft is an Assistant Professor of Ecology at Harvard University who specializes in terrestrial ecosystem dynamics. His research investigates how ecological processes affect the structure, composition, and biophysical and biogeochemical functioning of terrestrial ecosystems at regional to global scales. Professor Moorcroft received his undergraduate degree from Cambridge University, and his doctorate from the Department of Ecology and Evolutionary Biology at Princeton University. After spending three years as postdoctoral researcher at the Princeton Environmental Institute, he joined the Harvard faculty in 2001.

Tuesday, April 5
A158, LSRC
4:00 - 5:15

Climate Change in the U.S. Congress: An Update on Congressional Action and How Science Informs (or Doesn't Inform) the Debate
Manik Roy, Ph.D., Director of Congressional Outreach, Pew Center on Global Climate Change

Five years ago, there was virtually no action in the United States Congress on global climate change. Three years ago, the U.S. Senate passed a bill to have the largest emitters of greenhouse gases (GHG) track and disclose their emissions. A year-and-a-half ago, 44 senators supported a Lieberman-McCain bill to cap U.S. GHG emissions. Today, several conservative Republican senators are for the first time urging action to address climate change. Why the recent burst (by congressional standards) of activity? What policy options are being discussed? Where is the U.S. House of Representatives in all this? How is science used (and abused) in the debate?

Manik Roy is the Director of Congressional Affairs for the Pew Center on Global Climate Change, where he manages communication between the Center and the United States Congress. Dr. Roy has had twenty-two years of experience in environmental policy, working most recently for Senator Frank R. Lautenberg and Representative Henry A. Waxman. Prior to working in Congress, Dr. Roy was the director of the pollution prevention policy staff of the U.S. Environmental Protection Agency, and a pollution prevention specialist with the Massachusetts Department of Environmental Protection and the Environmental Defense Fund. Dr. Roy holds a Ph.D. in public policy from Harvard University. He also holds a Master of Science degree in environmental engineering and a Bachelor of Science degree in civil engineering, both from Stanford University.

Thursday, April 7
LSRC A158
4:00 - 5:15

Putting a Human Face on Science (Getting Media Attention for Environmental Topics)
Michael Tennesen, 2nd CGC Writer in Residence & Nicholas School Environmental Media Fellow

A science and nature writer, Tennesen has written more than 400 stories in such publications as Smithsonian, National Wildlife, Audubon, Wildlife Conservation,Air and Space, and Discover. He wrote Flight of the Falcon for Key Porter Books (1994) and is the author of The Complete Idiot's Guide to Global Warming (2004).
Michael Tennesen is a graduate of the University of California at Los Angeles and has been a full time freelance journalist for better than 20 years.

Thursday, April 21
A158, LSRC
4:00 – 5:15pm

Catchment (water shed) hydrology research in South Africa: past, present and future
David Le Maitre, Conservation Biologist–Hydrologist, Environmentek, Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa

South Africa is a semi-arid country with a mean annual rainfall of about 450 mm compared with a world average of about 860 mm. Almost 60% of the country gets less than 500 mm per year and only 12% more than 750 mm. Only 9% of the rainfall ends up in the streams and rivers as surface runoff. This is far lower than the world mean value of 34% but similar to that of Australia and Zimbabwe. Less than 0.5% of the country is covered in indigenous closed forest. The shortage of suitable timber for construction and other purposes was recognised in the mid 19th century and this realisation led to the progressive afforestation of areas with pines, eucalypts and Australian acacias. This afforestation programme was controversial because many farmers and scientists argued that replacement of native vegetation (shrubland, grassland) with plantations reduced the amount of water in streams draining those catchments. Others argued that afforestation would trap more moisture from the air and increase flows. A forest hydrology research programme was launched in the 1930s to address this controversy and has continued at various levels of intensity to this day. This research shows conclusively that afforestation reduces the surface runoff, a finding which is in line with research in other countries. The idea that forests bring more water still has strong support, at least in much of Africa. This can be explained by changes in infiltration and seasonality of flows following land degradation, and a model is proposed to explain this conundrum.
The reductions in surface runoff are very important because plantations typically are situated in the high rainfall regions and high yielding catchment areas of the country. Currently, plantations account for an incremental loss (relative to the natural vegetation) of about 3.5% of the annual surface runoff although they occupy only 1.3% (1.5 million ha) of the country. This research is continuing and has been extended using techniques such as tree sap-flow and micrometeorology (e.g. energy balance) to estimate evaporation and soil moisture balance and flux at the hillslope scale.
The results of the catchment-scale hydrological research provided the basis for introducing legislative control over afforestation in 1972 and under new the National Water Act (1998) as a “stream flow reduction activity”. The research findings were also used to estimate the impacts of invasions by woody introduced species on surface runoff in South Africa. A crude model was developed to estimate the impacts of these invasions. This gave an estimate that (when the total invaded area of 10.1 million ha was adjusted to its equivalent area with 100% canopy cover, namely 1.7 million ha) invasions have reduced mean annual runoff by 6.7%. These findings have been used to support a national weed clearing programme (Working for Water) which is currently running on an annual budget of USD 60 million.
The predicted impacts of climate change in South Africa are drastic. Vegetation studies indicate that most of the western regions will become semi-desert. There will be relatively little change in the eastern regions but there are substantial uncertainties. A research project aimed at assessing the hydrological implications of the predicted climate has just been launched. The long-term records from the research catchments also provide a unique, continuous record of rainfall and runoff which spans a period of nearly 70 years which can be used in this assessment. An initial analysis of these records indicate that there may be a decline in rainfall, and thus in the runoff, in these critical catchments but further, more detailed assessments are needed.

Dr David Le Maitre has a Ph.D. in plant ecology and is a conservation biologist and hydrologist, employed by the South African Forestry Research Institute (Department of Water Affairs and Forestry) from 1979-1990 and by the CSIR (a statutory research council) since 1990. He has more than 20 years of research experience in the ecology of Cape fynbos vegetation and also has been involved for more than 10 years in research on the impacts of plantations and alien plant species on water resources and ecosystems. He has developed expertise in assessing the hydrological and ecological impacts of invading alien plants and the dynamics of invasion processes. He has a special interest in the ecological role of groundwater, particularly in groundwater-dependent ecosystems. He has also been involved in the assessment, maintenance and conservation of biodiversity, particularly the development and use of indicators. He has published widely in the scientific literature, especially in the field of the fire-related ecology of fynbos and the hydrological impacts of alien plant invasions. He has played key roles in developing:
• Guidelines and tools for identifying groundwater-dependent ecosystems and assessing the groundwater Reserve (South African National Water Act).
• Development of monitoring systems for assessing the impact of city-scale groundwater abstraction in the Cape Table Mountain Group aquifer.
• Approaches for modelling the impacts on invasive plant species on water resources for medium-scale catchment (basin) water supply scheme analyses.
• An analysis of the impacts of plantations on surface water resources (for the national Department of Water Affairs & Forestry).
• An assessment of extent and impacts of alien plants on water resources in South Africa (Water Research Commission for the Working for Water Programme).
• Formulation of a research programme for groundwater-vegetation interactions (Water Research Commission).

Tuesday, May 3 -- CANCELLED
Location: TBA
4:00 - 5:15

Looking for carbon in all the wrong places: Carbon dynamics in the Rocky Mountains
Dave Schimel, Senior Scientist, Terrestrial Sciences, Climate and Global Dynamics Division, National Center for Atmpospheric Research

Analysis of satellite data and simulation models clearly shows that a disproportionate share of US carbon uptake takes place in mountains, where now-traditional micrometeorological and airborne techniques are widely assumed to be unusable. We conducted an integrated surface, airborne and modeling analysis of carbon fluxes in the Rocky Mountains, first to develop techniques for scaling carbon fluxes in extreme complex terrain, and second to confirm indirect estimates suggesting active carbon storage. The results show that meteorological techniques can be applied in the mountains, and that respiration fluxes that are challenging to quantify in conventional sites can be estimated at large scales in the mountains. Airborne budgets provide a useful complement to surface observations, increasing the value of both. Even airborne snapshots provide a powerful view of the seasonal cycle at the regional scale. We show an assimilation-model based breakdown of eddy covariance fluxes into photosynthesis, autotrophic and heterotrophic respiration and NPP and use this as a basis for hypotheses about the relationship between truly regional satellite-constrained estimates of photosynthesis and similarly scaled airborne estimates of net ecosystem exchange. Overall, while no single method provides all the desired regional information, the synthesis of methods provides a nearly comprehensive view.

Thursday, June 23
A247 LSRC
4:00 pm -- 5:15pm

Grassland afforestation effects on water and salts dynamics
Marcelo Nosetto, Grupo de Estudios Ambientales – IMASL, Universidad Nacional de San Luis & CONICET San Luis, Argentina.

Vegetation changes, particularly those involving transitions between tree- and grass-dominated covers, can modify evaporative water losses and, as a consequence, salt accumulation patterns. Water use in /Eucalyptus grandis/ plantations and the native humid grasslands that they replace in Central Argentina were explored using a remote sensing approach, suggesting an almost two-fold raise of evaporative water losses in afforested areas. Afforested stands used more water both in dry and wet periods indicating both, better access to water sources and higher evaporative capacity. Salt distributions patterns in soils occupied by tree plantations and native grasslands were examined in the Argentinean Pampas and the Hungarian Hortobagy. Both regions displayed large salt accumulation in the vadose zones of afforested areas suggesting that trees, through groundwater consumption and solute exclusion, triggered a salinization process in deep soil layers. However, lower salt concentration observed in shallow soil layers in Hortobagy under tree plantations indicate that trees in that region may have also enhanced water infiltration. Highly promoted as a carbon sequestration means, tree plantations in grassland ecosystems could have a strong impact on the hydrological cycle with cascading effects on salts dynamics.

Marcelo Nosetto is a graduate student working in “Grupo de Estudios Ambientales” in the University of San Luis in Argentina. His work involves the exploration of land use changes impacts on ecosystem function, specifically afforestation in grassland ecosystems. He uses a combination of plot, catchments and remote sensing approaches to uncover the effects of this land-use shift on water, carbon and salts dynamics. He is participating in several projects related to land-use change and its effects on ecosystem functioning and regional climate, which involve collaborations with researchers at Duke University (Jackson lab), Hungary and Uruguay.

FALL 2004

Thursday, September 9
A158, LSRC
4:00 - 5:15

Forest Responses to Elevated Atmospheric CO2: Contrasting Patterns of Carbon Allocation in Oak Ridge and Duke FACE Experiments
Richard J. Norby, Oak Ridge National Laboratory

The Free-Air CO2 Enrichment (FACE) experiment at the Oak Ridge National Laboratory provides a valuable opportunity to compare the responses of a deciduous sweetgum forest with those of the evergreen pine forest in the Duke FACE experiment. The Oak Ridge FACE experiment is in a closed-canopy stand of sweetgum (Liquidambar styraciflua) trees on the Oak Ridge National Environmental Research Park. The trees have been exposed since 1998 to elevated CO2 in two 25-m diameter plots using similar technology to that used in the Duke FACE experiment. Net primary productivity (NPP) is measured through allometric analysis of stem growth, weighing of leaf litter, and minirhizotron analysis of fine root production. NPP has been higher each year in plots with 550 ppm CO2 compared to plots in ambient air. The average increase has been 22%, and there is no indication of a loss in response over time. Annual production of fine roots was more than doubled in CO2-enriched plots, and this response was the primary component of the increase in NPP. Aboveground wood production, however, increased significantly only during the first year of treatment. The allocation pattern is the primary difference between the response of this deciduous stand and that of the loblolly pine stand in the Duke FACE experiment. NPP of the pine stand has been stimulated by elevated CO2, and the stimulation has persisted through time, but the extra C has been recovered in stems, not in root production. This difference in allocation pattern has important implications for biogeochemical cycling, including the potential for these forests to sequester C. The preferential allocation of additional carbon to fine roots, which have a fast turnover rate in this species, rather than to stemwood, reduces the possibility of long-term enhancement by elevated CO2 of carbon sequestration in biomass. However, sequestration of some of the fine root carbon in soil pools is not precluded, and there may be other benefits to the tree from a seasonally larger and deeper fine root system. The contrasting responses of the forest stands in the FACE experiments at Oak Ridge and Duke demonstrate the importance of understanding C allocation patterns and tissue turnover rates as determinants of ecosystem response to elevated atmospheric CO2.

Richard Norby is a Distinguished Research Scientist in the Environmental Sciences Division at the Oak Ridge National Laboratory (ORNL), where he has worked since 1981. He received his education at Carleton College with a B.A. in chemistry awarded in 1972, and at the University of Wisconsin-Madison, where he received a Ph.D. in forestry and botany in 1981. His research interests include tree physiology, forest ecology, and global change. Norby has been conducting experiments on the effects of rising atmospheric CO2 concentrations on forest tree species since 1982. He is the principal investigator of the Oak Ridge Experiment on CO2 Enrichment of Sweetgum, in which a closed-canopy deciduous forest is being exposed to elevated CO2 using free-air CO2 enrichment (FACE) technology. He also leads an ongoing experiment investigating the interactions between CO2, warming, and soil moisture in an old-field community. Norby was a task leader for CO2 research within the Global Change and Terrestrial Ecosystems core project of the International Geosphere-Biosphere Programme, and he also serves as a Environment Section editor of New Phytologist. He received the Scientific Achievement Award of the Environmental Sciences Division in 1992 and was elected fellow of the American Association for the Advancement of Science on 1995. A complete CV may be found at http://www.ornl.gov/~rjn.

Thursday, November 4
A158, LSRC
4:00 - 5:15

Linking genome, physiological, and ecosystem responses to rainfall variability in a mesic grassland
Phil Fay, University of Minnesota, Duluth, Natural Resources Research Institute, Center for Water and the Environment

The Rainfall Manipulation Plot Experiment (RaMPs) is an ongoing multi-factor climate change experiment at the Konza Prairie Biological Station in northeastern Kansas - that implements forecast changes in temperature and rainfall patterns associated with energy production and consumption on a native grassland ecosystem. The RaMPs experimental infrastructure examines two key, predicted environmental changes: 1) increased temperature (1-2°C), and 2) more variable precipitation regimes, specifically increased time between rainfall events and events of greater intensity. It is an ideal platform for this research since most of the relevant organismic-through-ecosystem responses to climate change have been characterized over the last 6+ years, with monitoring still ongoing. After 6 years of experimentally increased rainfall variability, we have observed impacts at multiple levels of biological organization. These include lower mean and increased variability in soil moisture, decreased aboveground net primary production and soil CO2 flux, both of which will have important implications for C storage and cycling over the long term. Recent results from the RaMPs has demonstrate that genomic data can be collected from plants under field conditions and directly linked to plant physiological responses underlying climate change impacts on ecosystem structure and function. Our immediate goals are to conduct detailed, spatially and temporally explicit genomic sampling in concert with leaf level physiological measurements on two dominant C4 grasses in this ecosystem, and then scale these to the emergent community and ecosystem level responses based on differential responses of the individual species. The research will bridge a fundamental divide between two disciplines in biology traditionally focusing on divergent domains of inference, strengthening both fields by developing and testing a novel, integrative approach, thereby providing the knowledge necessary to plan mitigation and policy for the climatic alterations facing society.

Dr. Fay is a Research Associate at the Natural Resources Research Institute. His research interests span ecosystem, plant population and physiological ecology, and plant/animal interactions in grassland ecosystems. He uses a combination of laboratory, greenhouse and large scale field manipulations to determine the role of climatic variability and extreme climatic events in structuring grassland ecosystems. His main projects involve field scale manipulations of rainfall inputs and temperature in native tallgrass prairie at the Konza LTER site, and new or developing projects will focus on linkages between the plant genome and ecosystem properties, and regional variation in ecosystem responses to climate variability. His work has been supported by NSF, USDA, and DOE, and appeared in numerous international journals.

Thursday, November 11
A158, LSRC
4:00 - 5:15

The Importance of Comparing Apples to Apples: Matching MODIS to Flux Towers
Hans Peter Schmid, Department of Geography, Atmospheric Science, Indiana University, Bloomington; Director of the Institute for Research in Environmental Science

Satellite derived estimates of ecosystem-atmosphere carbon exchange have the advantage of global coverage, but need to be verified by in-situ flux measurements at flux towers. This work addresses problems and issues associated with matching MODIS products to flux tower derived gross photosynthetic exchange of carbon dioxide (GPE) at the hand of 7 km x 7 km MODIS product subsets centered on the AmeriFlux tower in Indiana (MMSF~flux). The principal concerns here are that (i) the footprint of turbulent flux measurements is typically considerably smaller than a 1 km square MODIS pixel, (ii) that the flux footprint is non-stationary and varies its size and location according to the flow and turbulence conditions in the atmospheric boundary layer, and (iii) that MODIS products of GPE are typically 8-day composites derived from eight or less valid satellite passes and simulated meteorological conditions.

To shed light on these issues, high resolution LAI (derived from Ikonos and Landsat/ETM+ satellites) will be overlaid with computed flux footprints to examine the area-to-area representativeness of flux measurements over various time scales. In particular, we will examine whether the averaging power of the spatially evolving flux footprint over an 8-day integration period (matching the MODIS time scale) is usually sufficient to provide fluxes with acceptable spatial representativeness to serve as a benchmark for MODIS products. We compare eight-day composites of MODIS and tower fluxes, using simulated and locally measured meteorological information, and relate the comparison to measures of spatial representativeness of the flux measurements.

Hans Peter Schmid is Associate Professor in the Atmospheric Science Program of the Department of Geography at Indiana University, Bloomington. His research interests includes biosphere-atmosphere interactions, the atmospheric boundary layer and micrometeorology over inhomogeneous surfaces. His specialty is footprint modeling and the development of objective methods to scale-up from footprint to ecosystem fluxes. Dr. Schmid is co-Director of IU's Institute for Research in Environmental Science (IRES). He received his Ph.D. from the University of British Columbia in Geography and Atmospheric Science.

Tuesday, November 16
4:00—6:00pm, Law School, Rm 3043
Webcast now available >

Can Markets Protect the Climate? Prospects for Greenhouse Gas Emissions Trading in the US and Europe
click for detailed symposium information >

Speakers:
Peter Zapfel, European Commission, Directorate General - Environment (abstract & bio > | presentation >)
Tim Profeta, JD-MEM, Duke Law and Nicholas School, '97, currently counsel to Senator Joseph Lieberman (bio > | presentation >)

Discussants:
Joseph Goffman, Attorney, formerly at Environmental Defense (bio >)
Bruce Braine, Vice President, Strategic Policy Analysis, American Electric Power (bio > | presentation >)

Moderator:
Jonathan Wiener, Professor of Law and Environmental Policy and Director, Center for Environmental Solutions

Tuesday, November 30
A158, LSRC
4:00 - 5:15

Projecting climate change impacts on species and ecosystems: Perspectives from the southern Hemisphere
Guy F Midgley, Climate Change Research Group, South African National Biodiversity Institute, Cape Town, South Africa.

Obvious differences in the latitudinal distribution of continental land mass between the southern and northern hemispheres seems at least partly responsible for some interesting contrasts in emphasis in ecological thinking among terrestrial ecologists of the two hemispheres. In particular, disturbance by fire and drought have attracted relatively more attention in the south, due to the prevalence of flammable subtropical and temperate ecosystems, drought-prone arid- and semi-arid ecosystems, and the influence of ENSO-related climate phenomena. These preoccupations are also reflected in thinking about anthropogenic climate change impacts, and I will discuss some of the insights that are emerging from this perspective, using mainly southern African examples.

Dr. Midgley is a plant physiologist and specialist scientist at the National Botanical Institute (NBI), now South African National Biodiversity Institute, in Cape Town, SA. He is involved in multiple projects related to climate change, including lead scientist of a group that is investigating the effects of rising temperatures on the Karoo flora; primarily funded by Conservation International. See: http://www.nbi.ac.za/homepage.htm, “Effects of CO2 on natural vegetation in South Africa”. See also this review of climate change impacts, “In a Nutshell”, based on research by Dr. Midgley, and others : http://www.nbi.ac.za/frames/researchfram.htm/.


SPRING 2004

Friday, February 13
A158, LSRC
4:00 - 5:15

Causes and Consequences of Plant Functional Diversity: Biotic Effects on Ecosystem Processes and Responses to Global Change
Peter B. Reich, F.B. Hubachek Sr. Chair (in Forest Ecology and Tree Physiology) and Distinguished McKnight University Professor in the College of Natural Resources at the University of Minnesota.

Why aren’t all plants the same? How and why are they different, how and why are they not different, and what are the implications for communities and ecosystems, especially in the face of global change? In this talk, we will visit the concept of plant traits and their relationships, asking to what degree leaf traits are driven by natural selection and biophysics into the same constellations world-wide, and whether this gives us clues to help us generalize about the ways in which plants influence their communities and ecosystems? In doing so, I will present new data from a study of 2,300 species at 175 sites around the world, and also present results from several site-based studies that show how plants radically influence soils much faster than is typically appreciated. Finally I will discuss how both divergence among and diversity of traits may influence terrestrial ecosystem response to global environmental change, such as in CO2, N deposition, and temperature.

Dr. Reich is an ecologist interested in global change and the sustainability of managed and unmanaged terrestrial ecosystems. His work includes a range of studies from scaling relationships across organizational, temporal and spatial gradients, to an integrated focus on mechanisms linking ecophysiology, community dynamics and ecosystem processes. He is active in an array of research activities that range from an open-air multi-factor experiment with elevated carbon dioxide in grasslands; to studies of boreal forest sustainability in the face of fire suppression, logging, and climate change; to leading an international consortium to develop a global plant ecophysiological data base.

Professor Reich has written more than 200 articles published in peer-reviewed international scientific journals or books; and has been engaged in research in tropical, temperate and boreal ecosystems on five continents. He has served on the editorial boards of leading international journals, and received numerous honors, such as the Pound Research Award (University of Wisconsin), the Presidential Young Investigator Award (National Science Foundation), and the Distinguished McKnight University Professorship (University of Minnesota). Professor Reich received a B.A. from Goddard College in Vermont with a major in physics and creative writing, an M.S. in forest ecology from the University of Missouri, and a Ph.D. in environmental biology from Cornell University. He joined the faculty of the University of Minnesota in 1991.

This seminar is co-sponsored by the Biology Department and the Duke University Program in Ecology (UPE).

Thursday, February 19
A158, LSRC
4:00 - 5:15

Global Change and Ecosystem Models: Problems, Products and Potential
Dr. Steven McNulty, USDA Forest Service, Southern Global Change Program, Raleigh, NC

Global change is a general term for atmospheric (including climate, ozone, CO2, and nitrogen deposition) and landuse use change. There has been increasing interest regarding potential global change impacts on people and the environment (including forests) since the early 1990’s. However, there are two serious impediments in studying global change impacts on forest ecosystems. First, it is nearly impossible to gain consensus on the degree and rate that global change is occurring because there are so many environmental, economic, and political factors driving the change. Second, it is financially and logistically impossible to devise an experiment that can simultaneously test all of the factors controlling and impacted by global change. For example, synergist relationships between global change drivers and natural resource areas are to be expected but are not implicit. Therefore, individual components of global change are studied at a fine spatial resolution, and models are used to integrate; 1) multiple atmospheric changes with multiple ecosystem processes such as forest growth, mortality, regeneration, and water use; 2) economic impacts both within the forest sector and between other economic sectors; and 3) across spatial and temporal scales. I will begin the presentation by addressing some of the major problems associated with assessing multiple co-occurring global change impacts on forest ecosystems. Next, I will present some of the latest results and maps of regionally integrated global change models predictions on current and future forest ecosystem productivity, biodiversity, water use, economic value, and resource availability. Then I will conclude the presentation with some thoughts on the likely future directions in global change study, modeling and assessment.

Steven McNulty has authored or co-authored over 75 papers associated with climate change, wildfire, human population change, ozone, atmospheric CO2 change, and nitrogen deposition impacts on forest ecosystem structure and function. His research focuses on regional to continental scale integrated modeling of environmental stress impacts on forest productivity, hydrology, He has served as the Manager and Project Leader of the USDA Forest Service’s Raleigh based, Southern Global Change Program (SGCP) since 1996, and he has a Joint USDA Faculty Appointment with NCSU, and adjunct faculty appointments with Beijing Forestry University and the University of Toledo. He received a B.S. and M.S degrees in Natural Resources from the UW Madison, and a Ph.D. (1991) in Natural Resources from UNH. Dr. McNulty served as a US Congressional Fellow in the office of Charles Taylor (11th District, NC) during the 106th Congress (2002), the chair of the USDA National Symposiums on carbon sequestration (2000 and 2002), and the federal chair of the National Assessment of Climate Change Impacts on US Forests. Prior to joining the SGCP, he spent five years as a research ecologist with the USDA Forest Service, stationed at the Coweeta Hydrologic Laboratory.

Thursday, March 4
A158, LSRC
4:00–5:15pm

Ocean-Atmosphere Interactions in the "Greenhouse" Climate of the Eocene and a comparison with other paleoclimates
Dr. Matthew Huber

Paleoclimatology can answer critical questions about climate and climate change. Most critically: What is the ‘‘natural,’’ unforced variability of the climate system? What are the responses of the system to known, external forcing? Interactions, between components of the Earth System, i.e. the ocean, atmosphere and biosphere, or between major modes of climate variability and the mean state, remain key areas of uncertainty in our understanding of climate dynamics. Past periods of extreme global warmth or cooling, exemplified by the Eocene (55-35 Mya) or Last Glacial Maximum (21 Kya), provide a test of theories for these interactions.

Variability, through its role in climate and in the detection of climate change, is currently the focus of much attention, partially because recognition of modern climate trends depends on characterizing modes of variability on decadal and longer times scale, and partially because nonlinear interaction between variability and the mean state may play a fundamental role in the evolution of the climate system. Paleoclimate records of interannual and lower frequency variability generated from, e.g., tree ring time series, coral isotopic variations or varved sediments, can directly supplement observational records where they are continuous and overlap or they can provide windows into the operation of the climate system in the deep past when the records are ‘‘floating’’ in time. Consequently, proxy-derived records for variability can play a pivotal role in identifying the stability of leading modes of variability and are also critical for constraining the relationship between global climate change and the spatial-temporal structure of these modes. The ability of the ocean-atmosphere system to transport heat poleward may be sensitive to changes in ocean-atmosphere interaction, including modes of interannual variability, as well as changes in boundary conditions, e.g. opening and closing of ocean gateways.

I present results comparing model predictions of modes of variability for the Eocene, Cretaceous, LGM, and modern, and explore how these predictions compare with those of theory and the implications for maintenance of the mean state in these simulations. I find that most modes of variability are quite robust to changes in boundary conditions, and that they likely played a role in the climates of the past, and by extension, are likely to play a significant role in the future. Controls on heat transport by the atmosphere and ocean are discussed and implications for the two climate dynamics paradigms, "polar amplification" and "tropical thermostating" are drawn.

Matthew Huber is a climate dynamicist interested in the physical and biogeochemical mechanisms that govern the major aspects of Earth's climate. He is currently an Assistant Professor in the Earth and Atmospheric Sciences Department at Purdue University. Huber received his BA in Geophysics from the University of Chicago in 1994, where he worked with R. T. Pierrehumbert studying the relative humidity distribution of the tropics. He investigated Lagrangian turbulence of the troposphere in the Atmospheric Sciences Department at UCLA while working with M. Ghil and J. C. McWilliams (MS, 1997). For his Ph.D., Huber worked with L. C. Sloan at UC Santa Cruz to gain a better understanding of the coupled ocean-atmosphere-sea ice system in the super 'greenhouse' Eocene climate, and to verify the predictions of a coupled climate model with paleoclimate proxies. In 2001, Huber moved to the Danish Center for Earth System Science at the Niels Bohr Institute in the University of Copenhagen, where he investigated the stability of modes of interannual variability in different climates and the causes of major climate transitions in the Cenozoic (such as the initiation of Antarctic glaciation).

Huber believes that most of our current understanding of climate is focused on modern processes and state parameters, and consequently our theoretical and numerical tools are essentially linearizations around a basic state that is unrealistically fixed. Huber hopes that a broader consideration of the history of climate and Earth System will enable a deeper understanding of the physics of climate. His current work focuses on the mechanisms that govern equator-to-pole and vertical temperature gradients in the atmosphere and ocean, the factors influencing the distribution of water vapor, clouds, and precipitation in the atmosphere, and the nonlinear interaction between the background state and variability in determining the dynamics and phenomenology of the system. Several of his current projects focus on controls on ocean heat transport and it's relationship interaction with the atmosphere, within paleoclimate contexts, and as constrained by paleoclimate proxies.

Thursday, March 18
A158, LSRC
4:00–5:15pm
Co-sponsored by CGC and the Biology Superspeakers Program Series

How to Solve the Problem of Greenhouse Warming.
Dr. Steve Pacala

To solve the problem of greenhouse warming, humanity must stabilize atmospheric CO2 at a level that would prevent serious damage to humans, human institutions and ecosystems. The widespread perception that the problem is intractable stems from an inappropriate focus on the period after the year 2050. We already possess cost-effective technology to limit the fossil fuel emissions over the next half century so that atmospheric CO2 follows a trajectory leading to a safe maximum concentration.

Three questions will be addressed. How serious is the problem of greenhouse warming and what is a safe level for greenhouse gasses in the atmosphere? How much must emissions be reduced to achieve a safe stabilization target and how confidently can we compute the required cuts? How can we best achieve the required cuts through the year 2050? The majority of the talk will focus on the third question and will enumerate the technological options for reducing emissions that are already deployed at an industrial scale and have shown a capacity to grow market share rapidly.

There are six such options that would each be capable of supplying 1/7 of the required emissions reductions or more: carbon capture with geologic carbon sequestration, increased energy efficiency, renewable electricity and fuels, substitution of natural gas for coal, nuclear electricity and ecological carbon storage. All of these would need to be pursued simultaneously because it would be impossible (or at least very expensive) to grow any one fast enough, and because most would bring new environmental problems. New environmental problems include risks from CO2 that leaks from sequestration sites, climate change from large-scale wind power, and decreased air quality from organic carbon emitted by plantation trees.

Dr. Stephen W. Pacala is the Frederick D. Petrie Professor of Ecology and Evolutionary Biology at Princeton University. He has researched problems in a wide variety of ecological and mathematical topics. These include the maintenance of biodiversity, the mathematics of scaling, ecosystem modeling, ecological statistics, the dynamics of vegetation, animal behavior, the stability of host-parasitoid interactions, the relationship between biodiversity on ecosystem function, and field studies of plants, lizards, birds, fish, insects, and parasites. Since moving to Princeton University, Dr. Pacala has focused on problems of global change with an emphasis on the biological regulation of greenhouse gases and climate. He currently directs the Princeton Carbon Mitigation Initiative.

Dr. Pacala completed an undergraduate degree in biology at Dartmouth College in 1978 and a Ph.D. in ecology at Stanford University in 1982. He was Assistant and Associate Professor at the University of Connecticut from 1982 to 1992, and then moved to Princeton University as Professor of Ecology in 1992. He was awarded the Frederick D. Petrie Chair in 2000. He has served on numerous editorial and advisory boards.

Friday, March 19
Room 118, BIOSCI
Co-sponsored by CGC and the Biology Superspeakers Program Series
4:00 - 5:15

Forest Inventory Data Falsify Ecosystem Models of CO2 Fertilization
Dr. Steve Pacala

We analyze tree growth data from Wisconsin forest inventories completed in 1968, 1983, 1996 and 2002. These show that the rate of forest growth decreased steadily over the period, in contrast to the increases predicted by CO2 fertilization models. Measured growth rate changed an average of -0.27% y-1 (95% confidence range: -0.05% to -0.49% y-1), whereas the prediction for CO2 fertilization is 0.16% y-1 (corresponding to a ß of 0.36). The high statistical precision is due both to large sample sizes and positive correlations among the growth rates from different time periods within the same plot. Decreased growth occurred in stands of all ages, and so our results are not caused by age-related declines in growth (although highly significant age-related declines were also detected).

Data allowing a direct examination of growth rates over several decades are available only for Wisconsin, but Caspersen et al. (2000) introduced an indirect method for detecting past changes in growth rate using only two sequential inventories. This method was criticized by Joos et al. (2002), who claimed that it lacked the statistical power to falsify state-of–the-art ecosystem models of CO2 fertilization. We explain both the sound points and the critical errors in Joos et al.’s argument, introduce a transparent and analytically tractable version of Caspersen et al.’s method, and check its ability to detect the decreasing growth rates in the Wisconsin data. The results show that the indirect method accurately characterizes the past changes that actually occurred, and has sufficient statistical power to falsify CO2 fertilization models, including the model in Joos et al. (2002).

We discuss the implications of decreasing Wisconsin growth rates, together with other reasons for skepticism about the future magnitude of CO2 fertilization. In particular, the steep reductions in fossil fuel emissions required to stabilize atmospheric CO2 at 500 ppm must begin more than a decade sooner if the predictions of the CO2 fertilization models in the IPCC Third Assessment (Prentice et al. 2001) are incorrect. The difference between a terrestrial carbon sink that grows because of CO2 fertilization, and one that shrinks because it is caused by recovery from past land use, is the difference between the luxury of a substantial delay and the need to act now.

Dr. Stephen W. Pacala is the Frederick D. Petrie Professor of Ecology and Evolutionary Biology at Princeton University. He has researched problems in a wide variety of ecological and mathematical topics. These include the maintenance of biodiversity, the mathematics of scaling, ecosystem modeling, ecological statistics, the dynamics of vegetation, animal behavior, the stability of host-parasitoid interactions, the relationship between biodiversity on ecosystem function, and field studies of plants, lizards, birds, fish, insects, and parasites. Since moving to Princeton University, Dr. Pacala has focused on problems of global change with an emphasis on the biological regulation of greenhouse gases and climate. He currently directs the Princeton Carbon Mitigation Initiative.  Dr. Pacala completed an undergraduate degree in biology at Dartmouth College in 1978 and a Ph.D. in ecology at Stanford University in 1982. He was Assistant and Associate Professor at the University of Connecticut from 1982 to 1992, and then moved to Princeton University as Professor of Ecology in 1992. He was awarded the Frederick D. Petrie Chair in 2000. He has served on numerous editorial and advisory boards.

Wednesday, March 24
A158, LSRC
4:00 - 5:15

On the Coupled Geomorphological and Ecohydrological Organization of River Basins
Ignacio Rodriguez-Iturbe, Department of Civil and Environmental Engineering, Princeton University

Water balance at the daily level is used to link the observed patterns of basin organization to soil moisture dynamics. The co-organization of the spatial patterns of the soil moisture probabilistic parameters and the observed vegetation distribution is linked through the template of the drainage network. It is shown that such co-organization exhibits self-affine characteristics in their distribution across river basins.

Dr. Rodriguez-Iturbe received his undergraduate degree in Civil Engineering at Universidad del Zulia, 1963 ( Venezuela), his M.S. at the California Institute of Technology, 1965 (CA), and his Ph.D. at Colorado State University, 1967(CO). He has co-authored more than 150 peer-reviewed articles and 6 books--most recently a book with Amilcare Porporato on Ecohydrology. His articles have appeared in the most prestigious journals of hydrology, as well as such interdisciplinary journals as Science and Nature. His research in these publications has been highly regarded and widely cited, leading to honorary degrees from 21 universities, and more than 40 awards, including the Huber Research Prize by the American Society for Civil Engineers (1975), the Horton Research Award by the American Geophysical Union (1975), the James B. Macelwane Award by the American Geophysical Union (1977), and the Horton Medal by the American Geophysical Union (1998). Dr. Rodriguez-Iturbe is a member of the National Academy of Engineering (1988), he was recently awarded the Stockholm Water Prize (2002), the most prestigious price in Water Resources, and he also is listed among the ISIHighlyCited.com individuals in the area of Ecology/Environment.

This seminar is co-sponsored by the Department of Civil and Environmental Engineering, Duke University

Thursday, April 8
A158, LSRC
4:00 - 5:15

Anthropogenic Nitrogen Mobilization Drivers, Consequences and Opportunities for Action
Dr. James Galloway, Environmental Sciences, University of Virginia

Food and energy production converts N2 to reactive N species that cascade through environmental reservoirs and in the process impact human and ecosystem health. This seminar will examine the impact of this increased N mobilization on the global N cycle by contrasting N distribution in the late-19th century with those of the late-20th century. Primary findings are:

•we have a good understanding of the amounts of reactive N created by humans, and the primary points of loss to the environment;

•we have a fair understanding of the degree of distribution, and the resulting impacts on people and ecosystems;

•we have a poor understanding of nitrogen’s rate of accumulation in environmental reservoirs, which is problematic due to the cascading effects of N in the environment, including enhanced rates of atmospheric reactions, fertilization of terrestrial and aquatic ecosystems, loss of ecosystem biodiversity, and increased emission of greenhouse gases;

In addition, we have a good understanding, in general, of what must be done to reduce the amount of Nr created by human action. The challenge is how to minimize reactive N creation while also maximizing food and energy production.

James N. Galloway is Professor of Environmental Sciences at the University of Virginia. Dr. Galloway received the B.A. degree in Chemistry and Biology from Whittier College in 1966 and the Ph.D. degree in Chemistry from the University of California, San Diego in 1972. Following a postdoctoral appointment with Gene Likens at Cornell University, he accepted a position as Assistant Professor of Environmental Sciences at the University of Virginia in 1976. He served as President of the Bermuda Biological Station for Research from 1988 to 1995, and as chair of Environmental Sciences, University of Virginia from 1996 to 2001. He is currently chair of the International Nitrogen Initiative, a program sponsored by SCOPE and IGBP, and is a member of the EPA Science Advisory Board. In 2002 he was elected a Fellow of the American Association for the Advancement of Science. His research on biogeochemistry includes the natural and anthropogenic controls on chemical cycles at the watershed, regional and global scales. His current research focuses on beneficial and detrimental effects of reactive nitrogen as it cascades between the atmosphere, terrestrial ecosystems and freshwater and marine ecosystems.

Wednesday, April 22
A158, LSRC
12:00-1:15pm

Regime Shifts in the Northern Rockies: A key to understanding climate-fire-human interactions
Lisa Graumlich, Big Sky Institute for Science and Natural History, Montana State University

In the past decade, atmospheric scientists uncovered evidence for a fundamental climatic regime shift in the winter of 1976-1977 driven by changes in sea surface temperatures in the Pacific Ocean. Ecologists in the Pacific Northwest have documented synchronous and substantial ecosystem responses to the 1977 event. Accumulating evidence from long-term climate records suggests that such regime shifts are the norm. For regions such as the Northern Rockies this regime-like behavior results in extended (>10 yr) periods of drought alternating with more mesic conditions. In this paper, I describe efforts by my lab group to define the nature and causes of climate regime shifts in the Northern Rockies and to define the consequences of these regime shifts for ecosystem processes, especially disturbance processes such as fire. Wildfire in the 20th century turns out to be a particularly intriguing topic because of the potential for feedbacks between regime shifts in climate and similarly abrupt shifts in fire management policies and practices.

Dr. Lisa J. Graumlich’s position as Executive Director of the Big Sky Institute for Science and Natural History at Montana State University allows her to combine her career-long interest in mountain regions and natural areas with her concerns for sustainability. As a researcher, she uses tree-ring records to investigate how climate variation affects forests and disturbance processes such as wildfire.. Dr. Graumlich is also active in developing program and institutions that address critical questions of global environmental change. In 19993, she was chosen as the first Director of the University of Arizona’s Institute for the Study of Planet Earth (ISPE). While Director of ISPE, she developed an integrated program of research, education, and outreach focusing on the impacts of climatic variability on semi-arid regions. In 1999, she moved to Montana State University to direct the Mountain Research Center (MRC). In 2001, she was selected as the Executive Director of MSU’s Big Sky Institute (BSI). Her goal for BSI is to develop an integrated program linking science, education and decision making in the Greater Yellowstone Ecosystem and other similarly large and complex ecosystems.

Dr. Graumlich received her Ph.D. from the University of Washington (1985). She was named an Aldo Leopold Leadership Fellow in 1999 and was elected as Fellow of the American Association for the Advancement of Science in 2004.

Monday, April 26
A148, LSRC
10:00–11:15am

Rolling Easements and Other Free-Market Solutions to Sea Level Rise
Jim Titus, Global Change Information Branch, U.S. Environmental Protection Agency

For the last several thousand years, sea level has risen so slowly that for most practical purposes, it has been constant. And so people have developed our coast as if water levels do not rise, as if shores do not erode. But they do.

Some homes that were once a safe distance back from the shore now stand between the dunes and the ocean, in the public right of way. Should that right of way be maintained by removing the structures, or should we let Nature take the blame when the homes are inevitably lost to the sea during the next major storm as the shore migrates inland? Or should we give up these public beaches if the buildings are more valuable, by constructing stone revetments and seawalls? Or shall we keep both the homes and the beaches through sand replenishment? People have different opinions on the best approach—but few would dispute that all of the options for dealing with erosion along the Atlantic Ocean are widely discussed and considered by high-level decision makers. Because North Carolina and the coastal counties value their ocean beaches, the primary policy question is how much public money do we invest on sand replenishment to protect private property that must otherwise be removed.

Along the sounds, rising seas and eroding shores confront us with the same three choices. But the costs and benefits associated with each of the options seem to be leading us in a different direction. Waves are smaller along the sounds, which makes the cost of shoreline armoring small compared with the value of property being protected. Therefore, except in cases of extreme subsidence, homeowners have no economic reason to retreat along sounds. The armoring eliminates the intertidal zone, but because recreation and transportation along bay shores is minimal compared with the ocean, the public tolerates the elimination of soundside beaches.

Although most people are content to see the intertidal shores replaced with shore protection structures, horseshoe crabs, sea turtles, terrapins, king fisher, and numerous other shorebirds require estuarine beaches for feeding and breeding. Mudflats and tidal wetlands are directly or indirectly important to most aquatic species. If only a portion of the shore is armored, these species can go elsewhere; but the loss of most natural shores would be problematic.

In the 1970s, Congress and the States did something that in retrospect, seems truly amazing: they placed most of our tidal wetlands and beaches off limits to development. The coastal dry lands are being developed, but as long as the sea does not rise and the shores do not erode, tens of thousands of square miles of rich habitat are protected—as well as tens of thousands of linear miles of tidal shores. Over the next decade or so, these ecosystems seem safe. But as one looks farther into the future, it seems increasingly likely that the sea will rise enough of eliminate existing tidal wetlands and beaches.

Humanity is changing the atmosphere and gradually warming the climate through a mechanism commonly known as the “greenhouse effect.” In the last century, the Earth’s average surface temperature has risen about 1 degree Fahrenheit. The warmer temperatures have raised sea level 3-4 inches by expanding ocean water and melting small mountain glaciers. Tide gauges show that the sea has risen about one foot relative to the North Carolina Coast, with about 6 inches attributable to subsidence. There is a general consensus that average worldwide sea level has risen 4-8 inches in the last century—various theories have been offered for the discrepancy between the observed rise and what we are able to explain.

Many scientists expect sea level rise to accelerate over the next several decades. Rising temperatures will continue to melt mountain glaciers and expand ocean water, and the portion of Greenland where temperatures are warm enough to melt ice will may gradually increase. A Monte Carlo analysis by EPA suggested a median estimate in which the sea rises 10 inches more in the next century than in the last century, with a 1% chance of an extra 3 feet. That analysis and similar projections by the United Nations Intergovernmental Panel on Climate Change calculate that sea level rise has been accelerating over the last fifty years. Yet the data shows no such acceleration. The data does show that the sea has been rising more rapidly in the last century than during the last several thousand years. Some scientists who prefer data over theory have concluded that the current rate of sea level rise probably includes whatever acceleration from greenhouse gases we might expect to see over the next few decades. No one is seriously projecting a deceleration of sea level rise, except for areas like Bangkok and parts of Texas where withdrawals of groundwater and other fluids have been curtailed.

EPA has long recommended that coastal planners and managers prepare for the consequences of sea level rise, not because an impending catastrophe awaits us, but because there are many cost effective opportunities to prepare now—opportunities that might be lost if we wait. The most important thing to do now is start deciding which areas will be protected with dikes, which areas will be elevated, and which areas will retreat. The cost of elevating a community can be modest if fill is simply brought in as roads are rebuilt, or yards are re-landscaped. But city engineers and property owners need a signal that this is the plan—why bother if the community will be encircled by a dike instead? Preserving coastal ecosystems may require the longest lead time of all. EPA and North Carolina Seagrant have been working with local authorities to develop maps depicting the areas that will be protected from rising sea level.

North Carolina was one of the first states to adopt erosion-based setbacks along the ocean. For some states, those setbacks were a way of delaying the day of reckoning for 30-60 years; but in North Carolina, there tended to be an implicit assumption that homes will eventually be lost or relocated. The setback simply ensured that erosion did not prevent the owner from enjoying a reasonable lifetime for the structures (e.g. duration of the 30-year mortgage). These setbacks do not apply along sounds, but even if they did, the day of reckoning there generally means building a shore protection structure.

Texas has made an important contribution to the nation’s tools for saving wetlands and beaches as sea level rises: the rolling easement. Elsewhere, this author demonstrates that in a free market economy with rational buyers and sellers, the rolling easement is an order of magnitude more economically efficient than a coastal setback. Although the rolling easement in Texas refers to a public right under the common law, people are also starting to think of it as a type of conservation. The primary benefits are that the riparian owner gets compensated, and the “moral hazard” risk that the terms of the agreement will not be enforced is less, because conservancies and conservation agencies would own the easements. Rolling easements are an efficient instrument for allocating the risk of sea level rise, because the environmentalist purchaser perceives the risk of sea level rise to be greater than the typical coastal property owner, and weighs the long-term more as well (i.e. discounts future returns at a lower discount rate).

In North Carolina, the Nature Conservancy is starting to think about long-term planning for ensuring that wetlands survive rising sea level. The rolling easement is one possible tool. Even if policy makers prefer to avoid interfering with the gradual elimination of wetlands as sea level rises, private conservancies can do a lot to ensure that wetlands can migrate inland.
click for map


FALL 2003

Wednesday, October 1
A150 LSRC, 4:00pm

Analysing observed changes in climate extremes
Lisa Alexander

Since the Intergovenmental Panel on Climate Change (IPCC) Second Assessment Report concluded that there was not enough evidence to adequately assess changes in observed climate extremes, a concerted international effort was established to fill in these gaps. For many reasons, however, a lot of countries are more inclined to release derived data in the form of annual indicator time series than to release their original daily observations. For the IPCC Third Assessment Report in 2001, this led to the production of a global dataset of derived indicators based on temperature and precipitation to clarify whether the frequency and/or severity of climatic extremes changed during the second half of the 20th century. Coherent spatial patterns of statistically significant changes emerge, particularly an increase in warm summer nights and a decrease in frost days and intra-annual temperature range. Indicators based on daily precipitation data show more mixed patterns of change but a significant increase has been seen in the number of heavy rainfall events with a significant decreasing trend in the number of consecutive dry days. However, large areas of the globe are still not represented, especially Africa and South America and the international effort continues to gain more information in these regions.

Lisa Alexander received a BSc(Hons)in Applied Mathematics, Queens University, Belfast, N. Ireland, and an MSc in Computational Science, Queens University, Belfast. Since 1998 she has worked for the Hadley Centre for Climate Prediction and Research as a climate research scientist. Her main area of research is analysing changes in the observed climate, both regional and global, with a particular emphasis on climate extremes.

Wednesday, October 8
A158 LSRC, 4:00pm

Assessing Uncertainty in Mesoscale Numerical Weather Prediction
Montserrat Fuentes

Current methods of meteorological forecasting produce predictions with unknown levels of uncertainty, particularly in regions with few observational assets. Forecast errors and uncertainties also arise from short-comings in model physics. With the ability to estimate the uncertainty in predictions, forecasters would have a powerful tool to make decisions. The goals of our work are to develop methods for evaluating the uncertainty of mesoscale meteorological model predictions, and to create methods for the integration and visualization of multisource information derived from model output, observations and expert knowledge. We do this by extending the recently developed Bayesian melding approach. We also will develop a new approach to assess the performance of mesoscale numerical models, and show how it can also be used to remove the bias in model output. We specify a simple model for both numerical model predictions and observations in terms of the unobserved ground truth, and estimate it in a Bayesian way. We applied these statistical methods to weather mesoscale models (MM5) and to air quality numerical models (Models-3).

Montserrat Fuentes is an associate professor in the Statistics Department at North Carolina State (Ph.D. from the University of Chicago in 1998). Dr. Fuentes also has an associate status in the Marine Earth Atmospheric Sciences Department at NCSU. She spent 6 months as a postdoc in the National Center of Atmospheric Research (NCAR) before joining NC State. She has worked on spatial-temporal statistics and applications to atmospheric pollution and meteorology, and in 2003, received the Abdel El-Shaarawi Young Research's Award in recognition of outstanding contributions to environmetric research. She is currently a member of the model evaluation team at EPA. Dr. Fuentes has developed new statistical methods applied to weather forecasting and air pollution, and has collaborated with the air quality modelers and scientists at EPA and NCAR, monitoring network design, spatial interpolation of environmental processes, evaluation of air quality and weather numerical models, assessment of uncertainty in air quality prediction, data assimilation, ensemble forecast and the statistical assessment of geographic areas of compliance with air quality standards.


Wednesday, October 15
A158 LSRC, 4:00pm

The Conquest of North American Forests by Alien Insects and Pathogens: Case History of the Population Biology and Management of Gypsy Moth Spread
Andrew “Sandy” Liebhold

Alien insects and diseases are having devastating ecological effects on North American forests. This problem is well illustrated by the gypsy moth, Lymantria dispar, which was accidentally introduced from Europe to N. America in 1869 by an amateur naturalist. Since that time, the range of this insect has gradually expanded and outbreaks of this insect have damaged millions of ha of forest. The gypsy moth’s radial rate of range expansion over the last 40 years has averaged about 20 km/yr. Comparison of predictions from a simple reaction-diffusion model with historical spread rates indicate that accidental movement of life stages (by humans) has greatly accelerated the spread of the species.

As has been found in several other alien species, spread occurs by a type of “stratified dispersal” in which isolated colonies are founded ahead of the advancing front; these colonies gradually enlarge and eventually coalesce with the rest of the insect’s range. This phenomenon has been captured in a model that we have used to develop optimal strategies for retarding the spread of this species. Implementation of this strategy is currently underway; results to date indicate that range expansion can be reduced by ca. 50%. The gypsy moth’s range still has not reached over 2/3 of its potential range in North America but life stages are often accidentally introduced to new areas well beyond the expanding population front. Sometimes these introductions establish isolated colonies and eradication is attempted once they are detected.

Analysis of historical data on isolated colonies indicates the dominance of Allee effects and stochasticity in the dynamics of low-density, isolated populations. This information was used to parameterize a model that can be used to evaluate eradication strategies. These results can be generalized and applied to the development of strategies for managing invasions of other types of alien organisms.

Sandy Liebhold is a Research Entomologist with the Northeastern Research Station of the USDA Forest Service located in Morgantown, WV (Ph.D. from University of California, Berkeley 1984). Dr. Liebhold also is adjunct faculty with Penn State and West Virginia Universities. His research revolves around various aspects of forest insect population ecology but most of his work focuses on two areas: 1) the spatial dynamics of forest insect outbreaks and 2) the population biology of forest insect invasions.


Wednesday, October 29
A158 LSRC, 4:00pm

Fire and the global carbon cycle
James T. Randerson

During the 1997–98 El Niño, the terrestrial biosphere experienced drought conditions that triggered widespread increases in fire activity. Here I present a study that combined satellite-based estimates of burned area and an inverse analysis of atmospheric CO anomalies to evaluate the contribution of fire emissions from different continents to trace gas variability during this period. We found that Southeast Asia accounted for ~60% of the global fire emissions anomaly during the El Niño, and that significant and previously underestimated contributions from Central America (20%), northern boreal regions (10%), and South America (south of the equator; 10%) were also critically important in terms of explaining atmospheric trace gas anomalies. Globally, total carbon emissions from fires were 2 Pg C/yr higher in 1998 than in 2000, and accounted for ~2/3 of the CO2 growth rate anomalies during the study period.

Dr. Randerson is a biogeochemist interested in global carbon and nutrient cycles. He uses atmospheric trace gas observations, satellite data, and models to study the biosphere. He is currently investigating pathways of rapid carbon loss from terrestrial ecosystems including fire emissions and permafrost degradation. His group works at field sites in Alaska and Siberia. Dr. Randerson is currently an Assistant Professor at UC Irvine, Department of Earth System Science; he received a Ph.D. in Biological Sciences from Stanford University (1998) and a BS in Chemistry from Stanford (1992).


Wednesday, November 5
A-158 LSRC 4:00pm

Ecological Forecasting, Coupling Ecosystem Hydrodynamics and Carbon Transport, and Ocean Climate Modeling: Updates from the First Three CGC Working Groups

The Center on Global Change (CGC) funds new and innovative faculty/post-doc/graduate student collaborations across disciplines in the area of global change. These working groups typically involve both research and graduate teaching. The principal investigators of each of the first three CGC working groups will discuss their group's activities:

Ecological Forecasting (Jim Clark, Dean Urban, Pankaj Agarwal, Michael Lavine)
Presented by Mike Dietze (Ecology) and Satish Govindarajan (Computer Sciences)

The ability to anticipate ecological change in regions of rapid development is one of the greatest challenges to environmental scientists. Mike and Satish will provide an overview of a forest simulator being developed to model population and ecosystem responses to environmental change.

Coupling Ecosystem Hydrodynamics and Carbon Transport (John Albertson, Gaby Katul, Ram Oren, Andrea Bertozzi)
Presented by John Albertson (Civil and Environmental Engineering)

Terrestrial systems play an important role in regulating atmospheric CO2 and water cycling. However, there are large uncertainties in estimates of present terrestrial carbon uptake, and even larger uncertainties in predicting the dynamic response of net ecosystem carbon exchange to future climate. Collaborative efforts to develop predictive numerical models of the coupled water and carbon transport within ecosystems at multiple spatial and temporal scales will be described.

Ocean Climate Modeling (Susan Lozier, Dick Barber, Gabi Hegerl, Yi Chao, Fei Chai, Mark Reed)
Presented by Susan Lozier (Earth and Ocean Sciences)

The oceans play a major role in determining global climate, both as a reservoir of carbon and heat, and through the distribution of heat, freshwater, and carbon. However, there is limited understanding of the complex oceanic lag times and linkages between radiative input and ocean response. The results of the work of physical and biological oceanographers, a climatologist, ocean modeler, and computational scientist to understand how ocean biology and physics respond to a climate perturbation, and the extent to which this response is fed back to the climate system, will be described.

Wednesday, November 12
A158 LSRC, 4:00–5:15pm

Transgenic pines at the interface of private and public lands:
A case study in landscape genomics

Claire G. Williams

Landscape genomics pertains to the use of DNA sequence data or other types of genomics analysis to make inferences about past, present or future ecosystem changes. Some of my landscape genomics research areas include 1) deducing the response of a species to Holocene climate change, 2) using DNA from ancient wood to infer early human impact on maritime forests, and 3) exploring timber origin in nautical archaeology.

A present-day application of landscape genomics explores the risk of transgenic forest tree invasiveness at the interface of private and public lands. Modeling transgenic P. taeda as an invasive colonizer shows that its seeds and pollen alike travel long distances at meso-transport levels and that subsequent colonization will be substantial. The consequences of colonization can be modeled using net fitness models to predict transgene spread. Risks associated with transgenic pine escape and colonization include species displacement or ecosystem disruption as well as human health because pine pulping byproducts are used as food additives, soaps, cleaners and industrial lubricants. Risk analysis has raised interesting questions about options for transgenic pine biosafety. Options range from a complete moratorium on transgenic plantings to reproductive sterility research, to mandates for early transgenic testing removal or alternative biocontainment zone designs. These options must be considered not only in light of potential benefits but also climate change projections which suggest that many southern US pine species—transgenic or otherwise—will become more invasive given elevated CO2 levels.

Claire Williams is a professor in genetics and forestry at Texas A&M University; her seminar presentation is based on collaborations with the Center on Global Change, the Nicholas School and the Forest History Society at Duke University as well as the University of British Columbia’s Faculty of Forestry in Canada.

 


SPRING 2003


Thursday, January 30
A158 LSRC, 4:00pm

Life in Marine Sediments: Probing the Limits of Earth’s Deep Biosphere
David C. Smith, University of Rhode Island

The presence of an active microbial community inhabiting deeply buried marine sediments has previously been inferred from profiles of chemical compounds involved in microbial metabolism (e.g., sulfate and methane). Studies on recent ODP Legs to quantify microbial abundance in cores have confirmed their presence down to at least 800 m below the sea floor. Extrapolation of these results suggests that the cumulative biomass in subsurface marine sediments comprises a significant portion of the total biomass on Earth. Recently, the capabilities of the JOIDES Resolution have been expanded so that microbiological experiments can now be conducted onboard. This allows microbiologists to better understand what controls microbial distribution and activity and consequently their biogeochemical impact in the marine subsurface. Approaches include measuring rates of metabolic reactions, cultivating microbes recovered from the cores, and characterizing the microbial community through nucleic acid analysis. These efforts will provide insights into the adaptations of microorganism to this environment and will help us define the limits of the deep biosphere on Earth.

Dr. David Smith is an assistant professor of oceanography at the University of Rhode Island. His areas of specialization and current research include marine ecology with an emphasis on food web dynamics as related to marine biogeochemistry. Dr. Smith received his Ph.D. in marine biology from Scripps Institute of Oceanography, University of California, San Diego in 1994. Dr. Smith has sailed as a microbiologist on ODP Legs 185, 190 and 201. (Host: Paul Baker, EOS)


Thursday, March 27
A150 LSRC, 12:00pm

The Atlantic thermohaline circulation and its role in climate variability and change
Tom Delworth, Geophysical Fluids Dynamics Laboratory, NOAA

An overview is presented of the role of the Atlantic thermohaline circulation (THC) in climate variability and change, and the factors which can influence the THC. The THC has a potentially important effect on Atlantic climate through its meridional transport of heat and freshwater. On decadal to centennial time scales, fluctuations in these transports can have a substantial impact on Atlantic sea surface temperatures, as well as possible impacts on the climate of adjacent continental regions. Modeling studies suggest that observed SST multidecadal variations in the 20th century may have been caused by THC fluctuations. The THC changes can affect the meridional position of the Intertropical Convergence Zone, thereby potentially altering tropical convection and large-scale atmospheric circulation.

Thomas L. Delworth has worked at the NOAA Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey since 1984. He is a member of the Climate Dynamics and Prediction Group. He received his Ph.D. from the University of Wisconsin in 1993. As a graduate student, he wrote his thesis on soil wetness and climate variability. Primarily, his research interests have focused on decadal to centennial climate variability and change. He has examined the role of the ocean in the climate system, with special emphasis on the Atlantic and Arctic regions. He has also examined hyrdologic variability and change over continental regions. (Host: Gabi Hegerl, EOS)


Thursday, April 3 CANCELLED
A158 LSRC, 4:00pm

The optimal stability window and marine ecosystem variability in the strait of Georgia, British Columbia
Ann Gargett, Old Dominion University


Thursday, April 10
A158 LSRC, 4:00pm

Advanced technology paths to global climate stability: energy for a greenhouse planet
Marty Hoffert, New York University

Stabilizing climate is an energy problem. To set ourselves on a course towards climate stabilization will require a build-up within the coming decades of new primary energy sources that do not emit carbon dioxide to the atmosphere, in addition to efforts to reduce end-use energy demand. Mid-century CO2 emissions-free primary power requirements could be several times what we now derive from fossil fuels (~1013 W), even with improvements in energy efficiency. Here we survey possible future energy sources, evaluated for both their capability to supply the massive amounts of CO2 emissions-free energy required and their potential for large-scale commercialization. Possible candidates for primary energy sources include terrestrial solar, wind, solar power satellites, biomass, nuclear fission, nuclear fusion, fission-fusion hybrids and fossil fuels from which carbon has been sequestered. Non-primary power technologies that could contribute to climate stabilization include: conservation, efficiency improvements, hydrogen production, storage and transport, superconducting global electric grids and geo-engineering.

Marty Hoffert is professor of physics and former chair of the department of applied science at New York University. His research includes energy science & technologies, global climate change, oceanography, biogeochemical cycles, fluids and plasmas and wireless power transmission. His recent work focuses on technology paths for transitioning away from fossil fuels whose CO2 emissions are freely vented to the atmosphere to energy futures in which humankind's power derives from radically different primary sources. Major collaborative multi-disciplinary studies in which he is the lead author include Advanced Technology Paths to Global Climate Stability: Energy for a Greenhouse Planet, published in the Nov. 1, 2002 issue of Science, and Energy Implications of Future Stabilization of Atmospheric CO2 Content, which appeared in the October 29, 1998 issue of Nature. (Host: Tom Crowley, EOS)

Wednesday, April 16 (Informal Seminar)
CGC, 11:00am

The NAO and the Gulf Stream: Basin scale interactions to regional scale variability
Avijit Gangopadhyay, University of Massachusetts Dartmouth

The low-frequency impact of the North Atlantic Oscillation (NAO) on the Gulf Stream system is discussed from a multiscale perspective. Specifically, the impact of the NAO on the Gulf Stream system is described in terms of two basin-scale gyre-specific dynamic responses: (i) the wind-driven response associated with the subtropical gyre centered on the Azores High, and (ii) the thermohaline response associated with the subpolar gyre centered on the Icelandic Low. Both temporal and spatial coverage of NAO effects are considered.

Thursday, April 17
A158 LSRC, 4:00pm

Climate Variations and Change: What can we say with confidence?
Thomas R. Karl, National Climatic Data Center, NOAA

Documenting climate change and variability is a formidable task made difficult due to a variety of observing characteristics that affect our observing systems both today and in the past. A review of data from the ice ages to the space age, reveals considerable information as well as substantial uncertainties. These data will be explored to show what we know with confidence and what remains uncertain and why. Opportunities for better climate information will also be identified.

Dr. Karl is a fellow of the American Meteorological Society and the American Geophysical Union, and a national associate of the National Research Council. In 2002 he was elected to serve on the Council of the American Meteorological Society. In addition to Dr. Karl’s participation on various committees, he has also testified to the U.S. Congress and briefed cabinet level officials, the Vice President, and the President of the United States. Dr. Karl is author of many climatic atlases and technical reports and has well over 100 published articles. In addition to his contributions to numerous journals, Dr. Karl has also served as editor or contributor to eleven commercial textbooks on topics ranging from the 1988 U.S. drought to global climate observing. (Host: Tom Crowley, EOS)

Wednesday, April 23 (Informal Seminar)
CGC, 11:00am

Ocean Modeling: Linking physical and biological processes
Ping-Tung Shaw, NCSU

Upwelling of subsurface water in the South China Sea and sinking of dense water plumes in the Arctic continental margin, two processes of potential contribution to global change, are discussed. The South China Sea is adjacent to the warm pool of the western Pacific. Weakened upwelling in the South China Sea during El Niño is known to result in warming of the surface water. The effects of variation in circulation on biogeochemical processes are studied in a numerical model with added biogeochemical components at 0.4° resolution. The model reproduces main features of seasonal variation in chlorophyll patterns in regions of strong upwelling. However, discrepancies in the dispersion of high chlorophyll patches are found. Insufficient data to properly constrain boundary conditions for dissolved inorganic nitrogen and the inadequate model resolution are likely the source of errors.

Wednesday, April 23 (Informal Seminar)
A247 LSRC, 4:00pm

The Art and Role of Climate Modelling
Hans von Storch, German Hydrological Institute

In this talk, the art of quasi realistic climate modeling is reviewed. Its limitations—such as the failure to immediately constitute knowledge (insight into climate dynamics) or to provide regional detail, or the impossibility for positive verification—are discussed. The talk is concluded with a short discourse about the contemporary public role of climate models.

Thursday, May 1
203 Teer, 3:00pm

{note: time and location change}

Aerosols and Climate
John Seinfeld, California Institute of Technology

The role of aerosols is now recognized to be perhaps the major uncertainty in the understanding of how the Earth's climate will evolve in the next decades. Aerosols produce competing climatic effects, both cooling and warming, and interact with clouds in complex ways. We will review what is known and quantifiable about the effect of aerosols on climate and discuss where future challenges lie.

John H. Seinfeld is the Louis E. Nohl Professor in the Divisions of Chemistry and Chemical Engineering and Engineering and Applied Science at the California Institute of Technology. He is currently vice chair of the NRC Committee on Atmospheric Chemistry. He received his Ph.D. in chemical engineering from Princeton University in 1967. Dr. Seinfeld is the author of more than 400 scientific papers and several books, including Atmospheric Chemistry and Physics: From Air Pollution to Climate Change (1998). (Host: Prasad Kasibhatla, ESP)

Thursday, May 1
104 Old Chemistry, 11:00am

Remote Influences on South Americal Climate Variability
Andrew W. Robertson
International Research Institute for Climate Prediction (IRI), The Earth Institute at Columbia University

The climate of South America is strongly influenced by the surrounding oceans on many time scales, ranging from the intraseasonal to the interdecadal. I will focus on subtropical South America, east of the Andes, where the South Atlantic Convergence Zone is a major organizing circulation feature. I will use NCEP/NCAR reanalysis data to discuss the remote influences of ENSO, and GCM experiments to investigate the role of Atlantic SST anomalies. Some evidence of NAO & PDO influence on longer time scales will also be presented, using a century of Plata basin river records.


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FALL 2002

Thursday, September 5
Center on Global Change, 4:00pm

Measuring land-atmosphere exchange in complex terrain
John Finnigan, CSIRO

Aerodynamic methods of measuring land-atmosphere exchange rely on using the mixing inherent in the turbulent atmosphere as an averaging operator, thereby avoiding the crippling sampling problem that occurs if average surface exchange is estimated by adding many measurements from soil chambers or leaf cuvettes. It has a venerable history but recent long-term continuous measurements from flux towers in the world-wide FLUXNET program have called into question many basic assumptions embodied in its practical application.

Dr. John Finnigan is with CSIRO (Australia) Atmospheric Research and serves as interim director of the CSIRO Centre for Complex Systems Science. (Host: Gabi Katul, ESP)

Thursday, October 17
A247 LSRC, 4:00pm

Tropospheric ozone as a climate gas and air pollutant: the case for controlling methane
Daniel J. Jacob, Harvard University

Human activity has caused a global-scale increase in tropospheric ozone
over the past century, with important implications for both climate change
and surface air quality. Dr. Jacob will briefly review the current state of
understanding of the global budget of tropospheric ozone and show that the radiative forcing of climate by ozone is more uncertain (and potentially much larger) than is usually assumed—and that radiative forcing is a rather poor index for quantifying the perturbation to climate by ozone. Thus ozone is less efficient at warming the surface, and more efficient at cooling the stratosphere, than the same radiative forcing increment of carbon dioxide. He will examine possible strategies to decrease the climate forcing from ozone in the future and show that emission controls on methane would provide an efficient vehicle with benefits for both climate change mitigation and air quality. A discussion of ongoing work at Harvard to improve understanding of regional methane emissions through top-down model analyses will conclude the seminar.

Dr. Jacob is Gordon McKay Professor of Atmospheric Chemistry and Environmental Engineering at Harvard University. He received his Ph.D. in environmental engineering in 1985 from the California Institute of Technology. He does research in the chemical composition of the atmosphere and its perturbation by human activity with work on global three dimensional modeling of atmospheric chemistry and climate change, aircraft measurement campaigns, satellite data retrievals and analyses of atmospheric observations. (Host: Prasad Kasibhatla, ESP)

Friday, October 25
201 Old Chemistry, 4:00pm

Responses of coastal wetlands to rising sea level
James T. Morris, University of South Carolina (co-sponsored with EOS)

Sea level rise is likely to accelerate as a consequence of global warming. Long-term measurements at North Inlet, SC show that a recent acceleration in the rate of sea-level rise has led to increases in marsh productivity, averaging 32 g m-2 yr-1, and biogeochemical cycling. Spartina alterniflora, the dominant macrophyte in east coast salt marshes, maintains the elevation of its habitat within a narrow portion of the intertidal zone by accumulating organic matter and trapping inorganic sediment. The long-term stability of these ecosystems is explained by interactions among MSL, land elevation, primary production, and sediment accretion. This equilibrium is adjusted upward by increased production of S. alterniflora and downward by an increasing rate of relative sea-level rise (RSLR). Adjustments in marsh surface elevation are slow in comparison to interannual anomalies and long-period (decadal) cycles of sea level, and this lag in the marsh response results in significant variation in annual primary productivity. A theoretical model predicts that the system will be stable against changes in relative mean sea level when surface elevation is greater than that which is optimal for primary production. When surface elevation is less than optimal, the system will be unstable. The model predicts that there is an optimal rate of RSLR at which the equilibrium elevation and depth of tidal flooding will be optimal for plant growth. However, the optimal rate of RSLR also approaches an upper limit. Beyond this limit, the plant community cannot sustain an elevation that is within its range of tolerance. Moreover, the range of tolerance is proportional to tidal amplitude. For mesotidal estuaries with high sediment loading, such as those on the U.S. southeast coast, the limiting rate of RSLR was predicted to be at most 1.2 cm/yr, which is 3.5 times greater than the current, long-term rate of RSLR.

Dr. James T. Morris is a professor of biological and marine sciences at the University of South Carolina. He received his Ph.D. in 1979 from Yale University. His research spans the basic and applied aspects of the physiological ecology of plants adapted to wetland habitats and the biogeochemistry and systems ecology of wetlands, primarily salt and freshwater intertidal wetlands. (Host: Brad Murray, EOS)

Wednesday, October 30
A156 LSRC, 12:30pm

The prospects for a fragmented climate regime
Henry D. Jacoby, MIT (co-sponsored with the Center for Environmental Solutions)

The first attempt at a common global climate regime is ending in fragmentation. It seems likely (though far from certain) that within the next few years Russia will ratify the Kyoto Protocol, completing the requirements for entry into force. It is similarly unlikely that the US will accept the existing Kyoto structure, which would require abandoning its growth-indexed approach to emissions targets and its insistence on developing country participation. Other developed nations may follow the US lead or take still other approaches. Yet any effective response to the global climate threat ultimately will require some degree of global collaboration. In the opening talk, results from the MIT Environmental Prediction and Policy Analysis (EPPA) model will be used to predict likely achievements under the Kyoto and Bush programs, and to explore possible avenues for future negotiations. It will raise questions for subsequent discussion, including the limits to a Kyoto-style approach to a global regime, possible gains from a looser structure, and puzzles regarding the venue within which a coherent approach might be sought.

An economist with a background in engineering, Henry (Jake) Jacoby is a professor of management in the MIT Sloan School of Management and co-director of the MIT Joint Program on the Science and Policy of Global Change. He has been director of the Harvard Environmental Systems Program, director of the MIT Center for Energy and Environmental Policy Research, associate director of the MIT Energy Laboratory and chair of the MIT faculty. His career interest is in issues of economics and policy in the areas of energy, natural resources and environment. The MIT Joint Program on the Science and Policy of Global Change brings together a group of natural and social scientists and policy analysts for joint work focused mainly on the threat of global climate change and the assessment of efforts to mitigate human interference with the climate system. (Host: Jonathan Wiener, CES)

Wednesday, November 13 (Informal Seminar)

Interpreting Woody Plant Richness from Seasonal Ratios of Photosynthesis across Oregon
Richard Waring, Distinguished Professor Emeritus, Forest Science Department, Oregon State University

Thursday, November 14
A247 LSRC, 4:00pm

Genomic response to ecological change: finding the lost pines
Claire G. Williams, Texas A&M University

DNA signatures carry a record of past population dynamics and thus can be used to reconstruct a plant's response to radical shift in climate change after glaciation. In this study, DNA signatures were interpreted within a framework of geological and historical records, population genetics theory and geographic information systems (GIS), Using a wealth of geological, historical, climatic data, we constructed specific hypotheses about
population response to radical climate change events in central Texas over the past 10,000 years. The Lost Pines, a set of scattered pine islands islands in central Texas, is disjunct from the larger range of Pinus taeda L. in the southern quadrant of North America. Study objectives were 1) to test for bottleneck events in the Lost Pines, 2) to test if this population is indeed the species' post-Pleistocene retreating edge and 3) to test whether its contemporary distribution patterns are constrained by edaphic patterns. Constructing and testing these hypotheses has been an ongoing collaborative effort with archaeologists, ecologists, GIS experts and geologists.

Dr. Williams is a professor in genetics and forestry at Texas A&M University. A 2002 recipient of a Guggenheim Fellowship, she is on sabbatical at the Center on Global Change this autumn while she completes a book on the evolution and ecology of conifers for Cambridge University Press. (Host: Barbarb Braatz, CGC)


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SPRING 2002

{All seminars are presented in A247 LSRC unless otherwise noted}

Thursday, January 17


A study of the response of ocean biology to future climate change
Jorge Sarmiento, Princeton University

Climate models predict that global warming will cause major increases in
oceanic stratification that are likely to have a large impact on marine
biology. Six different coupled climate model simulations of future climate
change are examined to determine the range of behavior of those physical
properties of global warming simulations that are likely to be most relevant
to the ocean biological response. Satellite color and ocean climatological
observations are used to develop an empirical model for predicting
chlorophyll from the physical properties predicted by the global warming
simulations. Application of this empirical model to the global warming
simulations suggests that the oligotrophic (tow productivity) gyres of the
oceans will expand and experience reduced biological production. High
latitude regions that are presently characterized by deep winter mixing will
tend to experience increased biological production. Our scientific
understanding of this issue is only at the most rudimentary level at present.

Dr. Sarmiento received his Ph.D. from Columbia University in 1978. He
joined the Princeton University faculty in 1980 and was appointed director of
its atmospheric and oceanic sciences program, continuing in that position
until 1990. (Host: Tom Crowley, EOS)

Thursday, January 24

Understanding Historical and Predicting Future Climate Change
Simon Tett, Hadley Centre

The twentieth century has shown two periods of climate change: from about 1910 to 1940 and from the mid 1970s to present. What might be the causes of these changes? As we only have one Earth we cannot easily carry out controlled experiments to explore the reasons for these changes. Using climate models allows investigation of the possible causes of these changes.
The physical principals by which these models work will be described. How they have been used to understand 20th century climate change will be alsobe described. These same models can be used to predict possible future climate change. Results from those simulations will be shown.

Dr. Simon Tett is a senior scientist at the Hadley Centre, which he joined in January 1991. He has carried out research into simulated climate variability, climate change, and detection and attribution of observed climate change using three generations of Hadley Centre coupled models. (Host: Tom Crowley, EOS)

Thursday, February 21

Cycles and epidemic waves in measles dynamics
Ottar Bjornstad, Penn State University

For predator-prey and parasite-host systems, ecological theory suggests that 'traveling waves' are the most striking outcome of spatial-temporal
interactions. To test for the occurrence of this phenomenon. Dr. Bjornstad
investigated measles outbreaks in England and Wales. They showed that
dramatic hierarchical waves of measles Infection move regionally from large cities to small towns. Their model suggests a novel dynamical explanation for the waves. The study firmly demonstrates 'forest fire' dynamics in an endemic epidemiological context.

Dr. Bjornstad is a theoretical ecologist working as an assistant professor in entomology and biology at The Pennsylvania State University. His main
interests are population ecology and population dynamics with particular
emphasis on mathematical and computational aspects. Also an adjunct
assistant professor in statistics, he carries out research in statistical ecology and in methods for analyzing spatiotemporal data. (Hosts: Jim Clark, Biology, and Dan Richter, ESP)

Thursday, March 21

Nuclear vs. Renewables vs. Decarbonized Fossil Fuels in the Race to Zero Emissions
Robert H. Williams, Princeton University

Radical technological change will be needed to address effectively the
multiple environmental and energy supply security challenges posed by
conventional energy in the 21st century—of which climate change is the
most daunting. Stabilizing the C02 concentration in the atmosphere at 450-550 ppmv might be necessary to prevent major disruptions of climate. So doing would require shifting to energy technologies characterized by near-zero emissions of greenhouse gases. Nuclear energy, renewable energy, and decarbonized fossil energy with C02 sequestration are all candidate options for realizing deep reductions in greenhouse gas emissions. It is helpful to consider electricity generation and "fuels used directly" separately in understanding the competition among these primary energy sources in climate change mitigation.

Dr. Williams is a senior research scientist at Princeton University's Center for Energy and Environmental Studies. His research interests span a wide range of topics relating to advanced energy technologies, energy strategies and energy policy for both industrialized and developing countries. (Host: John Strohbein, Biomedical Engineering)

Thursday, April 4

Detection of anthropogenic climate change
Gabi Hegerl, Duke University

The atmospheric concentration of carbon dioxide has increased since the
industrial revolution and is projected to keep increasing In the future. Global models of the earth's climate system simulate substantial global warming due to this change in the composition of the atmosphere. Since the rate of warming depends on uncertain feedbacks in the climate system it is desireable to estimate what part of the warming in the observed climate
record Is anthropogenic and to assess if the model simulations are realistic. The goal is to distinguish the anthropogenic climate change from variability that is inherent in the climate system and from the response to other, natural, mechanisms which Influence the mean state of the earth's climate, such as variations in solar radiation or climate effects of volcanism.

Dr. Hegerl is an associate research professor in the division of earth and
ocean sciences at Duke University. Her interests include statistical
climatology, climate variability, climatic extremes and climate of the last
millennium. (Host: Prasad Kasibhatla, ESP)

Thursday, April 18

Lightning and Climate: The Water Vapor Connection
Colin Price, Tel Aviv University

The amplitude of future global warming will depend strongly on how upper tropospheric water vapor (UTWV) changes in response to greenhouse gas forcings. There are arguments In support of both positive and negative water vapor feedbacks. To understand these feedbacks it is necessary to understand how UTWV varies on different spatial and temporal scales. However, monitoring long-term changes in water vapor is very difficult, and no single method is in place, or planned, to deal with this problem.

In this paper evidence is presented showing the close link between UTWV variability and global lightning activity. Continental deep convective storms that transport large amounts of water vapor Into the upper troposphere dominate the variability of global UTWV, while also being the storms that produce the majority of our planet's lightning. Furthermore, integrated global lightning activity can be continuously observed from a single location on the earth's surface via the Schumann Resonances (SR), an electromagnetic phenomenon in the atmosphere produced by global lightning. Therefore, observations of the SR may supply a cheap, convenient method of studying the long-term variability of global UTWV.

Dr. Price received his Ph.D. in 1993 from Columbia University where his
research dealt with global climate change, having a special focus on global lightning activity. As a postdoctoral student at the Lawrence Livermore National Laboratory, his research dealt with lightning-produced NOx and the implications for tropospheric chemistry. Since 1995 he has been on the faculty of Tel Aviv University in the department of geophysics and planetary sciences. (Host: Steve Cummings, Electrical & Computer Engineering)


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Last updated November 17, 2005