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.
^ return to top
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 assumedand 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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