DURHAM, N.C. – China’s annual carbon dioxide (CO2) emissions exceeded 10 gigatons in 2018 for the first time in history and are expected to continue to grow. The nation’s leaders have pledged to peak CO2 emissions by 2030 and to reach carbon neutrality by 2060.

Achieving that goal will require harnessing ocean-based CO2 removal as well as land-based removal methods, such as trees and technology.

However, there has been little research to date assessing how much carbon China’s oceans can store, which ocean-based removal approaches hold the most potential, and what the challenges of harnessing them might be.

A new report published this spring by researchers at Duke University and Duke Kunshan University takes a big first step toward answering these questions.

The report, “Ocean-Based Carbon Removal Landscape in China,” synthesizes the current state of knowledge on ocean-based CO2  removal in China through extensive stakeholder interviews and scientific literature review.

The researchers identify and assess the potential of four ocean-based CO2 removal approaches—seaweed cultivation, artificial upwelling, offshore carbon storage, and microbial carbon pump—that are either currently in use in China or have been proposed there. They also identify the challenges each approach may entail, and where further research is needed.

Junjie Zhang, associate professor of environmental economics at Duke’s Nicholas School of the Environment and director of the Environmental Research Center at DKU, wrote the report with Weijie Wang, a postdoctoral fellow at DKU’s Environmental Research Center.

Among other conclusions, they find that seaweed cultivation holds good potential but is subject to seasonality, which might have an effect on its carbon sequestration capabilities; offshore carbon storage also holds promise but is not yet widely practiced; and the artificial upwelling and microbial carbon pump approaches still need to be field-tested to determine their feasibility and efficacy at large scales and in a warming climate.   

“Historically, our ocean has absorbed about one-third of excess carbon dioxide in the air, contributing to ocean warming and increased acidification, which is wreaking havoc on the marine ecosystem and negatively affecting coastal communities,” Zhang and Wang write in the report.

“A number of innovative approaches to ocean-based carbon dioxide removal have been proposed that enhance the ocean’s natural ability to safely remove and sequester carbon dioxide while also helping to improve ocean health and increase the resilience of marine ecosystems against climate change impacts.

“It is crucial to research and validate the efficacy of these approaches to ensure they offer meaningful climate and community benefits,” Zhang and Wang write. “This report is a step in that direction.”

Support for the report was provided by the Climateworks Foundation.

This story aligns with the Duke Climate Commitment, which unites the university’s education, research, operations and public service missions to address the climate crisis.

 

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