Amazon peatlands could soon pass from a carbon sink to a carbon source

Arizona State University News Release

November 19, 2018

Amazon peatlands could soon pass from a carbon sink to a carbon source

In the press – As long as man does not find a way out of the climate disaster we have caused, we must rely on natural carbon sinks, such as oceans and forests, to suck up carbon dioxide of the atmosphere. These ecosystems are deteriorating under the effect of climate change. Once destroyed, they can not only stop absorbing carbon from the atmosphere, but begin to emit it.

Ecosystems that harbor a type of carbon-rich soil called peat are the most effective natural carbon sinks on the planet. When they are not disturbed, they store more carbon dioxide than any other type of vegetation on Earth. But when they are drained and deforested, they can release nearly 6% of global carbon dioxide emissions each year. Climatologists worry that many carbon-absorbing peatlands will soon do the opposite.

"The importance of peatlands is now recognized by their ability to store carbon in the soil, which is about twice the content of all the world's forests," said Hinsby Cadillo-Quiroz, Associate Professor at the School of Life Sciences of Arizona State University. co-author of a new study. "Until a few years ago, the global role of tropical peatlands in the Amazon rainforest was completely unknown and misunderstood."

Now, a multi-institutional research team is studying the dynamics and controls that affect Amazon peatlands. One of the critical questions uses past records to predict what may happen in the future.

"If the area we examined could represent the entire Amazon or tropical peatlands, the loss of peat carbon in the atmosphere under future climate scenarios should be a major concern for our society" said Qianlai Zhuang, a professor of Earth, atmospheric and planetary. at Purdue University and lead author of the study. "Peatlands act as a" terrestrial ocean "because of their carbon sequestration, but will this large amount of peat carbon be released in a warmer climate, causing further warming?" Zhuang said.

In collaboration with members of the ASU team and Florida International University, Zhuang has turned to the peat bogs of the Peruvian Amazon to try to answer this question.

According to a land-based model dating back 12,000 years to 2100 AD, this relatively small basin could lose up to 500 million tons of carbon by the end of the century. That's about five percent of the world's total annual carbon emissions from fossil fuels, or 10 percent from the United States, released into the atmosphere.

According to most estimates, South America will become both warmer and wetter by the end of the century. The team's findings, published November 19 in the Proceedings of the National Academy of Sciences, show that higher temperatures lead to greater loss of carbon from peat, while increased precipitation slightly improves carbon accumulation. long-term peat. Together, this will likely increase peatland carbon losses in the atmosphere.

Peatlands in western Amazonia in Peru remain almost intact, but this is not the case in most places where peat stocks are large and are cleared to make way for agriculture. Peatlands in parts of the world, including Canada, Siberia and Southeast Asia, have already become important sources of carbon. The same fate could soon arrive for the Peruvian peat bogs.

"The intensification of agriculture and the increasing disruption of land use, such as forest fires, threaten the persistence of peat carbon stocks. These peatland ecosystems can become carbon sources instead of sinks, unless the necessary steps are taken, "Zhuang said.

Cadillo-Quiroz said, "Our assessment is valuable regionally as it addresses the future dynamics of soil carbon that can affect the global atmosphere and delineate at a very precise scale the regions of the Amazon Basin and the types peatlands that can generate greater carbon loss. climate scenarios. This information will likely be used to guide approaches to regional monitoring, land management and conservation. "

Collaborative research between ASU and Purdue aims to deepen analyzes of the fate of carbon in Amazon peatlands. "The wealth of data collected by our team in recent years will continue to provide new information on processes that affect carbon content and stability in Amazon peatlands," said Cadillo-Quiroz.

Researchers from Arizona State University, Purdue University, Carnegie Institution for Science, and Florida International University contributed to this work. The study was funded by the DEB program of the National Science Foundation and the Department of Energy.

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Media contact:

Sandra Leander, Manager, Media Relations and Marketing

ASU School of Life Sciences

480-965-9865, [email protected]

Kayla Zacharias, Purdue University, 765-494-9318, [email protected]

News from: Arizona State University School of Life Sciences and Purdue News

writers: Kayla Zacharias and Sandra Leander

sources

Hinsby Cadillo-Quiroz, [email protected]

Qianlai Zhuang, [email protected]

Related Websites:

School of Life Sciences at Arizona State University: https://sols.asu.edu/

Home page of Purdue University: http://www.purdue.edu