Why peatlands may start leaking massive amounts of carbon

Peatlands look quiet, but they hold one of Earth’s biggest secrets. These soggy landscapes cover only three percent of the planet’s land yet store over 30 percent of all soil carbon. They’ve kept that carbon locked away for thousands of years.

But new research warns that this natural balance may collapse. An extreme drought could make these ancient carbon stores leak four times more carbon than before.

When dryness turns dangerous

In future climate conditions – with higher heat and more carbon dioxide – peatlands could stop storing carbon and start releasing it.

“As temperatures increase, drought events become more frequent and severe, making peatlands more vulnerable than before,” said study senior author Yiqi Luo, a professor at Cornell University.

“We observed that these extreme drought events can wipe out hundreds of years of accumulated carbon.”

That means months of drought could undo centuries of climate stability. The carbon that once stayed buried underground could return to the air, speeding global warming.

More heat, more risk

Drought already weakens ecosystems. But this study reveals how warming and excess carbon dioxide make the problem far worse. The Intergovernmental Panel on Climate Change (IPCC) predicts extreme drought could become up to seven times more common soon.

Luo said that finding raises serious concern. “It’s a huge reservoir of carbon compared to any other ecosystem,” he said. “We need to find a way to mitigate climate change and bend the warming curve,” added Luo.

Every extra degree of heat pushes these wetlands closer to collapse. The more they dry, the more carbon escapes, feeding a cycle that strengthens climate change.

Peatland and carbon response

The team gathered data from the Spruce and Peatland Responses Under Climatic and Environmental Change (SPRUCE) site in northern Minnesota.

The Oak Ridge National Laboratory runs the project using giant, yurt-like chambers that mimic future temperatures and carbon dioxide levels.

In the summer of 2021, a severe drought hit the site. The researchers observed the water table sink deeper and recover more slowly under warmer and carbon-rich conditions. That delay exposed buried carbon to oxygen, releasing carbon dioxide (C02) into the air.

The carbon dioxide surprise

Luo expected heat to increase carbon loss but didn’t expect carbon dioxide to make it worse. Elevated carbon dioxide usually helps plants survive drought by improving water use. But this time, it amplified the loss.

“Previous studies indicated that elevated carbon dioxide can usually make extreme events less impactful, but our results indicate the opposite,” Luo said.

The combination of a 16°F (9°C) temperature rise and higher carbon dioxide levels caused a dramatic spike in emissions during the drought.

Peatlands carbon escapes fast

Postdoctoral researcher Quan Quan uncovered what happened inside the bog. Extra carbon dioxide boosted dissolved carbon in the water.

When drought drained that water and oxygen entered, the carbon reacted and escaped as gas. Elevated carbon dioxide alone improved growth slightly, but paired with heat, it turned deadly for carbon storage.

This experiment shows that even small environmental changes can transform peatlands from climate protectors into sources of pollution.

Protecting peatlands and carbon stores

Peatlands may seem small, but their role in stabilizing the planet is enormous. As the climate shifts, these carbon-rich wetlands stand at a crossroads.

Protecting them could keep billions of tons of carbon locked away. Ignoring them could unleash it all back into the sky.

These quiet ecosystems act like the planet’s lungs, absorbing and storing carbon that would otherwise trap heat in the atmosphere. Once drained or dried, though, peatlands switch roles and start emitting carbon instead of absorbing it.

The change can happen quickly, releasing centuries of stored carbon within months. Protecting these wetlands means protecting Earth’s climate stability – and the well-being of future generations.

Global effort, global warning

Luo’s group is part of a large team studying these effects. More than 250 scientists from institutes like ETH Zurich, Florida State University, and the Australian National University work together at the SPRUCE site. Their data feed global models predicting how peatlands will behave as the planet warms.

The collective research points to a clear conclusion: peatlands matter. Losing them would mean releasing ancient carbon in a burst that accelerates climate change.

Funding came from the U.S. Department of Energy, the National Science Foundation, and other agencies.

The study is published in the journal Science.

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