Arctic peatlands are expanding due to global warming

Arctic peatlands are expanding due to climate change, which for now allows them to capture large amounts of carbon, but this phenomenon could reverse and fuel further warming, according to a study published on Thursday (19).

Peatlands are wet ecosystems composed of carbon-rich, partially decomposed organic matter. They represent the largest natural carbon reserve on the planet.

An international team of researchers studied the current extent of peatlands in Arctic zones using satellite data, drones and field observations, and published their results in the scientific journal Communications Earth and Environment.

Experts conclude that there has been an “expansion of Arctic peatlands over the past 40 years,” likely in response to climate warming, which is much more pronounced in these regions than in the rest of the world.

The most visible change was observed where summer temperatures rose the most, such as in the Norwegian archipelago of Svalbard.

“The permafrost thaws a little bit, provides a water source for vegetation and the surface vegetation grows back. In this study, we specifically see lateral expansion,” a professor at the University of Quebec in Montreal, co-author of the study, told AFP.

“All these new vegetated surfaces that didn’t exist three decades ago are actively absorbing carbon,” he highlighted.

Another factor to consider: When land that was once dry becomes a peat bog, it initially emits methane, a potent greenhouse gas.

“But when a peatland remains wet for a while, methane emissions stabilize and then it becomes an even more potent carbon sink,” Karen Anderson of the University of Exeter in the UK, another co-author of the study, told AFP.

However, this virtuous carbon capture process could be threatened in the future by extreme heatwaves that dry out peatlands or expose them to devastating fires.

They then risk becoming net emitters of carbon. “In the short term, these expanding peatlands represent a growing carbon sink… but in the future this could reverse,” said Karen Anderson.

“Even though our study brings good news, it should not distract us from the urgent need to reduce greenhouse gases and stabilize our climate,” the researcher concluded.

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