Arctic peatlands are spreading as temperatures rise

Peatlands across the northern Arctic are spreading as the climate warms, offering a temporary boost in natural carbon storage. This new growth, forming at the edges of existing peat bogs, could help slow the pace of climate change – at least in the short term.

Researchers at the University of Exeter, with partners in Canada, Finland, and Norway, used satellite images, drone footage, and peat cores to track 16 sites across the European and Canadian Arctic.

By comparing imagery from 1985–1995 with the last two decades, they found clear signs of “peak-summer greening” at most sites – evidence that peat-forming mosses are steadily spreading outward.

The most dramatic changes were seen in regions that have warmed the most, like Svalbard.

A rapidly warming North

“The Arctic has warmed faster than the rest of the planet, with average temperatures increasing by about 4 °C in the last four decades,” said Dr. Katherine Crichton.

Warmer summers mean longer growing seasons and thicker plant cover. According to Dr. Crichton, this has improved growing conditions for plants, causing “greening” of the Arctic.

“We wanted to identify if this greening could be from peatland plant communities. We know from paleo records that warmer periods in Earth’s history led to more carbon being stored in peatlands.”

“Our new study puts these pieces together to examine whether our warming climate is causing peatland expansion – and we find strong evidence that it is.”

Peatlands: Small area, huge impact

Peat covers about three percent of Earth’s surface yet stores roughly 600 billion tons of carbon – more than all of the world’s trees combined.

“Our findings suggest Arctic peatlands are an increasingly important natural carbon sink, at least in the near term,” said Professor Karen Anderson of Exeter’s Environment and Sustainability Institute.

“But if temperatures continue to rise, we are likely to see changes in rainfall, and we are not sure how sustainable new or existing peatlands will be. Plus we could see increases of methane emissions at the same time.”

“So – while our study gives us some positive news – it does not detract from the urgent need to reduce greenhouse gas emissions and stabilise our climate.”

Years of surveying Arctic peatlands

The project has been in motion for more than a decade. It began with two small pilot studies – a peat-core survey in Canada and Finland and a drone-mapping test of remote sensing.

Funding was hard to come by. The team’s first grant bid went in back in 2013. A rejection followed in 2015, then two more in 2016. The green light finally came in 2018, and full fieldwork started the following summer.

Early trips set the tone. Dr. Crichton scoured Google Earth Engine for possible study sites. Professor Angela Gallego-Sala headed north to Svalbard, where the safety briefing included how to avoid hungry polar bears.

COVID-19 struck just as momentum built. “I was still at my desk using Google Earth Engine,” said Dr. Crichton. “Lockdown didn’t make any difference to the work I was doing.” Field teams stayed home, but mapping and permit work continued online.

Fieldwork in unfamiliar territory

Once borders reopened, the researchers headed to Bylot Island in 2021–22. The camp was basic; the only “shower” was a half-frozen lake. “It was light all the time. You could do fieldwork all day long and all night if you wanted to.”

Helicopters ferried the group to nameless tundra clearings. Pilots needed labels for pickup points, so patches of moss earned nicknames like “Glacial Nirvana” and “Angela’s Paradise.” Each core came up dark and wet, holding a record of centuries of stored carbon.

Farther west, an Inuit guide at Salluit led the team across peatlands teeming with black bears and reindeer. Each evening they caught fish and mussels for supper.

One morning, the guide shrugged at their mapped route: “You can go wherever you want.” That freedom left the crew – and their canoe – stranded on a sandbar at low tide.

“We pushed it a long way through the sand,” Professor Gallego-Sala said. “It was pretty tough – but it was also hilarious, and we managed to get it out.”

“Meanwhile, I’m still sat at my computer by the way,” said Dr Crichton, laughing. Her satellite work linked every muddy core to long-term imagery, confirming that the edges of Arctic peatlands are edging outward as the climate warms.

Peatlands are storing carbon – for now

“Going out for fieldwork is a short time in comparison to the rest of the work. There is lots of lab work to analyze the samples, then extensive data analysis before the findings can be written into a published paper.”

The study links local plant changes to a global climate trend. The team also warns that, under continued warming, today’s expanding peatlands may flip and release their stored carbon.

Until then, the slow creep of moss across Arctic ground remains one small buffer against rising greenhouse gases.

The full study was published in the journal Communications Earth & Environment.

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