As many as 20 regions in the Arctic are likely the most vulnerable to climate change, according to a new study. Almost all these hotspots have a common feature: Permafrost.
Permafrost refers to soil or rock whose temperature has been maintained at or below 0°C for at least two consecutive years. With climate change, permafrost thaws, threatening to lead to carbon emissions that have been locked in ice for thousands of years.
Of the 20 hotspots, 16 are in Eurasia, with the remaining in North America, according to the study published in the journal Geophysical Research Letters. “The Arctic and boreal regions are made up of diverse ecosystems, and this study reveals some of the complex ways they are responding to climate warming,” Sue Natali, lead of the Permafrost Pathways project at Woodwell Climate and co-author of the study, said in a statement. She explained that the most climate-stressed regions all contained permafrost, which is vulnerable to thaw as temperatures rise. “That is a really concerning signal,” the expert warned.
The team detected “neighbourhoods” or regions of particularly high levels of change during the past decade. To do this, they used three decades of geospatial data and long-term temperature records to assess temperature, moisture and vegetation states.
The analysis found that the far eastern Siberian tundra and central Siberia witnessed substantial land warming during 1997-2020. Tundra is a biome with almost no trees due to a short growing season and permafrost.
Further, the data showed that the tundra region was more hit than boreal forests, with 99 per cent of the Eurasian tundra region experiencing significant warming, compared to 72 per cent of Eurasian boreal forests. Boreal forests are northernmost forests on the planet and are dominated by species of spruce, fir, larch, pine, birch and aspen.
The warming is likely being fuelled by multiple factors such as loss of sea ice in the Arctic Ocean and changes in regional circulation patterns. Sea ice reflects light but its loss in polar regions, exposes the dark sea, which absorbs sunlight, contributing to warming. The increased solar heating further reduces snow and ice, perpetuating the cycle.
Apart from warming, the study found that some parts were getting drier, while others seeing wetter conditions. Some hotspots in Siberia and the Northwest Territories of Canada grew drier, but parts of North America, including Alaska’s Yukon-Kuskokwim Delta and central Canada, saw more increased surface water and flooding. The latter could be the result of thawing permafrost.
Climate warming has put a great deal of stress on ecosystems in the high latitudes, but the stress looks very different from place to place and we wanted to quantify those differences.Jennifer Watts, Arctic program director at Woodwell Climate and lead author of the study
“Detecting hotspots at the local and regional level helps us not only to build a more precise picture of how Arctic warming is affecting ecosystems, but to identify places where we really need to focus future monitoring efforts and management resources,” the expert said in a statement.
Local data and trend detection, the authors wrote, can support management and adaptation approaches that factor in unique and shifting conditions on the ground.
The researches also called for the need to better understand how severe disturbances such as fire are altering the Arctic, adding that there it is critical to have a finer spatial scale mapping of present and historic fire events across the Arctic‐boreal zone.