Arctic

Warming up faster than the rest of the world due to climate change, the Arctic region is becoming increasingly vulnerable to major disruptions in its finely balanced eco-, climate, and physical systems.

The Arctic region, located at the northernmost point on our planet, has warmed more than twice as fast as the rest of the globe since the 1970’s, a phenomenon called Arctic amplification. This enhanced warming is expected to accelerate in the coming decades, posing considerable social, economic, and environmental challenges in the Arctic. Drastic changes in the state of the Arctic are already happening: most noticeably, sea-ice cover has shrunk by more than 40% since 1979, while evidence suggests a poleward migration of terrestrial and marine biomes in the past decades as well. The damages to the Arctic system from warming will lead to considerable social, economic, and environmental costs if contributions under the Paris Agreement are not implemented.

The feedback processes that occur in the Arctic, from the sea ice to clouds, all play a role in regulating climate, on a regional and global scale. To this end, PolarRES seeks to better understand the societal and ecological impact of climate change in the Arctic, and most particularly the foreseen increase in boreal forest fires, permafrost thaw, trans-arctic shipping routes, and marine primary production. Such an analysis relies on finding realistic and plausible projections of climate change. This is done by leveraging a large ensemble of climate projections and some known covariabilities in the climate system, which we use to design storylines for climate change in the Arctic for the end of this century. Storylines are not meant to be an actual projection of climate change, which any model is currently unable to reliably provide, but rather represent a possible range of predictions that may be useful to stakeholders for testing possible extreme outcomes of climate change.

Storylines

Using well-known covariabilities between the warming of the lower troposphere, the warming of the Barents-Kara sea, and the near-surface warming over marine and terrestrial areas, we designed eight storylines of climate change that encompass a wide range of climatic outcomes. While all storylines share common features, such as a strong surface warming, increase in precipitation rates, poleward shift of the storm tracks, and extensive sea-ice loss, they also differ in the magnitude and pattern of these changes. For instance, the rate of warming can be differ considerably between marine and terrestrial areas, revealing the land-sea contrast. Likewise, precipitation rates can vary drastically over certain areas of the Northern hemisphere: for instance, the storylines provide two plausible outcomes for the end of the 21st century, in which Southern Scandinavia can become either drier or wetter with global warming. Future work will aim to downscale and analyse some of these storylines, to quantify the possible changes in climate risks.