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 1970s, a phenomenon called ‘Arctic amplification’. This enhanced warming is driven by a number of physical processes, some of which are poorly represented in the current generation of climate models. Climate models are the main tool to predict climate change. Climate models predict climate change based on fundamental laws of physics dictating changes in the state of the Earth System (e.g. atmosphere and ocean) combined with semi-empirical representations of processes lacking a comprehensive understanding (e.g. sea ice or cloud formation).
Arctic warming is expected to accelerate in the coming decades, posing considerable social, economic, and environmental challenges locally and globally. 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. The damages to the Arctic system from warming could lead to considerable social, economic, and environmental costs if contributions under the Paris Agreement are not implemented.
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 ecosystems. This relies on finding realistic and plausible projections of climate change. Using the storyline framework, PolarRES will leverage information from a large ensemble of climate projections to provide 4 climate predictions for the Arctic regions, representative of the possible realisations of climate change in the region. This will allow stakeholders to quantify the possible range of climate risks associated with global warming, using only a few climate projections.
Using 2 important factors of climate variability in the Arctic, i.e., the warming of the lower troposphere and of the Barents-Kara sea, we produced 4 climate change storylines, representative of the range of possible climate projections for the last 30 years of our century. We focus on changes in boreal summer, due to the greater relevance of this season to human activities and ecosystems. All storylines share common features such as a strong surface warming, an increase in precipitation rates, a poleward shift of the storm tracks, and extensive sea-ice loss. However, they also show stark differences in the magnitude and pattern of these changes. For instance, the rate of warming can 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 between storylines; for instance, Scandinavia may become either drier or wetter due to global warming, depending on the strength of the Barents-Kara sea warming. Future work will aim to downscale and analyse some of these storylines to assess changes in climate risks.