Projected Evolution of Compound Temperature-Precipitation Extremes in the Arctic: Insights from a multi-model High-Resolution regional climate ensemble

 

The polar regions are among the most affected by global warming, making them particularly vulnerable to extreme events with significant impacts on the cryosphere, permafrost, and wildfires. Record-breaking temperature and precipitation extremes are becoming increasingly widespread and intense globally.  Extreme heat events are projected to increase in frequency, intensity, and duration throughout the 21st century. Furthermore, a sea-ice-free Arctic is becoming a probable scenario. This raises critical questions with significant implications for hazard assessment and adaptation policies: how will compound temperature-precipitation extremes evolve in the polar regions, and which areas will be most vulnerable? Addressing these questions is challenging due to the coarse resolution of current state-of-the-art (CMIP6) future projections. We use state-of-the-art simulations from the EU project PolarRES. They offer an unprecedentedly high-resolution (11 km) Pan-Arctic ensemble developed within the Polar-CORDEX framework. The simulations downscale two different CMIP6 models that are representative of the spread for CMIP6 projections under the SSP3-7.0 scenario. They provide a continuous 120-year (1985-2100) time series of hourly temperature and precipitation data.  We assess compound temperature-precipitation extreme events in the Arctic by mid and end of the century, with a focus on the intensity and persistence of these extremes. This extensive dataset allows us to confidently (1) pinpoint areas that may become more vulnerable to increased occurrences of extreme events in the future, (2) compare near-term, mid-century and end-century distributions and patterns, and (3) identify emerging trends. A clustering analysis will be used to identify regions of the Arctic with similar precipitation-temperature characteristics. With this approach, we can determine whether regions with distinct climate profiles exhibit different trends and behaviours.