Human and land exposure to future recurrent unprecedented extremes

In the last decades, highly impacting climate extremes have become increasingly frequent in many different global hotspots. According to climate projections, such events are likely to become even more severe during the 21st century, to the point that under the less conservative scocio-economic scenarios, they could become so recurrent that they possibly constrain the ability to adapt and mitigate, especially in poorly developed countries.

This study investigates the future occurrence of unprecedented heatwaves, droughts, rainfall and snowfall, namely the time of their emergence and when and where they will become the new climate normals, defined here as at least one such event any other year. As input data, we use an ensemble of high-resolution bias-adjusted climate simulations from the ISIMIP3b family and we focus on four SSPs (SSP1 to SSP5, excluding SSP4). Using population, land-use, and GDP projections without climate change, we also analyse their exposure to such unprecedented climate extremes from 2041 to 2100, focusing on continental and macro-regional scales.

We also present preliminary results obtained by using emulated scenarios, with a special focus on the possibility of preventing such unprecedented extremes under low-emission scenarios (SSP1-1.9 and SSP1-2.6) with specific temperature overshoot trajectories. We show that limiting frequent record-breaking heatwaves and droughts could be highly beneficial, especially in regions with lower income and higher vulnerabilities as Africa and Latin America.

The results presented in this study are included in the framework of the EUNICE project, which aims at quantifying the economic and non-economic impacts of future climate extremes, providing robust quantification of uncertainties.