Will Half a Degree Make a Difference? Robust Projections of Indices of Mean and Extreme Climate in Europe Under 1.5°C, 2°C, and 3°C Global Warming

Based on high-resolution models, we investigate the change in climate extremes and impact-relevant indicators over Europe under different levels of global warming. We specifically assess the robustness of the changes and the benefits of limiting warming to 1.5 degrees C instead of 2 degrees C. Compared to 1.5 degrees C world, a further 0.5 degrees C warming results in a robust change of minimum summer temperature indices (mean, Tn10p, and Tn900p) over more than 70% of Europe. Robust changes (more than 0.5 degrees C) in maximum temperature affect smaller areas (usually less than 20%). There is a substantial nonlinear change of fixed-threshold indices, with more than 60% increase of the number of tropical nights over southern Europe and more than 50% decrease in the number of frost days over central Europe. The change in mean precipitation due to 0.5 degrees C warming is mostly nonsignificant at the grid point level, but, locally, it is accompanied by a more marked change in extreme rainfall.