Fig. 5: Change in the aridity pattern in the AWI-ESM low-CO₂ experiment compared to the high-CO₂ experiment.

Colors indicate aridity according to the Aridity Index (AI) based on the high-CO₂ experiment (i.e., AWI-ESM simulation with CO₂ at 568 ppmv). The AI is defined as the ratio between annual mean precipitation and potential evaporation: Hyper-arid (AI < 0.05), Arid (0.05 < AI < 0.2), Semi-arid (0.2 < AI < 0.5), Dry (0.5 < AI < 0.65), Humid (AI > 0.65), Cold (yearly potential evaporation <400 mm). The blue crosses mark regions where the climate type changed to more humid conditions in the low-CO₂ experiment compared to the high-CO₂ experiment. The black squares mark regions where the climate type changed towards more arid conditions in the low-CO₂ experiment. These dry and wet transition regions are identified based on the AI index. Overall, less arid conditions are observed over Central Asia in the low-CO₂ experiment. The blue oval indicates the approximate location of the Tarim Basin.