The Mediterranean basin and Northern Africa are projected to be among the most vulnerable areas to climate change. This research documents, analyzes, and synthesizes the projected changes in precipitation P, evapotranspiration E, net water supply from the atmosphere to the surface P–E, and surface soil moisture over these regions as simulated by 17 global climate models from the sixth exercise of the Coupled Model Intercomparison Project (CMIP6) under two Shared Socioeconomic Pathways, SSP2-4.5, and SSP5-8.5. It also explores the sensitivity of the results to the chosen climate scenario and model resolution and assesses how the projections have evolved from the fifth exercise (CMIP5). Models project a statistically robust drying over the entire Mediterranean and coastal North Africa. Over the Northern Mediterranean sector, a significant precipitation decrease reaching −0.4 ∓ 0.1 mm ${\mathrm{day}}^{-1}$ is projected during the 21st century under the SSP5-8.5 scenario. Conversely, a significant increase in precipitation of +0.05 to 0.3 ∓ 0.1 mm day⁻¹ is projected over South-Eastern Sahara under the same scenario. Evapotranspiration and soil moisture exhibit decreasing trends over the Mediterranean basin and an increase over the Sahara for both SSPs, with a notable acceleration from the 2020s. As a result, P-E is projected to decrease at a rate of about −0.3 mm day⁻¹ under the high-end scenario SSP5-8.5 over the Mediterranean whilst no significant changes are expected over the Sahara due to evapotranspiration compensation effects. CMIP6 and CMIP5 models project qualitatively similar patterns of changes but CMIP6 models exhibit more intense changes over the Mediterranean basin and South-Eastern Sahara, especially during winter.

中文翻译：

---

地中海盆地和北非地表水可用性的未来：CMIP6 演习的分析和综合

地中海盆地和北非预计将成为最容易受到气候变化影响的地区之一。本研究记录、分析和综合了这些地区的降水量 P、蒸散量 E、从大气到地表的净供水量 P-E 以及地表土壤湿度的预计变化，这些变化是由第六次演习中的 17 个全球气候模型模拟的。两个共享社会经济路径 SSP2-4.5 和 SSP5-8.5 下的耦合模型比对项目 (CMIP6)。它还探讨了结果对所选气候情景和模型分辨率的敏感性，并评估了第五次演习 (CMIP5) 中预测的演变情况。从统计数据来看，模型预测整个地中海和北非沿海地区将出现严重干旱。地中海北部地区降水显着减少，达到-0.4∓0.1毫米 ${\mathrm{天}}^{-1}$预计在 SSP5-8.5 情景下于 21 世纪发生。相反，在同样的情况下，预计撒哈拉东南部地区的降水量将显着增加+0.05至0.3 ∓ 0.1 mm day ^{-1 。}对于这两个 SSP，蒸散量和土壤湿度在地中海盆地呈现出下降趋势，而在撒哈拉沙漠则呈上升趋势，并且从 2020 年代开始显着加速。因此，在高端情景 SSP5-8.5 下，地中海地区的PE 预计将以约 -0.3 mm day ^{-1的速度下降，而由于蒸散补偿效应，预计撒哈拉沙漠不会出现重大变化。}CMIP6 和 CMIP5 模型预测了性质相似的变化模式，但 CMIP6 模型在地中海盆地和撒哈拉东南部表现出更强烈的变化，特别是在冬季。