40% of global population, who resides in Asian monsoon region is at high risk from extreme hot summer events, which is expected to increase by 25%/30 years under RCP8.5 scenario. Using Community Earth System Model (CESM) Large-ensemble simulations we assess the relative contribution of external forcings and internal variability on hot extremes over South and East Asia. Climate change projects surface mean temperature to reach 2.0 °C and 5.0 °C by ~2050 and ~2100, respectively, making the region uninhabitable under exposed conditions. Internal variability will partly obscure anthropogenic warming over South and Southeast Asia; however, East Asia will experience a 4–6 fold rise in record breaking hot events in later periods. Nevertheless, beyond 2.35 °C warming internal variability will decrease over South Asia due to weaker albedo feedback on unforced internal variability. Our results contradict the existing hypothesis that warming will increase volatility in weather patterns everywhere, particularly the Asian monsoon regions.

居住在亚洲季风区的全球人口中有 40% 面临夏季极端炎热事件的高风险，在 RCP8.5 情景下，这一风险预计每 30 年增加 25%。使用社区地球系统模型（CESM）大型集合模拟，我们评估了外部强迫和内部变率对南亚和东亚极端高温的相对贡献。气候变化预计到 2050 年和 2100 年地表平均温度将分别达到 2.0 °C 和 5.0 °C，使该地区在暴露条件下无法居住。内部变化将部分掩盖南亚和东南亚的人为变暖；然而，东亚地区后期破纪录的热点事件将增加4-6倍。然而，超过 2.35 °C，由于非受迫内部变率的反照率反馈较弱，南亚地区变暖的内部变率将减少。我们的结果与现有的假设相矛盾，即变暖将增加各地天气模式的波动性，特别是亚洲季风地区。