State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China.
Vrije Universiteit Amsterdam, Department of Earth Sciences, Boelelaan 1085, 1081 HV, Amsterdam, the Netherlands.
Nat Commun. 2022 Jul 15;13(1):4124. doi: 10.1038/s41467-022-31782-7.
Climate projections are essential for decision-making but contain non-negligible uncertainty. To reduce projection uncertainty over Asia, where half the world's population resides, we develop emergent constraint relationships between simulated temperature (1970-2014) and precipitation (2015-2100) growth rates using 27 CMIP6 models under four Shared Socioeconomic Pathways. Here we show that, with uncertainty successfully narrowed by 12.1-31.0%, constrained future precipitation growth rates are 0.39 ± 0.18 mm year (29.36 mm °C, SSP126), 0.70 ± 0.22 mm year (20.03 mm °C, SSP245), 1.10 ± 0.33 mm year (17.96 mm °C, SSP370) and 1.42 ± 0.35 mm year (17.28 mm °C, SSP585), indicating overestimates of 6.0-14.0% by the raw CMIP6 models. Accordingly, future temperature and total evaporation growth rates are also overestimated by 3.4-11.6% and -2.1-13.0%, respectively. The slower warming implies a lower snow cover loss rate by 10.5-40.2%. Overall, we find the projected increase in future water availability is overestimated by CMIP6 over Asia.
气候预测对决策至关重要，但其中包含不可忽视的不确定性。为了降低亚洲地区（世界上一半人口居住的地区）预测的不确定性，我们利用四个社会经济共享路径下的 27 个 CMIP6 模型，建立了模拟温度（1970-2014 年）和降水（2015-2100 年）增长率之间的新兴约束关系。结果表明，通过约束，未来降水增长率被成功缩小了 12.1-31.0%，其值分别为 0.39±0.18mm/年（29.36mm/°C，SSP126）、0.70±0.22mm/年（20.03mm/°C，SSP245）、1.10±0.33mm/年（17.96mm/°C，SSP370）和 1.42±0.35mm/年（17.28mm/°C，SSP585），这表明原始 CMIP6 模型高估了 6.0-14.0%。相应地，未来温度和总蒸发增长率也分别被高估了 3.4-11.6%和-2.1-13.0%。变暖速度较慢意味着积雪损失率降低了 10.5-40.2%。总的来说，我们发现 CMIP6 对亚洲未来水资源可用性的增加预测过高。
