Met Office Hadley Centre, Exeter EX1 3PB, UK.
NCAS-Climate, University of Reading, Reading RG6 6BB, UK.
Nat Commun. 2016 Dec 6;7:13667. doi: 10.1038/ncomms13667.
For adaptation and mitigation planning, stakeholders need reliable information about regional precipitation changes under different emissions scenarios and for different time periods. A significant amount of current planning effort assumes that each K of global warming produces roughly the same regional climate change. Here using 25 climate models, we compare precipitation responses with three 2 K intervals of global ensemble mean warming: a fast and a slower route to a first 2 K above pre-industrial levels, and the end-of-century difference between high-emission and mitigation scenarios. We show that, although the two routes to a first 2 K give very similar precipitation changes, a second 2 K produces quite a different response. In particular, the balance of physical mechanisms responsible for climate model uncertainty is different for a first and a second 2 K of warming. The results are consistent with a significant influence from nonlinear physical mechanisms, but aerosol and land-use effects may be important regionally.
为了适应和缓解规划，利益相关者需要有关不同排放情景和不同时间段下区域降水变化的可靠信息。目前大量的规划工作假设全球每升温 1 摄氏度会大致产生相同的区域气候变化。在这里，我们使用 25 个气候模型，比较了三种全球集合平均变暖 2 摄氏度的降水响应：快速和较慢的方式来实现第一个高于工业化前水平的 2 摄氏度，以及高排放和缓解情景之间的本世纪末差异。结果表明，尽管达到第一个 2 摄氏度的两种途径导致了非常相似的降水变化，但第二个 2 摄氏度会产生截然不同的响应。特别是，导致气候模型不确定性的物理机制的平衡在第一个和第二个 2 摄氏度的变暖中是不同的。这些结果与非线性物理机制的显著影响一致，但气溶胶和土地利用的影响可能在区域内很重要。
