Broad range of 2050 warming from an observationally constrained large climate model ensemble
Broad range of 2050 warming from an observationally constrained large climate model ensemble
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DOI：
10.1038/ngeo1430
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发表时间：
2012-04-01
影响因子：
18.3
通讯作者：
Allen, Myles R.
中科院分区：
文献类型：
--
作者：
Rowlands, Daniel J.;Frame, David J.;Allen, Myles R.
对气候系统的三个方面--平衡气候敏感性、海洋热吸收率和历史气溶胶强迫--以及它们背后的物理过程的不完全理解导致了我们对21世纪世纪全球平均温度演变的评估中的不确定性（1，2）。迄今为止，对这些不确定性的探索依赖于尺度方法（3，4）、简化气候模式的大型集合（1，2）或复杂耦合大气-海洋环流模式的小型集合（5，6），这些模式对独立来源（7-9）得出的关键气候系统特性的不确定性的代表性不足。在这里，我们提出的结果从一个多千元扰动物理系综的瞬态耦合大气-海洋环流模式模拟。我们发现，模型版本再现观测到的地表温度变化在过去的50年中，全球平均温度增加1.4-3 K，到2050年，相对于1961-1990年，在一个中等范围的强迫情景。这一变暖范围与政府间气候变化专门委员会第四次评估报告（10）提供的专家评估大致一致，但比通常用于气候影响评估的机会整体（5）所观察到的变暖范围更大。从我们的模拟中，我们得出的结论是，到21世纪中叶，全球变暖比早期的估计更强烈，这与最近观察到的温度变化和温室气体排放的中期“无缓解”情景是一致的。
Incomplete understanding of three aspects of the climate system-equilibrium climate sensitivity, rate of ocean heat uptake and historical aerosol forcing-and the physical processes underlying them lead to uncertainties in our assessment of the global-mean temperature evolution in the twenty-first century(1,2). Explorations of these uncertainties have so far relied on scaling approaches(3,4), large ensembles of simplified climate models(1,2), or small ensembles of complex coupled atmosphere-ocean general circulation models(5,6) which under-represent uncertainties in key climate system properties derived from independent sources(7-9). Here we present results from a multi-thousand-member perturbed-physics ensemble of transient coupled atmosphere-ocean general circulation model simulations. We find that model versions that reproduce observed surface temperature changes over the past 50 years show global-mean temperature increases of 1.4-3 K by 2050, relative to 1961-1990, under a mid-range forcing scenario. This range of warming is broadly consistent with the expert assessment provided by the Intergovernmental Panel on Climate Change Fourth Assessment Report(10), but extends towards larger warming than observed in ensembles-of-opportunity(5) typically used for climate impact assessments. From our simulations, we conclude that warming by the middle of the twenty-first century that is stronger than earlier estimates is consistent with recent observed temperature changes and a mid-range 'no mitigation' scenario for greenhouse-gas emissions.