Climate change under a scenario near 1.5 °C of global warming: monsoon intensification, ocean warming and steric sea level rise
Climate change under a scenario near 1.5 °C of global warming: monsoon intensification, ocean warming and steric sea level rise
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DOI：
10.5194/esd-2-25-2011
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发表时间：
2010-10
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影响因子：
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通讯作者：
J. Schewe;A. Levermann;M. Meinshausen
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文献类型：
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作者：
J. Schewe;A. Levermann;M. Meinshausen
抽象的。利用耦合的气候模式CLIMBER-3α（包含一个大气动力模式和一个三维海洋模式），研究了典型浓度路径（RCPs）的气候后果。我们比较了19个国家的最先进的大气-海洋环流模式（AOGCM）使用MAGICC 6的仿真。RCP是作为即将发布的IPCC第五次评估报告的标准情景而设计的，以涵盖目前讨论的未来温室气体浓度路径的全部范围。最低的RCP情景RCP 3-PD在CLIMBER-3α中预测，到21世纪中叶最大变暖略高于1.5 °C，此后温度缓慢下降，到2500年接近今天的水平。我们确定了两种减缓温室气体浓度峰值后全球冷却的机制：与混合相关的海洋热吸收引起的已知惯性;海洋对流的变化增强了高纬度地区的海洋热损失，使表面冷却速率降低了近50%。RCP 3-PD情景下的空间海平面上升在地表气温达到峰值后持续200年，稳定在2250 ℃左右30 cm。这与最高情景RCP8.5下到2250年空间海平面上升约1.3米和到2500年上升2米形成鲜明对比。根据RCP 3-PD，到21世纪下半叶，中等深度（300-800米）的最大海洋变暖将超过海面。即使在表面温度恢复到今天的数值之后，这种中深度变暖仍持续了几个世纪，对海洋生态系统、海洋甲烷水合物和冰架稳定性产生了潜在影响。由于陆地-海洋温度对比的增强，所有情景在全球变暖的情况下都会产生季风降雨的增强。
Abstract. We present climatic consequences of the Representative Concentration Pathways (RCPs) using the coupled climate model CLIMBER-3α, which contains a statistical-dynamical atmosphere and a three-dimensional ocean model. We compare those with emulations of 19 state-of-the-art atmosphere-ocean general circulation models (AOGCM) using MAGICC6. The RCPs are designed as standard scenarios for the forthcoming IPCC Fifth Assessment Report to span the full range of future greenhouse gas (GHG) concentrations pathways currently discussed. The lowest of the RCP scenarios, RCP3-PD, is projected in CLIMBER-3α to imply a maximal warming by the middle of the 21st century slightly above 1.5 °C and a slow decline of temperatures thereafter, approaching today's level by 2500. We identify two mechanisms that slow down global cooling after GHG concentrations peak: The known inertia induced by mixing-related oceanic heat uptake; and a change in oceanic convection that enhances ocean heat loss in high latitudes, reducing the surface cooling rate by almost 50%. Steric sea level rise under the RCP3-PD scenario continues for 200 years after the peak in surface air temperatures, stabilizing around 2250 at 30 cm. This contrasts with around 1.3 m of steric sea level rise by 2250, and 2 m by 2500, under the highest scenario, RCP8.5. Maximum oceanic warming at intermediate depth (300–800 m) is found to exceed that of the sea surface by the second half of the 21st century under RCP3-PD. This intermediate-depth warming persists for centuries even after surface temperatures have returned to present-day values, with potential consequences for marine ecosystems, oceanic methane hydrates, and ice-shelf stability. Due to an enhanced land-ocean temperature contrast, all scenarios yield an intensification of monsoon rainfall under global warming.