Sensitivity of climate to cumulative carbon emissions due to compensation of ocean heat and carbon uptake
Sensitivity of climate to cumulative carbon emissions due to compensation of ocean heat and carbon uptake
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DOI：
10.1038/ngeo2304
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发表时间：
2015-01-01
影响因子：
18.3
通讯作者：
Ridgwell, Andy
中科院分区：
文献类型：
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作者：
Goodwin, Philip;Williams, Richard G.;Ridgwell, Andy
气候模型实验表明，在几十年到百年的时间尺度上(1-5)，瞬时全球变暖与累计碳排放量几乎成正比。然而，在暂态气候模拟中，气候变暖和累计碳排放之间的这种近线性相关性是如何产生的，目前还不能定量地理解(6，7)。在这里，我们提出了全球变暖与累积碳排放量随时间变化的理论推导方程。对于大气-海洋系统，我们的分析确定了表面变暖对每1,000 pg碳排放1.5+/-0.7K的累积碳排放的响应。到本世纪末及以后，这种对地表变暖的反应通常会减少10-20%。由于海洋吸收热量和碳的部分相反影响，气候响应在几十年到百年的时间尺度上几乎保持不变(8)。如前所述，在许多世纪之后，由此产生的气候变暖与累计碳排放量成正比(9)。当我们结合对陆地碳吸收的估计(10)时，每排放1,000 pg碳，地表变暖响应将减少到1.1+/-0.5K，但这种修改不太可能显著影响气候响应随时间的变化。我们建议，我们的理论框架可以用来诊断气候模型中的全球变暖反应，并从机械上理解它们的预测之间的差异。
Climate model experiments reveal that transient global warming is nearly proportional to cumulative carbon emissions on multi-decadal to centennial timescales(1-5). However, it is not quantitatively understood how this near-linear dependence between warming and cumulative carbon emissions arises in transient climate simulations(6,7). Here, we present a theoretically derived equation of the dependence of global warming on cumulative carbon emissions over time. For an atmosphere-ocean system, our analysis identifies a surface warming response to cumulative carbon emissions of 1.5 +/- 0.7 K for every 1,000 Pg of carbon emitted. This surface warming response is reduced by typically 10-20% by the end of the century and beyond. The climate response remains nearly constant on multi-decadal to centennial timescales as a result of partially opposing effects of oceanic uptake of heat and carbon(8). The resulting warming then becomes proportional to cumulative carbon emissions after many centuries, as noted earlier(9). When we incorporate estimates of terrestrial carbon uptake(10), the surface warming response is reduced to 1.1 +/- 0.5 K for every 1,000 Pg of carbon emitted, but this modification is unlikely to significantly affect how the climate response changes over time. We suggest that our theoretical framework may be used to diagnose the global warming response in climate models and mechanistically understand the differences between their projections.