Pathways to 1.5 °C and 2 °C warming based on observational and geological constraints
Pathways to 1.5 °C and 2 °C warming based on observational and geological constraints
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DOI：
10.1038/s41561-017-0054-8
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发表时间：
2018-02-01
影响因子：
18.3
通讯作者：
Williams, Richard G.
中科院分区：
文献类型：
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作者：
Goodwin, Philip;Katavouta, Anna;Williams, Richard G.
将全球变暖限制在商定的目标之下需要限制碳排放，这是人为变暖的主要驱动力。然而，在预测可能排放的碳量方面存在很大的不确定性，部分原因是地球系统模型模拟数量有限，而且与目前的观测结果存在差异。在这里，我们展示了一种减少气候预测不确定性的新方法;使用理论和地质证据，我们生成了一个非常大的预测集合（3 x 10（4）），这些预测与9个关键气候指标的记录密切匹配，其中包括变暖和海洋热含量。我们的分析缩小了地表变暖预测的不确定性，并减少了平衡气候敏感性的范围。我们发现，比工业化前水平高出1.5摄氏度的变暖目标要求2017年初的碳排放总量低于195-205 PgC（超过66%的模拟），而只有当碳排放量低于395-455 PgC时，才有可能实现2摄氏度的变暖目标。按照目前的排放速度，这些变暖目标分别需要17-18年和35-41年才能实现，因此，开发一个更有碳效率的未来的窗口有限。
To restrict global warming to below the agreed targets requires limiting carbon emissions, the principal driver of anthropogenic warming. However, there is significant uncertainty in projecting the amount of carbon that can be emitted, in part due to the limited number of Earth system model simulations and their discrepancies with present-day observations. Here we demonstrate a novel approach to reduce the uncertainty of climate projections; using theory and geological evidence we generate a very large ensemble (3 x 10(4)) of projections that closely match records for nine key climate metrics, which include warming and ocean heat content. Our analysis narrows the uncertainty in surface-warming projections and reduces the range in equilibrium climate sensitivity. We find that a warming target of 1.5 degrees C above the pre-industrial level requires the total emitted carbon from the start of year 2017 to be less than 195-205 PgC (in over 66% of the simulations), whereas a warming target of 2 degrees C is only likely if the emitted carbon remains less than 395-455 PgC. At the current emission rates, these warming targets are reached in 17-18 years and 35-41 years, respectively, so that there is a limited window to develop a more carbon-efficient future.