Climate-carbon cycle uncertainties and the Paris Agreement
Climate-carbon cycle uncertainties and the Paris Agreement
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DOI：
10.1038/s41558-018-0197-7
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发表时间：
2018-07-01
影响因子：
30.7
通讯作者：
Vinuales, J. E.
中科院分区：
文献类型：
--
作者：
Holden, P. B.;Edwards, N. R.;Vinuales, J. E.
《巴黎协定》（1）旨在解决现有气候政策与符合“将全球平均气温增幅控制在远低于2摄氏度”的政策之间的差距。实现这一目标的可行性受到了质疑，既有可能要求负排放（2），也有关于气候碳循环系统敏感性的持续辩论（3）。使用一个全动态的三维气候-碳循环模型的一系列集合，由区域层面气候政策、经济和技术转型的综合评估模型的排放所迫，我们表明，对巴黎协定的合理解释在技术上仍然是可以实现的。具体来说，将峰值（十年）变暖限制在1.7摄氏度以下，或将世纪末变暖限制在1.54摄氏度以下，在我们的政策情景模拟中有50%发生在没有净负排放或任何政策领域过度严格的情况下。我们评估了两种减缓情景，分别为2017年后的200千兆吨碳排放和307千兆吨碳排放，量化了变暖，降水，海洋酸化和海洋生产力的时空变化。在快速脱碳下，十年变化在关键区域的平均响应中占主导地位，对决策产生重大影响，要求采用处理非线性时空响应的影响方法。在强减排条件下，忽略碳循环反馈的不确定性（可以解释47%的峰值变暖不确定性）是不合理的。
The Paris Agreement(1) aims to address the gap between existing climate policies and policies consistent with "holding the increase in global average temperature to well below 2 C". The feasibility of meeting the target has been questioned both in terms of the possible requirement for negative emissions(2) and ongoing debate on the sensitivity of the climatecarbon- cycle system(3). Using a sequence of ensembles of a fully dynamic three-dimensional climate-carbon-cycle model, forced by emissions from an integrated assessment model of regional-level climate policy, economy, and technological transformation, we show that a reasonable interpretation of the Paris Agreement is still technically achievable. Specifically, limiting peak (decadal) warming to less than 1.7 degrees C, or end-of-century warming to less than 1.54 degrees C, occurs in 50% of our simulations in a policy scenario without net negative emissions or excessive stringency in any policy domain. We evaluate two mitigation scenarios, with 200 gigatonnes of carbon and 307 gigatonnes of carbon post-2017 emissions respectively, quantifying the spatio-temporal variability of warming, precipitation, ocean acidification and marine productivity. Under rapid decarbonization decadal variability dominates the mean response in critical regions, with significant implications for decision-making, demanding impact methodologies that address non-linear spatio-temporal responses. Ignoring carbon-cycle feedback uncertainties (which can explain 47% of peak warming uncertainty) becomes unreasonable under strong mitigation conditions.