文章基本信息

标题：Increased importance of methane reduction for a 1.5 degree target
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作者：William J Collins ; Christopher P Webber ; Peter M Cox 等
期刊名称：Environmental Research Letters
印刷版ISSN：1748-9326
电子版ISSN：1748-9326
出版年度：2018
卷号：13
期号：5
页码：054003
DOI：10.1088/1748-9326/aab89c
语种：English
出版社：IOP Publishing Ltd
摘要：To understand the importance of methane on the levels of carbon emission reductions required to achieve temperature goals, a processed-based approach is necessary rather than reliance on the transient climate response to emissions. We show that plausible levels of methane (CH₄) mitigation can make a substantial difference to the feasibility of achieving the Paris climate targets through increasing the allowable carbon emissions. This benefit is enhanced by the indirect effects of CH₄ on ozone (O₃). Here the differing effects of CH₄ and CO₂ on land carbon storage, including the effects of surface O₃, lead to an additional increase in the allowable carbon emissions with CH₄ mitigation. We find a simple robust relationship between the change in the 2100 CH₄ concentration and the extra allowable cumulative carbon emissions between now and 2100 (0.27 ± 0.05 GtC per ppb CH₄). This relationship is independent of modelled climate sensitivity and precise temperature target, although later mitigation of CH₄ reduces its value and thus methane reduction effectiveness. Up to 12% of this increase in allowable emissions is due to the effect of surface ozone. We conclude early mitigation of CH₄ emissions would significantly increase the feasibility of stabilising global warming below 1.5 °C, alongside having co-benefits for human and ecosystem health.