Improved calculation of warming-equivalent emissions for short-lived climate pollutants
Improved calculation of warming-equivalent emissions for short-lived climate pollutants
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DOI：
10.1038/s41612-019-0086-4
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发表时间：
2019-09-04
影响因子：
9
通讯作者：
Macey, Adrian H.
中科院分区：
文献类型：
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作者：
Cain, Michelle;Lynch, John;Macey, Adrian H.
在特定时间，人为全球变暖主要取决于长期气候污染物（LLCPs）的累积总排放量（或存量），主要是二氧化碳（CO2），以及在该时间之前短期气候污染物（SLCPs）的排放率（或流量）。根据《联合国气候变化框架公约》（《气候公约》），温室气体排放的报告已采用100年全球升温潜能值（GWP），以二氧化碳当量（CO2-e）排放量标准化，但GWP的传统用法并不能充分反映LLCP和SLCP的不同行为，或其对全球平均表面温度的影响。GWP的另一种用法，表示为GWP*，通过将SLCP排放率的增加等同于CO2的一次性“脉冲”排放来克服这一问题。我们表明，这种方法，而传统的使用的改进，略低估了最近增加SLCP排放量对目前的变暖速度的影响，因为气候不立即响应辐射强迫。我们通过修改GWP* 定义来解决这个问题，该定义包含了对辐射强迫变化的短期和长期气候响应的术语。修订后的版本允许直接从报告的排放量计算“CO2-warming-equivalent”（CO2-we）排放量。因此，SLCP可以直接纳入与长期温度目标一致的碳预算，因为我们排放的每单位CO2都会产生大致相同的变暖量，无论是作为SLCP还是LLCP排放。这不是常规来源的CO2-e的情况。
Anthropogenic global warming at a given time is largely determined by the cumulative total emissions (or stock) of long-lived climate pollutants (LLCPs), predominantly carbon dioxide (CO2), and the emission rates (or flow) of short-lived climate pollutants (SLCPs) immediately prior to that time. Under the United Nations Framework Convention on Climate Change (UNFCCC), reporting of greenhouse gas emissions has been standardised in terms of CO2 -equivalent (CO2-e) emissions using Global Warming Potentials (GWP) over 100-years, but the conventional usage of GWP does not adequately capture the different behaviours of LLCPs and SLCPs, or their impact on global mean surface temperature. An alternative usage of GWP, denoted GWP*, overcomes this problem by equating an increase in the emission rate of an SLCP with a one-off "pulse" emission of CO2. We show that this approach, while an improvement on the conventional usage, slightly underestimates the impact of recent increases in SLCP emissions on current rates of warming because the climate does not respond instantaneously to radiative forcing. We resolve this with a modification of the GWP* definition, which incorporates a term for each of the short-timescale and long-timescale climate responses to changes in radiative forcing. The amended version allows "CO2-warming-equivalent" (CO2-we) emissions to be calculated directly from reported emissions. Thus SLCPs can be incorporated directly into carbon budgets consistent with long-term temperature goals, because every unit of CO2-we emitted generates approximately the same amount of warming, whether it is emitted as a SLCP or a LLCP. This is not the case for conventionally derived CO2-e.