Moving Beyond Global Warming Potentials to Quantify the Climatic Role of Ecosystems
Moving Beyond Global Warming Potentials to Quantify the Climatic Role of Ecosystems
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DOI：
10.1007/s10021-015-9879-4
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发表时间：
2015-09-01
期刊：
影响因子：
3.7
通讯作者：
Megonigal, J. Patrick
中科院分区：
文献类型：
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作者：
Neubauer, Scott C.;Megonigal, J. Patrick
几十年来，生态系统科学家一直使用全球变暖潜能值（GWP）来比较各种温室气体的辐射强迫，以确定生态系统是否对气候产生净变暖或冷却效应。从概念上讲，生态界继续使用全球升温潜能值可能是站不住脚的，因为使用全球升温潜能值需要隐含的假设，即温室气体排放是作为单一脉冲发生的;这种假设在生态系统研究中很少得到证明。我们提出了两个替代度量持续通量全球变暖潜力（SGWP，气体排放）和持续通量全球冷却潜力（SGCP，气体吸收）-使用时，气体通量持续随着时间的推移。对于甲烷和一氧化二氮的排放，SGWP通常大于GWP（高达40%），造成GWP和SGWP指标可能对生态系统的气候作用提供相反的解释的情况。此外，甲烷和一氧化二氮的动态在持续排放和吸收情况之间存在不对称性，产生了全球变暖潜势与全球变暖潜势之间非常不同的数值，并得出结论，吸收这些气体的生态系统在减少辐射强迫方面非常有效。虽然新的指标比全球升温潜能值更现实的生态系统通量，我们进一步认为，即使这些指标可能是不够的，试图了解生态系统的生命周期的气候作用的背景下。动态建模方法具有灵活性，可以考虑温室气体交换的时间变化率，并且不受固定时间范围的限制，可能比SGWP，SGCP或GWP更具信息性。最后，我们希望这篇文章将激发生态系统科学界关于评估生态系统作为全球气候调节者的作用的最适当方法的讨论。
For decades, ecosystem scientists have used global warming potentials (GWPs) to compare the radiative forcing of various greenhouse gases to determine if ecosystems have a net warming or cooling effect on climate. On a conceptual basis, the continued use of GWPs by the ecological community may be untenable because the use of GWPs requires the implicit assumption that greenhouse gas emissions occur as a single pulse; this assumption is rarely justified in ecosystem studies. We present two alternate metrics-the sustained-flux global warming potential (SGWP, for gas emissions) and the sustained-flux global cooling potential (SGCP, for gas uptake)-for use when gas fluxes persist over time. The SGWP is generally larger than the GWP (by up to similar to 40%) for both methane and nitrous oxide emissions, creating situations where the GWP and SGWP metrics could provide opposing interpretations about the climatic role of an ecosystem. Further, there is an asymmetry in methane and nitrous oxide dynamics between persistent emission and uptake situations, producing very different values for the SGWP vs. SGCP and leading to the conclusion that ecosystems that take up these gases are very effective at reducing radiative forcing. Although the new metrics are more realistic than the GWP for ecosystem fluxes, we further argue that even these metrics may be insufficient in the context of trying to understand the lifetime climatic role of an ecosystem. A dynamic modeling approach that has the flexibility to account for temporally variable rates of greenhouse gas exchange, and is not limited by a fixed time frame, may be more informative than the SGWP, SGCP, or GWP. Ultimately, we hope this article will stimulate discussion within the ecosystem science community about the most appropriate way(s) of assessing the role of ecosystems as regulators of global climate.