Setting cumulative emissions targets to reduce the risk of dangerous climate change
Setting cumulative emissions targets to reduce the risk of dangerous climate change
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DOI：
10.1073/pnas.0805800106
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发表时间：
2009-09-22
影响因子：
11.1
通讯作者：
Weaver, Andrew J.
中科院分区：
文献类型：
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作者：
Zickfeld, Kirsten;Eby, Michael;Weaver, Andrew J.
要避免“对气候系统造成危险的人为干扰”，需要稳定大气中温室气体的浓度，并大幅减少人为排放。在这里，我们提出了一种气候-碳循环耦合模型的反向方法，该方法允许我们在考虑到气候敏感性和碳循环对气候变化的反应的不确定性的情况下，估计任何给定水平的二氧化碳(CO2)排放量超过特定长期全球平均温度目标的概率。我们表明，要以至少0.66的概率将全球平均气温上升稳定在比工业化前水平高2摄氏度的水平，2000至2500年的累计二氧化碳排放量不得超过590 PB克碳(PGC)的中值估计(范围为200至950 PGC)。如果要以至少0.9的概率实现2摄氏度的温度稳定目标，则允许的总二氧化碳排放量中值为170 ppc(范围为-220至700 ppc)。此外，这些对累积二氧化碳排放量的估计与特定的温度稳定目标相一致，与实现稳定的途径无关。因此，我们的分析支持旨在避免危险的人为干扰的国际政策框架，该框架是在允许的温室气体排放总量的基础上制定的。
Avoiding "dangerous anthropogenic interference with the climate system'' requires stabilization of atmospheric greenhouse gas concentrations and substantial reductions in anthropogenic emissions. Here, we present an inverse approach to coupled climate-carbon cycle modeling, which allows us to estimate the probability that any given level of carbon dioxide (CO2) emissions will exceed specified long-term global mean temperature targets for "dangerous anthropogenic interference,'' taking into consideration uncertainties in climate sensitivity and the carbon cycle response to climate change. We show that to stabilize global mean temperature increase at 2 degrees C above preindustrial levels with a probability of at least 0.66, cumulative CO2 emissions from 2000 to 2500 must not exceed a median estimate of 590 petagrams of carbon (PgC) (range, 200 to 950 PgC). If the 2 degrees C temperature stabilization target is to be met with a probability of at least 0.9, median total allowable CO2 emissions are 170 PgC ( range, -220 to 700 PgC). Furthermore, these estimates of cumulative CO2 emissions, compatible with a specified temperature stabilization target, are independent of the path taken to stabilization. Our analysis therefore supports an international policy framework aimed at avoiding dangerous anthropogenic interference formulated on the basis of total allowable greenhouse gas emissions.