迄今为止，描述和预测气候对由人类活动产生的二氧化碳排放的响应的工作都集中在气候敏感性上：与二氧化碳数量加倍相关的平衡温度变化。但最近的研究工作表明，这种“Charney”敏感性（根据1979年首先采用这种方法的气象学家Jule Charney命名）可能是对地球系统全面反应的一种不全面表征，因为它忽略了碳循环、气溶胶、土地利用和陆地覆盖的变化。
Matthews等人提出关于气候系统对人类活动产生的二氧化碳排放的响应的一种新的度量，即碳-气候响应，或称CCR。他们将一个简化的气候模型、来自最近一次模型相互比较的一系列模拟结果以及历史上的约束因素结合起来，发现排放一万亿吨碳将引起1.0–2.1 oC的全球变暖，而且与排放的时间点或大气中二氧化碳浓度无关，这个CCR值与对二十一世纪的模型预测结果是一致的。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature 459, 829-832 (11 June 2009) | doi:10.1038/nature08047
The proportionality of global warming to cumulative carbon emissions
H. Damon Matthews1, Nathan P. Gillett2, Peter A. Stott3 & Kirsten Zickfeld2
1 Department of Geography, Planning and Environment, Concordia University, 1455 de Maisonneuve Blvd W., Montreal, Quebec, H3G 1M8, Canada
2 Canadian Centre for Climate Modelling and Analysis, Environment Canada, 3800 Finnerty Road, Victoria, British Columbia, V8P 5C2, Canada
3 Met Office Hadley Centre, FitzRoy Road, Exeter, Devon, EX1 3PB, UK
The global temperature response to increasing atmospheric CO2 is often quantified by metrics such as equilibrium climate sensitivity and transient climate response1. These approaches, however, do not account for carbon cycle feedbacks and therefore do not fully represent the net response of the Earth system to anthropogenic CO2 emissions. Climate–carbon modelling experiments have shown that: (1) the warming per unit CO2 emitted does not depend on the background CO2 concentration2; (2) the total allowable emissions for climate stabilization do not depend on the timing of those emissions3, 4, 5; and (3) the temperature response to a pulse of CO2 is approximately constant on timescales of decades to centuries3, 6, 7, 8. Here we generalize these results and show that the carbon–climate response (CCR), defined as the ratio of temperature change to cumulative carbon emissions, is approximately independent of both the atmospheric CO2 concentration and its rate of change on these timescales. From observational constraints, we estimate CCR to be in the range 1.0–2.1 °C per trillion tonnes of carbon (Tt C) emitted (5th to 95th percentiles), consistent with twenty-first-century CCR values simulated by climate–carbon models. Uncertainty in land-use CO2 emissions and aerosol forcing, however, means that higher observationally constrained values cannot be excluded. The CCR, when evaluated from climate–carbon models under idealized conditions, represents a simple yet robust metric for comparing models, which aggregates both climate feedbacks and carbon cycle feedbacks. CCR is also likely to be a useful concept for climate change mitigation and policy; by combining the uncertainties associated with climate sensitivity, carbon sinks and climate–carbon feedbacks into a single quantity, the CCR allows CO2-induced global mean temperature change to be inferred directly from cumulative carbon emissions.
