On the proportionality between global temperature change and cumulative CO2 emissions during periods of net negative CO2 emissions
On the proportionality between global temperature change and cumulative CO2 emissions during periods of net negative CO2 emissions
复制标题
关于二氧化碳净负排放期间全球温度变化与累积二氧化碳排放量之间的比例
DOI：
10.1088/1748-9326/11/5/055006
复制
发表时间：
2016
影响因子：
6.7
通讯作者：
H. D. Matthews
中科院分区：
文献类型：
--
作者：
K. Zickfeld;A. MacDougall;H. D. Matthews
最近的研究表明，全球平均地表空气变暖与累积的二氧化碳排放量大致成正比。这种比例关系受到了相当大的关注，因为它允许计算与温度目标相一致的累积CO2排放量（“碳排放量”），并且是模型相互比较的有用措施。在这里，我们使用一个地球系统模型来探讨这种关系是否持续在净负二氧化碳排放期间。在大多数将全球变暖限制在比工业化前高出2 °C的排放情景中，都要求二氧化碳排放量为负，在本世纪后半叶的若干情景中，排放量将变为净负。我们发现，对于大气CO2每年对称增加和减少1%的模式模拟，由于深海对先前增加的大气CO2的滞后响应，在净负排放期间，温度变化（ΔT）与累积CO2排放（CE）的关系是非线性的。当对这种滞后响应进行校正时，或者如果在系统与先前的CO2增加平衡之后应用CO2下降，则在净负CO2排放期间，ΔT与CE的关系接近线性。因此，可以计算正和净负CO2排放期的比例常数--瞬态气候对累积碳排放的响应（TCRE）。我们发现，在模拟与大气中的CO2的对称的每年增加和减少1%的TCRE是向上大于向下的CO2轨迹，这表明，积极的CO2排放是更有效的变暖比负排放在随后的冷却。我们还发现，负CO2排放的冷却效果降低，如果应用在较高的大气CO2浓度。
Recent research has demonstrated that global mean surface air warming is approximately proportional to cumulative CO2 emissions. This proportional relationship has received considerable attention, as it allows one to calculate the cumulative CO2 emissions (‘carbon budget’) compatible with temperature targets and is a useful measure for model inter-comparison. Here we use an Earth system model to explore whether this relationship persists during periods of net negative CO2 emissions. Negative CO2 emissions are required in the majority of emissions scenarios limiting global warming to 2 °C above pre-industrial, with emissions becoming net negative in the second half of this century in several scenarios. We find that for model simulations with a symmetric 1% per year increase and decrease in atmospheric CO2, the temperature change (ΔT) versus cumulative CO2 emissions (CE) relationship is nonlinear during periods of net negative emissions, owing to the lagged response of the deep ocean to previously increasing atmospheric CO2. When corrected for this lagged response, or if the CO2 decline is applied after the system has equilibrated with the previous CO2 increase, the ΔT versus CE relationship is close to linear during periods of net negative CO2 emissions. A proportionality constant—the transient climate response to cumulative carbon emissions (TCRE)− can therefore be calculated for both positive and net negative CO2 emission periods. We find that in simulations with a symmetric 1% per year increase and decrease in atmospheric CO2 the TCRE is larger on the upward than on the downward CO2 trajectory, suggesting that positive CO2 emissions are more effective at warming than negative emissions are at subsequently cooling. We also find that the cooling effectiveness of negative CO2 emissions decreases if applied at higher atmospheric CO2 concentrations.
影响因子：
4.3
作者：
Eby, M.;Weaver, A. J.;Zhao, F.
通讯作者：
Zhao, F.