Causes of climate change over the past 1000 years
Causes of climate change over the past 1000 years
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DOI：
10.1126/science.289.5477.270
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发表时间：
2000-07-14
期刊：
影响因子：
56.9
通讯作者：
Crowley, TJ
中科院分区：
文献类型：
--
作者：
Crowley, TJ
最近重建的北方的温度和气候强迫在过去1000年允许变暖的世纪被放置在一个历史背景下，气候变化的各种机制进行测试。从能量平衡气候模式模拟的观测结果的比较表明，多达41%至64%的人为前（1850年前）十年尺度的温度变化是由于太阳辐照度和火山活动的变化。从重建的温度时间序列中去除强迫响应产生的残差显示出与耦合模型控制运行的残差相似的变异性，从而支持模型作为气候系统低频变异性估计值的价值。去除所有强迫，除了温室气体从类似的1000年的时间序列的结果在一个非常大的20世纪后期变暖，密切同意从温室气体强迫预测的响应残差。20世纪后期气温上升的独特程度，加上对自然变率作用的限制有所改善，进一步证明温室效应已经超过了气候系统中自然变率的水平。21世纪全球变暖的预测远远超过了过去1000年的自然变化，也超过了对末次间冰期全球温度变化的最佳估计。
Recent reconstructions of Northern Hemisphere temperatures and climate forcing over the past 1000 years allow the warming of the 20th century to be placed within a historical context and various mechanisms of climate change to be tested. Comparisons of observations with simulations from an energy balance climate model indicate that as much as 41 to 64% of preanthropogenic (pre-1850) decadal-scale temperature variations was due to changes in solar irradiance and volcanism. Removal of the forced response from reconstructed temperature time series yields residuals that show similar variability to those of control runs of coupled models, thereby lending support to the models' value as estimates of low-frequency variability in the climate system. Removal of all forcing except greenhouse gases from the similar to 1000-year time series results in a residual with a very large late-20th-century warming that closely agrees with the response predicted from greenhouse gas forcing. The combination of a unique level of temperature increase in the late 20th century and improved constraints on the role of natural variability provides further evidence that the greenhouse effect has already established itself above the level of natural variability in the climate system. A 21st-century global warming projection far exceeds the natural variability of the past 1000 years and is greater than the best estimate of global temperature change for the last interglacial.