Increase in observed net carbon dioxide uptake by land and oceans during the past 50 years
Increase in observed net carbon dioxide uptake by land and oceans during the past 50 years
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DOI：
10.1038/nature11299
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发表时间：
2012-08-02
期刊：
影响因子：
64.8
通讯作者：
White, J. W. C.
中科院分区：
文献类型：
--
作者：
Ballantyne, A. P.;Alden, C. B.;White, J. W. C.
未来气候预测的最大不确定性来源之一是全球碳循环对气候变化的响应(1)。虽然目前约有一半的二氧化碳排放被陆地和海洋碳库吸收(2)，但模型预测这些碳库未来的碳吸收量将下降，从而导致碳-气候正反馈(3)。最近的几项研究表明，近几十年来，陆地（4-6）和海洋（7-10）的碳吸收率保持不变或有所下降。然而，其他工作对报告的下降提出了质疑（11-13）。在这里，我们使用全球尺度的大气CO2测量、CO2排放清单及其全部不确定性来计算过去50年全球CO2源和汇的变化。我们的质量平衡分析表明，在1960年至2010年期间，全球净碳吸收量每年显著增加约0.05亿吨碳，全球碳吸收量翻了一番，从每年2.4 +/- 0.8亿吨增加到5.0 +/- 9亿吨。因此，陆地和海洋碳汇不太可能在全球范围内减少。自1959年以来，人类向大气排放了大约3500亿吨碳，其中约55%进入了陆地和海洋。因此，确定增加全球碳吸收的机制和地点仍然是限制现代全球碳收支和预测未来碳-气候相互作用的关键挑战。
One of the greatest sources of uncertainty for future climate predictions is the response of the global carbon cycle to climate change(1). Although approximately one-half of total CO2 emissions is at present taken up by combined land and ocean carbon reservoirs(2), models predict a decline in future carbon uptake by these reservoirs, resulting in a positive carbon-climate feedback(3). Several recent studies suggest that rates of carbon uptake by the land(4-6) and ocean(7-10) have remained constant or declined in recent decades. Other work, however, has called into question the reported decline(11-13). Here we use global-scale atmospheric CO2 measurements, CO2 emission inventories and their full range of uncertainties to calculate changes in global CO2 sources and sinks during the past 50 years. Our mass balance analysis shows that net global carbon uptake has increased significantly by about 0.05 billion tonnes of carbon per year and that global carbon uptake doubled, from 2.4 +/- 0.8 to 5.0 +/- 0.9 billion tonnes per year, between 1960 and 2010. Therefore, it is very unlikely that both land and ocean carbon sinks have decreased on a global scale. Since 1959, approximately 350 billion tonnes of carbon have been emitted by humans to the atmosphere, of which about 55 per cent has moved into the land and oceans. Thus, identifying the mechanisms and locations responsible for increasing global carbon uptake remains a critical challenge in constraining the modern global carbon budget and predicting future carbon-climate interactions.