论文标题：Net carbon emissions from African biosphere dominate pan-tropical atmospheric CO2 signal

期刊：Nature Communications

作者：Paul I. Palmer,Liang Feng,David Baker,Frédéric Chevallier,Hartmut Bösch,Peter Somkuti

发表时间：2019/08/13

数字识别码：10.1038/s41467-019-11097-w

微信链接：https://mp.weixin.qq.com/s/cd2_ICqu1HP-DbItb81qtA

《自然-通讯》发表的一项研究Net carbon emissions from African biosphere dominate pan-tropical atmospheric CO2 signal通过卫星观测发现，位于热带的北非其二氧化碳（CO2）排放量比之前想得更多。研究结果使热带地区成了这种温室气体的意外净源。

图1：来自热带南美洲和热带非洲的CO2通量。图源：Palmer等

热带地区陆地生态系统的植被和土壤碳储量巨大。这些碳最后或继续封存在生物圈里，或以CO2的形式释放到大气中。由于该地区的测量数据稀少，研究人员一直难以预测这些碳的去向。

英国爱丁堡大学的Paul Palmer和同事利用多个卫星的观测数据，绘制了从2009到2017年期间，整个热带地区CO2排放的季节性趋势。虽然热带亚洲、澳大利亚、南美洲都是吸收和储存CO2的碳汇，但热带非洲每年大约会排放1.25万亿千克的碳，远超此前估计的水平。作者认为，持续土地退化导致的土壤中CO2的排放或在观测结果中占据了主要部分。

根据这些研究结果，有必要在发现此前未知的高排放地区后，对《巴黎协定》等气候变化缓解策略进行重新审视。天然CO2汇持续发挥作用可以极大地帮助实现这些策略的目标。不过，从热带地区大量CO2的意外排放来看，人为诱导的变化或将阻碍这些目标的实现。

摘要：Tropical ecosystems are large carbon stores that are vulnerable to climate change. The sparseness of ground-based measurements has precluded verification of these ecosystems being a net annual source (+ve) or sink (−ve) of atmospheric carbon. We show that two independent satellite data sets of atmospheric carbon dioxide (CO2), interpreted using independent models, are consistent with the land tropics being a net annual carbon emission of (medianmaximumminimum)(medianminimummaximum) 1.03+1.73−0.201.03−0.20+1.73 and 1.60+2.11+1.391.60+1.39+2.11petagrams (PgC) in 2015 and 2016, respectively. These pan-tropical estimates reflect unexpectedly large net emissions from tropical Africa of 1.48+1.95+0.801.48+0.80+1.95 PgC in 2015 and 1.65+2.42+1.141.65+1.14+2.42 PgC in 2016. The largest carbon uptake is over the Congo basin, and the two loci of carbon emissions are over western Ethiopia and western tropical Africa, where there are large soil organic carbon stores and where there has been substantial land use change. These signals are present in the space-borne CO2 record from 2009 onwards.

（来源：科学网）