Widespread subsidence and carbon emissions across Southeast Asian peatlands
Widespread subsidence and carbon emissions across Southeast Asian peatlands
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DOI：
10.1038/s41561-020-0575-4
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发表时间：
2020-06-04
影响因子：
18.3
通讯作者：
Harvey, Charles F.
中科院分区：
文献类型：
--
作者：
Hoyt, Alison M.;Chaussard, Estelle;Harvey, Charles F.
根据东南亚的大规模高分辨率遥感数据，热带泥炭地的沉降和碳排放主要与排水历史有关，而不是与土地利用类型有关。在过去的三十年里，东南亚2500万公顷热带泥炭地中的大部分都被砍伐和排水。因此，地下水位下降使泥炭暴露于氧化，将数千年积累的植物物质转化为二氧化碳，并导致地面沉降。在这里，我们量化了广泛的泥炭碳损失，使用干涉合成孔径雷达遥感地图沉降在90米的分辨率在2.7 Mha的泥炭地面积从2007年至2011年。超过90%的调查区域正在下沉，平均速度为2.2厘米/年（-1）。因此，该地区现在面临着生产性土地的丧失和洪水，因为许多泥炭地接近海平面。我们的测量结果表明，小农农业区和退化泥炭地的沉降速度与种植园相当，沉降速度在远离河流的地方增加，在排水后随着时间的推移而减少。由于其详细的空间分辨率，干涉合成孔径雷达提供了一个宝贵的工具，可用于确定土地使用和地理方面的排放量，并确定热点，以便更好地进行管理。最后，我们使用遥感地图来更新IPCC的排放因子，并计算2015年泥炭氧化的区域CO2排放量为155 +/- 30 MtC yr（-1），与区域化石燃料排放和泥炭火灾的幅度相似。
Subsidence and carbon emissions in tropical peatlands are primarily linked to drainage history, not land-use type, according to large-scale high-resolution remote sensing in Southeast Asia.Over the last three decades, most of the 25 million hectares of tropical peatlands in Southeast Asia have been deforested and drained. As a consequence, declining water tables are exposing peat to oxidation, converting plant material accumulated over millennia to carbon dioxide, and causing land subsidence. Here, we quantify the widespread peat carbon loss by using InSAR remote sensing to map subsidence at 90-m resolution across 2.7 Mha of peatland area from 2007 to 2011. Over 90% of the surveyed area is subsiding, with a mean rate of 2.2 cm yr(-1). Consequently, the region now faces loss of productive land and flooding because many peatlands are near sea level. Our measurements reveal that smallholder agricultural areas and degraded peatlands are subsiding at rates comparable to those of plantations, and that subsidence rates increase away from rivers and decrease over time following drainage. Because of its detailed spatial resolution, InSAR provides a valuable tool to identify emissions by land use and geography and to target hotspots for better management. Finally, we use remotely sensed maps to update IPCC emissions factors and calculate regional CO2 emissions from peat oxidation of 155 +/- 30 MtC yr(-1) in 2015, similar in magnitude to both regional fossil-fuel emissions and peat fires.