Climate change-induced peatland drying in Southeast Asia
Climate change-induced peatland drying in Southeast Asia
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DOI：
10.1088/1748-9326/ac7969
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发表时间：
2022-07-01
影响因子：
6.7
通讯作者：
Konings, Alexandra G.
中科院分区：
文献类型：
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作者：
Dadap, Nathan C.;Cobb, Alexander R.;Konings, Alexandra G.
当有机泥炭土足够干燥时，它们就会变得易燃。在东南亚泥炭地，大面积的森林砍伐和相关的排水造成了干旱条件，再加上厄尔尼诺导致的干旱，导致灾难性的火灾事件，向大气中释放大量的碳和致命的烟雾。虽然人为降解对泥炭湿度和火灾风险的影响已经得到了广泛的证明，但气候变化对泥炭可燃性的影响却知之甚少。这些影响可能主要通过土壤湿度的变化来调节。在这里，我们使用神经网络（训练来自NASA土壤湿度主动式被动卫星的数据）来模拟土壤湿度作为气候、退化和位置的函数。在RCP8.5强迫下，利用区域气候模式预估1985—2005年和2040—2060年的气候情景对神经网络进行了土壤湿度变化的预测。我们发现，降水减少和蒸发需求增加将导致土壤湿度中位数下降，降幅约为2015年和2019年厄尔尼诺干旱期间观测到的降幅的一半。根据以前的研究，这种减少可能会加速泥炭碳的排放。我们的研究结果还表明，与其他土地利用类型相比，树木覆盖较少的退化地区的土壤湿度可能对气候变化更为敏感，这促使泥炭地紧急恢复。气候变化可能在未来的土壤湿度状况中发挥重要作用，进而影响东南亚泥炭地未来的泥炭火灾。
When organic peat soils are sufficiently dry, they become flammable. In Southeast Asian peatlands, widespread deforestation and associated drainage create dry conditions that, when coupled with El Nino-driven drought, result in catastrophic fire events that release large amounts of carbon and deadly smoke to the atmosphere. While the effects of anthropogenic degradation on peat moisture and fire risk have been extensively demonstrated, climate change impacts to peat flammability are poorly understood. These impacts are likely to be mediated primarily through changes in soil moisture. Here, we used neural networks (trained on data from the NASA Soil Moisture Active Passive satellite) to model soil moisture as a function of climate, degradation, and location. The neural networks were forced with regional climate model projections for 1985-2005 and 2040-2060 climate under RCP8.5 forcing to predict changes in soil moisture. We find that reduced precipitation and increased evaporative demand will lead to median soil moisture decreases about half as strong as those observed during recent El Nino droughts in 2015 and 2019. Based on previous studies, such reductions may be expected to accelerate peat carbon emissions. Our results also suggest that soil moisture in degraded areas with less tree cover may be more sensitive to climate change than in other land use types, motivating urgent peatland restoration. Climate change may play an important role in future soil moisture regimes and by extension, future peat fire in Southeast Asian peatlands.