Greenhouse gas emissions intensity of global croplands
Greenhouse gas emissions intensity of global croplands
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DOI：
10.1038/nclimate3158
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发表时间：
2017-01-01
影响因子：
30.7
通讯作者：
West, Paul C.
中科院分区：
文献类型：
--
作者：
Carlson, Kimberly M.;Gerber, James S.;West, Paul C.
随着农业需求的增长，稳定农田温室气体（GHG）排放是减缓气候变化的一个关键组成部分（1-3）。排放强度指标——包括生产每千卡热量的二氧化碳当量排放量（“生产强度”）——可以突出区域、管理做法和作物作为潜在的缓解重点（4-7）。然而，排放强度的空间分布和作物分布一直不确定。在此，我们建立了2000年前后全球特定作物的温室气体排放和温室气体强度的高空间细节估计，报告了稻田管理、泥炭地排水和氮肥对CH4、CO2和N- 2o排放的影响。全球平均生产强度为0.16 Mg CO(2) / M kcal(-1)，但某些种植方式对排放的贡献不成比例。泥炭地排放(3.7 Mg CO（2) / M kcal(-1)）——集中在欧洲和印度尼西亚——占这些农田排放的32%，尽管泥炭地只产生作物总千卡的1.1%。甲烷排放(0.58 Mg CO（2) / M kcal(-1)）是一种重要的主食，提供15%的作物总千卡热量，占农田排放的48%，越南的生产强度过大。相比之下，施用氮肥产生的N2O排放量(0.033 Mg CO（2)e M kcal(-1)）仅占农田排放量的20%。我们发现，目前的温室气体总排放量在很大程度上与作物和国家的生产强度无关。因此，气候缓解政策应针对作物排放高、强度高的地区。
Stabilizing greenhouse gas (GHG) emissions fromcroplands as agricultural demand grows is a critical component of climate change mitigation(1-3). Emissions intensity metrics-including carbon dioxide equivalent emissions per kilocalorie produced ('production intensity')-can highlight regions, management practices, and crops as potential foci for mitigation(4-7). Yet the spatial and crop-wise distribution of emissions intensity has been uncertain. Here, we develop global crop-specific circa 2000 estimates of GHG emissions and GHG intensity in high spatial detail, reporting the effects of rice paddy management, peatland draining, and nitrogen (N) fertilizer on CH4, CO2 and N-2O emissions. Global mean production intensity is 0.16 Mg CO(2)e M kcal(-1), yet certain cropping practices contribute disproportionately to emissions. Peatland drainage (3.7 Mg CO(2)e M kcal(-1))-concentrated in Europe and Indonesia-accounts for 32% of these cropland emissions despite peatlands producing just 1.1% of total crop kilocalories. Methane emissions fromrice (0.58 Mg CO(2)e M kcal(-1)), a crucial food staple supplying 15% of total crop kilocalories, contribute 48% of cropland emissions, with outsized production intensity in Vietnam. In contrast, N2O emissions from N fertilizer application (0.033 Mg CO(2)e M kcal(-1)) generate only 20% of cropland emissions. We find that current total GHG emissions are largely unrelated to production intensity across crops and countries. Climate mitigation policies should therefore be directed to locations where crops have both high emissions and high intensities.