气候变化领域集成服务门户(CCPortal): Carbon emissions from cropland expansion in the United States

CCPortal

DOI	10.1088/1748-9326/ab0399
	Carbon emissions from cropland expansion in the United States
	Spawn S.A.; Lark T.J.; Gibbs H.K.
发表日期	2019
ISSN	17489318
卷号	14 期号:4
英文摘要	After decades of decline, croplands are once again expanding across the United States. A recent spatially explicit analysis mapped nearly three million hectares of US cropland expansion that occurred between 2008 and 2012. Land use change (LUC) of this sort can be a major source of anthropogenic carbon (C) emissions, though the effects of this change have yet to be analyzed. We developed a data-driven model that combines these high-resolution maps of cropland expansion with published maps of biomass and soil organic carbon stocks (SOC) to map and quantify the resulting C emissions. Our model increases emphasis on non-forest - i.e. grassland, shrubland and wetland - above and belowground biomass C stocks and the response of SOC to LUC - emission sources that are frequently neglected in traditional C accounting. These sources represent major emission conduits in the US, where new croplands primarily replace grasslands. We find that expansion between 2008-12 caused, on average, a release of 55.0 MgC ha-1 (SDspatial = 39.9 MgC ha-1), which resulted in total emissions of 38.8 TgC yr-1 (95% CI = 21.6-55.8 TgC yr-1). We also find wide geographic variation in both the size and sensitivity of affected C stocks. Grassland conversion was the primary source of emissions, with more than 90% of these emissions originating from SOC stocks. Due to the long accumulation time of SOC, its dominance as a source suggests that emissions may be difficult to mitigate over human-relevant time scales. While methodological limitations regarding the effects of land use legacies and future management remain, our findings emphasize the importance of avoiding LUC emissions and suggest potential means by which natural C stocks can be conserved. © 2019 The Author(s). Published by IOP Publishing Ltd.
英文关键词	agriculture; biofuels; carbon emissions; grassland; land use change; soil organic carbon; United States
语种	英语
scopus关键词	Agriculture; Biofuels; Forestry; Land use; Organic carbon; Sensitivity analysis; Carbon emissions; grassland; Land-use change; Soil organic carbon; United States; Magnesium compounds; agricultural extension; agricultural land; agricultural soil; anthropogenic effect; biofuel; carbon emission; carbon sequestration; grassland; grassland soil; land use change; soil carbon; United States
来源期刊	Environmental Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/154638
作者单位	Department of Geography, University of Wisconsin, Madison, United States; Center for Sustainability and the Global Environment, University of Wisconsin, Madison, United States
推荐引用方式 GB/T 7714	Spawn S.A.,Lark T.J.,Gibbs H.K.. Carbon emissions from cropland expansion in the United States[J],2019,14(4).
APA	Spawn S.A.,Lark T.J.,&Gibbs H.K..(2019).Carbon emissions from cropland expansion in the United States.Environmental Research Letters,14(4).
MLA	Spawn S.A.,et al."Carbon emissions from cropland expansion in the United States".Environmental Research Letters 14.4(2019).