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ARS Home » Plains Area » Mandan, North Dakota » Northern Great Plains Research Laboratory » Research » Publications at this Location » Publication #399641

Research Project: Sustainable Agricultural Systems for the Northern Great Plains

Location: Northern Great Plains Research Laboratory

Title: Variation in methodology obscures clarity of cropland global warming potential estimates

item Liebig, Mark
item BERGH, EMMA - University Of New Hampshire
item Archer, David

Submitted to: Journal of Environmental Quality
Publication Type: Review Article
Publication Acceptance Date: 3/2/2023
Publication Date: 5/8/2023
Citation: Liebig, M.A., Bergh, E.L., Archer, D.W. 2023. Variation in methodology obscures clarity of cropland global warming potential estimates. Journal of Environmental Quality. 52:549-557.

Interpretive Summary: Estimates of global warming potential can offer valuable insights into climate effects of agricultural systems. Global warming potential is a way to include the global warming impacts of multiple greenhouse gases. But assessments of global warming potential are complex. This can lead to differences in how global warming potential is estimated. To better understand how this important metric is estimated, we reviewed published literature reporting global warming potential estimates from cropland. The review found a broad range of approaches used to calculate global warming potential form cropland. To help people understand how estimates are derived, we propose a framework for presenting key metadata with global warming potential estimates. This would provide more transparency on how global warming potential estimates are calculated.

Technical Abstract: Global warming potential (GWP) estimates from agroecosystems are valuable for understanding management effects on climate regulation services. However, GWP estimates are complex, including attributes with high spatiotemporal variability. Published GWP estimates from cropland were compiled and methodological attributes known to influence GWP were extracted. Results revealed considerable diversity in approaches to estimate GWP. Among carbon balance methods, respiration methods were used most frequently (33%), followed by soil carbon stock change over time (30%). Twenty six percent of studies did not account for carbon change in GWP estimates. Duration of gas flux measurements ranged from 0.5 to 60 months, with weekly and sub-weekly sampling most common (34 and 33%, respectively). Carbon dioxide equivalent conversion factors generally aligned with IPCC recommendations through 2014 but diverged thereafter. This review suggests the need for increased transparency in how GWP estimates are derived and communicated. Presentation of key metadata alongside GWP estimates are recommended.