Errors in greenhouse forcing and soil carbon sequestration estimates in freshwater wetlands: a comment on Mitsch et al. (2013)
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Radiative forcing feedbacks from wetlands have been an important component of past climate change and will likely be so in the future, so accurately assessing the carbon (C) and radiative balances of wetlands remains an important research priority. This commentary shows that the paper by Mitsch et al. (Landscape Ecol 28:583–597, 2013) seriously underestimated the radiative forcing effect of methane (CH4) emissions and overestimated soil C sequestration in freshwater wetlands. The model that they used is flawed in double counting the atmospheric decay of CH4 and incorporating a single 100 year CH4 global warming potential. They also used a small number of sites and short-term soil dating that resulted in unrealistically high soil C sequestration rates, ignoring decay of the entire soil C pool and allochthonous inputs of C. They calculated the radiative balance instead of the radiative forcing of natural wetlands, making their calculations irrelevant to anthropogenic climate change. Irrespective of the radiative forcing of wetlands, they provide essential ecosystem services that are important to protect.
KeywordsWetlands Global warming potential Radiative forcing Methane Soil carbon sequestration
The comments of J. Patrick Megonigal, the associate editor, and two anonymous reviewers greatly improved this manuscript.
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