Prompt rewetting of drained peatlands reduces climate warming despite methane emissions

Peatlands are strategic areas for climate change mitigation because of their matchless carbon stocks. Drained peatlands release this carbon to the atmosphere as carbon dioxide (CO2). Peatland rewetting effectively stops these CO2 emissions, but also re-establishes the emission of methane (CH4). Essentially, management must choose between CO2 emissions from drained or CH4 emissions from rewetted peatland. This choice must consider radiative effects and atmospheric lifetimes of both gases, with CO2 being a weak but persistent and CH4 a strong but short-lived greenhouse gas. The resulting climatic effects are, thus, strongly time-dependent. We used a radiative forcing model to compare forcing dynamics of global scenarios for future peatland management using areal data from the Global Peatland Database. Our results show that CH4 radiative forcing does not undermine the climate change mitigation potential of peatland rewetting. Instead, postponing rewetting increases the long-term warming effect of continued CO2 emissions. Warnings against CH4 emissions from rewetted peatlands are therefore unjustified and counterproductive.