Prompt rewetting of drained peatlands reduces climate warming despite methane emissions.

Abstract

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 through continued CO₂ emissions.