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 (CO ₂). Peatland rewetting effectively stops these CO ₂ emissions, but also re-establishes the emission of methane (CH ₄). Essentially, management must choose between CO ₂ emissions from drained, or CH ₄ emissions from rewetted, peatland. This choice must consider radiative effects and atmospheric lifetimes of both gases, with CO ₂ being a weak but persistent, and CH ₄ 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 CH ₄ radiative forcing does not undermine the climate change mitigation potential of peatland rewetting. Instead, postponing rewetting increases the long-term warming effect through continued CO ₂ emissions.

Abstract

Drained peatlands are sources of CO ₂, and though rewetting could curb emissions, this strategy results in elevated methane release. Here, the authors model peatland emissions scenarios and show that rewetting is a critical way to mitigate climate change despite potential methane increases.