PT - JOURNAL ARTICLE AU - Anke Günther AU - Alexandra Barthelmes AU - Vytas Huth AU - Hans Joosten AU - Gerald Jurasinski AU - Franziska Koebsch AU - John Couwenberg TI - Prompt rewetting of drained peatlands reduces climate warming despite methane emissions AID - 10.1101/748830 DP - 2019 Jan 01 TA - bioRxiv PG - 748830 4099 - http://biorxiv.org/content/early/2019/08/29/748830.short 4100 - http://biorxiv.org/content/early/2019/08/29/748830.full AB - Peatlands are strategic areas for climate change mitigation because of their matchless carbon stocks1–4. Drained peatlands release this carbon to the atmosphere as carbon dioxide (CO2) 5,6. Peatland rewetting effectively stops these CO2 emissions7,8 but also re-establishes the emission of methane (CH4) 9,10. Essentially, management must choose between CO2 emissions from drained or CH4 emissions from rewetted peatland. This choice must consider the radiative effects as well as the atmospheric lifetimes of both gases, with CO2 being a weak but persistent and CH4 a strong but short-lived greenhouse gas11. The resulting climatic effects are, thus, strongly time-dependent. Yet, common metrics like global warming potential (GWP) and its ‘sustained flux’ variants12,13 fail to account for temporal dynamics and how these relate to expected global warming dynamics.We used a radiative forcing model to compare forcing dynamics of global scenarios for future peatland management using areal data from the Global Peatland Database14. 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. Unlike CO2 (and N2O) from drained peatlands that accumulates in the atmosphere, possible CH4 emission spikes upon rewetting do not add to expected peak warming when rewetting occurs before 2050. Warnings against high CH4 emissions from rewetted peatlands9 are therefore unjustified.