Datensatz

Zusammenfassung

The global distribution of potential wetlands and their methane (CH₄) emissions at the present-day and the Last Glacial Maximum (LGM) are estimated using a GCM simulation of LGM climate, a vegetation model, and simple algorithms for determining wetland area based on topography and soil moisture, and CH₄ emissions based on ecosystem carbon turnover in wet soils. LGM wetland area was 15% larger than present, but CH₄ emissions were 24% less. Extensive wetlands were simulated on the exposed continental shelves. The soil CH₄ sink was simulated as 14 Tg now but <0.5 Tg at the LGM. CH₄ emissions at LGM were limited by substrate availability, in turn due to low atmospheric CO₂. The glacial-interglacial change in atmospheric CH₄ concentration cannot be completely attributed to changes in the wetland source.