Marshland conversion to cropland in northeast China from 1950 to 2000 reduced the greenhouse effect

摘要: It has been well recognized that converting wetlands to cropland results in loss of soil organic carbon (SOC), while less attention was paid concomitant changes methane (CH 4 ) and nitrous oxide (N 2 O) emissions. Using datasets from the literature field measurements, we investigated SOC emissions CH N O due marshland conversion northeast China. Analysis documented crop cultivation area indicated 2.91 Mha were converted over period 1950-2000. Marshland resulted ~240 Tg introduced ~ 1.4 138 Gg 0 cropland, reduced greatly marshland, cumulatively ~28 50 years. Taking into account O, global warming potential (GWP) at a 20-year time horizon estimated be ~180 CO 2_ eq.yr -1 1950s ~120 _eq.yr 1990s, with ~33% reduction. When calculated 100-year horizon, GWP ~73 _eq. yr ~58 ~21% concluded China greenhouse effect as far is concerned. This reduction attributed substantial decrease marshland. An extended inference declining growth rate atmospheric since 1980s might related wetlands, but this connection needs confirmed.