Land use related sources of greenhouse gases: Present emissions and possible future trends

Abstract

Atmospheric carbon dioxide, which causes 50% of greenhouse warming, is increasing by 0.5% per year. Reducing and reversing deforestation would slow the increase, but plantations the size of Europe would sequester only 20–30% of the accumulation. Methane's concentration is increasing at a rate of 1% per year, and 70–90% comes from biotic sources. Even if drastic reductions in the world's cattle population, slash and bum agriculture and fuelwood burning could be achieved, CH 4 would probably continue to increase. Atmospheric nitrous oxide, with almost exclusively biotic sources, contributes 5% to global warming and is increasing at 0.2–0.3% per year. The causes are poorly understood, but reductions in the use of N fertilizer and careful soil management may be effective.