IMPACT OF CLIMATE-CHANGE ON GRASSLAND PRODUCTION AND SOIL CARBON WORLDWIDE

The impact of climate change and increasing atmospheric CO2 was modell ed for 31 temperate and tropical grassland sites, using the CENTURY mo del. Climate change increased net primary production, except in cold d esert steppe regions, and CO2 increased production everywhere. Climate change caused soil carbon to decrease overall, with a loss df 4 Pg fr om global grasslands after 50 years. Combined climate change and eleva ted CO2 increased production and reduced global grassland C losses to 2 Pg, with tropical savannas becoming small sinks for soil C. Detectio n of statistically significant change in plant production would requir e a 16% change in measured plant production because of high year to ye ar variability in plant production. Most of the predicted changes in p lant production are less than 10%.