Loss of carbon absorption another impact of drought

The latest issue of Science carries some concerning research showing a reduction in the level of trees/plants to provide carbon sinks for the planet. Drought and changed rainfall patterns have apparently led to this reduction of plant coverage but this in turn places an urgent emphasis on taking steps to replace plant loss as well as develop other alternative methods to capture carbon emissions.

Science 20 August 2010:

Vol. 329. no. 5994, pp. 940 - 943
DOI: 10.1126/science.1192666

Drought-Induced Reduction in Global Terrestrial Net Primary Production from 2000 Through 2009
Maosheng Zhao* and Steven W. Running

Terrestrial net primary production (NPP) quantifies the amount of atmospheric carbon fixed by plants and accumulated as biomass. Previous studies have shown that climate constraints were relaxing with increasing temperature and solar radiation, allowing an upward trend in NPP from 1982 through 1999. The past decade (2000 to 2009) has been the warmest since instrumental measurements began, which could imply continued increases in NPP; however, our estimates suggest a reduction in the global NPP of 0.55 petagrams of carbon. Large-scale droughts have reduced regional NPP, and a drying trend in the Southern Hemisphere has decreased NPP in that area, counteracting the increased NPP over the Northern Hemisphere. A continued decline in NPP would not only weaken the terrestrial carbon sink, but it would also intensify future competition between food demand and proposed biofuel production.

Numerical Terradynamic Simulation Group, Department of Ecosystem and Conservation Sciences, the University of Montana, Missoula, MT 59812, USA.