Drought-Induced Reduction in Global Terrestrial Net Primary Production from 2000 Through 2009
Terrestrial net primary productivity (NPP, the amount of atmospheric carbon fixed by plants and accumulated as biomass) increased from 1982 through 1999, which has been attributed to factors such as nitrogen deposition, CO2 fertilization, forest regrowth, and climatic changes. Zhao and Running (p. 940) used satellite data to estimate global terrestrial NPP over the past decade and found that the earlier trend has been reversed and that NPP has been decreasing. Combining this result with climate change data suggests that large-scale droughts are responsible for the decline. Future widespread droughts caused by global warming may thus further weaken the terrestrial carbon sink.