Large-scale reductions in gross primary productivity and evapotranspiration caused by the 2012 US drought

Drought severely impacts biosphere-atmosphere carbon and water fluxes of terrestrial ecosystems by reducing productivity, carbon uptake and water transport to the atmosphere. The 2012 US drought was among the most intense and widespread drought events in the US since the ‘Dust Bowl' period in the 1930s. Drought conditions started developing during an exceptionally warm spring, intensified throughout the summer and were most severe in the Central US (Great Plains), with devastating effects on agricultural production. We synthesize the impact of the 2012 drought on ecosystem carbon and water fluxes across the Contiguous United States using eddy covariance data from 30 AmeriFlux sites and remote sensing data from MODIS. We found widespread reductions in gross primary productivity and evapotranspiration of more than 30% in the Great Plains and beyond during the summer months. Drought intensity and duration were directly linked to these changes in ecosystem fluxes. As drought frequencies and intensities are predicted to increase in the future, we discuss the implications of our results for drought susceptibilities of different land-use types.