Russia Browning: The 2010 Heat Wave Was Not an Isolated Event

Record-high temperatures and wildfires eliminated nearly a third of Russia's 2010 wheat crop. Similar crop losses in Ukraine and Kazakhstan, combined with a Russian export ban, roiled international grain markets. Here we show that the 2010 crop failures were not isolated events, but rather the continuation of a decade-long browning trend across much of the Eurasian "breadbasket". Over the period 2001-2010, we find that nearly 40% of the Eurasian wheat belt (EWB) exhibited significant negative trends in the Normalized Difference Vegetation Index (NDVI). The height of the Russian heat wave was caused by severe atmospheric blocking during July and August of 2010. However, we find highly negative NDVI anomalies during the early growing season preceding the onset of atmospheric blocking; suggesting that land surface feedbacks linked to early season drying amplified the blocking event's severity and duration. The unusually warm and dry early growing season preceding the heat wave was consistent with the highly negative phase of the North Atlantic Oscillation (NAO) which emerged in 2009/2010. We also find an empirical link between the NAO's recent downward trend and browning of the EWB. Recent evidence that receding Arctic sea ice is forcing a downward trend in the NAO suggests the possibility that global climate change played a role in the Russian heat wave. Food security models predicting that the EWB will contribute an increasing share of global wheat production due to climate-change effects including longer growing seasons and warmer winters may be unrealistic given observed trends.