The cost of heat waves and droughts for global crop production

Heat waves and droughts are a key risk to global crop production and quantifying the extent of this risk is essential for insurance assessment and disaster risk reduction. Here we estimate the cumulative production losses of six major commodity groups under both extreme heat and drought events, across 131 countries, over the time period of 1961-2014. Our results show substantial variation in national disaster risks that have hitherto gone unrecognised in regional and global average estimates. The most severe losses are represented by cereal losses in Angola (4.1%), Botswana (5.7%), USA (4.4%) and Australia (4.4%), oilcrop losses in Paraguay (5.5%), pulse losses in Angola (4.7%) and Nigeria (4.8%), and root and tuber losses in Thailand (3.2%). In monetary terms we estimate the global production loss over this period to be $237 billion US Dollars (2004-2006 baseline). The nations that incurred the largest financial hits were the USA ($116 billion), the former Soviet Union ($37 billion), India ($28 billion), China ($10.7 billion) and Australia ($8.5 billion USD). Our analysis closes an important gap in our understanding of the impacts of extreme weather events on global crop production and provides the basis for country relevant disaster risk reduction.