If temperature varies strongly from day to day, the economy grows less. Through these seemingly small variations climate change may have strong effects on economic growth. This shows data analyzed by researchers from the Potsdam Institute for Climate Impact Research (PIK), Columbia University and the Mercator Research Institute on Global Commons and Climate Change (MCC). In a new study in Nature Climate Change, they juxtapose observed daily temperature changes with economic data from more than 1,500 regions worldwide over 40 years—with startling results.