Hotter Temps = Lower Incomes

Global warming may reduce incomes in the United States, according to a National Bureau of Economic Research study (NBER Working Paper 20750, $5). In an analysis of 40 years of U.S. county-level data, the researchers find a productivity decline of 1.7 percent for every 1.8°F  rise in daily average temperature. "A weekday above 30°C (86°F) costs an average county $20 per person," they report, noting: "Hot weekends have little effect."