AFP: The US East Coast is sweltering in a record-hot summer but it could endure twice as many sweaty days by mid-century without action on climate change, an environmental group said Wednesday. The US capital, Washington, is on track for 50 days in 2010 in which the mercury crosses 90 degrees Fahrenheit (32 Celsius), a number that could rise as high as 100 by 2050, the National Wildlife Federation said in a study. The group, which supports action against climate change, said that …