A gas flare burns at a fracking site in rural Bradford County, Pennsylvania January 9, 2012. REUTERS/Les Stone

(Reuters) – The U.S. electric industry knew as far back as 1968 that burning fossil fuels might cause global warming, but cast doubt on the science of climate change and ramped up coal use for decades afterward, an environmental watchdog group said on Tuesday.
The California-based Energy and Policy Institute, which opposes fossil fuels, cited documents it obtained. It said its research mirrors reporting conducted by InsideClimate News about Exxon Mobil’s early understanding of climate change, which triggered an investigation by New York’s Attorney General.
The documents released by the EPI showed the Edison Electric Institute industry group was warned at its annual convention in 1968 by a member of then-President Lyndon Johnson’s administration that carbon emissions from fossil fuels could change the climate and trigger “catastrophic effects.”
The electric industry’s research organization, the Electric Power Research Institute, then began studying the issue in the 1970s and produced its own research …