- “There is no doubt”: Exxon Knew CO2 Pollution Was A Global Threat By Late 1970s | DeSmog has uncovered Exxon corporate documents from the late 1970s stating unequivocally “there is no doubt” that CO2 from the burning of fossil fuels was a growing “problem” well understood within the company. http://www.desmogblog.com/2016/04/26/there-no-doubt-exxon-knew-co2-pollution-was-global-threat-late-1970s?utm_source=daily+carbon+briefing&utm_campaign=f809da4a48-cb_daily&utm_medium=email&utm_term=0_876aab4fd7-f809da4a48-303423917 74 comments worldnews