If governments are serious about climate change, a portion of oil and gas reserves of major energy companies would not be usable. Carbon Tracker has done an interesting analysis of this issue.
http://www.economist.com/news/business/21577097-either-governments-are-not-serious-about-climate-change-or-fossil-fuel-firms-are
http://www.economist.com/news/business/21577097-either-governments-are-not-serious-about-climate-change-or-fossil-fuel-firms-are