While carbon dioxide is often blamed for global warming, methane is actually 85 times more potent when it comes to trapping heat. (techtimes.com)
The U.S. Conference of Mayors said it strongly opposed Trump's action and vowed to continue efforts to reduce greenhouse gas emissions blamed for global warming. (chicagotribune.com)
The president has said he won't approve Keystone if it's found to significantly increase U.S. emissions of carbon dioxide, the chief greenhouse gas blamed for global warming. (businessinsider.com)