Climate Central: The proposed Keystone XL Pipeline and the greenhouse gases that would be released because of it have been at the heart of the debate over whether the pipeline should be built in the U.S. since it was first proposed in 2008.
The U.S. State Department estimated in its final environmental review of Keystone XL that the pipeline would lead to the emission of between 1 million and 27 million tons of carbon dioxide annually, but won't significantly worsen climate change.
A new study published Sunday...