(Reuters) - President Donald Trump will follow through on a campaign pledge to pull the United States out of a global pact to fight climate change, a source briefed on the decision told Reuters on Wednesday. U.S. carbon emissions fell last year to a 24-year-low and are expected to continue declining over the next decade as power companies keep shutting old coal plants to generate more electricity from natural gas and renewables. The U.S. Energy Information Administration projected total carbon dioxide (CO2) emissions from energy consumption would fall to 5,135 million metric tons in 2017, down from 5,171 million metric tons in 2016, lowest since 1992. 
Factbox: U.S. carbon emissions seen declining over next decade