Britain’s Conservative government on Wednesday approved the United Kingdom’s first new coal mine in three decades, a decision condemned by environmentalists as a leap backwards in the fight against climate change. Hours earlier, the government reversed a ban on building new onshore windfarms in Britain. Opponents called that announcement a cynical attempt to offset criticism of the mine decision. Cabinet Minister Michael Gove decided the mine in the Cumbria area of northwest England would have “an overall neutral effect on climate change and is thus consistent with government policies for meeting the challenge of climate change,” the government said. It said coal from the mine would be used to make steel — replacing imported coal — rather than for power generation. The mine will extract coking coal, the type used in steelmaking, from under the Irish Sea and process it on the site of a shuttered chemical plant in Whitehaven, …