SCOTUS decreed that the U.S. EPA must decide whether the climate-change effects of carbon dioxide endanger public health, and, at long last, the agency is moving on that decision — kinda. In a letter to U.S. lawmakers Thursday, chief Stephen Johnson wrote that the EPA is writing proposed rules for regulation of CO2 emissions “from stationary and mobile sources” and will sometime this spring “present and request comment on the best available science including specific and quantifiable effects of greenhouse gases relevant to making an endangerment finding.” We can hardly wait.

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