The U.S. Supreme Court on Thursday dealt a major blow to the Environmental Protection Agency's power to regulate carbon emissions that cause climate change. The decision by the conservative court majority sets the stage for further limitations on the regulatory power of other agencies as well.

By a vote of 6 to 3, the court said that any time an agency does something big and new – in this case addressing climate change – the regulation is presumptively invalid, unless Congress has specifically authorized regulating in this sphere.

"That's a very big deal because they're not going to get it from Congress because Congress is essentially dysfunctional," said Harvard law professor Richard Lazarus, an expert on environmental law. "This could not have come at a worse time" because "the consequences of climate change are increasingly dire and we're running out of time to address it."...

In other words, an agency "can't simply retrofit an old statute to create new tools or new mechanisms" to address a problem that is generally within the agency's jurisdiction...

The issue before the court was how the EPA can regulate coal-fired power plants, which in this country are the single largest source of carbon emissions that cause climate challenge...

The decision, for instance, casts a cloud of doubt over a proposed Securities and Exchange Commission rule that would require companies offering securities to the public to disclose climate-related risks – like severe weather events that have or likely will affect their business models. Also in jeopardy is a new interim rule adopted by the Federal Energy Regulatory Commission "aimed at treating greenhouse gas emissions and their contribution to climate change the same as all other environmental impacts [the Commission] considers."...