US President Barack Obama has unveiled what he called “the biggest, most important step we have ever taken” in tackling climate change.

The aim of the revised Clean Power Plan is to cut greenhouse gas emissions from US power stations by nearly a third within 15 years.

The measures will place significant emphasis on wind and solar power and other renewable energy sources.

However, opponents in the energy industry have vowed to fight the plan.

“I’m convinced no challenge provides a greater threat to the future of the planet,” Mr Obama said. “There is such a thing as being too late.”

Those opponents say Mr Obama has declared “a war on coal”. Power plants fired by coal provide more than a third of the US electricity supply.

The revised plan will aim to cut carbon emissions from the power sector by 32% by 2030, compared with 2005 levels.

“We are the first generation to feel the impacts of climate change, and the last generation to be able to do something about it,” Mr Obama said. He likened the plan to taking 166 million cars off the road in terms of environmental impact. He called taking a stand against climate change a “moral obligation”.

Mr Obama brushed off the notion that the plan is a “War on Coal” that will kill jobs and said he is reinvesting in areas of the US known as “coal country”.

“Scaremonging” tactics will not work to stop the proposal, he said.

“If we don’t do it nobody will. America leads the way forward… that’s what this plan is about. This is our moment to get something right and get something right for our kids,” he said.