Hoping to position the United States to take the lead in global negotiations later this year to combat climate change, President Barack Obama unveiled a bold plan on Monday to slash emissions of carbon dioxide from power stations at home by almost a third within 15 years.

Detailing the new regulations, dubbed America’s “Clean power plan”, Mr Obama asserted that “no challenge poses a greater threat to our future, the future generations, than the changing climate”. He warned: “We only get one planet; there is no plan B.” He noted that hitherto the federal government had never attempted to curb CO2 from power plants.

“This is one of those rare issues, because of its scope, that, if we don’t get it right, we may not be able to reverse; we may not be able adapt sufficiently,” Mr Obama said. “There is such a thing as being too late when it comes to climate change… The science tells us we have to do more.”

The landmark proposal, the biggest climate change measure ever attempted by the US, triggered an instant political and legal backlash as several states prepared to challenge the rules in the courts and Republican presidential runners accused Mr Obama of declaring war on the already beleaguered coal sector.

It means that climate change will take centre stage in the coming presidential election. In 2012, it barely featured. Hillary Clinton, the leading Democratic candidate, had already stated her support for the emissions plan. “It will need defending. Because Republican doubters and defeatists – including every Republican candidate for president – won’t offer any credible solution,” she said.

Whereas an earlier version of the plan required a 30 percent nationwide cut in carbon dioxide emissions by 2030, compared to 2005 levels, the final iteration toughens that target to 32 percent. Unchanged is the pledge Mr Obama will take to final negotiations for a global United Nations treaty on climate change in Paris in December to cut overall emissions from all sources of pollution by 26 to 28 percent by 2030.

The UN Secretary General Ban Ki-moon lauded the “visionary leadership” of Mr Obama. “We believe that this plan shows the United States’s determination to address global warming while also saving money and growing [economically],” Stéphane Dujarric, Mr Ban’s spokesperson, said. The power-plant rules as written would force US energy companies to retire hundreds of coal-fired plants across the country, a potentially devastating blow to the coal sector. States with big coal interests, notably Wyoming, Kentucky and West Virginia, are set to lead the effort to derail them.

The plan also puts an expanded emphasis on renewable sources of energy in place of coal and increasingly also of natural gas, putting the US on course to derive 28 percent of its power from sources such as solar and wind by 2030, compared to 22 percent in an earlier draft.

“Climate change will not be solved by grabbing power from states or slowly hollowing out our economy,” Jeb Bush, the former Florida Governor, said at the weekend. The National Mining Association formally requested that the plan be put on hold pending the outcome of legal challenges.

It is not clear that Republicans promising to fight the new regulations will necessarily be on the right side of popular American opinion. A New York Times poll conducted in January suggested that two-thirds of Americans are likely to favour politicians willing to address climate change.

President Obama’s announcement came as more than 20 wildfires raged across California in a fire season exacerbated by climate change and by a devastating drought, now deep into its fourth year.