In what he calls the most significant step the U.S. has ever taken to fight global warming, President Barack Obama has said that he will impose even steeper cuts on greenhouse gas emissions from U.S. power plants.

The move comes a year after Obama had proposed unprecedented carbon dioxide limits. In a video posted to Facebook, the President said that the limits being imposed were based on extensive data. Obama is of the view that without tough action, the world will face more extreme weather and escalating health problems like asthma. 

"Climate change is not a problem for another generation. Not anymore," Obama said, according to NBC News.

According to officials, who weren't authorized to comment by name and requested anonymity, Obama had mandated a 30-percent nationwide cut in carbon dioxide emissions by 2030, compared to 2005 levels in the initial proposal. However, the final version will require a 32-percent cut.

The news was applaued by environmental groups who termed it a historic move that proves the global effort against climate change is beginning in earnest. Hillary Rodham Clinton, Democratic presidential candidate, vowed to defend Obama's plan if she's elected to replace him.

"It will need defending. Because Republican doubters and defeatists - including every Republican candidate for president - won't offer any credible solution. The truth is, they don't want one," Clinton said in an effort to use her support for the plan to draw a contrast with her GOP competitors, reports the Associated Press.

Even before the rule has been finalized, more than a dozen states announced plans to fight it. Led by Senate Majority Leader Mitch McConnell of Kentucky, some Republican governors have declared that they won't comply. Non-compliance will result in a confrontation with the Environmental Protection Agency, which by law can force its own plan on states that fail to submit implementation plans.

Obama's move to reduce power plant emissions is seen as an effort to increase his credibility among nations whose commitments and support he needs to finalize a global climate treaty later this year in Paris. The U.S. has pledged to cut overall emissions by 26 percent to 28 percent by 2025, compared to 2005 as its contribution to that treaty, reports The Huffington Post.