In a move expected to result in years of legal wrangling, President Obama yesterday announced the most ambitious plan yet to sharply cut carbon pollution emitted by power plants.

The president said it was "the single most important step America has ever taken in the fight against global climate change."

The proposal calls for a 32 percent reduction from 2005 levels over the next 15 years – an increase from the 30 percent cut Obama called for last year. Under the latest version, states will have more time to comply with the requirement.

Obama said; "No challenge poses a greater threat to our future, and future generations, than a changing climate.”

The White House says that by 2030, the strategy will prevent up to 3,600 premature deaths; 90,000 asthma attacks in children and 300,000 missed workdays and schooldays.

"We are pleased to see that President Obama’s commitment to addressing the growing impacts of climate change is coming to fruition,” said Christine McEntee, executive director and CEO of the American Geophysical Union. “When it comes to climate change, its causes and its impacts, the science is clear and the scientific community is in agreement. We cannot continue to delay action. The costs are too high.”

Opponents say the plan will cost jobs and increase energy prices. United Mine Workers of America (UMWA) president Cecil E. Roberts said the rule will cause suffering on coal miners and their families, primarily in Appalachia.

"These hard-working miners have given their health, their limbs and far too often their lives to create the foundation of the America we live in today,” said Roberts. “We cannot solve global climate change on their backs. They deserve much better than the fate this rule has in store in them.”

Obama also announced he will become the first president to visit the Alaskan Arctic in order to draw attention to the impact of climate change.