President Obama said the rule to cut carbon emissions his Environmental Protection Agency proposed Monday would bolster economic growth while also improving public health by reducing exposure to pollutants linked to respiratory and heart ailments.

The proposed rule amounts to the largest agency action ever on climate change, as it would call for reducing carbon emissions 30 percent below 2005 levels at 1,000 power plants by 2030.

While emissions are at their lowest in two decades and have declined 16 percent below 2005 levels, Obama noted in a conference call to reporters that "it's just not good enough" and that tackling emissions presents an "important opportunity" to grow the economy through innovation into cleaner energy sources.

Obama, who didn't take questions during the call, said acting on climate was essential to ensure "future generations are able to enjoy this beautiful blue ball in the middle of space that we’re a part of." He also praised the rule's flexibility, as the EPA will allow states to use a menu of options as a credit toward meeting the standard.

The Obama administration is portraying the proposed rule, scheduled for finalization in June 2015 with states filing implementation plans that must get EPA approval a year later, as an economic winner. It's rolling the rule out during a tenuous time for congressional Democrats, as a handful of Senate Democrats in red-leaning states are wary that the proposed rule could give their GOP opponents ammunition heading into November.

The White House is urging Democrats to go on the offensive and to tout the proposed rule's EPA-estimated $90 billion in climate- and health-related benefits. Much of those gains would come from reducing smog-forming pollutants from coal-fired power plants that contribute to asthma and heart attacks, and through mitigating exposure to extreme weather some scientists have linked to climate change.

"You should expect that there is going to be a heated debate in Washington," Obama said, adding that opponents to the rule would "try to make spin overwhelm substance."

Republicans and several industry groups, however, said it was the White House that was throwing curveballs.

“The president's plan is nuts, there's really no more succinct way to describe it. Americans are still asking ‘where are the jobs?' and here he is proposing rules to ship jobs overseas for years to come," House Speaker John Boehner, R-Ohio, said in a statement that said the proposed rule would raise electricity prices.

The EPA, for its part, said that electricity prices would on average be 8 percent lower by 2030 if states pursued certain energy efficiency policies.

But manufacturing and other industry groups were more skeptical, saying the rule had the potential to raise electricity rates in some parts of the country.

And American Electric Power, a coal-reliant utility that operates in 11 states, noted that some states would have to curb emissions more than others to achieve the EPA's goal of slashing emissions 30 percent by 2030.

"It appears that for many states where we operate, the reduction requirements could be much more than 30 percent by 2030. Climate change is a global issue, and some states should not bear a disproportionate share of the cost of U.S. action to cut emissions," the Columbus, Ohio-based utility said in a statement.