What’s new in final version of Obama’s climate change plan?

President Barack Obama on Monday is set to unveil the final version of his comprehensive – and controversial – climate change policy.

The modified Clean Power Plan, which calls for significant cuts of carbon emissions from the nation’s power plants and for their replacement with lower-carbon resources, is expected to accommodate opposition to the initial version of the plan, which the Environmental Protection Agency proposed last year. The changes would include a later start date for enforcing the rule than originally suggested.

If enacted, the plan would represent the biggest step ever taken by an American president against global warming.

“Climate change is not a problem for another generation,” Obama said in a video posted early Sunday on the White House Facebook page. “Not anymore.”

In its initial version, the Clean Power Plan’s goal was to cut carbon emissions from power plants by 30 percent below 2005 levels by 2030. The EPA would start enforcing the rule in 2020, and states would be in charge of drafting their own plans to meet the target – “an attempt to be politically and practically flexible in implementation,” The Christian Science Monitor’s Peter Grier wrote.

The new version is expected to increase the carbon emissions reduction target to 32 percent while pushing the start date back to 2022. The EPA plans to achieve this partly by giving states credit for renewable energy projects launched in the next few years, Bloomberg reports. Experts also expect the EPA to clarify rules on interstate emissions trading as a way to help them meet carbon-reduction targets, and to revise earlier assumptions of how quickly states can swap coal for natural gas, according to Reuters.

“They will be updating information on renewables and efficiency to incorporate data that wasn’t included the first time around,” David Doniger, a director at the Natural Resources Defense Council, told the wire service. “That really ups what you can get out of those sources.”

The changes are in part a result of criticism from the energy and manufacturing industries and some energy-producing states, who have said that the original timeline for expanding natural gas pipelines and shutting down coal plants was too short and could result in power shortages and higher electricity costs for consumers.

Many Republicans and representatives of the coal industry have called the policy a “war on coal,” with GOP presidential candidates pledging to try and roll back the plan if elected, according to the New York Times.

Senate majority leader Mitch McConnell (R) of Kentucky has even urged governors to defy the EPA’s rule, and as of May at least 15 states were challenging the regulation in court.

The new rule “is in many ways stronger than the proposed rule, but at the same time gives states the flexibility they need,” an administration official who spoke on the condition of anonymity told the Times.

The Obama administration has already committed to reducing the country’s carbon emissions by 26 to 28 percent by 2025 ahead of a global climate change conference in Paris in December – a goal that some experts say will be impossible to achieve without making significant reforms in the power industry.

“The power sector remains the largest single source of [US] emissions,” Karl Hausker, a senior fellow at the Washington-based World Resources Institute’s Global Climate Program, told the Monitor in May. “You can’t get any serious reductions in the US total, unless you have a strong plan for the power sector.”