His actions on climate change have faced opposition from Republicans and even some Democrats who fear the impacts on the US economy. The issue is already being raised among candidates for next year’s presidential election, as much of the work will lie with his successor. Democratic front-runner Hillary Clinton has already expressed support.
Opponents plan to sue, and to ask the courts to block the rule temporarily. Many states have threatened not to comply.
The Obama administration last year proposed the first greenhouse gas limits on existing power plants in US history, triggering a year-long review. These final changes aim to address concerns raised by both environmentalist and the energy industry.
Some changes further cut the heat-trapping gases blamed for global warming. Other changes delay implementation and eliminate certain options that states could use to show they’re cutting emissions, making it harder to comply.
Some states will be given a more lenient target, while others will have tougher targets to meet. The Obama administration has yet to disclose those state-specific targets.
Power plants will have to attain an even lower level of carbon dioxide pollution to be in compliance. Mr Obama’s proposal from last year set the target as a 30 per cent nationwide cut by 2030, compared to the levels in 2005. His new plan calls for a 32 per cent cut in the same time period.
Left unchanged is Mr Obama’s overall goal for US emissions cuts from all sources of pollution. As the US commitment to a major global climate treaty that Mr Obama is championing, the US committed to cutting its emissions 26 per cent to 28 per cent by 2030, compared to 2005.
Power plants account for roughly one-third of all US emissions of the heat-trapping gases blamed for global warming, making them the largest single source.
Obama’s revised plan relies more heavily on renewable energy sources like wind and solar replacing dirtier coal-fired power plants. Mr Obama now wants the US to get 28 per cent of its power from renewables by 2030, compared to 22 per cent in his earlier proposal.