Failure to act on climate change could cause an estimated 57,000 deaths in the United States from poor air quality by 2100, the Obama administration has argued in a new report that warns of dire effects of global warming.
Monday's report underscores the costs of inaction on climate change as well as the benefits from taking action now.
The report comes as Republicans in Congress seek to undo the administration's environmental policies, including an expected plan by the Environmental Protection Agency to target coal-fired power plants, and days after Pope Francis issued a stern warning about global warming's consequences, especially for the poor and under-developed nations.
The White House report is part of a week-long effort to emphasize climate change to mark the two-year anniversary of a "climate action plan" announced by President Barack Obama.
While the most severe effects of global warming would not be felt for decades, the Obama administration said decisions about climate change need to be made now.
"Decisions are not going to wait 50 years," EPA Administrator Gina McCarthy told reporters at a White House briefing. "They are today's decisions."
The report says actions to slow climate change could save about $US3.1 billion ($A3.99 billion) in expected costs from sea-level rise and storm surge in 2100.
Actions begun in the next few years could reduce droughts by at least 40 per cent by 2100 and save an estimated 6 to 8 million acres from being burned by wildfires, the report said.
The Republican-controlled House is expected to vote this week on a bill to scale back the plan on coal-fired power plants, the centrepiece of Obama's second-term push to act on climate change as a key part of his environmental legacy.
The bill would allow states to opt out of the plan if the governor determines it would cause significant rate hikes for electricity or harm reliability of service in the state.
Obama has managed to thwart Republican efforts in the past, but they are renewing their efforts now that they control the Senate as well as the House.
