"These costs will take the form of either greater damages from climate change or higher costs associated with implementing more rapid reductions in greenhouse gas emissions. In practice, delay could result in both types of costs," the report said.
While there's much uncertainty as to how much global temperatures could rise in a given period, White House officials said that's no reason to not take action, noting that waiting a decade to act would increase mitigation costs 40 percent.
"A range of economic literature has shown this uncertainty is an argument for basically buying insurance today," said Jason Furman, chairman of the White House Council of Economic Advisers.
The justification was this: Once the economic effects of climate change take root, playing catch-up becomes more expensive.
It will be harder to control the effects of climate change once more carbon dioxide gets baked into the atmosphere, the report noted. That would come at a cost of deferred investment in low-carbon technology and research, along with damages such as decreased agricultural productivity and battered coastlines.
Pooling from 16 studies that used a range of climate models, the report found that global economic output would fall 0.9 percent if temperatures rose 3 degrees Celsius, rather than 2 degrees, above pre-industrial levels by 2100. For the United States alone, 0.9 percent of gross domestic product equaled roughly $150 billion in 2014 dollars, the report noted.
The report comes as the White House is ramping up efforts to promote its climate policies as a model for other nations ahead of international negotiations next year in Paris, where countries will seek enough carbon-cutting commitments by 2020 to avoid a 2 degree Celsius increase by century's end.
"These costs are not one-time: they are incurred year after year because of the permanent damage caused by additional climate change resulting from the delay," the report said.
The Environmental Protection Agency is holding a series of public hearings across the country this week to defend its proposed carbon emissions rule for power plants. The effort also will get an airing at a Senate Environment and Public Works Subcommittee on Clean Air and Nuclear Safety hearing Tuesday, which will touch on economic risks posed by climate inaction.
"We don’t have to sacrifice a healthy economy for a healthy environment," she said in a Monday call with reporters.
Congressional Republicans and some industry groups disagree, at least so far as the EPA's proposal goes, which aims to cut the power sector's emissions 30 percent below 2005 levels by 2030. They say that the rule would handcuff the economy if other nations fail to enact similar restrictions.
"Administrator McCarthy clearly must only be listening to her friends in the environmental community, as she noted earlier today the ‘overwhelming support’ for flexibility these standards will offer while going so far as forecasting economic growth and prosperity, if implemented. The funny thing is she has yet to back up those claims with facts, and we all know that is probably because they simply don’t add up," said Laura Sheehan, senior vice president for communications at the American Coalition for Clean Coal Electricity.
But McCarthy said the Obama administration's proposal is "changing the tone" of climate discussions in the international arena.
John Podesta, a White House adviser who has taken a lead role on the administration's climate policy, said that China has grown serious about making significant carbon reductions as a way to address domestic air quality concerns.
"I think the fact that the U.S. exercised a lot of leadership under the climate action plan ... certainly caught their attention," Podesta said.
White House officials announced more actions Tuesday designed to tackle greenhouse gas emissions, this time hitting methane, a short-lived greenhouse gas that is 24 times more potent than carbon dioxide.
Dan Utech, President Obama's top climate and energy adviser, said the Energy Department would roll out two measures aimed at reducing leaks from aging pipelines that carry the fuel. The DOE will offer grants for developing technology to detect methane leaks, and it will release a new framework for an existing voluntary program to improve infrastructure efficiency.
The news comes just days after an EPA inspector general report said federal regulators aren't doing enough to stop methane leaks.