But Senators Maria Cantwell, Democrat of Washington, and Susan Collins, Republican of Maine, who jointly requested the report, said between the lines of a conservative government audit was an urgent economic message that Washington should heed.
“The Government Accountability Office — if you will, the chief bean counter — is basically telling us that this is costing us a lot of money,” Ms. Cantwell said. “We need to understand that as stewards of the taxpayer that climate is a fiscal issue, and the fact that it’s having this big a fiscal impact on our federal budget needs to be dealt with.”
The report, two years in the making, comes as the Senate prepares to vote this week on a $36.5 billion disaster-relief package to fund hurricane relief, a flood insurance program and wildfire recovery efforts in the West.
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Ms. Cantwell and Ms. Collins noted that the White House Office of Management and Budget had calculated that extreme weather events over the past decade cost the federal government $350 billion.
Both asserted that the study should help move Congress and the administration past partisan fights over the science of global warming and toward a search for solutions — something they said could be problematic given that the Trump administration is rolling back many of former President Barack Obama’s climate change initiatives.
“My hope is the administration will take a look at this report and realize there is an economic impact here that is significant,” Ms. Collins said. “We simply cannot afford the billions of dollars in additional funding that’s going to be needed if we do not take into account the consequences of climate change.”
The G.A.O. study draws on interviews with 26 scientific and economic experts and 30 studies, though it focuses most heavily on the only two national-scale studies analyzing the economic effects of climate change. One of them is an ongoing research project being produced by the Environmental Protection Agency, and the other is a study by several organizations led by the Rhodium Group that analyzed the potential costs associated with climate change in coastal property, health, agriculture, energy, labor productivity and crime.
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Trevor Houser, a partner at the Rhodium Group, which led the American Climate Prospectus study, said the accounting was on the conservative side. The agriculture analysis, for example, looked only at how changes in temperature and precipitation would affect four commodity crops. It did not study the fiscal fallout of events like wildfires and did not take into account the costs of infectious diseases linked to climate change.
“Climate change is clear and present danger to the U.S. economy and the fiscal health of the U.S. government, and that risk is really unevenly spread,” Mr. Houser said. “It needs to be actively managed by the federal government.”
J. Alfredo Gomez, one of the lead authors of the G.A.O. study, said the federal government had identified climate change as a significant economic risk since 2013. This study, he said, asks the administration to use the detailed data to prepare for the inevitable.
Robert N. Stavins, an economist at Harvard University, said he doubted the study would convince either Republicans in Congress or the White House to act.
“The G.A.O. study is conservative, it’s not alarmist, it’s realistic and balanced and they go out of their way to point out all of the uncertainties involved,” Mr. Stavins said. “I don’t see any likelihood it’s going to be taken seriously.”