The Trump administration should craft a climate risk assessment based on the economic harm global warming creates, the Government Accountability Office recommends in a new report.
The report, made public Tuesday, cites recent scientific studies showing the costs of extreme weather events, such as floods and droughts, are likely to increase as the events become more common and intense because of climate change.
"The appropriate entities within the Executive Office of the President ... should use information on the potential economic effects of climate change to help identify significant climate risks facing the federal government and craft appropriate federal responses," the GAO report says. "Such responses could include establishing a strategy to identify, prioritize, and guide federal investments to enhance resilience against future disasters."
Over the last decade, according to the Office of Budget and Management, the federal government has incurred direct costs of more than $350 billion because of extreme weather and fire events, including $205 billion for domestic disaster response and relief; $90 billion for crop and flood insurance; $34 billion for wildland fire management; and $28 billion for maintenance and repairs to federal facilities and federally managed lands, infrastructure, and waterways.
The federal government this year alone has spent $300 billion to respond to the most expensive year for wildfires on record, on top of Hurricanes Harvey, Irma, and Maria.
Climate change costs are expected to rise in future decades.
"Climate change impacts are already costing the federal government money, and these costs will likely increase over time as the climate continues to change," the GAO report says.
The recommendations come as the Trump administration has overturned Obama-era guidance asking federal agencies to prepare for the effects of climate change and has sought to delay or undo regulations intended to limit emissions of planet-warming pollutants such as carbon dioxide and methane. Many climate scientists blame greenhouse gases emitted from burning fossil fuels for driving man-made climate change.
Sens. Maria Cantwell of Washington state, the top Democrat on the Senate Energy and Natural Resources Committee, and Susan Collins of Maine, a moderate Republican, requested in November 2015 that the GAO do a "comprehensive study on the costs and risks to the U.S. government from climate change."
The duo collaborated on a "cap and dividend" carbon pricing bill in 2010 that would have required energy producers to bid in monthly auctions for "carbon shares." Most of the revenue raised by the bill would have been provided to consumers in the form of a dividend.
Cantwell and Collins say the report demands action from Congress.
"My colleagues no longer have to take it from me — the Government Accountability Office tells us climate change will cost taxpayers more than a half a trillion dollars this decade, and trillions more in the future unless we mitigate the impacts," Cantwell said.
Collins tried to appeal to the fiscal sensibility of fellow Republicans who have opposed taking action to mitigate climate change because of economic concerns.
"We cannot ignore the impact of climate change on our public health, our environment, and our economy," Collins said. "This nonpartisan GAO report contains astonishing numbers about the consequences of climate change for our economy and for the federal budget in particular. I hope the release of this analysis will cause all of us to think more broadly about this issue, take a harder look at the economic consequences of inaction, and use what is known about climate risks to inform federal policy."
In its report, GAO refers to a November 2016 assessment by the Office of Management and Budget and the Council of Economic Advisers that found recurring costs incurred by the federal government as a result of climate change could increase by $12 billion to $35 billion per year by midcentury and by $34 billion to $112 billion per year later in the century.
Those costs include money for wildfire suppression, coastal disaster relief, and federal insurance for property and crops.
GAO, Congress' investigative arm, acknowledges shortcomings in its reporting.
The office says of 30 studies it reviewed that were published in 2005 or later, it could identify only two that provide "national-scale information" about the economic effects of climate change in the U.S. It also interviewed more than 20 experts, researchers, and consultants.
The studies can produce imprecise results because of information and modeling limitations associated with climate modeling uncertainty, limited information for specific economic sectors, and challenges of predicting impact over long periods, the office said.
Yet the GAO says the studies still have important takeaways.
"Several experts we interviewed noted that even though the methods produce imprecise results, they can convey useful insight into broad themes about potential climate damages across sectors in the United States," the report said. "By using information on the potential economic effects of climate change to help identify significant climate risks and craft appropriate federal responses — such as establishing a strategy to guide federal investment to enhance resilience against future disasters — the federal government could take an initial step."