Republican lawmakers from President Trump on down are bristling at the idea of taking steps to mitigate climate change for fear of disrupting the economy in the wake of a U.S. government report outlining the dangers to the environment.

“I don’t believe it,” Trump said on Monday when asked about potentially large damage climate change could cause to the U.S. economy

Sen. Mike Lee, a Utah Republican, flatly said he was against a carbon tax set at any price.

“All the proposals I’ve seen so far that would address any of these issues would devastate the U.S. economy and have little or no benefit that is demonstrable from our standpoint,” Lee said on “Meet the Press” on Sunday. “And so I have yet to see a proposal that would bring this about. I think if we’re going to move away from fossil fuels, it’s got to be done through innovation.”

Before there can be any discussion of what is an acceptable trade-off, it’s important to know what is at stake. The Fourth National Climate Assessment found that annual losses could reach hundreds of billions of dollars, more than the output of some states.

“Without more significant global greenhouse gas mitigation and regional adaptation efforts, climate change is expected to cause substantial losses to infrastructure and property and impede the rate of economic growth over this century,” the report says.

“Regional economies and industries that depend on natural resources and favorable climate conditions, such as agriculture, tourism, and fisheries, are increasingly vulnerable to impacts driven by climate change. Reliable and affordable energy supplies, which underpin virtually every sector of the economy, are increasingly at risk from climate change and weather extremes.

“The impacts of climate change beyond our borders are expected to increasingly affect our trade and economy, including import and export prices and U.S. businesses with overseas operation and supply chains,” the report goes on.

It arrived at the “hundreds of billions of dollars” conclusion by referencing a 2017 study in Science, from authors including Solomon Hsiang, which mapped the impact on agriculture, crime, coasts, energy, heat mortality, and labor as a function of global average temperature change.

There’s a big difference on the economic impact depending on how hot the planet gets. The Hsiang paper estimates that every one degree Celsius higher in global temperature results in a loss of about 1.2% of GDP.

The Paris agreement, which the Trump administration has said it would pull out of, attempts to limit the long-term globally averaged temperature to 2 degrees Celsius, or 3.6 degrees Fahrenheit, above preindustrial levels.

There also will be a big distribution in impact based on geography — for some counties, as much as 28% of its income could be wiped out, whereas in others, there could actually be gains of around 1%.

The climate change report focused on two scenarios, one in which temperatures are 5.4-to-11 degrees Fahrenheit hotter, and another 2.3-to-6.7 degrees hotter.

So what carbon tax could keep temperatures in a low range? The United Nations Intergovernmental Panel on Climate Change said that to keep temperatures only 1.5 degrees Celsius higher, a carbon tax ranging from $135 to $5,500 per ton by 2030 would be needed.

To put that in perspective, let’s look at the one carbon tax proposal from a Republican lawmaker, Rep. Carlos Curbelo of Florida. He would price carbon at $24 a ton in 2020. That proposal, a Columbia University analysis found, would not crush the economy — it would shave about two-tenths off GDP each year, as electricity prices rise by about 8% each year and gasoline prices by less than a dime a gallon.

A report meanwhile finds the highest end of the U.N. recommendation would mean a gas tax of a whopping $49 a gallon.

Any carbon tax would encounter tough resistance in Congress. All but six House Republicans voted for a resolution opposing any carbon tax at any price. The last Democratic effort, so-called cap-and-trade, died in the U.S. Senate in 2010.