The latest installment of the National Climate Assessment, a major government report on climate change, is once again revealing the mess of contradictions between the Trump administration’s messages and its actions on reducing greenhouse gas emissions in the face of rising temperatures.

The report is required by a law in place since 1990, which is why the White House has to release it, however grudgingly. However, they did rush to publish the assessment ahead of schedule on Black Friday, a move some scientists saw as an attempt to bury the findings. And now that it’s out, Trump told reporters Monday, he “didn’t believe it.”

BREAKING: Trump on dire warning issued by his administration on economic effects of climate change: 'I don't believe it' — The Associated Press (@AP) November 26, 2018

The National Climate Assessment draws on input from 13 federal agencies, including NASA and the Defense Department, with contributions from 300 scientists. The latest volume spans more than 1,600 pages, and a key recurring theme is that climate change will be devastating to the US economy.

Exhausted fisheries, declining crop yields, deteriorating infrastructure, lost tourism, and extreme weather damages all stemming from climate change will slice hundreds of billions of dollars out of the US economy. By the end of the century, climate change could cost the United States $500 billion per year.

But most striking is how the report highlights the incongruence of what the science says about climate change and what the Trump administration is doing about it. While the warnings about the destruction from rising seas, extreme weather, and forced relocation grow more dire, and while researchers warn that time is running out to limit warming, the White House is still trying to weaken rules governing greenhouse gas emissions.

Doing so in the face of the overwhelming science has forced the executive branch to invoke bizarre rationales to continue to avoid doing anything to reduce emissions and to prepare for the effects of climate change.

The National Climate Assessment emphasizes the high costs of doing nothing about climate change

The White House is in the process of rolling back the Clean Power Plan and fuel economy rules, regulations that respectively target emissions from power generation and vehicles, the two largest sources of greenhouse gases.

President Trump’s rationale for weakening climate change rules is that they’re too expensive, saying last month that “what I’m not willing to do is sacrifice the economic well-being of our country for something that nobody really knows.”

It’s a theme other Republicans echoed over the weekend as they downplayed the National Climate Assessment’s findings.

Dana Bash asks Sen. Joni Ernst if the Senate should take action to mitigate the effects of climate change. Ernst: "Our climate always changes and we see those ebb and flows through time ... We need to always consider the impact to American industry and jobs" pic.twitter.com/FjOMgIcmED — John Whitehouse (@existentialfish) November 25, 2018

However, the report shows that doing nothing about climate change is expensive, and we’re already paying the costs. “With continued growth in emissions at historic rates, annual losses in some economic sectors are projected to reach hundreds of billions of dollars by the end of the century — more than the current gross domestic product (GDP) of many U.S. states,” according to the assessment. On the other hand, fighting climate change and adapting to its consequences is already yielding financial benefits as it spurs the growth of new industries. The avoided costs of future harms will boost the economy further.

The White House is contorting itself in bizarre ways to avoid acting on climate change

The National Climate Assessment joins a long history of climate science at the White House. Benjamin Hulac at E&E News reported this month that every president since John F. Kennedy has been briefed or received warnings about the changes humanity has wrought on the global climate.

Compared to prior reports, the fourth National Climate Assessment goes further in estimating the economic damages from climate change. It also draws on a suite of new research published since the last report came out in 2014, highlighting advances in how we understand extreme weather, ocean circulation, melting ice, and humanity’s role in the climate. It shows that the impacts of climate change will be more extensive than previously thought, leaving no region of the country insulated from the consequences of warming.

Since the first report was published in 2000, the National Climate Assessment has become one of the most robust works in climate change science and the impacts of warming on the United States. The Executive Office of the President oversees the report. Some scientists were worried that the White House would tamper with the report’s conclusions, leading some researchers to leak drafts of the report. However, there’s no evidence that the White House has altered the assessment.

Trump has nonetheless made his disdain for climate change and the regulations around it clear. But a government agency can’t simply undo an environmental rule on a whim; they have to justify a rollback on the grounds that the existing regulation violates the law, that it isn’t supported by the science, or that its replacement will be better.

Here, the Trump administration has repeatedly tripped up. Since the 2007 Massachusetts v. EPA Supreme Court decision, the Environmental Protection Agency has been required to regulate greenhouse gases. Changing this precedent would require a massive, years-long legal effort to overturn the decision, and the administration hasn’t shown much appetite to take up this challenge.

That means the government still has to come up with regulations around climate change to replace the rules they want to discard. To justify getting rid of rising fuel economy standards, a huge step toward limiting carbon emissions from cars and trucks, the Trump administration has cited safety. They’ve argued that new fuel efficiency rules make cars more expensive, thereby making it harder for people to buy newer, safer cars.

But internal emails at the EPA showed that the agency found the proposed rollback would increase highway fatalities.

Buried in Trump’s fuel economy rollback proposal is a grim vision of the future under climate change. It projects carbon dioxide concentrations in the atmosphere reaching more than 789 parts per million, almost double current levels, leading to a drastically warmer world. The EPA used this projection to argue that the Obama-era fuel economy rules would do little to avert the amount of warming the Trump administration is expecting, so a weaker rule won’t make much of a difference to the global climate.

Similarly, the EPA’s assessment of its own proposal to roll back the Clean Power Plan, the Affordable Clean Energy proposal, found that the United States would face 1,400 additional premature deaths each year due to increases in air pollution under the new rule. The replacement regulation would also serve as a bailout for aging coal power plants, some of the biggest sources of greenhouse gases.

The National Climate Assessment, which is overseen by the White House, makes it even more difficult to argue for these changes since it shows just how dangerous climate change will be if the United States does nothing.

The National Climate Assessment could help activists fight Trump’s rollbacks

Many of the administration’s proposals to undo climate change regulations are tied down in lawsuits, so the White House has pursued a de facto policy of stalling to keep some rules from going into effect.

Now the National Climate Assessment gives environmental groups and activists more ammunition in their legal fight against these changes. “The report affirms what we’ve all known: The costs of climate change under a business as usual scenario are phenomenal,” said Michael Burger, executive director of the Sabin Center for Climate Change Law at Columbia University. “I think that this should help opponents of the rollbacks both politically and in court.”

Many environmental rules hinge on cost-benefit analyses. While the latest assessment doesn’t explicitly make that calculation, it does show that climate change places a huge economic burden on the United States, which undermines the government’s efforts to ignore or downplay the issue. That this report comes from Trump’s White House only gives it more weight.

But will the latest volume of the National Climate Assessment force Trump to reconsider? It’s unlikely. “Unfortunately, I think that for this White House, it won’t change a thing,” Burger said.