Yet that 2014 report did little to sway skeptical Republicans who have dismissed climate change as sketchy science and a liberal hobby horse. Representative Lamar Smith, a Texas Republican and a leading critic of climate science in Congress, responded by calling it a “political document,” emphasizing the lingering uncertainties in the report. He has also derided the expertise of what he calls “so-called self-professed climate scientists.”
Mr. Smith’s response highlighted a longstanding and uncomfortable dynamic: When scientific studies conflict with ingrained political values, it is all too easy to dismiss the scientists themselves as biased or to migrate toward a different set of authorities, however marginal, who can poke holes in an inconvenient report.
Similarly, few observers expect this new report to influence the Trump administration, which has pushed to repeal federal regulations on the greenhouse gases that lead to global warming and whose officials have expressed doubt about the causes of a warming planet.
“I think there are a range of attitudes and sentiments within the administration about causes of and risks associated with climate change,” said Michael McKenna, a Republican energy lobbyist and adviser to the Trump transition. “But two things everyone seems to share are a concern that climate sensitivity is overblown and a sturdy skepticism about any and all possible ‘remedies’ that have been proposed.”
“I don’t see where this report is going to alter either of those sentiments,” he said. “Nor do I think it should.”
Researchers who study public attitudes toward climate change are also skeptical that science alone can spur people to care about the issue.
“If someone is already not on board with climate science or is just disengaged and feels like it doesn’t matter, more information about ocean acidification or attribution of extreme weather events isn’t going to change their minds,” said Katharine Hayhoe, a professor of political science at Texas Tech University who contributed to the federal climate report.
But that doesn’t mean public attitudes about climate change are frozen forever, incapable of shifting, added Dr. Hayhoe, who has made a habit of reaching out to conservatives and other skeptics of climate change.
One major disconnect she has found is that many people don’t think climate change will affect them personally. A recent survey by the Yale Program on Climate Change Communication found that the majority of Americans think that global warming will negatively affect the country, but only a small minority thought that they themselves would suffer.
Dr. Hayhoe suggested that the second part of the National Climate Assessment, still in draft form and due out in 2018, could help alter those views. That report will explore in vivid detail the impacts that global warming will have on local communities, documenting trends like the sharp rise in tidal flooding that is already beginning to swamp cities like Hampton Roads, Va.
There is some evidence that even policymakers skeptical of human-caused global warming will take notice of worsening local impacts and act accordingly. Gov. Scott Walker of Wisconsin, for instance, has largely disavowed climate science. But in December, his state emergency management agency nonetheless released a sweeping plan to prepare for higher temperatures and heavier rainfall events in the future.
“While there remains some debate about the cause of climate change, there has been a documented change in weather patterns over time in Wisconsin,” the report noted, adding later, “Climate resilience is a state and national priority.”
Dr. Hayhoe has also found that many conservatives are more skeptical about climate science when they think that the solutions to global warming look suspiciously like a liberal wish list involving extensive government intervention.
But there are signs that those attitudes are slowly shifting. Both solar and wind power, which have always been broadly popular, are growing fastest in many Republican-leaning states — a trend that could do far more than endless scientific reports to break the deadlock around climate politics.
“The place where I often tend to find common ground is when we can agree on solutions,” said Dr. Hayhoe. “Because if someone supports the growth of clean energy, does it matter why they support it?”
On that score, the Trump administration is less likely to rethink its priorities. Support for renewable energy and action on climate change often contradicts other key political priorities, such as supporting coal-mining communities and the domestic oil industry.
Even so, some observers wonder if the new climate science report could at the very least increase international pressure on the White House to take climate change more seriously, particularly after President Trump said he would withdraw the United States from the Paris climate agreement.
“I don’t think it’s going to have any impact on the policies of this administration,” said Paul Bledsoe, a former Clinton White House climate change adviser. “But it highlights how isolated the administration’s position on climate change has become internationally.”