If Trump fails to take climate change seriously, the federal government may do little to address the threat of a warming planet in the next four years. A presidential administration hostile to climate science also threatens to deepen, or at the very least prolong, the skepticism that already exists in American political life. “If the Trump administration continues to push the false claim that global warming is a hoax, not happening, not human caused, or not a serious problem, I’d expect many conservative Republican voters to follow their lead,” said Anthony Leiserowitz, the director of Yale University’s Program on Climate Change Communication.

The entrenchment of climate-science denial is one of the ways the United States appears to be exceptional relative to the rest of the world. A comparative 2015 study of nine conservative political parties in countries such as Canada, Germany, and Spain concluded that “the U.S. Republican Party is an anomaly in denying anthropogenic climate change.” Meanwhile, Americans were least likely to agree that climate change is largely the result of human activity in a 2014 survey of 20 countries, including China, India, Australia, and Great Britain.

Scientific reality does not seem to have escaped the distorting influence of political polarization in the United States. A paper published in Environment earlier this year suggests that as the Tea Party pushed the Republican Party further to the political right, it helped solidify skepticism of man-made climate change within the GOP. That happened as the Tea Party incorporated “anti-environmentalism and climate-change denial into its agenda,” the authors write, and subsequently became part of a broader “denial countermovement” made up of fossil-fuel companies as well as conservative think tanks and media outlets.

As the ideological divide between Republicans and Democrats has widened, so has the partisan divide over climate change. Scientific evidence that human activity is the leading cause of global warming has continued to accumulate in recent years, and the evidence for man-made climate change is now overwhelming. In spite of that, Republicans are slightly less convinced than they were a decade and a half ago that the Earth is getting warmer as a result of human activity. Democrats have moved in the opposite direction and become more likely to say that man-made climate change is real. This year, Gallup found that while 85 percent of Democrats believe human activity has lead to higher temperatures, only 38 percent of Republicans agree.

In a deeply divided country, adopting views on climate change that conflict with scientific evidence can actually be a rational choice. Liberals and conservatives frequently spend time with like-minded individuals, and people across the political spectrum may have a better chance of fitting in if they embrace shared partisan beliefs—regardless of whether those beliefs contradict scientific fact. This helps explain why highly educated Republicans are actually more likely to reject climate science. Yale University professor Dan Kahan put it this way in a 2012 Nature article:

For members of the public, being right or wrong about climate-change science will have no impact. Nothing they do as individual consumers or individual voters will meaningfully affect the risks posed by climate change. Yet the impact of taking a position that conflicts with their cultural group could be disastrous. … Positions on climate change have come to signify the kind of person one is. People whose beliefs are at odds with those of the people with whom they share their basic cultural commitments risk being labelled as weird and obnoxious in the eyes of those on whom they depend for social and financial support.

The complexity of climate science may have made it easier for global warming to get caught up in partisan politics as well. Voters look to the positions adopted by their political party as a kind of mental shortcut when deciding what to make of complicated subjects such as climate change, according to research from Cynthia Rugeley of the University of Minnesota, Duluth, and John David Gerlach of Western Carolina University. That means that if Trump continues to voice climate skepticism after taking office, he could further cement skepticism among conservative voters. “I think it will reinforce climate denial among those who already doubt its existence. To that extent, yes, it will deepen denial,” Rugeley said in an interview.