The White House came under political fire earlier this month after it blocked a State Department intelligence expert from delivering written testimony on climate change. The expert’s findings were censored because they did not “jibe” with the President’s views. The administration’s rejection of climate science is nothing new, but criticism is mounting. In testimony before Congress this week, three former Republican administrators of EPA administrators blasted the President’s rejection of science.

President Trump and his fellow climate change deniers will not lose sleep over the testimony of former EPA administrators, but they may not be able to ignore for long the growing tide of public opinion. Recent polls indicate elevated concern about climate change among independents and moderate and conservative democrats. Climate change is now the top concern of over 80% of Democratic voters – higher priority even than healthcare.

Nothing focuses the mind on climate change quite as much as extreme weather events. When scientists first began warning about the impacts that greenhouse gas emissions might have on the climate, the threat was theoretical. Not anymore. Voters are seeing the impact of climate change in real time.

Any single extreme weather event, like recent record-breaking flooding in the Midwest, may or may not be climate related. But the increasing severity and frequency of extreme weather events clearly demonstrate something is wrong.

Global anxiety about climate change could turn into a political tidal wave. It may or may not arrive on our shores in time for the 2020 elections, but, when it does, it could hit with catastrophic force.

It’s already cresting in Europe. A speech at the UN’s climate conference in Poland last year by Swedish teenager Greta Thurberg electrified audiences and spurred students all across the world to protest climate change inaction by repeatedly boycotting school on Fridays. Barricades erected by Extinction Rebellion create massive traffic jams in London. Climate activists are queuing up at the polls. The Green Party made major gains in the recent elections for the European Parliament, particularly in Germany, France, and the United Kingdom.

That tidal wave is now headed in our direction. Thanks to record-setting droughts, heatwaves, catastrophic flooding and wildfires, voters in the U.S. can now see what’s coming. Deadly hurricanes in the Gulf, forest fires in the West, record droughts in the South and Southwest, record flooding in the Midwest and Northeast—virtually every region of the country has now experienced a major disaster that may have been caused or exacerbated by climatic changes.

The economic impacts will soon come into sharper focus in the form of lower crop yields for farmers and higher insurance premiums for homeowners. When they do, climate change will become a pocketbook issue for millions of older Americans, including those living in the flood-soaked areas of the Midwest.

Younger Americans, those who have the most to lose from climate change, are not just concerned; they are angry. They are fearful, and rightly so, that the willful ignorance of climate change deniers constitutes an existential threat to their future. When they start to vote in larger numbers, the mounting wave of climate concern will become a political tsunami.

It may not take much for it to wipe out the last holdouts of climate change denial in the U.S. A recent analysis of Gallup polls taken in the past two years indicates that concerns about climate change are higher in the Northeast and the West, but a clear majority of voters in the South (60%) and the Midwest (62%) also believe that “the seriousness of global warming is generally correct or underestimated.”

A UN global assessment released last month warned that as many as one million species are at risk of extinction in the coming decades as a consequence of climate change and environmental degradation. Four hundred experts from more than 50 countries contributed to the assessment. It makes it clear that humanity is in danger of overwhelming the planet and destroying the underpinnings of civilization. A paper just published in Australia argues that climate change threatens to end civilization as we know it as early as midcentury.

If climate change poses an existential threat to humanity, it certainly poses an existential threat to the political fortunes of climate change deniers. A growing number of Republicans in Congress are now voicing their concerns about climate change. For the sake of their party and their country, they need to make their voices heard.

This op-ed by Population Institute President Robert Walker originally ran on July 17, 2019 in Newsweek