The federal government’s Fourth National Climate Assessment, released the day after Thanksgiving, puts an exclamation point to what most of us already knew. This country (not to mention the rest of the world) faces an existential threat from climate change that is far more grave than North Korean nukes, unfair Chinese trade practices, Russian-cyber meddling in U.S. elections, the threat of jihadi terror attacks, the opioid epidemic, or illegal immigration.

Yet President Donald Trump continues to deny, minimize and just plain ignore unequivocal warnings issuing from scientists in his own administration, from the scientific community at large, and from the undeniable realities of increased flooding, sea level rise, drought, and forest fires affecting every region of the country.

A team of more than 300 federal and non-federal experts, led by the National Oceanic and Atmospheric Administration (NOAA), has concluded that the “global average temperature has increased by about 1.8 degrees F from 1901 to 2016, and … the evidence consistently points to human activities, especially emissions of greenhouse or heat-trapping gases, as the dominant cause.”

Of even more concern for our neck of the woods, the assessment states, “By 2035, … the Northeast is projected to be more than 3.6°F (2°C) warmer on average than during the preindustrial era. This would be the largest increase in the contiguous United States and would occur as much as two decades before global average temperatures reach a similar milestone.”

The regional impacts to the Northeast are predicted to be varied and dramatic, ranging from less distinct seasons, milder winters and earlier springs to warmer and more acidic oceans, higher sea levels and more intense storm activity. These, in turn, will affect virtually everything that makes Maine unique, including its winter recreational industry, the health of its marine and wildlife populations, the integrity of its forests, and the contours of its coastline.

This assessment should be required reading for everybody.

I doubt that Trump read a word of it, but that didn’t stop him from commenting on it. To the extent the report’s conclusions suggest the need for governmental policy changes to discourage production and use of fossil fuels, Trump’s not about to support them. After all, that could spoil his political rallies in states like North Dakota, West Virginia, Kentucky, Oklahoma and Texas, where coal, oil and natural gas are extracted. So, he’ll do what he always does when faced with inconvenient truths – shrug his shoulders and pretend reality is in the eyes of the beholder, namely his.

Trump’s public statements about the report have ranged from “I don’t believe it” to “as to whether it’s man-made … I don’t see it not nearly like it is.”

Science, unlike religion, isn’t about the individual belief, even if that individual is a U.S. president. It’s about formulating and testing theories through observation, measurement, controlled experimentation, and verification of predictions. If a belief can’t be substantiated through rigorous scientific techniques, it ends up on the junk pile of debunked ideas.

Even if the direst warnings of the assessment’s authors are somewhat overstated, they can’t be simply ignored. Given the gravity of the risk, it’s only prudent to engage in the kind of forecasting, planning, and preventative action that a prudent person would resort to in any other area of life where the economic and human stakes were high.

Instead Trump has staffed key environmental posts in his administration with coal and petroleum industry lobbyists and lawyers and moved to reduce regulatory restrictions on power plants emissions, motor fuel mileage standards, and oil and gas drilling, the very activities which produce most greenhouse gases, on the theory that these restrictions are job killers.

In fact, climate change is the real killer (as the Paradise, California fire, among other recent catastrophes, has vividly demonstrated) and not just of human life. According to The National Climate Assessment, “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.”

Not only is the federal government abdicating responsibility for addressing climate change at home, it’s leaving the field of international cooperation on the issue. In 2017 Trump announced that he plans to withdraw the U.S. from the 2015 Paris Agreement on climate change mitigation, thereby impairing its chances of success.

It’s encouraging that Maine Governor-Elect Janet Mills has promised to make climate change a high priority and to fight Trump administration environmental policies, but, even if she’s successful, Maine can’t significantly alter climate change on its own.

The environment respects no political boundaries. Climate change is a national and international problem. Ultimately it will have to be addressed – the sooner the better — through vigorous action and broad collaboration across political boundaries throughout this nation and around the planet.