If possible, put aside Donald Trump’s hate for minorities, his refusal to release his tax returns on billions in income, his draft deferments and his repugnant insults of women.

Put aside his ignorance of foreign affairs — the man who said “ I know more than the generals” was described as “ a national disgrace” by a real general, Colin Powell — and his traitorous embrace of Russia’s Vladimir Putin.

There is one single issue that proves that Trump is unqualified to be president: his repeated claim that global warming and climate change are a hoax. He has repeated that line many times, and again in one of his many lies, he says he never said it.

On Nov. 6, 2012, Trump said on Twitter that “ The concept of global warming was created by the Chinese to make U.S. manufacturing non-competitive.” In January 2014, he tweeted to NBC News: “ Is the country still spending money on the GLOBAL WARMING HOAX?” Then last year, he repeated “ I don’t believe in climate change.”

Now, Trump’s position should not be too surprising. Although he differs with the GOP on some issues, many Republicans think global warming — the well-documented historic increases in temperatures, sea level rise and oceanic acidification as well as reductions in Arctic Sea ice and snow cover — is a hoax.

Ignoring the 97 percent consensus among world climate scientists, the National Academy of Sciences and the United Nations Intergovernmental Panel on Climate Change, Trump and the GOP would rather echo the chants of organizations skeptical of global warming and funded by the fossil fuel industries than do what is right. Such blatant disregard for the truth in the face of overwhelming evidence suggests complete ignorance or total indifference to the potentially catastrophic threat of climate change.

As rising seas endanger coastal nations, imagine the chaotic effects of displacing millions of people worldwide. Hungry, desperate migrants seeking shelter, food and livelihood are likely to resort to violent and unlawful means to save themselves and their families. If not violence, then death from starvation and disease from infections would claim lives. The European migration crisis, a result of Syria’s civil war, would pale in significance to the dire consequences of climate change.

President Barack Obama and Hillary Clinton are right to consider climate change the leading long-term threat. A safe and prosperous future demands adherence to facts, prioritization of threats and development of a comprehensive action plan. Human existence will depend upon it as global warming induces mass migrations that could trigger conflict, even use of nuclear weapons.

Another climate-related issue that demonstrates how the tea-party-tied GOP hurts the national interest is its opposition to ratification of the Law of the Sea Treaty. Almost all nations have approved the treaty, and the United States has less leverage in negotiations to determine the boundaries of the Arctic Ocean because the GOP prevents ratification.

The willingness of Trump and the GOP to deny overwhelming scientific evidence and the reality of climate change not only hinders international efforts but also blocks the ability of the U.S. government — the world’s leader — to take preventive steps to plan for major improvements in infrastructure for coastal cities and regions.

At a meeting of the eight-nation Arctic Council in Portland this month, Maine Sen. Angus King highlighted the need to recognize the threat of climate change to enable planning for massive infrastructure needs. After hearing a Maine scientist predict that the melting of global ice sheets could drive up sea levels a foot in the next 15 years, King said, “Pretty scary. Imagine an extra foot of water in Scarborough Marsh.”

Sadly, climate change is not the only major issue that has suffered from dishonest treatment by candidates and the media. The rampant lack of truthfulness in this presidential election is dismaying but increasingly common in the age of instant and superficial coverage. As George Orwell said, “Political language is designed to make lies sound truthful and murder respectable, and to give the appearance of solidity to pure wind.”

A good question we may hear from our grandchildren in a couple of decades, as the Arctic Ocean is full of tourist ships and oil tankers, Atlantic Coast cities and beaches are underwater, insect-carrying diseases spread northward and polar bears are an afterthought, “Grandpa, did you vote for that guy who called climate change a Chinese hoax?”

Frederic Hill was a foreign correspondent for The Baltimore Sun and is the author of “Ships, Swindlers and Scalded Hogs.” He lives in Arrowsic. Walter Kozumbo was a scientist and manager for the U.S. Air Force. He lives in Baltimore.