Recently CNN sat down with 10 Democratic presidential contenders to discuss climate change. For seven hours.

Those who stayed awake heard some quite startling plans for America’s future, should one of these candidates defeat President Donald Trump next year and get the opportunity to deal with “the greatest threat facing humanity,” as the left-wing magazine Jacobin has called climate change.

With a Democratic president, we’ll ban plastic straws, fracking, the coal industry, offshore drilling, nuclear power, incandescent light bulbs, possibly cheeseburgers. We’ll impose carbon taxes, make cars more fuel-efficient, question the continued feasibility of airline travel, build solar and windmill farms galore. The prospects are boundless.

Oddly, no candidate appeared to discuss how climate change is already threatening people — those at the end of a gun barrel. Saving the planet has apparently become a cause for some mass shooters.

Six months ago a loon named Brenton Tarrant shot up a mosque in Christchurch, New Zealand, killing 51 people. The commentariat focused on the fact that Tarrant was an unrepentant white nationalist who aimed to murder Muslims. True enough.

But discussed to a lesser degree was that Tarrant was a self-proclaimed “eco-fascist” who fervently believed in climate change, and who felt, as he wrote in his manifesto, one way to “save the environment” was to shoot a bunch of brown people.

“The environment is being destroyed by over population (sic),” he wrote, “kill the overpopulation and by doing so save the environment.” Tarrant also said children are “ultimately destructive to nature and culture,” and that with capitalism, “The natural environment is industrialized, pulverized and commoditized.”

This theme emerged again in August, when a Tarrant disciple, Patrick Crusius, killed 22 Hispanics in El Paso, Texas. He, too, had a manifesto. “(M)ost of y’all are just too stubborn to change your lifestyle. So the next logical step is to decrease the number of people in America using resources. If we can get rid of enough people, then our way of life can become more sustainable,” he wrote.

Crusius added: “(O)ur lifestyle is destroying the environment of our country. The decimation of the environment is creating a massive burden for future generations. Corporations are heading the destruction of our environment by shamelessly overharvesting resources.”

Ironically, Crusius’s last sentence was a view shared by Connor Betts, the mass shooter in Dayton, Ohio. While they were not necessarily the motivation for the massacre he committed, Betts’s left-wing politics, per his Twitter history, included references of the need to kill in order to save the planet.

Betts retweeted one meme that read: “The planet isn’t dying, it’s being killed. The capitalists responsible have names and addresses.” In another climate change-related tweet shared by Betts, the original poster had noted, “The good news is that if we don’t have a right to a life-sustaining climate we could probably argue that murder is also legal.”

On one hand, we have white-power whackos who adopt an easy calculus to fix this problem: environmentalists assert that climate change is a man-made phenomenon. Thus, more people equals more resource consumption, and more warming. So, saving the planet simply becomes a function of reducing population, especially that of migrants from the less-white parts of the world who are overpopulating the planet and supplanting the white race.

On the other hand, we have nuts like Betts, who proclaimed his support for Sen. Elizabeth Warren. Warren endorses the Green New Deal, which calls for ending reliance on fossil fuels within a decade. Warren also has attacked big energy companies as a major source of climate change. Earlier this year she wrote that the Trump administration was expanding “fossil fuel extraction that destroys pristine sites across the country while pouring an accelerant on our climate crisis.” As shown at the CNN town hall, her views are common among the Democratic contenders.

Writing recently in GQ, contributing editor Luke Darby argued, “If governments don’t deal with climate change — if they fail to address it now or prepare for the worst outcomes later— then attacks like the ones in El Paso and Christchurch will likely come more often. The extremists will try to take matters into their own hands.”

Yet it’s not far-fetched to believe that on the other side some could be driven to extreme measures by constant ranting about Big Oil’s culpability on climate change and indifference to the planet’s health.

Maybe we could dial back the end-of-days, apocalyptic rhetoric that climate change will destroy the world in 10 years unless we elect Democrats to cram down wholesale behaviorial changes on us. Perhaps such scaremongering is driving some violent desperation as well.

Bill Thompson (bill.thompson@theledger.com) is the editorial page editor of The Ledger in Lakeland, Florida.