WHAT DOES it mean that July was the hottest month ever recorded? One could explain it away as a blip — if it did not come in the context of steadily warming average global temperatures over the course of decades. One could ignore it — if the signs of a changing climate were not everywhere on Earth, from shifting growing seasons, to more extreme weather, to exotic pests invading new places, to the thawing of long-frozen areas of the Arctic. But given these signals and many more, July’s swelter is yet another warning of things to come, a future that cannot be shrugged off as impossible, acceptable or, depending on one’s form of climate denial, inevitable. The fate of human civilization is at stake.

The official word came Monday, when the European Union’s Copernicus Climate Change Service announced that July 2019 was 0.07 degrees hotter than July 2016, the previous peak month. The past half-decade is likely to become the warmest five-year period ever recorded. Even more ominously, July’s scorching temperatures came in the absence of a warming El Niño effect. The consequences included huge wildfires, a dangerous heat wave in Western Europe and the massive release of meltwater from the Greenland ice sheet.

“This is not science fiction,” said Petteri Taalas, secretary general of the World Meteorological Organization. “It is the reality of climate change. It is happening now, and it will worsen in the future without urgent climate action.”

“Human influence on the climate system is clear,” the U.N. Intergovernmental Panel on Climate Change warned in 2014. The “warming of the climate system is unequivocal.” July having been the warmest month on record means that at no previous time have the experts’ sometimes dry-sounding warnings seemed to have been seared so miserably into the experience of millions of human beings.

In the midst of this unprecedented month, where was the man who, by dint of office but not behavior, is the leader of the free world? Engaging in a racist tweet offensive against minority Democratic members of Congress. Holding a White House social media summit with right-wing extremists. Promising nationwide immigration raids. Meanwhile, his administration plotted yet more rollbacks of environmental rules.

Because climate change is already underway, the question that faces humanity is not whether our species will endure shifts in the environment to which it is accustomed — but how titanic those shifts will be. The longer the world waits to change course, the worse the consequences. President Trump may be immune from the facts, but everyone else in his administration and in his party must ask themselves: Is what you are doing worth the contempt that future generations will feel about your willful ignorance and inaction?

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