And all the while, the problem keeps getting worse. Not long ago, a planet that warms by 2 degrees Celsius over the course of the coming century was considered an unimaginable catastrophe to be avoided at any cost. Today, 2 degrees — a level of warming that might induce death from air pollution on the order of “25 Holocausts,” Mr. Wallace-Wells notes — is looking like our best hope. On our current track, we’re shooting for at least 3 degrees of warming, according to the United Nations; according to the Trump administration, we’re headed for at least 4 degrees.

Four degrees of warming will wreak devastation unparalleled in human history. Hundreds of millions will die prematurely, large sections of the planet will be rendered uninhabitable, great herds of humanity will be on the run, and in the most prosperous remaining places, economic growth of any kind might be the exception rather than the norm.

That’s the current path. Yet just about nobody in any position of power talks about global warming with anything reflecting the required level of honesty and alarm. The Green New Deal, the high-level strategy document put out last week by Representative Alexandria Ocasio-Cortez of New York and her allies, lacks any specificity for how we might accomplish its goals. Not even democratic socialists will frankly describe the costs of averting a warming planet.

And the swiftness with which critics pounced on the Green New Deal suggests that even as the climate gets undeniably less hospitable, we’ll still fall into the same old political trap in which climate remains a small, partisan issue rather than the all-consuming emergency it ought to be.

The whole thing is tragic and lazy, when what we need is heroism and bravery.

If the aliens attacked, we’d do better. I’m sure of it.

We would understand the stakes in the battle ahead. We would apprehend the necessity of sacrifice and perseverance. We would be able to perceive what is happening to our planet and our species as what it plainly is: a war for survival.

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