“There is infinite hope,” Kafka tells us, “only not for us.” This is a fittingly mystical epigram from a writer whose characters strive for ostensibly reachable goals and, tragically or amusingly, never manage to get any closer to them. But it seems to me, in our rapidly darkening world, that the converse of Kafka’s quip is equally true: There is no hope, except for us.

I’m talking, of course, about climate change. The struggle to rein in global carbon emissions and keep the planet from melting down has the feel of Kafka’s fiction. The goal has been clear for thirty years, and despite earnest efforts we’ve made essentially no progress toward reaching it. Today, the scientific evidence verges on irrefutable. If you’re younger than sixty, you have a good chance of witnessing the radical destabilization of life on earth—massive crop failures, apocalyptic fires, imploding economies, epic flooding, hundreds of millions of refugees fleeing regions made uninhabitable by extreme heat or permanent drought. If you’re under thirty, you’re all but guaranteed to witness it.

If you care about the planet, and about the people and animals who live on it, there are two ways to think about this. You can keep on hoping that catastrophe is preventable, and feel ever more frustrated or enraged by the world’s inaction. Or you can accept that disaster is coming, and begin to rethink what it means to have hope.

Even at this late date, expressions of unrealistic hope continue to abound. Hardly a day seems to pass without my reading that it’s time to “roll up our sleeves” and “save the planet”; that the problem of climate change can be “solved” if we summon the collective will. Although this message was probably still true in 1988, when the science became fully clear, we’ve emitted as much atmospheric carbon in the past thirty years as we did in the previous two centuries of industrialization. The facts have changed, but somehow the message stays the same.

Psychologically, this denial makes sense. Despite the outrageous fact that I’ll soon be dead forever, I live in the present, not the future. Given a choice between an alarming abstraction (death) and the reassuring evidence of my senses (breakfast!), my mind prefers to focus on the latter. The planet, too, is still marvelously intact, still basically normal—seasons changing, another election year coming, new comedies on Netflix—and its impending collapse is even harder to wrap my mind around than death. Other kinds of apocalypse, whether religious or thermonuclear or asteroidal, at least have the binary neatness of dying: one moment the world is there, the next moment it’s gone forever. Climate apocalypse, by contrast, is messy. It will take the form of increasingly severe crises compounding chaotically until civilization begins to fray. Things will get very bad, but maybe not too soon, and maybe not for everyone. Maybe not for me.

Some of the denial, however, is more willful. The evil of the Republican Party’s position on climate science is well known, but denial is entrenched in progressive politics, too, or at least in its rhetoric. The Green New Deal, the blueprint for some of the most substantial proposals put forth on the issue, is still framed as our last chance to avert catastrophe and save the planet, by way of gargantuan renewable-energy projects. Many of the groups that support those proposals deploy the language of “stopping” climate change, or imply that there’s still time to prevent it. Unlike the political right, the left prides itself on listening to climate scientists, who do indeed allow that catastrophe is theoretically avertable. But not everyone seems to be listening carefully. The stress falls on the word theoretically.

Our atmosphere and oceans can absorb only so much heat before climate change, intensified by various feedback loops, spins completely out of control. Some scientists and policymakers fear that we’re in danger of passing this point of no return if the global mean temperature rises by more than two degrees Celsius (maybe more, but also maybe less). The I.P.C.C.—the Intergovernmental Panel on Climate Change—tells us that, to limit the rise to less than two degrees, we not only need to reverse the trend of the past three decades. We need to approach zero net emissions, globally, in the next three decades.

This is, to say the least, a tall order. It also assumes that you trust the I.P.C.C.’s calculations. New research, described last month in Scientific American, demonstrates that climate scientists, far from exaggerating the threat of climate change, have underestimated its pace and severity. To project the rise in the global mean temperature, scientists rely on complicated atmospheric modelling. They take a host of variables and run them through supercomputers to generate, say, ten thousand different simulations for the coming century, in order to make a “best” prediction of the rise in temperature. When a scientist predicts a rise of two degrees Celsius, she’s merely naming a number about which she’s very confident: the rise will be at least two degrees. The rise might, in fact, be far higher.

As a non-scientist, I do my own kind of modelling. I run various future scenarios through my brain, apply the constraints of human psychology and political reality, take note of the relentless rise in global energy consumption (thus far, the carbon savings provided by renewable energy have been more than offset by consumer demand), and count the scenarios in which collective action averts catastrophe. The scenarios, which I draw from the prescriptions of policymakers and activists, share certain necessary conditions.

The first condition is that every one of the world’s major polluting countries institute draconian conservation measures, shut down much of its energy and transportation infrastructure, and completely retool its economy. According to a recent paper in Nature, the carbon emissions from existing global infrastructure, if operated through its normal lifetime, will exceed our entire emissions “allowance”—the further gigatons of carbon that can be released without crossing the threshold of catastrophe. (This estimate does not include the thousands of new energy and transportation projects already planned or under construction.) To stay within that allowance, a top-down intervention needs to happen not only in every country but throughout every country. Making New York City a green utopia will not avail if Texans keep pumping oil and driving pickup trucks.

The actions taken by these countries must also be the right ones. Vast sums of government money must be spent without wasting it and without lining the wrong pockets. Here it’s useful to recall the Kafkaesque joke of the European Union’s biofuel mandate, which served to accelerate the deforestation of Indonesia for palm-oil plantations, and the American subsidy of ethanol fuel, which turned out to benefit no one but corn farmers.

Finally, overwhelming numbers of human beings, including millions of government-hating Americans, need to accept high taxes and severe curtailment of their familiar life styles without revolting. They must accept the reality of climate change and have faith in the extreme measures taken to combat it. They can’t dismiss news they dislike as fake. They have to set aside nationalism and class and racial resentments. They have to make sacrifices for distant threatened nations and distant future generations. They have to be permanently terrified by hotter summers and more frequent natural disasters, rather than just getting used to them. Every day, instead of thinking about breakfast, they have to think about death.