We know the planet is warming. We know we’re causing it. We know it will result in drought, plague, famine, disease, drowned coastlines, mass extinctions. But we also know that many of the worst of these outcomes will be borne not by ourselves—and not even by our children and grandchildren—but by distant generations, still to come, who will inherit the earth from us in whichever state we care to leave it.

 

What is the moral relevance of time? Does someone born in 2119 count any less than someone who is alive right now? If so: why? If not: what do we owe these future people, and at what cost to ourselves? Does it matter that we will never meet them, or that they can never do anything for us? Can we assume that they will be richer and more technologically advanced than we are now? Does it make any difference that they have no fixed identities, or that who they will be, and indeed whether they will exist at all, depends on our actions and decisions? Philosophers have long enjoyed these strange questions, but for the first time—faced with our complicity in an increasingly uninhabitable earth, and our narrowing window in which to evade it—they are coming to have a more urgent public resonance.

 

Non-specialists first became aware of what was happening to the climate in the 1990s. At that time, among these unknown “future people” was one Greta Thunberg. A girl to be born in Sweden in 2003: who would first hear about climate change when she was eight; who would find this revelation so horrifying that she would descend into a years-long depression; who would be diagnosed with Asperger’s syndrome; who would renounce air travel and overconsumption and animal products; who would leave school to strike outside the Swedish parliament to demand more political action; and who has now, just a year later, become one of the most powerful environmental activists in the world. Last month she traveled by sailboat to the UN Climate Summit in New York, and there (repressing tears) she declared to the assembled delegates: “The young people are starting to understand your betrayal. The eyes of all future generations are upon you, and if you choose to fail us, I say we will never forgive you.”

 

These accusations have been variously received. In the laughing and clapping at the UN address you sense both condescension and relish: that she is providing some sort of yearned-for rebuke. She’s been called a puppet, and she’s been claimed as a mascot. She’s been attacked by the right-wing American press (dismissed as “a mentally ill Swedish child” and compared to Stephen King’s Children of the Corn), and she’s been hailed as “the Joan of Arc of climate change.” To her credit she seems quite indifferent to all of these appraisals, the approving and disapproving alike. Although the saviour narrative gets to her: “You come to young people for hope. How dare you?”

 

Thunberg will be seventeen in a few months, but an important part of her power is in coming across as much younger than she is. She looks about ten (her small frame a consequence, reportedly, of the eating disorder that emerged during her battle with depression), and her manner is closer to that of a prodigious child than the traits we’d typically associate with the teens of Generation Z. Her rhetoric regularly invokes the moral categories (or even caricatures) of “the child” and “the adult”: what each role should entail, and how unfairly they have been reversed in our present crisis. “You’re acting like spoiled, irresponsible children,” she told the European Economic and Social Committee. Or, on another occasion: “You’re not mature enough to tell it like it is. Even that burden you leave to your children.”

 

We are born in a state of innocence—victims of the world as it is—but at some point, this precious coat wears through. Our innocence turns into a sort of participation, and our participation turns into a sort of endorsement. We stop being in a world which is unjust, unequal and cruel, and we become part of that injustice, inequality and cruelty. No small part of Thunberg’s message, and the discomfort of receiving it, is this accusation that our innocence with regards to climate change has now passed: we have known too much for too long, and we have done nothing about it. Indeed, since the dawning of our awareness—in just a few decades—we have added more carbon to the atmosphere than in all the accumulated millennia before. As David Wallace-Wells writes: “We have done more damage knowingly than we ever managed in ignorance.”

 

What could explain this? “If you really understood the situation and still kept on failing to act, then you would be evil,” Thunberg says. But our inertia is not straightforwardly a matter of malice, or even self-interest. There seems to be an immense psychological obstacle in taking the future into account in the way that’s now required of us. Just think of the contempt we show even to our future selves: we leave them to deal with our snowballing debts and mounting deadlines and our smoking-related cancers. (The things I’ve done to my future self really ought to be criminal, and yet there will be no one around to be punished for these crimes except their victim).

 

We have generated so many ways of defying our natural limitations. We can dart around the globe in mere hours; we can communicate with audiences of millions using just our thumb upon a screen; we can wage deadly warfare from the comfort of an office cubicle; and as it turns out, we can change the earth’s atmosphere. But our moral psychology hasn’t kept pace with these growing powers, or with the intricate links of cause and effect that turn our individually harmless actions into collective catastrophes. It’s an immense struggle for us to even imagine the new transgressions and categories of harm and injustice that we’re now generating.

 

So we are inclined to say, in our defence, that it’s all much more complicated than Thunberg makes out. It’s complicated to address a collective action problem on such an unprecedented scale. It’s complicated to know what’s required of us personally and what can only be solved politically. It’s complicated because we have invested so much in an idea of modernity which is premised on growth, and an idea of growth which is premised on burning through fuel. It’s complicated to get any one nation to forsake these ideas, and it’s even more complicated to get all of them to forsake them simultaneously. It’s complicated because while some nations have been binging on this fuel for centuries now, others are only just arriving at the table. It’s complicated because there is now a conflict between remedying the injustices we’ve inherited from the past, and reducing the injustices we are perpetuating on the future.

 

All of this seems true enough. But complexity is also such a convenient alibi. It is here, especially, that Thunberg serves as a necessary corrective. It is complex, yes, but it is simple too, in ways we mustn’t lose sight of. And if (to paraphrase Arundhati Roy) we must accept the adult obligation to never simplify what is complicated, we must also recognize the child’s wisdom, and never complicate what is simple.

 

Have you ever seen the clip of the young boy realising, for the first time, that when we eat meat, we’re eating animals? He looks about three years old. “The octopus isn’t real is it?” he asks. I suppose he’s just double checking: because surely the octopus we marvel at in the aquarium and the picture books has nothing to do with the rubbery chunks now on his plate? Surely we didn’t behead an animal just to spruce up lunch? It’s extraordinary to watch: for the precocious and open-hearted child, yes, but also for his mother. She is present throughout his interrogation only as a kind and truthful answering voice. “Why are you crying now?” he asks her eventually. But we already know the answer. She’s crying because his questions were once her questions, and the world’s brutality was once not her fault. She’s crying because she has just realised that now it is.