It’s a radiant morning in Fitzrovia, central London. Hydrangeas spill from outdoor pots and a crocodile of high-energy, hi-vis-wearing primary schoolchildren ripples along the cobbled street, squealing with laughter. Upstairs, in the living room of Ian McEwan’s stylish mews house, the windows are wide open. A bird darts in and out. As this pleasing scene unfolds, a sense of unease begins to flood our conversation. Britain’s national novelist is weighing up our chances of total annihilation.

“I think it would take a lot to create human extinction,” McEwan, 77, reassures me in his measured, professorial voice. “There are too many of us in too many corners.” And then, riffing off Adam Smith, he adds: “There’s a lot of ruin in a planet and we can do terrible things to it.”

Those terrible things are painstakingly laid out in his 18th novel, What We Can Know, which is set in 2119 on a ruined planet. A combination of nuclear war and ecological collapse, known as the “Derangement”, have led to a series of tsunamis that have killed off more than half the earth’s population and left the survivors living in a desolate waterworld.

America is a hell zone of rival warlords. Nigeria is the world’s standing superpower. Britain, meanwhile, is an isolated archipelago, “as peaceful and dull as a Hampshire parsonage in a Jane Austen novel”, as the protagonist Tom Metcalfe puts it. Our distant relatives move over drowned cities in sailing boats, watch the dolphins return to the Swindon Straits and marvel at the fact that we once thought nothing of flying 2,000 miles for a bit of sun.

“There’s something very sad about the idea that the future would envy us,” McEwan says, and indeed, this might just be his most melancholy novel. He has given us violence, psychopathy, incest, murder, torture, even penis amputation — yet none of his novels has left me feeling quite so ambiently disturbed.

What We Can Know is also a mystery. Tom is a humanities scholar at the University of the South Downs on England’s longest island, stretching 38 miles. He specializes in the literature of the early 21st century and is obsessed by one work in particular, an epic love poem, A Corona for Vivien, written by the great poet Francis Blundy for his wife. It was read aloud once at a literary dinner party in 2014 but then the sole copy was mysteriously lost.

Tom’s life’s work is to piece together what happened at this “immortal dinner” from emails, WhatsApps and journal entries — and just maybe to discover the whereabouts of the legendary poem, which he hopes is buried at Francis and Vivien’s Gloucestershire barn (not far from McEwan’s Cotswolds manor house near Stroud).

What We Can Know may well have created a new genre: the postapocalyptic campus novel. Imagine AS Byatt’s Possession crossed with Cormac McCarthy’s The Road. Dark academia meets the big ideas novel, all conveyed in McEwan’s trim, beautifully ordered sentences. He insists it’s not dystopian fiction, but “a novel of highly nuanced, fragile optimism” about our “moral responsibilities to the future”. We still have time to act, he stresses.

He was initially wary of writing another story about environmental disaster after his satirical novel Solar (2010) went down badly with American reviewers, some of whom felt the future of the planet was no laughing matter.

“Either you write a kind of dystopian future, which I think has a paralyzing effect on people’s morale, or you are paralyzing the novel with moral concerns,” he says. “I have been pondering how to get round this, and my only answer to this is you have to not just write about climate change. You have to find a way to write about something else.”

That something else here is sexual jealousy. What Tom and his fellow academic Rose uncover is a gossipy melodrama of love triangles and quadrangles among a group of Oxford poets and academics. I had a hunch as I was reading that much of the dinner party dialogue was lifted from McEwan’s own circle, which has included Martin Amis, Christopher Hitchens, Salman Rushdie and Julian Barnes as well as the poets Craig Raine and James Fenton.

Salman Rushdie and McEwan at the Booker Prize awards ceremony in 1998, where McEwan’s novel Amsterdam won the titular prize.

McEwan confirms his inspiration for one scene, in which the pompous Blundy ticks off a young man for using the adverb “hopefully”, came straight from Amis and Hitchens’s bar talk. “Martin and Christopher said only f***ing nitwits and illiterates say ‘hopefully’. To them, it was all part of the decline of the West, full of idiots who were going around saying, ‘hopefully’. I wish they were alive to read my riposte.”

He also confirms that the central poem has a real-life source in a sonnet sequence, Marston Meadows, written during the pandemic by the Oxford poet John Fuller for his wife, Prue, to celebrate their long love. “I was so taken by this poem that it led me into a novel,” he says.

And while the first 50 pages are not as instantly appealing as Atonement or Enduring Love, or as driven as Saturday, as a whole this feels like McEwan’s most richly layered work — “a gathering up of all I know”, he tells me. He says he didn’t do any research for the book. “I’ve lived enough life, and I want to just treat my mind as a garden through which I can stroll.”

It’s perhaps no surprise, then, that the story contains echoes of just about all his works. As in Saturday, there is a moving description of the effects of Alzheimer’s on patient and carer (McEwan lost his mother to the disease; his son William leads a Cambridge research team to find a cure). And it employs his signature trick: the withheld narrative, a secret that acts like a time bomb, waiting to unsettle everything.

At times the book is almost too sad to take in, especially given the sense of social order unravelling in the past ten years. Of Donald Trump’s second term, McEwan says: “I didn’t really think he’d have a second crack at the presidency, nor did I think it would be quite as radical as it’s turned out to be. It’s worse than we dreamt of … I mean, look at his so-called art of the deal with Putin. He always has all the cards and he throws them out — extraordinary.” McEwan chose 2014 as the halcyon year because he already wasted enough time “stewing” over Brexit and Trump.

The author himself seems perfectly at ease, enthusing about his grandchildren’s reading habits or a recent trip to Umbria with his wife, the author Annalena McAfee. But he admits to an abiding “metaphysical gloom” — “that sense of not trusting the future any more”. He describes the strangeness of lying in the comfort of his bed listening to the BBC’s international editor, Jeremy Bowen, on the radio deliver reports about amputee children in Gaza. He believes our casual consumption of these horrors, scrolling our phones over our morning coffee, may have “coarsened us”.

He also describes “quite a fierce argument” he got into about the Israel/Gaza conflict with his host in Italy. “I’d only been there ten minutes, and I thought, I mustn’t lose my temper. And I didn’t. I remained calm — but I think that we have become a little inured to human suffering.”

What position did he take, I ask. “That we shouldn’t be selling Israel weapons,” he states, and that “the civilian population of Gaza is caught between the murderous nihilism of Hamas and the murderous nihilism of the Israeli government”. He adds later that it’s “nonsense” to say criticism of Binyamin Netanyahu’s government is antisemitic. “The lesson of the Holocaust was that the indiscriminate killing of large numbers of people is wrong. Not that Israel may do whatever it wants. That’s the wrong lesson. It’s as simple as that.”

He finds it “insane” that people are being arrested for attending pro-Palestine marches. “Lots of elderly Quakers and retired professors of chemistry, all kinds of emeritus people being carted off by the police.” But unlike Sally Rooney, he’s not convinced that authors speaking out makes that much difference. He’s now stopped signing public letters to call for a ceasefire, he says. Surely as our so-called national novelist he has a powerful voice? “I’m quite sparing with it. Nearly every controversy that I’ve got involved with — and I’m not even on social media — just generates hot air.”

In the 1980s he was a part of the European Nuclear Disarmament movement and the terror of nuclear Armageddon has loomed over much of his work. It’s there in the depiction of Berlin during the Cold War in The Innocent (1990), in On Chesil Beach (2007), where the lovers meet at a CND meeting, and in his semi-autobiographical Lessons (2022), where a schoolboy during the Cuban missile crisis succumbs to his female teacher’s advances because he doesn’t want to be vaporized a virgin.

A scene from The Innocent (1993), an adaptation of McEwan’s book of the same name.

McEwan views the wave of hope that followed the collapse of the USSR as a brief blip followed by a slow regression. “We live in a time where Russia, China and the USA are all massively accelerating their production of nuclear weapons and modernizing them. There’s no point marching through Aldermaston, it won’t change a thing.”

But McEwan, raised in a working-class family, also paints a picture of progress and social mobility for his cohort. He was born in 1948 (the year before the Soviet Union got the bomb) to David, who worked his way up to be a major in the army, and Rose, a housewife, and was a beneficiary of the long postwar period of equity and uplift.

“My parents left school at 14. I had an incredibly good state education. It astonished my father that I went to university.” When he was growing up, he says, “you could depend broadly that the political programs had a chance of working. Now, the issues that torment the British psyche — shortage of housing, extraordinary disparities of income and prospects — seem too embedded to shift.”

He acknowledges his own good luck, not only in his generational wealth but also to be part of a literary Rat Pack who met often and, despite various fall-outs, remained close. Among this clique he is perhaps the most successful. But this novel seems to suggest that the real, most indispensable writers are not the novelists but the poets. It’s a sentiment that has been echoed by Amis and Rushdie.

McEwan and Amis were constantly discussing their favorite verse, particularly Philip Larkin’s, and he misses the “pile of coded references” they used to share since Amis died of esophageal cancer in May 2023.

“Martin was probably the most passionate reader I’d ever met,” he says. “He read all day, pencil in hand. He never spoke about being ill. He never complained about it. He didn’t want to be thought of as someone who was ill. But in one email, when we were discussing a book, he said, ‘I’m no longer reading with a pencil in my hand,’ and I knew that that was probably the closest he’d come to complaining to me about his state of health. I think the pencil represents an idea of the future. About a week later he was dead.”

McEwan talks about the loneliness of this stage of life, as you lose more and more friends. But he likes to remind himself that “in the old age stakes, I’m still, well, no longer a toddler, but maybe just going into the reception class of primary school in the art of getting old.”

I ask the dreaded question about legacy and he’s quick to answer. “I’d like to be remembered for more than Atonement.” He’s excited about the film of My Purple Scented Heart, his 2016 short story, which is being directed by Nina Raine (daughter of the poet), starring The White Lotus’s Aimee Lou Wood and Industry’s Marisa Abela. They are transforming it from a tale of literary jealousy between two men into one involving two women.

Keira Knightley and James McAvoy in Atonement (2007), directed by Joe Wright.

His favorite of his novels, he says, is Black Dogs (1992) “because it’s almost forgotten and it has much that is key to all the rest”. It pits a religious, intuitive sense of the world against a rational one and McEwan says he’s closer to trusting the rational these days. But don’t confuse rational for unemotional. He can be moved to tears by a Schubert piece on the radio or the recent death of his beloved 12-year-old border collie, Rab.

“I’ve cried more than once over the death of my dog. He was such a good friend to me. I know that many people who don’t have a dog or are not keen on them would think it was something strange. But he was part of the family. Such a personality, and we realized that the rhythm of our daily lives was all around him. That sudden absence has really been quite a big thing for us.”

Does he, I ask, think much about his own death? “I’m aware of it all the time, not in a tragic way,” he says. “It’s more a sense of stepping out on a sunny day and thinking, ‘Oh, this is so wonderful. I’ve got to treasure it because there might not be much of it left.’ It’s that sense of just how extraordinary it is, even simple things like vision … the reality of it, the sharpness, the color, the immediacy. Just everything is so precious.”

Johanna Thomas-Corr is the literary editor at The Sunday Times of London