Aaron Bastani interviews Bill McGuire, professor emeritus of geophysical and climate hazards at University College London, volcanologist, and author of Hothouse Earth and The Fate of the World. McGuire argues that climate breakdown is accelerating far faster than most people — and especially political elites — are prepared for: 2026 has brought the UK’s worst arable harvest on record, unprecedented drought, and a heatwave that started in May. He walks through five billion years of Earth history to show there is no precedent for today’s rate of heating, dismisses geoengineering as a dangerous delay tactic, and says societal and economic breakdown could begin “anytime from the 2040s” on current trajectories. He also explains why he personally moved uphill to the Peak District and why he thinks billionaires’ New Zealand boltholes won’t save them.
McGuire describes a childhood passion for rocks and fossils, an abandoned astronaut ambition (his maths wasn’t good enough), and a PhD spent on Mount Etna (1977–1980) — “eating pasta, drinking red wine and looking at rocks.” He moved into lecturing and volcanic hazards, then in the late 1990s began asking how volcanoes and earthquakes interact with climate, funded by European Commission research grants. His documentary work included Super Volcano (1999, mostly about Yellowstone) and Mega Tsunami: Wave of Destruction (2000), based on his research on La Palma in the Canaries, where a ~500 cubic kilometre flank of the Cumbre Vieja volcano is slowly slipping and will one day collapse into the North Atlantic, initially raising a wave up to a kilometre high. Timing is unknown — “hundreds of years, thousands, even… but it could be next year.” He flags Campi Flegrei, the volcanic caldera in the middle of Naples, as Europe’s most under-appreciated hazard: decades of swelling, a recent magnitude-4.7 earthquake, and an eruption possible “almost at any time.” Yellowstone, by contrast, shows no eruption signs — its magma is not connected up.
After the 2004 Indian Ocean tsunami, Tony Blair’s government set up a natural hazards working group (chaired by David King, with McGuire as a member) recommending global monitoring and response plans for catastrophic geophysical events. The report was handed to the UN around 2006 and “was never seen again.” McGuire stresses that many disasters aren’t even improbable: the fault behind the 2004 tsunami was known and overdue, and an American geophysicist spent his own money warning villages and officials to no avail. Politicians, he says, simply aren’t interested — as seen in the weak response to this year’s UK fire wave.
The 2003 heatwave (38°C in London, then a national record) convinced McGuire and his family they couldn’t cope with another. In 2007 they moved to a 500-person village 1,000 feet up in the Peak District, near Derby’s rail links, into a house built in 1676 with two-thirds-of-a-metre stone walls that keep out the heat. The move was also about a small village school, an acre of land for growing food, and — only half-jokingly — sea levels: “if all the ice melts, the sea will come up just to Derby.” He rejects the survivalist label but is preparing on common-sense lines: more water butts and harvesting, seed saving, and soon bulk storage of flour, sugar and cooking oil in the cellar.
2026 is the UK’s worst arable harvest on record; the other three worst have all come since 2020. Over the past five years Britain lost the equivalent of a year’s bread supply, and the National Farmers Union has warned of food shortages. McGuire: once you reach rationing, “everything changes. Everything’s up for grabs.” As a climate scientist he expected this trajectory, but “the speed is just staggering” — much sooner than he predicted. The summer’s heat was also unusual in its shape, not just its size: 35°C in May, 38 days at or above 30°C, four consecutive months over 30°C, and drought places recording two rainless months — nearly double the 1976 benchmark of 37 days.
El Niño is the planet’s second-biggest climate signal after the seasons; the record event (1877) reached about 2.7°C in the eastern Pacific, and current estimates point towards something approaching 4°C — unprecedented, with unknown knock-on effects. Because 2024 already averaged over 1.6°C above pre-industrial on the back of the last El Niño, McGuire expects 1.7°C or higher next year. He calls the 20-year averaging convention for confirming 1.5°C “bonkers” — it would take a decade to confirm a breach — and says fossil-fuel interests exploit the ambiguity. At ~1.48°C and 40 billion tons of annual CO2 emissions, “1.5’s been dead in the water for years,” yet COP conferences still ritually pledge to hold it. He prefers “global heating” to “global warming” and “climate breakdown” to “climate change,” because the honest words match the direction of travel.
McGuire and Bastani take a tour of deep history: the Mars-sized body Theia that struck the early Earth, forming the Moon, tilting the planet and giving us seasons and tides; the emergence of single-celled life within a few hundred million years; the “boring billion” of stasis; and the Cambrian explosion 540 million years ago, when hard parts began leaving fossils. The centrepiece is the PETM (Paleocene–Eocene Thermal Maximum, 56 million years ago): a hyperthermal event that raised temperatures 5–8°C over a few thousand years via volcanic CO2 plus a methane-hydrate feedback. Today’s heating is running roughly ten times faster, with a rate of carbon injection far beyond anything in the geological record. Even worse was the Permian–Triassic “Great Dying” 250 million years ago, which eliminated some 95% of life. Other stops: the 8.2-thousand-year event, when post-ice-age crustal rebound triggered magnitude-8 Scandinavian earthquakes, a giant submarine landslide off Norway, and a tsunami that swept Scotland’s Shetland Isles — a vivid case of climate and geology interacting; and the Roman Warm Period, Medieval Warm Period and Little Ice Age, which were regional European fluctuations driven mostly not by the sun — the standard denier talking point (including Piers Corbyn’s solar theories) collapses because these were not global events and solar variation cannot explain modern warming. The year 536 may have been the worst in recorded history to be alive, thanks to overlapping volcanic eruptions cooling Europe.
The planet has cooled for 50 million years; we are now rewinding that decline. Current warming has already returned us to the last interglacial (the Eemian, ~120,000 years ago, 1–1.5°C above pre-industrial). At 2–3°C we reach Pliocene conditions of about 3 million years ago — a best case that still implies seas eventually 15–25 metres higher. Atmospheric CO2 (~430 ppm) was last this high around 15 million years ago, when temperatures stood 7–8°C above pre-industrial — hotter than CO2 alone explains, possibly due to breaking up tropical cloud cover, a process McGuire says is already observable. He thinks even at 4°C feeding eight billion people becomes desperately hard; at 6°C of average warming, land temperatures of 40–60°C make much of the planet effectively uninhabitable.
Dry-bulb heat (ordinary temperature) is survivable in dry air; at 35°C wet-bulb — heat plus saturation humidity — the body can no longer cool by sweating, and organ failure follows within about six hours regardless of shade or water. Such conditions once occurred only briefly in the Gulf, South Asia, Central America, before storms broke them; now they are lengthening and spreading (China’s humid North China Plain, home to 400 million, is a particular worry, as is southern Europe eventually). Asked about the mass-casualty scenario in Kim Stanley Robinson’s The Ministry for the Future, McGuire says that a few years ago he’d have put it mid-century; on current speed, within 20 years “wouldn’t be a surprise.” Rising seas follow the same acceleration: from 1.5mm to nearly 5mm a year, with doubling every ~20 years — he wouldn’t be surprised by 2 metres by 2100, enough to put the sea into Cambridge through low-lying East Anglia.
Burning all known fossil reserves would add ~3.5 trillion tons of CO2 to the 2.5 trillion already emitted and warm the planet by around 16°C — rendering it essentially uninhabitable — a fact he throws at those who see no reason to stop. On solar radiation management, he notes volcanic precedent: sulphur injections disrupt monsoons and weather patterns. The scheme would require maintaining ~20 million tons of SO2 in the atmosphere indefinitely, cool only about 1°C, demand universal global buy-in, and end in “termination shock” if stopped — “like giving a poisoned patient an antidote while pumping them full of more poison.” Carbon removal fails on scale: crushed basalt on farmland would need to cover half the world’s fields to remove 2 billion of the 40 billion tons we emit annually. Sensible local measures — white roofs, mass tree planting — he endorses; Silicon-Valley-style planetary pilots he expects would be quickly detected and would anger monsoon-dependent countries like India. Electric cars, he concedes (he’s on his fourth, his village leaves little choice), are “the least bad” but a like-for-like billion-car swap solves nothing — the Jevons paradox means efficiency breeds consumption, and real transformation means low-carbon public transport.
Decarbonization is the crux: 38 of the 41 billion tons of annual CO2 come from burning fossil fuels. The UK’s new prime minister, Andy Burnham, gets credit for acknowledging climate breakdown but criticism for being “pragmatic” about North Sea oil and gas — the right framing, McGuire says, is “we cannot afford to burn this,” and a war-footing rollout of heat pumps, boilers’ retirement, and renewables. Meat matters for health, land and biodiversity, but fossil fuels are the decisive front. On becoming multiplanetary, he doubts we’ll last long enough, invoking Fermi’s paradox: technological intelligence without wisdom self-destructs — “we’ve got intelligence. We’ve got no wisdom.” He coins Homo sultus (“stupid sapiens”) in The Fate of the World, calls the biodiversity crisis the first great extermination (rather than the “sixth extinction,” since the previous five had no deliberate agent), and recalls the 100-million-strong passenger pigeon flocks that were shot into oblivion within decades. Finally, the billionaires’ New Zealand retreat fails on its own logic: when society collapses, servants and security staff have no reason to obey — money means nothing. As he puts it, the future warlord of post-apocalyptic New Zealand “will be a former kitchen porter.”