McGuire's Climate Warning: Coastal Cities Face Drowning Without Action

Volcanologist Bill McGuire has written a book about the future by studying the past. The geological record, he argues, never lies—and what it tells us about the centuries ahead is grim. His latest work opens with a stark comparison: three million years ago, during the mid-Piacenzian Warm Period, the Earth's sea levels sat roughly 25 meters higher than they do today. If atmospheric carbon dioxide concentrations remain where they are now, McGuire warns, that same fate awaits us. Every coastal city on the planet will be submerged. The water will claim vast stretches of land where hundreds of millions of people currently live.

What makes McGuire's argument particularly forceful is his contempt for the political half-measures that have become routine. Politicians in Ireland and beyond have recently retreated from climate commitments, framing their retreat as pragmatism. McGuire calls this "dangerous drivel." There is no pragmatism in doing less than the science demands, he insists. There is only recklessness. The choices being made now, he believes, will shape a world inherited by our children—a world fractured not just by climate breakdown but by the suspicion, prejudice, and violence that scarcity and displacement breed.

The summer of 2026 seems to have crystallized McGuire's sense of urgency into something sharper: anger. He describes humanity's relationship to the climate crisis in terms that suggest a shift in his thinking. We are no longer sleepwalking toward catastrophe, he argues. We are walking toward it with our eyes open, fully aware of what we are doing, and choosing to proceed anyway. That conscious choice—that deliberate disregard for consequence—appears to have moved him from concern into something closer to fury. "I am drawing on this anger in the fight to stop the madness," he says.

Yet McGuire is careful to distinguish between justified outrage and the paralysis of despair. He did not write this book to demoralize readers or to encourage the kind of fatalism that leads to inaction. His stated purpose is the opposite: to galvanize people into fighting back. There is still much to fight for, he insists. The catastrophe is not yet inevitable.

For readers encountering climate science for the first time, the book serves as a solid, if unsparing, entry point. McGuire does not soften his language or hedge his conclusions. Those already steeped in climate literature may find the material repetitive, even preachy at moments. But McGuire is most compelling when he anchors his argument in concrete, almost tactile examples. Every liter of gasoline burned today, he notes, represents the compressed remains of 24 tonnes of plant life from the prehistoric past. The continents themselves drift across the Earth's surface at a speed comparable to the growth of human fingernails—a comparison that somehow makes geological time feel both vast and intimate at once. These moments of vivid illustration are where his argument gains its full weight.