On 15 June 1991, the volcano Mount Pinatubo on the island of Luzon in the Philippines erupted violently, releasing an ash cloud on a scale so vast that seeing a photograph of it boggles the human mind. The eruption spewed out something north of 17 million tonnes of sulphur dioxide. For context, that’s roughly equivalent to 1,700 Eiffel Towers’ worth of material ejected out of the ground and into the sky.
The effects were global, albeit quite temporary. As a result of the explosion, NASA estimates that temperatures worldwide fell by about half a degree Celsius on average over the following fifteen months.
I lead with this because it reveals climate change as something that can be physically reduced. How does that work? Well, in this case the aerosol particles released by the volcano reflected sunlight back into space, reducing the amount that reaches the planet.
The Earth is warmed by sunlight. It cools by radiating heat back out into space. This is a delicate balance. Greenhouse gases absorb some of that outgoing heat. Raise their atmospheric concentration and the planet retains more energy, thus leading to warming.
The greenhouse effect, of course, is partially responsible for making this planet habitable in the first place. Atmospheric water vapour, carbon dioxide and other such gases keep the surface far warmer than it would otherwise be. That’s essential for life as we know it.
But industrial civilisation is changing the balance of the equation. Before industrialisation, the atmospheric carbon dioxide level stood at around 280 parts per million. The global monthly mean exceeded 428 parts per million in April 2026. This, obviously, is a rapid increase in a relatively short time span.
Effectively, current estimates are that human activity has raised global surface temperature by roughly 1.4°C on average compared with the second half of the nineteenth century. And so the public—especially in the West—has been relentlessly told by climate activists, science communicators, governments and so forth: take one fewer flight. Turn down the heating. Plant a tree. Check your “carbon footprint”. Get ready for “net zero”. But these efforts take place inside a global energy system moving decisively in the opposite direction.
