The trail of clues that our planet might be heating faster than we realised

This July, during Britain’s record-breaking hot summer, a curious row broke out on X over climate science.

Reform’s deputy leader Richard Tice shared a Telegraph article headlined: “Heatwaves caused by fall in pollution.” He said cleaner air, rather than carbon dioxide, was behind higher temperatures and claimed the public had been “gaslit”.

He was wrong to suggest that carbon dioxide is not the primary driver of global warming. But the science he was distorting is real – and much more interesting than his original claim.

The fossil fuels that we’ve been burning for more than a century produce two very different kinds of pollution. As is well known, carbon dioxide warms the Earth. But less well-known is sulphur pollution, which forms vast numbers of tiny particles in the air and reflects sunlight back into space, partly counteracting the warming effect of carbon.

Thanks to clean-air policies around the world – like the US’s Acid Rain Program in the early 1990s, that reduced gas pollution from power plants – sulphur emissions are falling sharply while carbon dioxide emissions remain near record highs.

Scientists increasingly believe the loss of that cooling effect is slightly speeding up global warming.