A major new study has concluded that much of the UK's recent surge in extreme summer heat has been driven by cleaner air rather than increasing air pollution, with researchers arguing that decades of falling aerosol emissions have allowed more of the sun's energy to reach the Earth's surface.
The research, conducted by scientists at the Barcelona Supercomputing Center in collaboration with the UK Met Office, found that the sharp reduction in sulphate pollution since the 1980s has played a major role in Europe's temperatures. The findings were published in the journal Geophysical Research Letters. Europe has warmed around twice as fast as the global average since the 1980s and is now approximately 2.3°C warmer than pre-industrial levels, compared with a global average of roughly 1.3°C.
Researchers say much of that additional warming can be traced to cleaner skies following international efforts to reduce air pollution, including the 1987 Montreal Protocol, which dramatically cut emissions of ozone-depleting substances and contributed to a broader reduction in atmospheric aerosols. "On the one hand, the cleaner air lets more sunlight reach the surface," said Professor Markus Donat of the Barcelona Supercomputing Center. "On the other hand, we think that this additional energy causes atmospheric circulation changes that bring even more heat to Western Europe."
Sulphate particles reflect sunlight back into space, producing a cooling effect. As those particles have disappeared from the atmosphere, more solar energy reaches the ground, increasing surface temperatures. The study also found that cleaner air has altered atmospheric circulation by weakening the temperature contrast between the Arctic and the tropics. Researchers say this has slowed large atmospheric Rossby waves and increased the likelihood of persistent "heat dome" weather patterns becoming locked over Europe.
Scientists linked the phenomenon to several of Europe's most severe recent heatwaves, including those experienced in 2003, 2006, 2015, 2018, 2019 and the record-breaking temperatures seen across Britain in June 2026, when temperatures reached 37.3°C at Santon Downham in Suffolk. Lead author Pedro Roldán-Gómez said the reduction in sulphate pollution has effectively revealed more of the warming caused by greenhouse gases. "Now that the sulphates are disappearing over Europe we can see the full impact of the carbon dioxide emissions," he said. "Most of this excess warming over Europe can be linked to the reduction of particle emissions."
With sulphate emissions now largely stabilized across Europe, the researchers said the continent's additional warming relative to the rest of the Northern Hemisphere could begin to slow, although similar "unmasking" effects may emerge elsewhere as other regions continue reducing air pollution.
