Britain’s intense summer heatwaves may be a consequence of cleaner air, as new research suggests decades of falling pollution have allowed more of the Sun to reach the Earth’s surface.
The study, published in Geophysical Research Letters, concludes that much of the additional warming across Britain and western Europe since the 1980s is linked to the sharp decline in airborne particles known as aerosols, which previously reflected sunlight back into space.
Europe has warmed around twice as fast as the global average over the past four decades, with this summer alone set to bring a fourth heatwave next week.
While global temperatures have risen by approximately 1.3C since the pre-industrial era, Europe has experienced an increase of about 2.3C, leaving scientists searching for explanations for the continent’s more frequent extreme heat events.
Working with the met Office, researchers from the Barcelona Supercomputing Centre found reductions in sulphate emissions have played a significant role.
Sulphates, once released in large quantities through industrial activity, acted as a cooling shield by reflecting solar radiation.
As air quality improved and pollutants declined, more sunlight reached the Earth’s surface, therefore amplifying temperatures.
The researchers also found that cleaner air has altered circulation in the atmosphere, trapping heat in place.
Additional heat is believed to weaken the temperature difference between the poles and the tropics, slowing the jet stream and increasing the likelihood of persistent weather patterns.
These stalled systems can trap high-pressure “heat domes” over Europe, prolonging periods of extreme heat.
Professor Markus Donat, of the Barcelona Supercomputing Centre, said cleaner air has a dual effect.
He said: “On the one hand, the cleaner air lets more sunlight reach the surface. On the other hand, we think that this additional energy causes atmospheric circulation changes that bring even more heat to Western Europe.”
Scientists believe this mechanism contributed to the heatwaves seen this summer, as well as major European heat events in 2003, 2006, 2015, 2018 and 2019, which resulted in tens of thousands of excess deaths and widespread agricultural damage.
The study also suggests current climate models have underestimated the influence of atmospheric changes.
While many models predicted jet stream shifts would slightly reduce European warming, researchers instead found circulation changes increased excess warming by almost 30 per cent.
Lead author Pedro Roldán-Gómez said Europe has warmed around 1C more than other regions in the Northern Hemisphere since 1980, and about 1.5C more than the global average.
The researchers stressed that reducing sulphate pollution remains a major public health success, and that keeping such emissions would have worsened the overall effects of climate change.
Instead, the findings suggest cleaner air has “unmasked” the full impact of greenhouse gases already present in the atmosphere.
With sulphate emissions in Europe now largely stabilised, scientists expect the continent’s rate of excess warming may begin to slow, leaving future temperature rises more closely tied to greenhouse gas emissions.
However, they warned that as Asian nations continue to reduce air pollution, similar warming effects could emerge in other parts of the world.
