Climate breakdown has extended the pollen season in the UK and mainland Europe by between one and two weeks since the 1990s, a study has found, adding itchy eyes and runny noses to the harm wrought by fossil fuel pollution.

The finding may be less dramatic than the floods and wildfires typically associated with a warming planet but represents a “huge” increase in the combined suffering of tens of millions of people, the researchers say.

“It’s one of those everyday indicators that show something is getting a little worse for a lot of people,” said Joacim Rocklöv, an environmental epidemiologist at the University of Heidelberg and co-director of the report. “The suffering of people from these changes can be very large.”