Climate change lengthens Europe’s pollen season, study warns

Climate breakdown is quietly extending pollen seasons across Europe, adding weeks of misery for allergy sufferers while scientists warn the health impacts of global warming are already deepening across the continent.

Climate change has extended the pollen season in the UK and mainland Europe by between one and two weeks since the 1990s, according to a new study, cited by The Guardian, intensifying the burden of hay fever and adding to the wider health impacts of fossil fuel-driven warming.

The research, published in the Lancet medical journal, found that warmer temperatures and rising carbon dioxide levels are allowing plants to produce more pollen for longer periods, worsening allergic reactions that can range from mild discomfort to severe health complications.

The change may appear modest compared with floods, wildfires and heatwaves, but researchers say its cumulative impact is significant.

“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.”

The study found that pollen seasons for birch, alder and olive trees began between one and two weeks earlier in 2015–24 compared with 1991–2000. It also recorded a sharp increase in pollen intensity: since the last update of the report in 2024, the seasonal severity of birch and alder pollen has risen by 15–20% in southern UK, northern France, Germany and parts of eastern Europe.

Experts say climate change is also altering the distribution of allergenic plants. Separate research highlights the spread of invasive species such as common ragweed, which is expected to become a widespread health issue across Europe as it expands into new regions.

“Pollen allergies are a health risk of climate change,” said Katharina Bastl, a pollen researcher at the Medical University of Vienna, who was not involved in the study. “Global warming has already had an impact on pollination, [though] it is not that easy to assess and varies regionally.”

The report forms part of the Lancet Countdown, a major annual assessment compiled by 65 researchers from 46 academic and UN institutions, tracking 43 indicators of climate and health. It paints a broader picture of worsening climate-related health pressures across Europe.

Heat-related deaths have increased by an average of 52 deaths per million people over the study period, while daily extreme heat warnings have quadrupled. The report also found that climate change is facilitating the spread of infectious diseases, with the potential transmission of dengue fever more than tripling in recent decades.

Extreme weather conditions are also intensifying, with 983 of 1,435 European regions experiencing longer periods of “extreme to exceptional” summer drought over the past decade compared with the previous 40 years.

The authors warn that adaptation is now urgent, calling for greener cities, improved public health guidance, and a shift away from fossil fuel dependence. Annual fossil fuel subsidies reached €444bn in 2023, the report found, as governments sought to offset the energy shock following Russia’s invasion of Ukraine.

Cathryn Tonne, an environmental epidemiologist at the Barcelona Institute for Global Health and co-director of the report, said the “window for action” is narrowing but that meaningful benefits remain possible.

“Redirecting investments from fossil fuels into clean energy, improving air quality, safeguarding vulnerable groups and preparing health systems for rising climate shocks will deliver immediate and long-term health benefits.”

Despite the worsening trends, the report also highlights areas of progress. Deaths linked to fine particle pollution from transport in the EU fell by 58% between 2000 and 2022, while deaths from electricity-related pollution dropped by 84%.

“It’s a huge change,” said Rocklov. “It shows we can really benefit from the transition away from fossil fuels, and we can do it in a short time.”

By Sabina Mammadli