Hay fever sufferers are now enduring symptoms for up to two weeks longer than they did in the 1990s, a new review has revealed, directly attributing the extended misery to the escalating climate crisis. The Lancet Countdown in Europe 2026 report highlights that climate change has "prolonged the pollen season", significantly increasing the duration of exposure to allergens for millions.
The report, published in The Lancet Public Health, details how shifting weather patterns are altering the flowering seasons of plants that release allergenic pollen. Researchers observed an earlier start to the season by one to two weeks for birch, alder, and olive pollen between 2015 and 2024, when compared with the period of 1991 to 2000. Hay fever, an allergic reaction to pollen from trees, grass, and weeds, typically worsens in warm, humid, and windy conditions when pollen counts are highest, usually from late March to September.
Anne Biggs, deputy head of clinical services at Allergy UK, underscored the widespread impact: "Hay fever impacts millions of people in the UK each year. While for some their symptoms can be mild, for many their hay fever symptoms impacts their quality of life." She added that "research and understanding into the timing and length of the different pollen seasons is vital to support clinicians to ensure treatment and management of allergic conditions can be optimised."
Dr Samantha Walker, director of research and innovation at Asthma and Lung UK, warned of severe health implications. "A longer pollen season will bring more misery for people with hay fever," she stated. "We know from a recent survey that nearly half of people with asthma and more than a quarter of those surveyed with COPD experience symptoms triggered by pollen. If people are allergic to pollen, it can inflame their airways and cause terrifying breathing conditions, which can lead to life-threatening asthma attacks and COPD flare-ups."
The findings emerge as a separate allergy strategy, backed by charities, patients, and doctors, points out that the UK has some of the highest allergy rates globally, affecting 39 per cent of children and 30 per cent of adults. This strategy also warns that care and treatment for allergies are "dramatically under-resourced" within the NHS.
Beyond hay fever, the comprehensive report on climate change and health in Europe, compiled by 65 researchers from 46 academic and UN institutions, paints a stark picture of broader health risks. It reveals a 318 per cent increase in heat health warnings across Europe compared with the 1990s, indicating a significant rise in heat-related health dangers. The authors estimate approximately 62,000 deaths in Europe were attributable to heat in 2024 alone, with nearly all European regions experiencing increased heat-related mortality between 2015 and 2024 compared to 1991-2000.
The report also highlights a concerning surge in mosquito-borne viruses across Europe, with the average risk for dengue outbreaks increasing by 297 per cent between 2015 and 2024 compared with 1981 to 2010.
Professor Joacim Rocklov, from the University of Heidelberg and co-director of the Lancet Countdown Europe, issued a grave warning: "Across Europe, the health impacts of climate change are intensifying faster than our response is keeping up. Rising heat, worsening household air pollution, exposure to infectious diseases and growing threats to food security are placing millions of people at risk today – not in a distant future." He stressed that "the choices we make now will decide whether these health impacts worsen quickly or whether we begin moving toward a safer, fairer and more resilient Europe."
The authors further caution that continued reliance on fossil fuels exacerbates these health risks. Dr Hannah Klauber, from the Lancet Countdown Europe’s working group on economics and finance, commented: "As the conflict in Iran brings renewed uncertainty and suffering for people across the region, we are again reminded that as long as Europe relies on fossil fuels our economies, our public budgets and ultimately our health will remain vulnerable." She concluded: "Accelerating the transition to clean, secure energy is not only an environmental necessity, but a vital opportunity to safeguard for people’s wellbeing."
