Hay Fever and Allergies: Why Millions of Germans Suffer - Climate Change and Invasive Plants Worsen Germany's Hay Fever Crisis

Hay fever, an allergic reaction to pollen, is becoming more prevalent in Germany, affecting around 12 million people. Climate change and shifting environmental conditions are making pollen seasons longer and more intense. At the same time, invasive plants like common ragweed are spreading rapidly across the country.

Since 2020, the area infested by common ragweed (Ambrosia artemisiifolia) has grown sharply. Warmer temperatures and better monitoring have pushed the total affected land from roughly 870 hectares in 2020 to over 1,400 hectares by 2024. The worst-hit regions include Baden-Württemberg's Rhine Valley, parts of Bavaria (Upper and Lower Franconia), Rhineland-Palatinate, and areas of North Rhine-Westphalia.

Higher CO₂ levels are fuelling plant growth and increasing pollen production. Milder winters also cause pollen seasons to start earlier and last longer. Air pollutants—such as fine particulate matter, ozone, and nitrogen oxides—can irritate airways, making allergic reactions worse.

Genetics play a role in allergy risk, with children of allergic parents more likely to develop sensitivities. Epigenetics, where environmental factors switch genes on or off, can also influence susceptibility. Lifestyle matters too: frequent fast food consumption may raise allergy risks, while a vegetable-rich diet could ease symptoms. Meanwhile, early exposure to dirt and microbes, like that experienced by children on farms, appears to lower the chances of developing allergies.

The combination of climate change, invasive species, and pollution is making hay fever harder to avoid. With pollen seasons stretching longer and allergens becoming more potent, millions in Germany face worsening symptoms. Experts suggest dietary and environmental adjustments may help reduce individual risks.