How climate change is making seasonal allergies worse

Studies from US and European universities show that, with rising temperatures over the past three decades, trees and grasses are pollinating earlier. Agro-meteorology stations show pollen counts have climbed by up to 21 percent in some regions.

Researchers confirmed that ragweed produces more aggressive pollen under high carbon-dioxide concentrations in experimental settings. This translates into longer and more severe symptoms for allergic rhinitis and asthma patients.

Clinicians report that cases not controlled by allergy tablets alone are up about 12 percent on the previous year. Public-health authorities recommend updating pollen-tracker apps and expanding early-warning systems that advise patients to limit outdoor activity on high-risk days.