Health and Climate Change

The Intergovernmental Panel on Climate Change's (IPCC) Sixth Assessment Report (AR6) concluded that climate risks are appearing faster and will become more severe sooner than previously expected, and it will be harder to adapt with increased global heating.

Research shows that 3.6 billion people already live in areas highly susceptible to climate change. Between 2030 and 2050, climate change is expected to cause approximately 250 000 additional deaths per year, from undernutrition, malaria, diarrhea, and heat stress alone.
One of the most noticeable impacts of climate change is the rise in allergies, particularly when the air becomes laden with pollen from blooming flowers and trees. Approximately 30% of the global population suffers from pollen-related allergies.

Recent research suggests that hotter temperatures could significantly exacerbate allergy seasons, with the spring bloom occurring up to 40 days earlier if greenhouse gas emissions continue at high levels. Conversely, in the fall, weeds and grasses may continue releasing pollen for up to 19 days later.

As temperatures rise, certain plants like oak and cedar are expected to produce more pollen overall, leading to increased rates of allergy attacks and asthma.

The early blooming of springtime flowers and trees is driven by warmer temperatures, as many plants use temperature cues to time their bloom. Conversely, in the fall, many weeds continue producing pollen until the arrival of winter. These pollen grains fill the air, carried by insects or drifting in the breeze, often triggering allergy symptoms and asthma attacks.

Allison Steiner, a professor of atmospheric sciences at the University of Michigan and co-author of the study, highlights this as an overlooked consequence of climate change with significant implications for human health.

This phenomenon is expected to be particularly pronounced in the Pacific Northwest, where alder trees are predicted to bloom earlier. Moreover, later-season plants may also start blooming earlier, resulting in overlapping pollen seasons that pose challenges for individuals sensitive to multiple allergens. Northern regions are likely to experience the most significant shifts in allergy seasons due to faster temperature increases.

William Anderegg, an associate professor of biology at the University of Utah, emphasizes the urgent need to address climate change, as it directly impacts people's health, particularly during allergy seasons.