Indy's allergy season is getting longer. Blame climate change.
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Most major U.S. cities, including Indianapolis, are suffering from longer allergy seasons amid human-caused climate change, a new analysis finds.
Why it matters: Millions of Americans endure runny noses, itchy throats, and worse health effects each spring allergy season.
Driving the news: The freeze-free growing season lengthened between 1970 and 2024 in nearly 90% of the 198 cities analyzed by Climate Central, a research and communications group.
- In Indianapolis, the freeze-free season grew by 19 days between 1970 and 2024.
How it works: Climate Central uses the freeze-free period — the number of consecutive days with minimum temperatures above 32°F — as a proxy for allergy season.
- Above-freezing temperatures allow for better plant growth, and thus the release of more sneeze-inducing pollen.
Between the lines: "Climate change makes pollen seasons not only longer, but also more intense due to heat-trapping pollution," per Climate Central's report.
- "Higher levels of planet-warming CO2 in the air can boost pollen production in plants, particularly in grasses and ragweed."
Threat level: Nationwide pollen production stands to dramatically increase alongside high CO2 pollution, per a 2022 study highlighted in the report.
The bottom line: Pass the allergy spray, would ya?