PHOENIX — If you feel like allergy season never seems to end, you’re not imagining it. Across the U.S., and right here in Arizona, climate change is making pollen problems worse — and stretching them out longer.

Longer growing seasons, longer allergy seasons

Warmer temperatures caused by carbon pollution are adding more “freeze-free” days to the calendar each year. That extra time allows plants to grow longer, bloom later, and release more pollen. A of 203 U.S. cities found the freeze-free season has grown about 15 days longer since 1970. In Arizona, that number averages 7 extra days for Prescott and Flagstaff.

Ragweed: The fall culprit

Ragweed is the main driver of fall allergies in Arizona. Just one plant can produce up to a billion pollen grains, light enough to float on the wind a

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