Weed and Ragweed Season Has Significantly Lengthened In Central Indiana Over The Past Ten Years

Pollen counts are affected by temperature, precipitation and atmospheric CO2 levels. Global climate change models suggest that atmospheric CO2 levels will double by the end of the century. Ragweed pollen counts have been shown to increase in response to increased CO2. We examined whether changes in atmospheric CO2 were associated with changes in weed pollen counts in central Indiana over the past ten years.