Remember the good old days when you only got the “spring sniffles” for a few weeks as the new leaves began sprouting on the trees? And doesn’t it seem like now, for some reason, you’re taking your antihistamine almost as often as you take your multi-vitamin? That’s not your imagination; that’s climate change at work.
A USDA scientist and his collaborators have proven that ragweed pollen in some parts of the northern United States and Canada now hangs around almost a month longer than it did as recently as 1995. The researchers’ results show those increases are correlated to seasonal warming shifts linked to climate change dynamics in the higher latitudes.
The scientists identified at least 10 locations—along a north-south line from Austin, Texas, to Saskatoon, Canada—that had at least 15 years of pollen data, from 1995 to 2009. The scientists compared the pollen data at each site to other data from the site, including latitude, the number of frost-free days, and delays in the onset of the first fall frost.
The news is enough to make your eyes water: From 1995 to 2009, the number of frost-free days at the higher-latitude study sites increased, and so did the length of the ragweed pollen season. In fact, by 2009, the pollen season was lasting anywhere from 13 days to 27 days longer than it had lasted in 1995. Also, there was a strong correlation between the length of the pollen season and the onset of the first frost of fall.
One of the biggest challenges in studying climate change is finding out how the plant kingdom is adapting to those changes. But the USDA scientist and his colleagues have reminded us that these changes don’t stop with crops—they also can have a significant impact on our health.
