Scientists agree that climate change will have many unforeseen consequences. One potential consequence that has been predicted but not widely discussed is the effect of rising CO2 levels on the production of pollen in common allergens.
In 2000, researchers at the USDA published the results of a study to test the effects of increased CO2 on pollen production in ragweed (Ambrosia artemisiifolia). They exposed ragweed specimens to differing levels of atmospheric carbon dioxide: 280 ppm (historical), 370 ppm (current), and 600 ppm (predicted). What they found makes me want to sneeze. Pollen production increased from 5.5 grams, to 10 grams to 20 grams respectively. According to the researchers, pollen production rose almost 400% with a 200% increase in CO2.
A study conducted by researchers at Harvard University in 2002 has produced similar results. According to the Harvard study, ragweed grown at 700 ppm CO2 produced 61 percent more pollen when compared to ragweed grown at 350 ppm.
That’s not all. More recent research by Duke University concluded that rising CO2 will likely give selective advantage to more poisonous forms of poison ivy (Toxicodendron radicans).
Clearly global warming is going to have impacts unforeseen by even the most discerning researchers. This is because global temperature increases, coupled with rising levels of atmospheric CO2, will impact so many different climatological and biological systems.
The implications are mind boggling. Even within the range of fairly well established research, like the relationship between ragweed and CO2, it is difficult to predict the effects this will have on our health care system and our quality of life. What is clear, however, is that we are in for some massive changes in the next 20 to 50 years.