The New York Times discusses weeds and climate change today.
But enhancing CO2 levels, Ziska has found, not only augments the growth rate of many common weeds, increasing their size and bulk; it also changes their chemical composition. When he grew ragweed plants in an atmosphere with 600 p.p.m. of CO2 (the level projected for the end of this century in that same climate-change panel “B2 scenario”), they produced twice as much pollen as plants grown in an atmosphere with 370 p.p.m. (the ambient level in the year 1998). This is bad news for allergy sufferers, especially since the pollen harvested from the CO2-enriched chamber proved far richer in the protein that causes the allergic reaction.