Global warming's impact on allergy sufferers in North America

The Asthma and Allergy Association of America in partnership with the National Wildlife Federation have issued a report on recorded impacts of to-date global warming trends in North American, specifically the effect on increased allergen production by plant life and extended allergy seasons.

In their report, released last Wednesday, the AAAA and NWF found that global warming will likely increase pollen counts in the atlantic coastal states and that the effect of climate change could push the economic cost of allergies and asthma well above the current $32 billion price tag. "The latest climate science makes it clear that allergies could get much worse," says Amanda Staudt, a climate scientist at NWF and the author of the report. "I really think this should be a wake-up call."

Higher concentrations of CO2 in the atmosphere generally speed plant growth, while warmer temperatures mean that spring - and with it, allergy season - arrives earlier. Spring-like conditions in the East are already arriving on average 14 days earlier than just 20 years ago.  The following chart indicates the change in vegetation growth in the United States over the past 16 year period, due to climate change.

Pollen from ragweed, which triggers most cases of spring hay fever, is projected to increase up to 100% between now and 2085 if fossil-fuel emissions continue to rise. More CO2 could make the ragweed pollen that exists more potent: if CO2 concentrations rise from current levels (385 parts per million) to 600 parts p.p.m., which could happen as soon as mid-century, ragweed pollen could become up to 70% more allergenic. An earlier, longer spring will just give ragweed more time to grow and give off pollen.

As the climate warms, it is likely to favor trees that produce pollen - like oaks and hickories - over pines, spruces and fir trees, which don't.  By 2100, once relatively cool states in the Northeast - including Vermont, New Hampshire and New York - could have the sort of highly allergenic trees now seen in the hotter Southeast, as species migrate north to adjust to the heat.

Look again at that data from 1990 to 2006, visible direct evidence of changes in vegetation in the United States brought about by a warming climate.  Yet another smoking gun with all the fingerprints of global warming and increased CO2 levels.

[ references : http://www.nwf.org/News-and-Magazines/Media-Center/News-by-Topic/Global-Warming/2010/~/media/PDFs/Global%20Warming/Reports/NWF_AllergiesFinal.ashx ; http://www.nwf.org/News-and-Magazines/Media-Center.aspx ]