From pages 46-48 of the March/April 2007 issue of The American Gardener, the official magazine for the American Horticultural Society....
The Arbor Day Foundation has taken climate data for the U.S. from 1990 to 2004 and reworked the Plant Hardiness Zone Map. Go to their site, http://www.arborday.org/media/mapchanges.cfm, to view the newly released map and to check out what your current zone is. Note that this page starts with the 1990 map, based on 1974 to 1986 data. If you hit the "Play" button, it will morph into their new 2006 map. Then, if you hit "Differences", you can see the areas that have changed designations. Here in Clearwater, our zone has gone from 6 to 7, based on this data. (Can you say "global warming"?)
Along these same lines, research reports some of the changes in plant life that we can expect with increased CO2 levels:
1) Plants with short life cycles will adapt more readily than plants with long life cycles. Thus, annual weeds are actually expected to benefit from climate change.
2) Poison ivy grows 3 times larger and more vigorously when exposed to the expected 2050 levels of CO2 than it does at current levels. The oil, urushiol, that produces the allergic reaction and rash in humans is also much more potent at these CO2 levels.
3) Higher levels of CO2 may have already doubled the amount of ragweed pollen produced within the last 50 years or so. At the expected rate of CO2 increase, it is expected to double again by 2100. (Ragweed pollen is, of course, highly allergenic, affecting some 85% of the U.S.'s allergy sufferers.)
Last, but certainly not least, apparently research from several universities is linking Parkinson's Disease to pesticide exposure. The Harvard School of Public Health reported that chronic, low level exposure to pesticides increased the incidence of Parkinson's by 70%. Another study (from Mayo Clinic) reports that estrogen seems to provide some protection from this process, so pesticide exposure is more likely to produce Parkinson's in men than in women. Several other studies cited link Parkinson's to dieldrin, maneb, and organochlorine pesticides in general.
Gaia's comment: Just because we hide our head in the sand and yell, "More research!" doesn't mean that environmental changes detrimental to human life are not occurring. It's long past time that we take responsibility for our actions and start proactively addressing the situation.