Did anyone catch Nova last night on PBS? Scary stuff...
One part of the show discussed how man-made global warming, caused by greenhouse gas emissions, have been partially offset over the years by global dimming, a phenomenon where pollutants from the same processes block or deflect some of the sun's rays, causing the opposite affect - global cooling.
While warming holds a significant edge over cooling, the cooling portion did help offset the warming significantly. Since scrubbers and catalytic converters and other polution prevention methods have taken hold, polution output in North America has been reduced significantly, thus tipping the balance much further towards warming.
Towards the end they reported that there are vastly different models that scientists use on the affects of all this on global temperatures, but one (admittedly closer to worst case) scenario had the earth gaining 25 F by 2100. If you want to invest in your great, great grandkids future, you might want to think about picking up some land inland from the Hudson Bay....
