My understanding is that there are lot of other things that can impact climate, some of them human caused, such as changing land usage, deforestation and urbanization. Generally, those have a more localized impact.

Globally, it appears, though, that things tend to balance out. Where one place experiences a warming, someplace else is experiencing an abnormally cool or cold period. For example:

“It is the winter that refuses to go away in northern Manitoba and most of the eastern Arctic.

Prolonged cold snowy conditions in the Hudson Bay area are expected to obliterate the breeding season for migratory birds and most other species of wildlife this year.

According to Environment Canada, the spring of 2009 is record-late in the eastern Arctic with virtually 100 per cent snow cover from James Bay north as of June 11.

May temperatures in northern Manitoba were almost four degrees C below the long-term average of -0.7, and in early June, temperatures averaged three degrees below normal.

National Oceanic and Atmospheric Administration images confirm snow and ice blanket all of northern Manitoba, part of northern Ontario and almost all of the eastern Arctic as of June 12. U.S. aerial flight surveys confirm the eastern Arctic has no sign of spring so far.” Big chill in Churchill – Winnipeg Free Press

Ten years from now, I honestly believe that the Earth will be cooler than it is now and continuing to cool and NOT because of anything that man will do to try to influence the climate.

And a colder planet is NOT a good thing. I’d prefer that global warming were a real issue rather than an expensive wild goose chase.