It was cold this winter. Indeed, it was so cold, that people are saying that man-made global warming cannot be true.
There is evidence to the contrary and evidence that warming is partly natural. It could be both sides are correct, since climatology is an exact science.
Where I part with most environmentalists, however (especially the Zero Population Growth types) is whether warming is a bad thing. Indeed, if man-made warming is true, then perhaps we would still be in the minor ice age which lasted from the 14th Century to the late 19th Century and that only industrialization ended the ice age.
How does that make warming a bad thing? Indeed, we have still not returned to 13th Century temperatures. It should never snow in either Washington, DC or London, England. Greenland should have pastureland. We don't have these things. In fact, variable weather is not the artifact of warming, it is the artifact of unstable cool periods.
We may still be in the tail end of the cold period now. If emitting carbon dioxide is all that is keeping us from a return to pre-industrialization weather, than I say Drill, Baby, Drill and thank God for dirty coal. Now, if sea levels rise so that rich beach condos are washed away, so much the better. Homo Sapiens is a migratory species. People will move before they die off and will probably have a better life for having expended the energy to move.