I think we can agree that something is happening. But what is it, and why? Some people insist that humans have caused all the changes we're seeing. Al Gore comes to mind. Ironically, it seems that every time he gives a speech on global warming, the city that he's in experiences either record cold or record snowfall. Robert Felix has an interesting theory about the climate. The link to his website is below. See the eighth link down the site.
Astronomers have found in the last few years that the sun's output is more variable than previously thought. That's bound to have some effect on the weather. Ironically, pollution helps keep the weather cool--particulates in the air block some of the sunlight from reaching the ground.
I will grant for the sake of argument that human activities have some effect on climate, but most people have no idea how puny human efforts are compared to nature. The eruption of Tamboro in 1815 in Indonesia put so much dust into the air, it altered weather around the world. 1816 was called "the year without a summer." New England had snow in June and killing frost in July.
In short, there are more variables to climate change than we typically hear about.