Before the global warming people tell us to stick our heads in the sand because the world is coming to an end (as we know it)....
Remember that the present earth climate, the one that "modern" humans have been living in, is over 100,000, that's one hundred THOUSAND years old. Now, let's look at the "rise in temperatures" that everyone is getting so worked up about. How long have accurate thermometers been around? About 50 years. And I mean thermometers that are accurate to 0.1 degrees, since it's always the global warming advocates telling us that the average temperature of the earth last year went up X.X degrees.
So, if there have been accurate thermometers for only the last 50 years or so, how can one believe any true temperature data beyond that ? The answer is you cannot. Especially when many of that temperature data is coming from cities that take temperature readings at or near an airport.
Next, it has been proven that the earth has cyclic climate changes. While I agree that the global rise in temperature has been faster than normal, it is not something that we can control all that much.