I am 26 years old. That means, in scientific terms, I have lived close to a generation (30 years). In that span of years, I have witnessed first-hand that the world is changing climatically. When I was going to kindergarten and elementary school, the snow would sometimes reach two meters high, and snow plows were heavily coveted.
As I grew into middle-school (different school systems, forgive me any inaccuracies), the snow would generally not be higher than a little over 1 meter high. As I went to highschool, snow would generally not reach higher than 0.5 meters. And in the last decade (better part of it anyway) I have generally not seen more than 20 centimeters of snow for the better part of the winter.

And all through this, I have also seen a rise in temperatures. With exception of some cold-streaks, I remember it generally being -20 C for most of the winter when I was in kindergarten and elementary school. Fast-forward to this winter: The coldest temperature we've had this winter, and that lasted three days, was -10 C.

This is not any evidence supporting the theory that humans are accelerating the global warming. It's just a statement of facts showing, from one persons view, that the Earth IS getting warmer.

We know CO2 can maintain heat more effectively than what the rest of gases in our atmosphere can do. We know we supply CO2 to the atmosphere by burning fossile fuel.

The question is, in my opinion: Is that a very bad thing? We, as a species, may have to evolve more to cope with this change. Can we do that fast enough? Probably not. We know the Earth has had the same amount of substances (periodic table) for as long as it has existed in the form we now know (with life). How come it has been able to sustain life if the environmentalists are correct in saying we are killing our planet? To me, they are right, if you add a statement to that: We are killing our planet as we know it today.

Before the world has become like the scenario in Highlander II: The Quickening (http://www.imdb.com/title/tt0102034/) I won't say either camp in this discussion is wrong or right. Maybe not even then, as it can be seen as a natural occurence only sped up by human interaction.