No matter which side of the fence you are on global warming, there is no doubt that the earth's temperature has been rising in recent times.
The debate will continue on how much man has influenced this, but the evidence of the warming itself is irrefutable.
Check out this HD Animation from NASA of Arctic Sea Ice Decline (note, my browser plays it slowly and erratically, so you might need the latest Quick Time updates).
Arctic Sea Ice key points
So, is this a natural cycle, human influence, or a combination of the two?
Right or wrong, the American Meteorological Society's official statement on climate change is very stern. In the "Final Remarks"it says "The dominant cause of this warming since the 1950s is human activity".