National Geographic.com has a short article called
Arctic Ice Isn't Refreezing in the Winter, Satellites Show. "For the second year in a row a large amount of Arctic sea ice did not refreeze during the winter as it normally does, a team of scientists reports. This trend may indicate an overall shrinking of Arctic ice cover due to rapid global climate change."
I'll agee that global warming can also occur naturally - but this is believed to have only happened after things like massive volcanic eruptions, or getting hit with a very large
meteor. Man has now "progressed" to the point where we can now create natural desasters on our own.