The ice started melting

Look at the image. It seems normal? Yes. It's a bear looking for food...but look to the mountains.
Do you found any difference? No? So, look this:

"The Earth's ice cover is melting in more places and at higher rates than at any time since record keeping began. Reports from around the world compiled by the Worldwatch Institute show that global ice melting accelerated during the 1990s-which was also the warmest decade on record.

Scientists suspect that the enhanced melting is among the first observable signs of human-induced global warming, caused by the unprecedented release of carbon dioxide and other greenhouse gases over the past century. Glaciers and other ice features are particularly sensitive to temperature shifts."

And now? As you can see, the ice is melting. It's time to do something while we have time.

What are you waiting for?
Tomorrow can be late...

Sources:

http://www.worldwatch.org/node/1673
http://leveesnotwar.org/Images/LNW_2007Arctic.IceMelt.jpg