Politically it is not correct to say such things, but reality is that the world has been under ice age for about 90% of time and livable temperatures we have now only have occurred 10% of time, so we are furtunate to live under these conditions.

It was an interesting article in "Nature" about 5 years ago where the author claimed that global warming due to human activity started about 5000 years ago due to deforestation and farming, and without this the temperature would now have been about 2 degrees colder than what it is.

He also concluded that without human involvement we are heading towards a new ice age. Actually he concluded that we are holding back the ice age by about 200-300 years due to our burning of fossile fuels. Unfortunately we are running out of fossile fuels to burn so eventually the ice age will come and devestate the world as we know it.

Basically, reading between his lines you could conclude "Enjoy the warmth while it lasts"