[TigersEye]

...the FACT that in recent history, within 4,500 years or so, the entire north pole and all the land within the artic circle was once a lush tropical enviroment, a fact proven by the huge amount of animal carcasses; elephants, rino's, hippo's, tigers, wolf, fox etc. discovered throughout the region in that last century...

Source please.

[Cementjungle]

Source please.

Here's an excerpt from such a source:

About 55 million years ago, in an event known as the Palaeocene-Eocene Thermal Maximum, there was a period of rapid global warming. Scientists have not had any exact records of the climate in that region, however. Now with the accumulated sediment, researchers were able to determine that summer surface temperatures of the Arctic Ocean reached as high as 64 degrees Fahrenheit and then rose to 73 degrees Fahrenheit.

Unlike today's warming, however, the ancient rise in temperature was not associated with human activity, of course.

And the link: http://www.livescience.com/environment/060531_arctic_climate.html