I've recently read "The goldilocks planet" for review (watch this space) and learned to appreciate the variability of Earth's climate on geological time scales. 3 million years ago (just a moment, for a geologist), we didn't have a permanent ice cap on the Arctic, and just over 30 million years ago, we didn't have one on the Antarctic either.
The way the carbon dioxide concentrations in the atmosphere are developing right now suggests that we may be heading back to those warmer days, and man-made climate change is happening faster than any previous geological climate change.
How are ecosystems in the Arctic and Antarctic responding to the loss of polar ice that is happening already? And which of their responses may lead to dangerous positive feedback loops? I've looked into these problems for my latest feature which is out in Current Biology today:
Life changes as polar regions thaw
Current Biology, Volume 22, Issue 14, R547-R550, 24 July 2012 doi:10.1016/j.cub.2012.07.009
Actress Lucy Lawless (Xena the warrior princess) took part in the Greenpeace campaign "Save the Arctic" (see this lovely interview in the Guardian. Maybe the scariest feedback loop of them all: that the disappearance of the Arctic ice will give us access to more fossil fuels to burn ...
PS More ice-melting news