There are 2, er 3 issues.
1) Is the ice melting? Y/N
Most people would say Y.
2) Is the melting unusual? Y/N
It is on the last 100-200 year or so timescale, but it's not clear if it is on other time scales. Scientists have to answer this.
3) Is the melting caused by what humans have done and are doing to the environment? Y/N
This is where it gets hairy. Some say yes; some say no; some say we don't know and won't know until we do more studies and shouldn't change economic policy until we do; some say we don't know but the risk is so large that we have to act as if we do know. Scientists and politicians have to answer this.
I'm in the "we don't know, we need more studies, and we should take the risk seriously but not exaggerate it" camp. I remember in grade school that we were taught that the next ice age was just around the corner. And I'm also given pause by the recent controversy about the [link|http://www.techcentralstation.com/102704F.html|"hockey stick"] temperature measurements/extrapolations. We need to know more, there's no doubt, but we shouldn't take the problem lightly.
Cheers,
Scott.
(Who realizes that there are some scenarios where ice ages can result from too much CO2 in the atmosphere.)