Since the high here today is due to be -7, all the schools are closed and the papers are talking about the coldest temps we have seen in 10 years, it seemed like a good day to say something about Global Warming. I think we can all agree that temperatures are either warming, cooling, or staying the same. It doesn't appear to be an ice age (although in MN today, we might not ALL agree with that), so other than Young Earth Creationists, that would mean that we are in an inter-glacial period -- they tend to run 10-20K years, and we have been in one for over 10K years, so at some point here, cooling is likely (like in the next few thousand years).
The last time we slipped into an ice age (20K+ years ago), the scientists were not gathering as much data, so we are a little imprecise on exactly how that happens. Does it warm first, then cool? Does it slowly cool? (like over a few thousand years), does it drop like a rock to the deep freeze? I'd say the scientific answer to that one is "we don't know". Now will humans cause the planet to warm "artificially" (interestingly, many scientists would consider us a product and PART of nature) ? If we do, we may head off 5K thick sheets of ice covering this part of the US, and I know Al Gore would find that to be a tragedy.
Might the planet be warming? Sure. Might it be caused by humans? Sure. How about caused by the Sun? I bet it could be that too. Some other sort of cycle that we don't understand (natural carbon release, water vapor ratios, methane, dust, etc) ? It seems impossible to believe that our scientists have ruled out "all other options" -- although it is never hard to believe that some group of politicians and the MSM may have done so.
I personally suspect that much like the stock market, there are lots of jumps and jags in larger scale trends that can really give folks a "head fake" if data from decades or even centuries is focused on rather than the longer term trends of millennea. Much as the market may go up for a few weeks, months, or even year in the midst of a decade long bear market, the temperatures can go up and down in shorter periods and the long term trend is hard to discern.