The other day I linked my Forbes column that showed that there was no upward trend in global hurricane number and strength, the number of US hurricane strikes, or the number of October hurricanes. Given these trends, anyone who wants to claim Sandy is proof of global warming is forced to extrapolate from a single data point.
Since I wrote that, Bob Tisdale had an interesting article on Sandy. The theoretical link between global warming and more and stronger Atlantic hurricanes has not been fully proven, but the theory says that warmer waters will provide energy for more and larger storms (like Sandy). Thus the theory is that global warming has heated up the waters through which hurricanes pass and that feed these hurricanes' strength.
Bob Tisdale took a look at the historical trends in sea surface temperatures in the area bounded by Sandy's storm track. These are the temperature trends for the waters that fueled Sandy. This is what he got:
If he has done the analysis right, this means there is no warming trend over the last 60+ years in the ocean waters that fed Sandy. This means that the unusually warm seas that fed Sandy's growth were simply a random event, an outlier which appears from this chart to be unrelated to any long-term temperature trend.
Update: I challenge you to find any article arguing that Sandy was caused by anthropogenic global warming that actually includes a long term trend chart (other than global temperatures) in the article. The only one I have seen is a hurricane strike chart that is cut off in the 1950's (despite data that goes back over 100 years) because this is the only cherry-picked cut off point that delivers an upward trend. If you find one, email me the link, I would like to see it.