There are some people who say that the recent upswing in hurricanes is a symptom of global warming, while others say that this is a predictable aspect of temperature cycles in the Atlantic. Here's my problem with arguments that say that x is causing deviation y from the normal: Just what exactly is normal? The problem is that defining normal is a conditional thing in a world filled with cycles. The normal that we know from the past five years may be all well and good for oil prices, but that is nothing when it comes to climate patterns.
Another hiccup: even if we do know the proper time scale for determining normal, do we have enough information to accurately describe the normal?
Our only recent measuring of the world, combined with the conceit that a human lifetime is significant, has left us in a poor position to complain about change. Another millenium or so should give us a sliver of perspective.