Correlation does not equal causation. Yes, the SSTs were warmer than normal. That doesn't mean that the SSTs caused things to happen. No one has yet provided a definitive link between how higher SSTs will lead to modulation of atmospheric features such as shear or the locations of subtropical ridges. I asked Chris Landsea that very question just a month or so ago, to which he was in agreement. That's more worthy of another topic, however.

I just find it hard to draw any link between storms and any single variable, especially when both sides note a marked and statistically significant decrease in wind shear in the Atlantic during the same time period as the increase in activity (Eidos et al. 2006 paper). When someone can use meteorology to put it all together, then we might understand more. All the slide linked above shows in conjunction with the AMO is what has been observed; it does not explain why those features are all correlated or why the AMO brings them about, nor does it account for any year-to-year variation. It would also suggest much more development in the main development region, which we did not see last year. Color me unconvinced on both sides of the debate.

I agree that SSTs are warming. But to say they are the only factor at play leaves out much -- 60%, if the current studies are correct -- of the variability. If the effect of the warming SSTs is spread out over a large area, the studies should mention that. But, if it is spread out over such a large area, it's not going to result in any changes to the atmospheric patterns. We need a study that brings it all together and explains why it happens.

(Moved these posts to the appropriate forum.)