Even with imperfect data and some uncertainty, it's hard to imagine what kind of errors might be in the data set to give you a long-term trend.

We're not even at the peak of the current cycle — we're only halfway up and already we're seeing activity in the North Atlantic that's 50 percent worse than what we saw during the last peak in 1950.

This trend in sea surface temperature that's sort of relentlessly rising and the hurricane intensity that's relentlessly rising (means that) it's with some confidence we can say that these two things are connected and that there's probably a substantial contribution from greenhouse warming.

We were not expecting to get caught up in the global warming debate when we published our initial research last September. But the whole question of global warming is something that has to be confronted.

That may seem like a small number, but it makes a huge difference in ocean temperature and it has many consequences.

Sea surface temperature is the one that consistently comes up. What we found is that all the variables have an effect, but those tend to be on a storm-by- storm basis and not over a longer period.