So it looks like some very busy scientists decided to look a little deeper into the effect that En Nino has on hurricane development. How deep? Try 5000 years deep. It's some nice outside the box type of thinking but looking into soil records. I don't know much beyond what the article states in terms of their methodology, but it seems a viable way of looking into the past with hurricanes.
That's one of the difficult parts about meteorology in general and climatology in particular. We only have meteorological data going back some hundred years or so. Other than that, we have to rely on things like ice cores and fossils to deduce the likely meteorological setting of what took place. The Little Ice Age? We don't know the temps were cooler then because somebody was taking readings out at the airport. We know it from documentation at the time, signs of glacial advancement, and other oblique references to the weather conditions at the time.
That's one reason that climatology is such a difficult science to explain to the general public. You start talking about ice cores and glacial creep and you start losing your audience. Still, a lot of important stuff comes out of research like what these guys up in Mass. are doing. I hope we see a lot more of it so that we can continue to learn and understand our world a little more.