El Nino activity was unusually active in the late 20th century compared to the last 700 years.
That's according to a recently published study led by two University of Hawaii researchers involving tree rings.
El Nino is a phenomenon that brings warmer-than-normal ocean temperatures to the tropical Pacific. It usually brings increased drought and a more active tropical cyclone season to Hawaii.
National Weather Service meteorologist Derek Wroe said, "It almost seems like it's a paradox that you'd have drier conditions with more hurricanes. But one thing to keep in mind here is that, when a hurricane passes over the islands, it's obvious that the destruction that that would cause would be immense. But one of the other things is that, it does bring water, but it brings so much water over a short period of time, that it really doesn't help us in the long run."
The two scientists conducted the study while at UH Manoa's International Pacific Research Center. They led a worldwide team that analyzed more than 2,000 tree rings, which are good recorders of temperature and rainfall.