"Over the long term, however, study findings show that global warming is the overarching factor [in ocean temperatures]; initial findings suggest that over the period 1970 to 2004 warmer sea surface temperature is the major factor in the increase in category 4 to 5 hurricanes globally... Data from Hurricane Katrina indicate that while sea surface temperature was warm enough for maintaining the hurricane along its entire path, the storm significantly intensified when it hit the deep pools of warm water in the Gulf of Mexico."