Warmer Oceans Create Stronger Hurricanes
Posted on March 22, 2006
Researchers have found that warmer sea surface temperatures are the main reason for the increase in strong hurricanes. Last season saw several extremely powerful hurricanes. A LiveScience article (on MSNBC.com) says warmer surface temperatures are hurricane fuel.
In the 1970s, the average number of intense Category 4 and 5 hurricanes occurring globally was about 10 per year. Since 1990, that number has nearly doubled, averaging about 18 a year.The article said the warmer temperatures were more important in creating strong hurricanes than other issues like weak wind shear. The article said that scientists expect this pattern of stronger hurricanes to continue. Australia has already been hit with a powerful hurricane this year -- Cyclone Larry.Category 4 hurricanes have sustained winds from 131 to 155 mph. Category 5 systems, such as Hurricane Katrina at its peak, feature winds of 156 mph or more. Last year, Wilma packed wind speeds of 175 mph and set a record as the strongest hurricane in terms of barometric pressure.
While some scientists believe this trend is just part of natural ocean and atmospheric cycles, others argue that rising sea surface temperatures as a side effect of global warming is the primary culprit.
According to this scenario, warming temperatures heat up the surface of the oceans, increasing evaporation and putting more water vapor into the atmosphere. This in turn provides added fuel for storms as they travel over open oceans.
