One of the key elements that influence the forming of hurricanes is a warm ocean surface.

When moist air passes over the warm ocean it is driven upwards. Strong winds remove the heat and encourage more warm air to rise. A chain reaction of rising and sinking air begins, creating 'convection' currents, and when the Earth's rotation adds a twist to this motion the hurricane spiral is formed.

An increase of 2C in the surface ocean temperature of the hurricane zones by 2100 could drive tropical storms into a higher gear. In the 1970's, there was an average of about 10 category 4 and 5 tropical cyclones per year globally. Since 1990, the number has almost doubled, averaging 18 per year globally.