Tropical revolving storms such as hurricanes, typhoons and cyclones have different impacts on rich and poor parts of the world.

In recent years there have been a large number of hurricanes and tornadoes which have caused widespread destruction and loss of life. Many scientists blame these extreme weather events on global warming, but others say they are part of a natural cycle. So what causes a hurricane, and is global warming to blame?

Hurricanes originate at sea and, in order to form, the water must be at least 27