What are hurricanes, typhoons and tropical cyclones?
Why the strongest storms are getting stronger?
The warmer the ocean, the more energy is available to fuel the storm energy - converting the heat from the moisture into destructive wind. The stronger is the wind, the higher is the storm surge. With sea water rise, this added storm surge is destructive.
Human causes the global warming. Unfairly, those who contributed most to the warming are not those who suffer most from the warming. In the case of Haiyan, they are the poor people in Philippines.