Usually a word or concept can be defined in just one sentence. A definition essay, however, needs to be several paragraphs. Therefore, the definition must be extended to include examples, details, personal experience, description, causes, effects, analysis, etc.
Global Warming Causes More Hurricanes. It could be that the tropical oceans will become warmer with a simultaneous decrease in upper atmosphere temperature, which will cause stronger convection, which will help tropical storms to become more organized and stronger so there will be stronger hurricanes.
The effects of an increase in global temperature include a rise in sea levels and a change in the amount and pattern of precipitation, as well as a probable expansion of subtropical deserts. Warming is expected to be strongest in the Arctic, with the continuing retreat of glaciers, permafrost and sea ice.