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.
But global warming will have additional, far-reaching effects on the planet. Warming modifies rainfall patterns, amplifies coastal erosion, lengthens the growing season in some regions, melts ice caps and glaciers, and alters the ranges of some infectious diseases.