An exemplification essay is a type of argumentative essay that provides specific examples to prove a point. If you're writing a thesis paper on the negative effects of global warming, it's not enough to say that it is bad for the environment. You have to be able to show definitive reasons that will convince readers that global warming is dangerous. Some examples would be:
Glaciers melting can lead to water shortages.
Climate change causes severe weather, like hurricanes and heat waves.
Changing ecosystems can lead to species extinction.