Answer:
Humans cause deforensation by cutting down trees.However overgrazing can result in desertification (the spread of desert like conditions)whereby it reduces the amount if places plant can grow. Humans also produce pollution such as the burning of coal which releases fossil fuels. This causes acid rain which weakens trees by dissolving nutrients in the soil.These such human impacts have triggered global warming and hence climate change, caused the quality of the air to worsen overtime and the contamination of water making it undrinkable in may cases. Hope this helps.