Final answer:
Human activities, particularly burning fossil fuels, agriculture, and deforestation, augment the levels of greenhouse gases such as carbon dioxide and methane, intensifying the greenhouse effect, which causes global warming and climate change.
Step-by-step explanation:
Human activities, primarily the burning of fossil fuels, agriculture, and deforestation, significantly increase the levels of greenhouse gases in the atmosphere, thereby enhancing the greenhouse effect. This exacerbation leads to global warming and more extreme weather patterns, due to the increased capture of heat within the Earth's atmosphere.
Deforestation for land clearing and agriculture, as well as cement manufacturing, contributes additional CO2. Methane is released from anaerobic conditions, such as in rice paddies or in the digestion systems of animals, as well as from natural gas fields, landfills, and melting clathrates under the ocean. These human-induced emissions of greenhouse gases strengthen the natural greenhouse effect by trapping more heat, leading to a hotter, more volatile global climate.