What is the primary greenhouse gas emitted through human activities?

The primary greenhouse gas emitted through human activities is carbon dioxide. This gas is released primarily from the burning of fossil fuels, such as coal, oil, and natural gas, for energy and transportation. Deforestation and other land-use changes also contribute to carbon dioxide emissions, as trees that would otherwise absorb CO2 are removed.

Carbon dioxide is significant in the context of climate change because it has a long atmospheric lifespan and can trap heat effectively, making it a key factor in the greenhouse effect. While other gases like methane and nitrous oxide are also important contributors to global warming, they are emitted in smaller quantities compared to carbon dioxide. Methane, for example, is more potent in the short term but is present in the atmosphere at much lower concentrations. Nitrous oxide has a similar situation, being emitted through agricultural and industrial activities but not at the same volume as carbon dioxide.

Ozone, while a greenhouse gas, primarily forms in the Earth's atmosphere as a result of chemical reactions between other pollutants and is not directly emitted in significant quantities from human activities. Thus, carbon dioxide stands out as the dominant greenhouse gas linked to human activity.