1. Burning of Fossil Fuels: Burning of fossil fuels like coal, oil and gas for electricity, transportation, industrial processes and other human activities has been the largest source of human-caused greenhouse gas emissions over the past century.

2. Deforestation: Cutting down of trees and other vegetation for agricultural activities, grazing, timber, and other land uses results in the release of carbon dioxide from the plants and soils into the atmosphere.

3. Agricultural Activities: Agricultural activities such as tilling soil, raising livestock, and using chemical fertilizers and pesticides contribute to the release of greenhouse gases like methane and nitrous oxide into the atmosphere.

4. Ozone Depletion: Ozone depletion in the stratosphere (the upper atmosphere) has resulted in a decrease in the amount of ultraviolet radiation that is blocked from reaching the Earth’s surface. This has contributed to an increase in the amount of solar radiation that reaches the Earth’s surface, leading to a warming of the atmosphere.

5. Industrial Processes: Industrial processes such as the production of cement, steel, aluminum, and other materials contribute to the emissions of greenhouse gases like carbon dioxide into the atmosphere.

6. Waste Disposal: Landfills, wastewater treatment plants, and other human activities that result in the disposal of waste materials into the environment contribute to the release of methane, a powerful greenhouse gas, into the atmosphere.

7. Methane from Animals: The digestive processes of animals such as cows, sheep, and other livestock result in the release of methane into the atmosphere.

8. Aerosols: Aerosols such as smoke, dust, and other particles released into the atmosphere by human activities can both absorb and reflect sunlight, resulting in a cooling effect at the Earth’s surface.

9. Urbanization: Urban areas can absorb and reflect more sunlight than natural environments, resulting in a warming effect at the Earth’s surface.

10. Natural Variations: Natural variations in the Earth’s climate, such as changes in solar radiation, volcanic activity, and other factors, can also contribute to climate change.