Increase of level of Greenhouse gasses in Earth's atmosphere is the main cause of Global Warming and Climate change. Increase of Greenhouse gasses is caused by burning of fossil fuel and deforestation.
The other cause of Global Warming and Climate Change are thinning of Ozone layer in Earth's atmosphere. CFC's (Chlorofluorocarbon) and Methyl bromide are the main contributor of destroying the Ozone layer. Thinner Ozone layer causes more UV rays to reach in Earth's surface from Sun. CFCs are commonly used as refrigerants, solvents, and foam blowing agents.