Answer
Global warming is caused by the production of carbon dioxide from the combustion of fossil fuels. Evidence that global warming is occurring is that Earth has warned by $0.6^{\circ}C$ in the last century due to an approximately 25% increase in atmospheric carbon dioxide.
Work Step by Step
Carbon dioxide is a greenhouse gas that allows visible light to enter the Earth's atmosphere but prevents heat from escaping. This causes global climate change and raises the Earth's average temperatures.
