Greenhouse Effect

Why does it get really hot inside a car parked in the sun? It's the greenhouse effect.

Over the past few centuries, people have been burning more amounts of fuels such as wood, coal, oil, natural gas and gasoline. The gases formed by the burning, such as carbon dioxide, are building up in the atmosphere. They act like greenhouse glass. The result some experts believe is the Earth heating up and undergoing global warming. How can you show the greenhouse effect?