Greenhouse gas

A greenhouse gas is a gas in the atmosphere that that stops heat from Earth from emanating into space and instead reflects it back to the Earth. These gases act as a greenhouse and make the Earth hotter than it would be without the gases. Having greenhouse gases in the atmosphere is natural and important for life on Earth, while having an excess amount can cause to overheating. The greenhouse gases contributing to the most heating on Earth is water vapor, with carbon dioxide, methane, nitrous oxide, chlorofluorocarbon, and ozone.