A greenhouse gas is found in the Earth’s atmosphere. It emits and absorbs radiant energy that is in the thermal infrared range. Its whole process is the primary cause of greenhouse effect.
Ozone, nitrous oxide, methane, carbon dioxide, and water vapor are the main greenhouse gases in the atmosphere. Without these gases, our planet’s average temperature will drop to -18 °C, instead of being at 15 °C.
Other planets also experience greenhouse effects – they include Titan, Mars, and Venus.