Greenhouse gases keep the Earth warm through a process called the greenhouse effect.If it were not for greenhouse gases trapping heat in the atmosphere, the Earth would be a very cold place.
The Earth gets energy from the sun in the form of sunlight. The Earth's surface absorbs some of this energy and heats up. That's why the surface of a road can feel hot even after the sun has gone down—because it has absorbed a lot of energy from the sun. The Earth cools down by giving off a different form of energy, called infrared radiation. But before all this radiation can escape to outer space, greenhouse gases in the atmosphere absorb some of it, which makes the atmosphere warmer. As the atmosphere gets warmer, it makes the Earth's surface warmer.
Carbon dioxide is the most important greenhouse gas emitted by humans, but several other gases contribute to climate change, too.
- Carbon dioxide (CO2)
- Methane (CH4)
- Nitrous oxide (N2O)
- Fluorinated gases
Greenhouse gases come from all sorts of everyday activities, such as using electricity, heating our homes, and driving around town.These greenhouse gases don't just stay in one place after they're added to the atmosphere. As air moves around the world, greenhouse gases become globally mixed .
