The greenhouse effect is caused by gases in the atmosphere that let sunlight through, but prevent some of the heat it generates from being re-emitted, acting as a blanket around the earth. If we had no greenhouse effect, the Earth would be around 33 degrees coller than it is, with temperatures averaging about -18 degrees Celsius. On the flip side, if we have too much of a greenhouse effect (ie concentration of greenhouses gases), it’s possible the planet can overheat.
