Our atmosphere acts like a blanket trapping heat and keeping Earth at a habitable temperature, it’s this retaining of heat that is referred to as the Greenhouse Effect. The greenhouse effect is caused by greenhouse gases that trap heat from the sun, the more greenhouse gases there are the more heat is retained HOW IT WORKS
The heat from the sun (solar radiation) has a very short wavelength and this can pass easily through the layer of greenhouse gases. This wavelength is called Ultraviolet radiation. As the UV rays strike the Earth, the Earth redirects the rays back into the atmosphere. We feel this as heat. The heat from the earth (terrestrial radiation) has a longer wavelength (infrared) some of this becomes trapped by the layer of greenhouse gases.

GREENHOUSE GASES
Water vapor (H20) is the most prevalent greenhouse gas and occurs naturally. Some greenhouse gases are both natural and man-made including carbon dioxide (CO2) & methane (CH4).

Describe the size of insolation when it strikes the Earth.

What would happen if there were no greenhouse gases to trap heat?