Earth's Energy and Heat Regulator
Retained by the Earth’s gravity, the atmosphere protects life on Earth from the harsh vacuum of outer-space, and filters out the Sun’s high energy rays, whilst allowing through those lower energy rays critical for life. The atmosphere absorbs large amounts of energy from the Sun, and much of the radiation emitted back from the Earths' surface; and when the atmosphere reaches its temperature limit, it emits excess heat in all directions - with some of this going back towards Earth (back radiation), and the rest going out into Space. The Earth, therefore, is heated by the Sun and the Atmosphere (the Greenhouse Effect), and for this reason it is estimated that Earth is 30°C warmer due to the presence of the Atmosphere. The Atmosphere also reduces temperature extremes between day and night (diurnal temperature variation), and between the equator and the poles.
If you are interested in finding out more about what the Earth's atmosphere is, and how it effects life on Earth, then click on the blog posts below.