The earth’s global average surface temperature in present climate is 15C (59F). Without the atmosphere, it would be -18C (-0.4F). About 33C or 59.4F colder; Atmosphere is the most important component of the earth’s climate. The atmosphere is a mixture of nitrogen (78%), oxygen (21%), and other gases (1%) that surrounds Earth. High above the planet, the atmosphere becomes thinner until it gradually reaches space. A sunlight beam that strikes at an angle is spread across a greater surface area, and is a less intense heat source than a beam impinging directly.