Some of the energy is absorbed by the atmosphere, some of it is reflected, and some is transmitted to the surface of the Earth as heat and light. If we did not have an atmosphere we would be a ball of rock that was too hot or too cold, most likely alternating between the two. In the long history of the planet, it took a long time for the correct balance to be found that would support life. When critics of the study of global change say that the scientists don't know what is happening, they usually mean the problem of determining the role of clouds in the atmosphere in global warming. Plants breathe in carbon dioxide and breathe out oxygen, while animals breathe in oxygen and exhale carbon dioxide, in a polite balance.
Human beings do many things that drastically affect the condition of the atmosphere.
The most commonly discussed resulting changes are the depletion of ozone from the high reaches of the atmosphere and the warming of the atmosphere because of increased carbon dioxide. The main ozone mass that interests us, however, is the layer of ozone in the upper atmosphere that absorbs and protects us from the ultraviolet radiation entering the atmosphere from the sun. We discovered in the 1970s that human-made chemicals, specifically fluorocarbons used in aerosol containers, ascended into the atmosphere and eliminated the ozone molecules that formed the protective layer. The other atmospheric issue related to global change is global warming. The increasing amount in the atmosphere seems to be most directly connected with increasing human activity, particularly the burning of fossil fuels and wood.