Atmosphere of Earth development of animals. Today's atmosphere contains 21% oxygen, which is great enough for this rapid development of animals. "Air pollution" is the introduction into the atmosphere of chemicals, particulate matter or biological materials that cause harm or discomfort to organisms. Stratospheric ozone depletion is caused by air pollution, chiefly from chlorofluorocarbons and other ozone-depleting substances. The scientific consensus is that the anthropogenic greenhouse gases currently accumulating in the atmosphere are the main cause of global warming. On October 19, 2015 NASA started a website containing daily images of the full sunlit side of Earth on http://epic.gsfc.nasa.gov/. The images are taken
Idealized greenhouse model for the required amount of heat energy finally to be radiated out into space from the top of the atmosphere. The greenhouse effect can be illustrated with an idealized planet. This is a common "textbook model": the planet will have a constant surface temperature T and an atmosphere with constant temperature T. For diagrammatic clarity, a gap can be depicted between the atmosphere and the surface. Alternatively, T could be interpreted as a temperature representative of the surface and the lower atmosphere, and T could be interpreted as the temperature of the upper atmosphere. In order to justify that T