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
Greenhouse and icehouse Earth in the solar constant, and oceanic and orogenic changes due to tectonic plate dynamics. Greenhouse and icehouse periods have profoundly shaped the evolution of life on Earth. A "greenhouse Earth" or "hothouse Earth" is a period in which there are no continental glaciers whatsoever on the planet, the levels of carbon dioxide and other greenhouse gases (such as water vapor and methane) are high, and sea surface temperatures (SSTs) range from 28 °C (82.4 °F) in the tropics to 0 °C (32 °F) in the polar regions. This state should not be confused with a hypothetical "hothouse earth", which is