Ozone depletion Ozone depletion Ozone depletion describes two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere (the ozone layer), and a much larger springtime decrease in stratospheric ozone around Earth's polar regions. The latter phenomenon is referred to as the ozone hole. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events. The main cause of ozone depletion and the ozone hole is manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants and foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons), referred to as ozone-depleting
The Layer Quaternity God on High" and "I will exalt thee my God" ". (Latin upper captions translated) Libavius' illustration and the marble sculpture of the Layer Quaternity share an identical pairing including a naked figure (lower pair), a bare-legged royal male and a regal draped female (upper pair) as well as the titled captions "Gloria" and "Labor", along with the symbols of palm branch, "rotundum", and moon. The similarities between the captioned phrases of Libavius' illustration to those of the single-word titles of the Layer Quaternity suggest that in time sequence, the Layer monument was based upon and installed before 1606, the