Global Warming and Global Cooling Related to Ozone Depletion
Panel 1: Under conditions normal before 1965, ultraviolet-C (UV-C) warmed the upper atmosphere, UV-B primarily warmed the ozone layer, and UV-A and visible light warmed Earth.
Panel 2: CFCs, when they rise to the level of very cold polar stratospheric clouds (PSCs), release chlorine that depletes ozone, causing more UV-B than usual to reach Earth's surface, thus cooling the ozone layer and warming Earth.
Panel 3:Effusive volcanoes emit chlorine and bromine, which deplete ozone, leading to global warming.
Panel 4: Explosive volcanoes similarly deplete ozone, but also eject megatons of water and sulfur dioxide into the lower stratosphere, forming globe-encircling aerosols whose molecules grow large enough to reflect and scatter sunlight, causing net global cooling.