Ozone Simulations for 1989 and 2028

April 07, 2009


Model Simulations: Paul Newman, Ozone Watch
Summary Author: Paul Newman, Stu Witmer, Jim Foster

In the news we often hear about what needs to be done to protect Earth's environment, but it's unusual to look back and see what might have been had we not made some changes. In 1989 the Montreal Protocol banned chlorofluorocarbons (CFCs) and other chemicals. The two images show model simulations of column ozone (the total amount of ozone between the Earth's surface and space) of the northern hemisphere for 1989 in the upper panel and 2028 in the lower panel. The colors indicate the levels of column ozone in the atmosphere with red-orange indicating high levels, while blue indicates low levels of ozone. In the model, the levels of ozone depleting substances (ODSs), such as chlorofluorocarbons, steadily increases at 3 percent a year starting in 1974. Over this time period, the amount of chlorine in the stratosphere increases from 3 chlorine-containing molecules per billion molecules of air to 15. In response, the global ozone level decreases by 18 percent between 1989 and 2028. Between 1975 and 2065, the steadily increasing ODSs destroy 2/3s of the ozone layer. Without the Montreal Protocol we could be experiencing enough UV radiation by now to notice higher incidences of skin cancer.