Ozone Layer Moves toward Recovery from 2020

On May 19, 2006, the National Institute for Environmental Studies (NIES) released its projection on the future recovery of the ozone layer based on simulations by the stratospheric chemical climate model (CCSR/NIES CCM). According to the data, the ozone hole is currently at its largest and massive ozone depletion is expected to continue for the time being. However, the simulation showed that the ozone hole would begin to shrink from around 2020, and that the ozone layer over Antarctica would recover to 1980 levels by the middle of the 21st century. Hence, the study concluded that the ozone hole would disappear.

The CCSR/NIES CCM is a numerical model co-developed by the NIES and the Center for Climate System Research of the University of Tokyo. This model applies complex feedback systems to its calculations, and these affect ozone density and distribution in the stratosphere: chemical processes of ozone formation and depletion, physical processes of atmospheric transport, and radiative processes of sunlight absorption and infrared radiation.

With the CCSR/NIES CCM, researchers conducted numerical simulations on the future structure of the ozone layer in consideration of the anticipated total emission of ozone-depleting substances, such as chlorofluorocarbons (CFCs) and halons, and concentration variation of greenhouse gases including carbon dioxide.

The results showed that ozone layer protection measures, which have been promoted globally, have worked effectively. However, it is also projected that a large ozone hole will remain over the coming decades. If more CFCs and halons than the quantities in the model are used or emitted, the recovery of the ozone layer would be delayed even further.

http://www.nies.go.jp/index.html

Posted: 2006/07/26 11:02:32 AM
Japanese version