Scientists from NASA’s Jet Propulsion Laboratory in Pasadena, California have managed to show via direct satellite observations that the worrisome ozone hole in the Antarctic region is slowly healing back to suggest that the ozone-depleting chlorine levels are slowly declining.
The ozone layer could be saved due to the worldwide ban on the use of chlorofluorocarbons which contains harmful chlorine that is responsible for the depletion of ozone layer. In comparison with records obtained in the year 2005, the overall ozone depletion rate has been reduced by 20 percent. The initial reading regarding the rate of depletion pertaining to high chlorine level was measured by NASA’s Aura satellite during the winter season in Antarctica.
The lead author of the study, Susan Strahan, an atmospheric scientist belonging to NASA’s GSFC (Goddard Space Flight Center) in Greenbelt, Maryland explained that it can be clearly observed that the chlorine level near the ozone layer is coming down while reducing the amount of depletion in the ozone.
Ozone layer is a particularly important aspect of Earth’s atmosphere. It mainly functions as an absorbent of the ultraviolet rays while protecting the life beneath from the harmful effects of the same. Without the protection provided by ozone layer, no life on Earth could survive. The absence of ozone layer would allow Sun’s ultraviolet rays to penetrate Earth’s atmosphere causing chronic skin diseases including skin cancer, damaged eyes, macular degeneration and so on.
CFCs are the chemical compounds which slowly rise up to the stratosphere level of Earth where it is broken down by the ultraviolet rays of the sun. Post-breakdown, chlorine atoms are released from the compound which reacts with ozone molecules breaking it into free oxygen molecule. The ozone layer present in the stratosphere is responsible for protecting the life below by absorbing the ultraviolet rays.
In order to put a halt to the Antarctic ozone depletion after its initial detection, all the nations from across the globe signed the Montreal agreement protocol which was initiated to reduce or ban the use of substances that cause the deterioration of ozone layer. This treaty was signed in the year 1985, just two years after the ozone hole near Antarctica was detected. The amendment initially proposed a regulated use of the substance which later changed to a complete ban of the CFC producing mechanisms.
The Geophysical Research Letters carried the findings of this study in the January 4 edition. The ozone depletion cycle is initiated in the Antarctic zone during the month of September which is winter for the southern periphery of Earth. The destruction of ozone is caused by a cycle of chlorine and bromine reactions which are a result of CFCs produced by human-based activities.
Scientists from NASA used the data extracted from JPL’s MLS (Microwave Limb Sounder) which is present aboard the Aura Satellite. Other satellites require the presence of sunlight to calculate the trace gases in the atmosphere. However, the MLS provides feasibility of calculating the amount of trace gases over the atmosphere of Antarctica during the southern winter which is mostly dark with very low temperatures.
The rate of depletion of ozone layer between the time periods of 2005 to 2016 was calculated to check the deterioration rate. The months from early June to the middle of September marked the best time to measure any change in the ozone level as the temperature is low enough to bar any depletion from high temperature. This means the only factor accountable for the deterioration during these months was the chlorine level.
Scientists are positive about the recovery of the ozone as the amount of CFCs gradually decreases but a total recovery might take a few decades. CFCs have a prolonged lifetime of 50-100 years which means these harmful chemicals are here to stay for a significant duration; post which the ozone layer can accelerate it’s healing. Scientists speculate that the accelerated healing of Antarctic ozone hole might occur somewhere from the year 2060 to 2080. However, a total healing of the same cannot be guaranteed.
The significant healing of ozone layer is good news that should be out amidst the general public to encourage better schemes to solve the problem of global warming and rapid climate change.