Scientists discovered an unusual ozone hole. This hole is seven times larger than the one above the continent of Antarctica, and is found in the tropics. This hole has been there for over 30 years.
It was Qing-Bin Lu, a scientist from the University of Waterloo in Ontario, Canada who revealed the existence of this ozone hole. This finding was surprising, because other scientists did not see it in the modeling most researchers use.
Quoted from News Week, Thursday (7/7/2022) the hole exists throughout the year and has been around since the 1980s. It is over an area that makes up half of the world's surface area and hosts half of the world's population.
An alarming gap is unfolding in the lower stratosphere above the tropics. Its depth is similar to that of the famous Antarctic ozone hole that appears during spring, but its area is much larger. The researchers estimate it was roughly seven times as large.
This condition is certainly worrying. Depletion of the ozone layer can cause higher levels of UV radiation to reach Earth's surface, which can increase the risk of skin cancer and cataracts in humans, weaken the immune system and destroy agriculture.
"The tropics constitute half of the planet's surface area and are home to about half the world's population. The existence of the tropical ozone hole can cause great global concern," Lu said.
"Depletion of the ozone layer can cause an increase in UV radiation at the ground surface, which can increase the risk of skin cancer and cataracts in humans, as well as weaken the human immune system, reduce agricultural productivity, and negatively impact organisms and sensitive aquatic ecosystems," he continued.
Analyzing the annual mean ozone change, annual ozone climatological differences and temperature changes over the past few decades reveals the scope of the new ozone hole.
Lu saw the ozone hole he discovered surprised his colleagues in the scientific community, because it was not predicted by conventional photochemical models.
However, the data fit well with the cosmic ray-driven electron reaction (CRE) model and strongly suggest the identical physical mechanisms at work for the Antarctic and tropical ozone holes.
Preliminary reports suggest the level of ozone depletion in the equatorial region is already endangering large populations and the associated UV radiation reaching this region is much greater than expected.
In the mid-1970s, atmospheric research showed that the ozone layer, which absorbs most of the Sun's ultraviolet radiation, may be depleted by industrial chemicals, especially chlorofluorocarbons (CFCs).
The discovery of the Antarctic ozone hole in 1985 confirmed ozone depletion caused by CFCs, and although bans on such chemicals help slow ozone depletion, evidence suggests ozone depletion is steadily increasing.
Lu said the tropical and polar ozone holes play a major role in cooling and regulating the temperature of the stratosphere, reflecting the formation of three 'temperature holes' in the global stratosphere.
He said the findings may prove important for better understanding global climate change. This latest discovery adds to previous studies of an electron-driven cosmic ray-driven ozone-depletion mechanism (CRE) that was originally proposed by Professor Lu and his colleagues about two decades ago.
"These findings require further study of ozone depletion, changes in UV radiation, increased cancer risk, and other negative effects on health and ecosystems in the tropics."