A “massive” ozone hole that should not be in the Earth’s atmosphere has been identified over almost the entire equatorial region.
The hole is a permanent hole in the planet’s ozone layer, seven times larger than the known Antarctic ozone hole that opens each spring.
According to his research, the hole has existed for more than 30 years and covers a huge area where half of the world’s population could be, said Professor Cheng Bin Lu, a scientist from the University of Waterloo in Ontario, Canada. affected.
Telling Independent : “Unlike the Antarctic ozone hole which only appears in the spring, the tropical ozone hole has appeared in all seasons since the 1980s, and its area is about seven times larger.
“[It] may cause global concern as it may lead to increased UV radiation at ground level and associated risks of skin cancer, cataracts and other negative health and ecosystem effects in the tropics. .
He said there were “preliminary reports showing that ozone depletion levels over the tropics were already threatening many of their populations, and that accompanying UV radiation was much higher. important than expected.
Speaking of finding a large area of depleted ozone, Professor Lu. told the Independent : “It seems inconceivable that the great tropical ozone hole has not been discovered before. But there are fundamental challenges to making this discovery.
First, a tropical ozone hole was not expected from mainstream photochemical theory. Second, unlike the seasonal Antarctic/Arctic ozone holes that appear primarily in the spring, the tropical ozone hole is essentially unchanged from season to season and is therefore not visible in the data from observed origin.
As with the Antarctic ozone hole, research has found that the natural value of ozone has been depleted by around 80% at the center of the tropical ozone hole.
The new research also highlights differences in prevailing theories about how ozone is depleted.
In the past, the presence of chlorofluorocarbons (CFCs) was considered the primary cause of ozone layer depletion. The 1987 Montreal Protocol, which banned it, saw its use drastically decline.
But despite the global ban, the largest, deepest and most persistent ozone holes – over Antarctica – were still observed in the late 2000s and in the period 2020-2021.
“This was unexpected from all models of climate photochemistry,” Prof Lu said.
Professor Lu and his colleagues two decades ago proposed a distinct theory of ozone depletion, known as the cosmic ray-induced electronic reaction (CRE), in which cosmic rays from the space reduce the ozone layer in the atmosphere.
Tell Independent : “The observed results strongly suggest that the Antarctic and tropical ozone holes must arise from an identical physical mechanism, and that the CRE mechanism showed excellent agreement with the observed data.”
“CFCs are undoubtedly the main ozone-depleting gases, but cosmic rays play a major role in the formation of polar and tropical ozone holes,” he added.
