Just as Earth's ozone layer is slowly recovering from a hazardous hole found in it nearly 40 years ago, this recovery is being impeded by the impact of climate change, said Jonathan Shanklin, a meteorologist at the British Antarctic Survey and one of the scientists who first discovered the ozone hole.
The ozone layer, located 10 to 50 kilometers (6.2-31 miles) above the earth's surface, is vitally important for its ability to absorb 99% of the ultraviolet rays that are harmful to human health, allowing the continued existence of life.
After scientists expressed concerns about the thinning of the layer, studies in the field accelerated in the late 1970s. Along with Shanklin, scientists Brian Gardiner and Joe Farman discovered the hole in 1985.
Two years after the discovery, heads of state and government gathered to sign the Montreal Protocol on Substances that Deplete the Ozone Layer in 1987, banning the use of chlorofluorocarbons (CFCs), chemicals which deplete the protective layer.
Marking Sept. 16, International Day for the Preservation of the Ozone Layer, Shanklin told Anadolu Agency that this year's ozone hole, which tends to expand between August and October while retreating from November to December, is just forming and is expected to continue growing over the coming weeks.
"Over the last 20 years, observations from space and the ground suggest that a slow recovery is underway," Shanklin said. "Although on average a recovery is underway, individual years can still experience severe ozone holes, and this was the case in both 2020 and 2021."
This year's ozone hole growth so far is "at the average rate over the last decade," he added.
Underlining that a complete recovery of the ozone layer is not expected in the short term, he said: "We will continue to have Antarctic ozone holes for another 50 years."
"That the recovery is underway is entirely due to the provisions of the Montreal Protocol, which controls the release of gases that may damage the ozone layer into the atmosphere," Shanklin said, pointing to the significance of the protocol.
He underlined the progressive character of the protocol, saying: "As scientific knowledge increases, additional gases can be added to the controlled list, and this is an extremely significant part of the protocol. The protocol is not locked into the state of scientific knowledge when it was first drawn up, but can change as scientific understanding changes."
Touching on factors that impede or slow down the recovery of the ozone layer, Shanklin said one is the release of novel ozone-depleting gases into the atmosphere. "Whilst these can be added to the protocol, it may take a decade for the effects to be sufficiently clear-cut for them to be added to the prohibited list."
Shanklin said another factor having a negative impact on the ozone layer is "the illegal release of known ozone-depleting gases into the atmosphere through ignorance or commercial greed."
He said that such a case recently came up in Southeast Asia but was eventually detected by ground-based atmospheric constituent monitoring. "Once the relevant authorities were made aware of the detection of illegal manufacture and release, they quickly took action and the rate of decline of these gases is now back on track," he said.
"The incident does, however, demonstrate that a better ground-based detection network is required," he cautioned.
Shanklin said climate change is another factor impeding the recovery of the ozone layer, explaining: "There are feedbacks between climate change and the ozone hole, with each affecting the other."
"Although the surface of the earth is warming, the ozone layer is cooling, which changes the rate of chemical reactions and atmospheric dynamics. This can add stability to the winter polar vortex, which then allows a longer period for ozone depletion to act. Recent years have seen significant Arctic ozone depletion," he added.
Shanklin criticized governments for not taking enough action to cut emissions of greenhouse gasses.
"Whilst governments talk about controlling the release of greenhouse gases such as carbon dioxide and methane into the atmosphere, there has been no significant change in their rate of release," he said. "Carbon dioxide in particular is still increasing at the 'business as usual' rate."
Underlining the interrelatedness of environmental problems, Shanklin said, "We also need to consider that there is not just one environmental crisis, but a multitude of them, which are all linked," referring to air pollution, soil degradation, and biodiversity loss in particular.
"It really needs a complete change of culture to recognize that we as the human population are the problem rather than putting sticking plasters (bandages) on each crisis individually," he said. "I fear that only a complete disaster will change enough minds to actually bring this change of culture to fruition."
Sounding a note of long-term mixed optimism, Shanklin said: "I should conclude by stating that whilst we are proceeding in a direction that is likely to produce a collapse of our present civilization, there is always hope and although we may exterminate humankind from the planet, other living things will survive."
