When the world gets its act, it can solve big problems. Example: the ozone hole, which, if everything goes according to plan, can be restored in the 2060s, according to a new report from the United Nations.
According to the report, a decades-old international treaty to ban chemicals that break down the ozone layer has led to their decline and "much more serious ozone depletion in the polar regions has been prevented." There is still work to be done, but this is certainly appreciated in the category Good news.
"We are on the verge of reversal," said Paul Newman, a scientist who helps NASA's Ozon Guard and chairman of the UN report, to Earther.
The report is released every four years and this is the fifth iteration. It follows an environmental problem in the eighties of the last century. We still feel the effects of today. The ozone hole is driven by a number of chemicals that are often found in aerosol cans, air conditioners and refrigerators, called chlorofluorocarbons and chlorofluorocarbons. These chemicals unleash chlorine in the stratosphere, which in turn can break down ozone molecules. When that happens, more ultraviolet light from the sun rises to the surface, increasing the risk of bad things such as skin cancer. The problem was particularly noticeable in Antarctica, where every spring a hole in the ozone layer began to emerge.
Scientists have identified the chemicals as problematic and policymakers have actually responded to them. The Montreal protocol was inked in 1987. After 30 years, the ozone hole remains an annual phenomenon. But the new report definitely adds to a study from 2016 that shows that the ozone hole has been recovering since 2000. If everything goes according to plan, the ozone level in the region could return to preconhole conditions within 40 years.
In other regions where the damage to the ozone layer was less severe, the return to normality could take place even faster. The Arctic and the middle latitudes of the northern hemisphere can be there by the 2030s, and the middle latitudes in the southern hemisphere can reach the ozone level of ozone by mid-century.
To achieve that timeline of ozone recovery, the world will have to continue to work to reduce other ozone-depleting chemicals and not throw a wrench into the recovery process in other ways. On a few levels there are some warning signs that scientists view.
The first is a mysterious revival in CFC-11, a chemical that was banned under the Montreal protocol. Although forbidden, research showed that it has increased since 2012 earlier this year. Most signals indicate that China is the culprit of illegal emissions, and it will have to be stopped to keep the recovery on the right track.
Another factor is what happens with the battle to combat the greenhouse effect. The ozone hole and climate change are largely separate problems, but they overlap slightly. The warming effect in the lower atmosphere associated with increased greenhouse gases also leads to cooling in the stratosphere, which is about 6-12 miles above the earth's surface. This can slow the ozone-depleting process, which could speed up the recovery in some locations.
At the same time, the report notes that increased warming by greenhouse gases is changing the planet's circulation in the atmosphere in ways that can lead to less ozone in the tropics and more in the Arctic and middle latitudes. So the reduction of greenhouse gas emissions, including the emissions of chemicals produced by replacing ozone-depleting chemicals, is still, you know, a good idea.
The last song is perhaps the most disturbing because we know so little about it. The report raises questions about what would happen if the world or even a rogue decided to cool the planet by sending small particles into the stratosphere. The process, known as geo-engineering, is achieved here with the possible consequences on the ground and would probably also be in the stratosphere.
"The problem is that our level of knowledge of natural levels of particles in the stratosphere is not that high," said Newman. "Geoengineering offers a challenge by disrupting natural levels of particles in the stratosphere on top of that impact on ozone."
So, let us not do that and try instead to try to repair the ozone hole and solve global warming here on the ground.