According to the UN, the hole in the ozone layer could heal in our lifetime

When the world is active, it can really solve big problems. Example: the hole in the ozone layer that, if everything went as planned, could be cured by the 2060s, according to a new UN report.

According to the report, a decades-long international treaty banning chemicals that deplete the ozone layer has led to their decline and "a much greater depletion of the ozone layer in the polar regions has been avoided ". There is still much to do in the category of good news.

"We are at the turning point," Earther Paul Newman, a scientist who is involved in managing NASA's Ozone Watch program and chairing the UN report, told Earther.

The report is published every four years and this is its fifth iteration. It traces an environmental problem of the 1980s whose effects we still feel. The hole in the ozone layer is fed by a number of chemicals commonly found in aerosols, air conditioners and refrigerators, called chlorofluorocarbons and hydrochlorofluorocarbons. These chemicals release chlorine into the stratosphere, which can break down the ozone molecules. When this happens, more of the sun's ultraviolet rays rise to the surface, increasing the risk of diseases such as skin cancer. The problem was particularly noticeable in Antarctica, where an ozone hole began to form each spring.

Scientists have identified chemicals as problematic and policy makers have acted accordingly. The Montreal Protocol was signed in 1987. After 30 years, the hole in the ozone layer continues to occur each year. But the new report definitely comes to complete a 2016 study showing that the hole in the ozone layer is about to be repaired since 2000. If everything goes as planned, the levels of ozone in The region could return to pre-hole conditions in the next 40 years.

In other areas where the depletion of the ozone layer has been less severe, the return to normal could be even faster. The Arctic and the mid-latitudes of the northern hemisphere could reach it by the 2030s, and the mid-latitudes of the southern hemisphere could reach the levels of the northern hemisphere. Ozone from the 1980s by the mid – century.

To meet this ozone layer recovery schedule, the world will need to continue working to reduce other ozone – depleting chemicals and not decisively compromise the recovery process. At some levels, scientists are watching for warning signs.

The first is a mysterious rise in CFC-11, a chemical banned by the Montreal Protocol. Although banned, research published earlier this year has shown that it has been on the rise since 2012. Most signs show that China is the cause of illicit emissions and that it will be necessary to stop to keep the recovery on track.

Another factor is what is happening with the fight against global warming. The hole in the ozone layer and climate change are usually distinct problems, but they overlap a bit. The warming effect in the lower atmosphere associated with the increase in greenhouse gases also leads to a cooling of the stratosphere, located about 6-12 miles above the surface of the planet. This can slow down the depletion process of the ozone layer, which could speed up the recovery in some places.

At the same time, The report notes that the increased warming due to greenhouse gases is changing the circulation of planets in the atmosphere, which can result in a reduction of the ozone layer in the tropics and more in the atmosphere. Arctic and mid-latitudes. So reducing greenhouse gas emissions, including those produced by alternatives to ozone-depleting chemicals, is probably, you know, a good idea.

The last issue is perhaps the most confusing because we know so little. The report raises concerns about what would happen if the world, or even a rogue state, decided to cool the planet by sending tiny particles into the stratosphere. The process, known as geoengineering, has potential consequences on the ground and should also be in the stratosphere.

"The problem with this is that our level of knowledge of natural levels of particles in the stratosphere is not so high," said Newman. "Geoengineering presents a challenge by disrupting the natural levels of particles in the stratosphere, in addition to this impact on ozone."

Maybe we do not do that and instead try to fix the hole in the ozone layer and solve global warming on the ground.