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

When the world comes together, it can really solve big problems. Example: the new UN report would fill the hole in the ozone layer that, if all went as planned, could be filled by the 2060s.

According to the report, a international treaty to ban ozone dating back several decades. The depletion of chemicals has led to their decline and "a much greater depletion of the ozone layer in the polar regions has been avoided". There is still work to be done, but it certainly falls into the category of "good news".

Paul Newman, a scientist who is involved in the management of NASA's Ozone Watch project and who chaired the UN report, told Earther.

The report is published every four years and is in its fifth edition. 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 over Antarctica, where a hole in the ozone layer 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 area could return to their pre-hole condition in the next 40 years.

In areas where the depletion of the ozone layer was less severe, the return to normal could be even faster The Arctic and the mid-latitudes of the hemisphere north could do so by the 2030s and mid – latitudes in the southern hemisphere could reach the ozone levels of the 1980s to mid – century.

To achieve this ozone recovery schedule. , the world will have to continue working to reduce other chemicals that deplete the ozone layer and not decisively jeopardize the recovery process. Scientists are seeing warning signs on many levels.

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

This is what happens 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 badociated 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 the process of depletion of the ozone layer, which could speed up recovery in some places.

At the same time, the report notes that the increased warming caused by greenhouse gases is changing the global circulation in the atmosphere so as to reduce ozone in the tropics and more in the Arctic and mid-latitudes. So reducing greenhouse gas emissions, including those produced by alternatives to ozone-depleting chemicals, is probably always a good idea, as you know.

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