Decades ago, the issue of a growing hole in the ozone layer was one of the world’s chief environmental concerns. Now, even though the hole has shrunk, a new report suggests that the ozone’s problems may be far from over.
The study, published this week in Nature Communications, has identified a new culprit that could be doing damage: dichloromethane.
When the landmark Montreal Protocol was passed in 1987, it prohibited the use of ozone-depleting chlorofluorocarbons (CFCs). However, the international agreement did not put any restrictions on dichloromethane — a situation the group of researchers are saying may need to be remedied.
The paper, published by a team from Lancaster University in the UK, is the first of its kind to reveal the impact of dichloromethane on the ozone.
“We’ve known that dichloromethane has been increasing in the atmosphere — however, there’s not been a concerted effort to assess what the impact of those increases could be for the ozone layer, and in particular for ozone recovery,” one of the study’s authors said.
Dichloromethane is primarily used as a paint remover but is also an industrial solvent in adhesives, textiles and electronics, and a blowing agent for polyurethane foams.
The study found that the atmospheric level of the chemical has doubled over the last decade — but the researchers did not pinpoint why emissions have grown so quickly.
When ozone depletion was discovered in the 1980s, the hole was mainly over Antarctica. Because the ozone layer protects the earth from damaging ultraviolent radiation, the revelation was met with deep concerns around the world.
The Montreal Protocol was undoubtedly pivotal in allowing the ozone hole to heal, and most experts now believe it will recover completely by about 2050. But a time-lapse model used by the Lancaster team suggest that if dichloromethane levels grow at the same rate as they have in the past decade, it could slow the ozone’s healing time by about 30 years.
The study’s authors say they hope that the research will sound the alarm, and trigger further studies and possible new regulations restricting dichloromethane.
