Key parts of the ozone layer are not healing

A new study shows that parts of the ozone are not healing as predicted.
By Joseph Scalise | Feb 08, 2018
Though recent research revealed that the ozone above Antarctica is slowly healing, the layer is not recovering over Earth's most highly populated regions, a new study published in the journalAtmospheric Chemistry and Physics reports.

In the research, a group of international scientists found that, despite conservation efforts, the ozone layer is thinning in the lower stratosphere above non-polar areas. The reduced protection is particularly concerning near the equator, where sunlight is the strongest.

Though scientists are not sure why the ozone layer is dropping at lower latitudes, they believe the decline is linked to a chemical used in paint stripper, as well as atmospheric circulation triggered by climate change.

"The study is in lower to mid latitudes, where the sunshine is more intense, so that is not a good signal for skin cancer," said study co-author Joanna Haigh, a researcher at Imperial College London, according to The Guardian. "It is a worry. Although the Montreal protocol has done what we wanted it to do in the upper stratosphere, there are other things going on that we don't understand."

To better understand the worrisome trend, the team combined measurements of atmospheric ozone from 11 different datasets to generate a record of the last 30 years. They then looked at ozone levels between the 60th parallels -- an area that ranges from Scandinavia, Russia and Alaska in the north to the tip of South America -- and studied the stratosphere.

That revealed the lower stratosphere, which contains the most ozone, had falling levels. As a result, it is likely going to stay in its depleted state rather than heal.

There is no set reason for this decline, but scientists postulate that global warming could be the cause.That is because ozone is produced by chemical reactions that occur over the tropics before large air circulation currents move them towards the poles. Warming trends could strengthen such currents, moving more ozone to the poles and leaving less at lower latitudes.

However, previous studies have also shown that "very short lived substances" (VSLS) -- industrial chemicals that destroy ozone -- could be a factor as well. Many believed they break down too quickly to make it to the stratosphere, but the new research once again calls them into question.

"The finding of declining low-latitude ozone is surprising, since our current best atmospheric circulation models do not predict this effect," said lead author William Ball, an atmospheric scientist at ETH Zurich university in Switzerland, according to Newsweek."Very short-lived substances could be the missing factor in these models."

There are many theories out there, but more research needs to be conducted before any can be confirmed. The team hopes they will be able to answer some questions in the coming months and help provide insight into why the ozone is collapsing in the way that it is.


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