More about "Ozone at lower latitudes is not recovering"

Guest Brief by Kip Hansen

My attention was captured by the same story posted earlier: “Ozone at lower latitudes is not recovering, despite Antarctic ozone hole healing“.

Here’s the thing, even more interesting — Sometimes the science news cycle throws up interesting juxtapositions. That story appeared as one half of an interesting pair which both appeared in my email inbox today.

“Reduced energy from the sun might occur by mid-century—now, scientists know by how much“ — over at Tallbloke’s place — features the illustration of the solar cycle at the left and refers to a story at Phys.org by the same title. [More on this further on.]

The other bit of Science News came from the journal Science in the most recent Science News email alert pointing me to this article: “Disturbing losses of protective ozone near Earth’s equator may be tied to short-lived chemicals”. This second item contains this image from NASA Goddard —

— which shows a band of lowered concentration of stratospheric ozone girdling the Earth over the tropics. We are informed that “new findings suggest that at mid-latitudes, where most people live, the ozone layer in the lower stratosphere is growing more tenuous—for reasons that scientists are struggling to fathom.”

By “more tenuous”, they mean specifically that “that ozone in the lower stratosphere between 60°S and 60°N has indeed continued to decline since 1998.”

The finding comes from a paper in Atmospheric Chemistry and Physics authored by William Ball and a host of others titled “Evidence for a continuous decline in lower stratospheric ozone offsetting ozone layer recovery”. The general thrust of the paper is that while the “ozone hole” has seen improvement, the ozone layer’s total thickness in the mid-latitudes is declining and Ball and his colleagues suspect that the culprit is “very short-lived substances” (VSLSs): ozone-eating chemicals such as dichloromethane that break down within 6 months after escaping into the atmosphere.” Many of the “VSLSs are of natural origin—marine organisms produce dibromomethane, for example—use of human-made dichloromethane, an ingredient in solvents and paint removers, has doubled in recent years.”

Now we have something new to worry about — yet another human-caused threat to health and safety — maybe an ingredient in paint thinners is causing a dangerous thinning of the protective ozone layer where most of us live.

On the Other Hand —

Over at Phys.org, solar scientists are carefully explaining what is happening with the Sun.  Bascially:

“The sun might emit less radiation by mid-century, giving planet Earth a chance to warm a bit more slowly but not halt the trend of human-induced climate change.

The cooldown would be the result of what scientists call a grand minimum, a periodic event during which the sun’s magnetism diminishes, sunspots form infrequently, and less ultraviolet radiation makes it to the surface of the planet. Scientists believe that the event is triggered at irregular intervals by random fluctuations related to the sun’s magnetic field.”

Well, that’s good news — the cool down of the Sun might save us from [cue scary music] Climate Change.

They also tell us this interesting little fact:

“The reduced energy from the sun sets into motion a sequence of events on Earth beginning with a thinning of the stratospheric ozone layer. That thinning in turn changes the temperature structure of the stratosphere, which then changes the dynamics of the lower atmosphere, especially wind and weather patterns. The cooling is not uniform. While areas of Europe chilled during the Maunder Minimum, other areas such as Alaska and southern Greenland warmed correspondingly.“

Have we seen “reduced energy from the sun”? I don’t know….maybe you do, but we do know that the Solar Cycle looks like this:

Could the thinning of stratospheric ozone in the Tropics be related to the reduced energy from the sun?

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Author’s Comment Policy:

This is just a note about two interesting papers appearing simultaneously. I don’t really have any opinion on the matter and am not very knowledgeable about either subject — the Sun or the Ozone Layer — so won’t be able to answer very many [any?] of your questions.

I’m interested in following the discussion in the comments.

Thanks for reading.

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