[Brandon Zalinsky]

Brandon Zalinsky  asked the Naked Scientists:
   
Dear Dr. Chris,
� 
What happened to the hole in the� ozone layer?�  A few years ago it was all the rage, but I haven't heard anything about it since then.
� 
Brandon
United States

What do you think?

[LeeE]

I suspect that the latest data is still being analysed, but the largest hole ever recorded seems to have occurred in 2006.  Have a read of:

http://en.wikipedia.org/wiki/Ozone_depletion

Some of the graphs in that article suggest that the degree of depletion is slowing down and leveling out.

[paul.fr]

It's no longer sexy enough for mainstream media to bother reporting it, they have a new way for us all to die and next week you may not even be aware that swine flu was around.

A good source is the blog by Dr Masters:
http://bit.ly/C5ijS

[Nizzle]

The funny thing is that the hole in the Ozone layer is shrinking, but the smaller hole speeds up global warming []
Go figure.

[Matthews dad]

Yes,Co2 is the new CFC. []

[dnwx]

Yes,Co2 is the new CFC. []

Not quite. nitrous oxide is the "most abundant ozone-depleting substance emitted by human activities "

http://www.weatherjackwilliams.com/archives/an-ozone-challenge-to-science-writers

NOAA’s announcement on Thursday that nitrous oxide is replacing chlorofluorocarbons (CFCs) as the most abundant ozone-depleting substance emitted by human activities offers a big challenge to science writers.

Making sense of ozone and the substances that deplete it is always a challenge because the atmospheric chemistry involved is complex.

This story is a continuation of the story I tell in Chapter 12 of The AMS Weather Book about how scientists worked out what was causing the Antarctic ozone hole and how this led to the first of a series of international treaties restricting use of substances that deplete stratospheric ozone.

That part of the book includes a graphic showing what ozone does and how substances such as CFCs harm it.

The Explorations: The Ozone Hole page on the book’s supplemental Web site gives the sources of information used in the book and also links to more information about ozone.

A good introduction to the nitrous oxide story is the one by Cornelia Dean, published on the New York Times Web site.

It is a good breaking news account of NOAA’s announcement, but I’d like to see her or some other science writer meet the challenge of writing  a more complete account that would not only carry the ozone depletion story into this century, but also offer insights into how science works.

One question that such a story could address is how much difference could nitrous oxide make in slowing the recovery of the ozone hole or in speeding up climate change.

A possible hook for a story is that nitrous oxide is not one of the substances regulated by the international treaties that have been doing a good job of reducing the amounts in the air of CFCs and other substances that harm ozone. Answering the question of why the international agreements don’t cover nitrous oxide offers an insight into the complications of science and making policy based on the science.

Peter Spotts gives the basic answer in his Christian Science Monitor story, which says nitrous oxide wasn’t included among the gases regulated because it “initially was seen as beneficial; when it reacts with the chlorine compounds, the reaction in effect neutralizes each other’s ozone-depleting traits.” Now, however with chlorine from CFCs and other substances becoming less abundant, less nitrous oxide is being neutralized.

Some other points a more complete story could include are:

•The study says that increasing nitrous oxide “would have implications for the
recovery of the polar ozone hole that might differ from that of global ozone.” What are these implications?  Does this mean the Antarctic ozone hole should continue recovering as expected?
•Why doesn’t nitrous oxide affect the Antarctic ozone hole as much as ozone elsewhere?
•What did the Intergovernmental Panel on Climate Change say about the warming potential of nitrous oxide in its 2007 report and could the NOAA study require a different assessment of nitrous oxide in the next IPCC report?

A story that answers these and other questions and puts the report in context with expert opinion of what it could mean for the future while making the science human by showing real people at work on answering questions could be a contender for a science writing prize.

An abstract of the study is on the AAAS Science Express Web site. It has links to a podcast of an interview with  A. R. Ravishankara, the study’s lead author. To download the complete report from the link on the abstract page you need either to be an AAAS member or buy a copy.

I would love to have a couple of first-rate stories to link from the Ozone Hole Explorations page noted above to keep the story up to date

http://www.weatherjackwilliams.com/jacks-books
http://www.amsweatherbook.com/AMS_12_explorations1.html
http://www.nytimes.com/2009/08/28/science/earth/28nox.html?hp
http://features.csmonitor.com/environment/2009/08/27/the-next-major-threat-to-the-ozone-layer-nitrous-oxide/
http://www.sciencemag.org/cgi/content/abstract/1176985

[dnwx]

"Laughing Gas: the latest threat to the ozone layer."
Time Magazine.


http://www.time.com/time/health/article/0,8599,1919139,00.html

[LeeE]

dnwx: the way that you've phrased your first posting is ambiguous and almost suggests that the quantity of NO2 surpassed the levels that CFCs reached.  Is this really the case or is it just that the levels of CFCs have reduced to the point where they have now fallen below that of NO2?