Chemists poke holes in ozone theory
Captain Compassion
News@Nature, 26 September 2007
http://www.nature.com/news/2007/070924/full/449382a.html
As the world marks 20 years since the introduction of the Montreal
Protocol to protect the ozone layer, Nature has learned of
experimental data that threaten to shatter established theories of
ozone chemistry. If the data are right, scientists will have to
rethink their understanding of how ozone holes are formed and how that
relates to climate change.
Long-lived chloride compounds from anthropogenic emissions of
chlorofluorocarbons (CFCs) are the main cause of worrying seasonal
ozone losses in both hemispheres. In 1985, researchers discovered a
hole in the ozone layer above the Antarctic, after atmospheric
chloride levels built up. The Montreal Protocol, agreed in 1987 and
ratified two years later, stopped the production and consumption of
most ozone-destroying chemicals. But many will linger on in the
atmosphere for decades to come. How and on what timescales they will
break down depend on the molecules' ultraviolet absorption spectrum
(the wavelength of light a molecule can absorb), as the energy for the
process comes from sunlight. Molecules break down and react at
different speeds according to the wavelength available and the
temperature, both of which are factored into the protocol.
So Markus Rex, an atmosphere scientist at the Alfred Wegener Institute
of Polar and Marine Research in Potsdam, Germany, did a double-take
when he saw new data for the break-down rate of a crucial molecule,
dichlorine peroxide (Cl2O2). The rate of photolysis (light-activated
splitting) of this molecule reported by chemists at NASA's Jet
Propulsion Laboratory in Pasadena, California1, was extremely low in
the wavelengths available in the stratosphere - almost an order of
magnitude lower than the currently accepted rate. "This must have
far-reaching consequences," Rex says. "If the measurements are correct
we can basically no longer say we understand how ozone holes come into
being." What effect the results have on projections of the speed or
extent of ozone depletion remains unclear.
The rapid photolysis of Cl2O2 is a key reaction in the chemical model
of ozone destruction developed 20 years ago2 (see graphic). If the
rate is substantially lower than previously thought, then it would not
be possible to create enough aggressive chlorine radicals to explain
the observed ozone losses at high latitudes, says Rex. The extent of
the discrepancy became apparent only when he incorporated the new
photolysis rate into a chemical model of ozone depletion. The result
was a shock: at least 60% of ozone destruction at the poles seems to
be due to an unknown mechanism, Rex told a meeting of stratosphere
researchers in Bremen, Germany, last week.
Other groups have yet to confirm the new photolysis rate, but the
conundrum is already causing much debate and uncertainty in the ozone
research community. "Our understanding of chloride chemistry has
really been blown apart," says John Crowley, an ozone researcher at
the Max Planck Institute of Chemistry in Mainz, Germany.
"Until recently everything looked like it fitted nicely," agrees Neil
Harris, an atmosphere scientist who heads the European Ozone Research
Coordinating Unit at the University of Cambridge, UK. "Now suddenly
it's like a plank has been pulled out of a bridge."
The measurements at the Jet Propulsion Laboratory were overseen by
Stanley Sander, a chemist who chairs a NASA panel for data evaluation.
Every couple of years, the panel recommends chemical kinetics and
photochemical data for use in atmosphere studies. Until the revised
photolysis rate has been evaluated, which won't be before the end of
next year, "modellers must make up their minds about what to do," says
Sander. One of the problems with checking the data is that the
absorption spectra of chloride compounds are technically challenging
to determine. Sander's group used a new technique to synthesize and
purify Cl2O2. To avoid impurities and exclude secondary reactions, the
team trapped the molecule at low temperatures, then slowly warmed it
up.
"Reactions in experimental chambers are one thing - the free
atmosphere is something else," says Joe Farman, one of the scientists
who first quantified the ozone hole over Antarctica3. "There's no
doubt that ozone disappears at up to 3% a day - whether or not we
completely understand the chemistry." But he adds that insufficient
control of substances such as halon 1301, used as a flame suppressor,
and HCFC22, a refrigerant, is a bigger threat to the success of the
Montreal Protocol than are models that don't match the observed
losses.
Hot topic
Meanwhile, atmosphere researchers have started to think about how to
reconcile observations of ozone depletion with the new chemical
models. Several thermal reactions, or combinations of reactions, could
fill the gap. Sander's group has started to study possible candidates
one by one - but so far without success.
Rex thinks that a chemical pathway involving a Cl2O2 isomer - a
molecule with the same atoms but a different structure - might be at
play. But even if the basic chemical model of ozone destruction is
upheld, the temperature dependency of key reactions in the process
could be very different - or even opposite - from thought. This could
have dramatic consequences for the understanding of links between
climate change and ozone loss, Rex says.
The new measurements raise "intriguing questions", but don't
compromise the Montreal Protocol as such, says John Pyle, an
atmosphere researcher at the University of Cambridge. "We're starting
to see the benefits of the protocol,
but we need to keep the pressure on." He says that he finds it
"extremely hard to believe" that an unknown mechanism accounts for the
bulk of observed ozone losses.
Nothing currently suggests that the role of CFCs must be called into
question, Rex stresses. "Overwhelming evidence still suggests that
anthropogenic emissions of CFCs and halons are the reason for the
ozone loss. But we would be on much firmer ground if we could write
down the correct chemical reactions."
Quirin Schiermeier
1. Pope, F. D., Hansen, J. C., Bayes, K. D., Friedl, R. R. & Sander,
S. P. J. Phys. Chem. A 111, 4322-4332 (2007).
2. Molina, L. T. & Molina, M. J. J. Phys. Chem. 91, 433-436 (1987).
3. Farman, J. C., Gardiner, B. G. & Shanklin, J. D. Nature 315,
207-210 (1985).
--
The object of life is not to be on the side of the majority but to
escape finding oneself in the ranks of the insane. -- Marcus Aurelius
Wherever I go it will be well with me, for it was well with me here, not
on account of the place, but of my judgments which I shall carry away
with me, for no one can deprive me of these; on the contrary, they alone
are my property, and cannot be taken away, and to possess them suffices
me wherever I am or whatever I do. -- EPICTETUS
Joseph R. Darancette
dar...@NOSPAMcharter.net
jame...@lycos.com
wrote:
> Chemists poke holes in ozone theory
I have long contended that the environmentalists were wrong and that
they have been ignoring the geological evidence. I mean there are
fossils of tropical vegetation and animal life found above the Arctic
Circle while in Siberia Mammoths have been discovered with tropical
vegetation not only in their stomachs but also between their teeth.
These frozen monsters are a testimony to the fact that the
environmentalists have absolutely no idea of what they are talking
about.
At the present rate of thaw that is to say as the ice caps thaw while
the yearly accumulations of snow continue to be reduced this planet
should regain its former self before Ice Age in about 75 years. It is
very simply really and no it does not take a rocket scientist to
figure it out either. As the snow and ice is reduced the air and water
temperatures rise. The more snow and ice is lost the faster the air
and water temperatures will rise. Eventually there will be no more
snow and ice and the planet's surface temperature will be stabilized
at a very comfortable temperature just as before the Ice Age say
somewhere around 80 to 85 degrees F year round.
There will not be any hurricanes or tornadoes nor will there be any
severe storm activity as it takes a mass of cold air coming into
contact with a large mass of warn moist air to create these natural
occurrences.
Here is a little something else to consider. Back say 600 years ago
there was more CO2 being produced then there has been over the past 50
or so years. Back then wild fires were allowed to burn themselves out
burning up several hundred thousand million acres every year. Some
were started by natural causes like lightening but most especially on
this continent were deliberately set by the native Americans to force
the buffalo and other wild animals in to traps where they could be
easily killed. They didn't have horses back then and the buffalo could
run a lot faster then they could so they used fire to control the
buffalo. Meanwhile on the other continent people burned wood and coal
for heating their houses. They also used oils to burn in their lamps
so they could see at night. Most of the oil used back then was fish
or whale oils which didn't do the environment any good. Not only that
but just as today there were volcanoes that spewed billions of metric
tons of contaminants into the atmosphere ever year. There is also
evidence that vast amounts of the rain forests were cleared by both
the Mayan and Incas to build their enormous cities and farms.
Now here is a little something else to take into consideration every
chemical that we have and use originated right here. And at the exact
same levels. When something is burned, the fire does not create more
CO2 the CO2 was already in whatever is being burned up. All that is
happening is the CO2 that was being held by whatever is now being
released into the atmosphere just as if it were rotting only a lot
faster.
If we are actually cleaner today then say 6 or 7 hundred years ago
then why are the ice caps just now starting to recede? Is it possible
that the ice caps and the snow have created an unnatural situation?
Could we be experiencing a normal climatic change?
za...@construction-imaging.com
>
> read more »
Do you not know that that the so-called Ozone Hole has nothing to do
with Global Warming or CO2 levels?
Captain Compassion
wrote:
Do you not know that the Ozone Hole was settled science?
"Penetrating so many secrets, we cease to believe in the unknowable.
But there it sits nevertheless, calmly licking its chops." -- H. L.
Mencken
Baldin Lee Pramer
wrote:
> Nothing currently suggests that the role of CFCs must be called into
> question, Rex stresses. "Overwhelming evidence still suggests that
> anthropogenic emissions of CFCs and halons are the reason for the
> ozone loss.
I know that you are attempting to portray the results of this article
as the opposite of what the above sentence states. Too bad. No juice
box for you.
BLP
Eli Green
> I have long contended that the environmentalists were wrong and that
> they have been ignoring the geological evidence. I mean there are
> fossils of tropical vegetation and animal life found above the Arctic
> Circle while in Siberia Mammoths have been discovered with tropical
> vegetation not only in their stomachs but also between their teeth.
> These frozen monsters are a testimony to the fact that the
> environmentalists have absolutely no idea of what they are talking
> about.
>
>
understanding of the topic at hand.
What year did you drop out of high school?
Does Rush and Fox News supply you with everything you know? Or do you
supplement it with World Net Daily, Newsmax and American Thinker?
Captain Compassion
Ignoring the standard political statement the article merely points
out how little is actually known about this stuff. Certainty and
settled science at best is a shaky business.
"Penetrating so many secrets, we cease to believe in the unknowable.
But there it sits nevertheless, calmly licking its chops." -- H. L.
Mencken
--
jame...@lycos.com
Yes I do now how about telling that to Gore and company.