High levels of molecular chlorine found in Arctic atmosphere

From the Georgia Institute of Technology

Scientists studying the atmosphere above Barrow, Alaska, have discovered unprecedented levels of molecular chlorine in the air, a new study reports.

Molecular chlorine, from sea salt released by melting sea ice, reacts with sunlight to produce chlorine atoms. These chlorine atoms are highly reactive and can oxidize many constituents of the atmosphere including methane and elemental mercury, as well activate bromine chemistry, which is an even stronger oxidant of elemental mercury. Oxidized mercury is more reactive and can be deposited to the Arctic ecosystem.

The study is the first time that molecular chlorine has been measured in the Arctic, and the first time that scientists have documented such high levels of molecular chlorine in the atmosphere.

“No one expected there to be this level of chlorine in Barrow or in polar regions,” said Greg Huey, a professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology in Atlanta.

The study was published January 12 in the journal Nature Geoscience and was supported by the National Science Foundation (NSF), part of the international multidisciplinary OASIS program.

The researchers directly measured molecular chlorine levels in the Arctic in the spring of 2009 over a six-week period using chemical ionization mass spectrometry. At first the scientists were skeptical of their data, so they spent several years running other experiments to ensure their findings were accurate.

The level of molecular chlorine above Barrow was measured as high as 400 parts per trillion, which is a high concentration considering that chlorine atoms are short –lived in the atmosphere because they are strong oxidants and are highly reactive with other atmospheric chemicals.

Molecular chlorine concentrations peaked in the early morning and late afternoon, and fell to near-zero levels at night. Average daytime molecular chlorine levels were correlated with ozone concentrations, suggesting that sunlight and ozone may be required for molecular chlorine formation.

Previous Arctic studies have documented high levels of oxidized mercury in Barrow and other polar regions. The major source of elemental mercury in the Arctic regions is coal-burning plants around the world. In the spring in Barrow, ozone and elemental mercury are often depleted from the atmosphere when halogens — chlorine and bromine — are released into the air from melting sea ice.

“Molecular chlorine is so reactive that it’s going to have a very strong influence on atmospheric chemistry,” Huey said.

Chlorine atoms are the dominant oxidant in Barrow, the study found. The area is part of a region with otherwise low levels of oxidants in the atmosphere, due to the lack of water vapor and ozone, which are the major precursors to making oxidants in many urban areas.

In Barrow, snow-covered ice pack extends in every directly except inland. The ultimate source of the molecular chlorine is the sodium chloride in sea salt, Huey said, most likely from the snow-covered ice pack. How the sea salt is transformed into molecular chlorine is unknown.

“We don’t really know the mechanism. It’s a mystery to us right now,” Huey said. “But the sea ice is changing dramatically, so we’re in a time where we have absolutely no predictive power over what’s going to happen to this chemistry. We’re really in the dark about the chlorine.”

Scientists do know that sea ice is rapidly changing, Huey said. The sea ice that lasts from one winter to the next winter is decreasing. This has created a larger area of melted ice, and more ice that comes and goes with the seasons. This seasonal variation in ice could release more molecular chlorine into the atmosphere.

“There is definite climate change happening in the Arctic,” Huey said. “That’s changing the nature of the ice, changing the volume of the ice, changing the surface

###

High levels of molecular chlorine in the Arctic atmosphere

Liao et al, Nature Geoscience (2014) doi:10.1038/ngeo2046

Abstract

Chlorine radicals can function as a strong atmospheric oxidant1, 2, 3, particularly in polar regions, where levels of hydroxyl radicals are low. In the atmosphere, chlorine radicals expedite the degradation of methane4, 5, 6 and tropospheric ozone4, 7, and the oxidation of mercury to more toxic forms3. Here we present direct measurements of molecular chlorine levels in the Arctic marine boundary layer in Barrow, Alaska, collected in the spring of 2009 over a six-week period using chemical ionization mass spectrometry. We report high levels of molecular chlorine, of up to 400 pptv. Concentrations peaked in the early morning and late afternoon, and fell to near-zero levels at night. Average daytime molecular chlorine levels were correlated with ozone concentrations, suggesting that sunlight and ozone are required for molecular chlorine formation. Using a time-dependent box model, we estimate that the chlorine radicals produced from the photolysis of molecular chlorine oxidized more methane than hydroxyl radicals, on average, and enhanced the abundance of short-lived peroxy radicals. Elevated hydroperoxyl radical levels, in turn, promoted the formation of hypobromous acid, which catalyses mercury oxidation and the breakdown of tropospheric ozone. We therefore suggest that molecular chlorine exerts a significant effect on the atmospheric chemistry of the Arctic.

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“How the sea salt is transformed into molecular chlorine is unknown.”
But I am sure they will find a way to make it our fault, create an expensive government program to mitigate it, and in the process shovel billions of dollars to political supporters who get into the “whatever is causing the chlorine” business.

Michael

How did this pass peer-review when the abstract mixes the terms chlorine radicals and molecular chlorine? I assume they mean atomic chlorine when they they chlorine radicals which is more reactive Molecular chlorine away from water is pretty chemically stable. Metals don’t react with it. I doubt organic material would either at any appreciable rate.

Vince

They already did make it our fault. It was the chlorine in the polar regions which was caused by CFCs in refrigerants which caused the ozone hole. Then we phased out CFCs years ago, so there might be some explaining to do about the new chlorine.

Mike McMillan

But, but, there shouldn’t be any chlorine up there because we banned chlorofluorocarbons to save the ozone hole. Or something like that.
When they did up the feel-good Montreal Protocol, did they consider the contribution of sea salt to atmospheric chlorine? Don’t know, but kinda doubt it.

Alan Robertson

“We don’t really know the mechanism. It’s a mystery to us right now,”
Molecular chlorine, from sea salt released by melting sea ice…
_________________
Beg your pardon- sea salt released from MELTing ice?
You should have stuck with the “we’re clueless” part.
You guys must have been listening to the “scientists” abourd the Akademik Shokalsiy, because one of them said that melting ice caused salt release which caused the ice to freeze and trap them in place and turn them into buffoons.
Oh, Nevermind. I get it. You’re making your bid to be buffoons, too.

Steve (Paris)

“The study is the first time that molecular chlorine has been measured in the Arctic, and the first time that scientists have documented such high levels of molecular chlorine in the atmosphere.”
Its the first time its been measured and its the first time such high levels have been measured…
Just a thought: if its the ‘first time’ they have been measured how in the world can you say ‘such high levels’???
I guess its good enough for climate science

Why would salt trapped in the ice go into the atmosphere as it melts instead of the water?

The Ol' Seadog.

Huh! “No one expected there to be this level of chlorine in Barrow or in polar regions,” About 4 years ago, when I began to look into CAGW and the Antarctic Ozone Depletion Area, I recalled sailing in the lower parts of the Roaring Forties and the accumulation of salt salt spray high up on the ships. I also noticed a correlation between the circumpolar lows and the Antarctic Ozone Depletion Area. I expressed views that there could be a connection on a facebook site
, but was ridiculed……

Martin A

Molecular chlorine, from sea salt released by melting sea ice, reacts with sunlight to produce chlorine atoms”
Er, I’m not sure if they know that sea salt in salty water (of which there is quite a lot in the ocean anyway, without having to invoke melting sea ice) does not spontaneously yield molecular chlorine.
Climate science: they make it up as they go along.

Steve B

400 parts per trillion is not high. I am presuming that trillion means 10^12 so 4 CL atoms to 10^10 other atoms and molecules. Nope not high at all.

John gorter

How much of this is a result of recent volcanic eruptions?

M Courtney

Steve (Paris) says atJanuary 15, 2014 at 12:42 am…

The study is the first time that molecular chlorine has been measured in the Arctic, and the first time that scientists have documented such high levels of molecular chlorine in the atmosphere.

Well, that could mean that molecular chlorine has been measured in the atmosphere in places other than the Arctic.
In which case the study could be finding that cold places – with little sunlight – are less efficient at breaking up molecular chlorine.
That would be a helpful and believable observation. Indeed it is not unexpected
.

L’ha ribloggato su planetvoicee ha commentato:
A very interesting article on a anomalous levels of molecular chlorine in the atmosphere in Alaska.
Take a look !!!

Patrick

““No one expected there to be this level of chlorine in Barrow or in polar regions,” said Greg Huey, a professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology in Atlanta.”
So, something never directly measured before was measured and the result exceeded expectations of this professor? Clearly the scientific method was AWAL during this study.

Leo G

Molecular chlorine released by melting sea ice? Sea ice melts from below sea level, no? How does that chlorine get released into the atmosphere considering it would exist as hypochlorite in ice and seawater?

So all this was found in 2009 and has been analyzed for the past four years, You’d think these folks would e interested enough to return to see what’s going on now, four years later. They
don’t seem to be very inquisitive about something they .say surprised them. Also lots and lots of “we don’t knows” and, in the end, a lack of words about what, if anything, this all means, if it
means anything.

wayne Job

The sea ice is changing dramatically they opine, there is less of it every year they say. Except that it has been increasing every year. They are pretending they are in the arctic, they best be careful one of those southern polar bears may get them.
They do not know what is causing it but it only happens during the day, it must be the penguins.
Simple lab experiment using the different frequencies of the electro magnetic spectrum would most likely give them a clue. They seem to be about as clued up as the ship of fools.
As for the traces of mercury down there, no one eats penguins except sea lions. Given enough time it may be a mineable resource.

Katherine

The major source of elemental mercury in the Arctic regions is coal-burning plants around the world.
Yeah? How can they be so sure of that? What’s their basis for this claim? How about all the naturally burning coal seams?

Schrodinger's Cat

I remember that in the early days of atomic absorption spectroscopy someone published a list of metals found in a potato. The list included numerous highly toxic heavy metals and the story made headlines in the press. The quantities involved were negligible so in a way it was a story about (almost literally) nothing.
This story sounds fairly similar.

Trygve Eklund

At high school in Tønsberg (Norway) in 1962, in the chemistry course, we titrated for free chlorine in sea water samples from different places in the Oslo fjord. At that time, we were taught that free chlorine was generated by the action of UV light on sea water.
I have tried to trace this information at some occasions (being once responsible for the follow-up of dioxins in the environment of interest to the Norwegian dairy industry), but failed to find any hard facts. Are there better chemists than myself reading this, so please come forward!

Kasuha

I guess this means we’re safe to return back to inexpensive CFCs from current expensive technology?

rogerknights

These chlorine atoms are highly reactive and can oxidize many constituents of the atmosphere including methane and elemental mercury . . . .

Would this be a significant amount?

Stephen Richards

Be afraid, be very afraid. The arctic has been doing this for millions of years. Be afraid. Oh and send us some money so we can find out how this might happen.

Kon Dealer

“Molecular chlorine, from sea salt released by melting sea ice” Did they really say this?
When water freezes it excludes solute (salts) from its crystal matrix. The surrounding seawater gets more salty and denser an so sinks- which drives the thermoHALINE circulation.
And these bozos got published in Nature??

One has measured a lot of chlorine (under form of chloride) at a lot of places, usually higher with winds from the seaside than from land side.
The main background indeed is caused by the oceans: not the melting sea ice, which is largely salt/chlorine free, but the open oceans which present a larger surface if the ice melts. Sea salt spray may be one source, but the Na-Cl bond is hard to split, as it needs a lot of energy. Alternative is HCl (hydrochloric acid) which evaporates from the ocean surface, even if the ocean waters are slightly alkaline, because it is a volatile molecule. The global emissions from that source are estimated at 300,000 tons per year:
http://volcano.oregonstate.edu/education/gases/man.html
Human and volcanic contributions completely dwarfed by the ocean releases…
HCl may rain out, but if precipitation is low, as is the case at Barrow, it remains longer in the atmosphere. It is easier to split in the atmosphere by UV sunlight than NaCl (common salt).
Another, much larger source is CH3Cl, methylchloride or chloromethane, also 99% natural, made by fungi in their chemical pathway to make strong chemicals that are capable of cracking lignin, the chaotic structures that make the glue which binds cellulose together in all plants. Fungi need the cellulose as energy food, but lignin stands in the way.
While most algue are minor sources, some of the main species found in the Arctic (including red algue in snow) are interesting sources:
http://en.wikipedia.org/wiki/Methyl_chloride
An extensive study of 30 species of polar macroalgae revealed the release of significant amounts of CH3Cl in only Gigartina skottsbergii and Gymnogongrus antarcticus.[
But the main source is the production of methylchloride by fungi:
http://aem.asm.org/content/64/8/2831.full
Most of the methylchloride is split up in the troposphere under UV light and the free chlorine radicals help to destroy a lot of organics in the troposphere, together with OH radicals, also made by UV light from water molecules. But because of the quantities involved, some may even reach the stratosphere, adding to ozone depletion, in this case an all natural cause…
So, in my opinion, the origin of the free chlorine is largely known, and probably more from the increased metabolism via the methylchloride route than from the salt/HCl route…

richardscourtney

Ferdinand Engelbeen:
I write to draw attention to your excellent post at January 15, 2014 at 2:10 am and especially your final paragraph.
Richard

John A

How the sea salt is transformed into molecular chlorine is unknown

If you haven’t identified the mechanism, how did you know the source?

izen

@- Katherine
‘The major source of elemental mercury in the Arctic regions is coal-burning plants around the world.’
Yeah? How can they be so sure of that? What’s their basis for this claim? How about all the naturally burning coal seams?
All this information is in the public domain and accessible with a quick web search.
Naturally burning coal seams are at most around 2% of all the coal burnt.
Mercury from burning coal has more than doubled the natural level of mercury in the environment, it is identiifable from the isotopic ratios.
http://www.ncbi.nlm.nih.gov/pubmed/22103560
Incidentally the molecular chlorine measured in this research has absolutely nothing to do with ozone depletion from CFCs in the polar stratosphere. It is far too reactive and water soluble to get out of the lower troposphere.

charles nelson

Back when I was in the industry we used to call this type of thing ‘pushing buttons’.
The buttons being pushed here are clearly marked Arctic, Chlorine and Mercury.
A successful paper pushes the right buttons to get published and a successful press
releases the idea into the MSM.
Warmists have been exploiting this technique since the very beginning.

Katherine says:
January 15, 2014 at 1:33 am
The major source of elemental mercury in the Arctic regions is coal-burning plants around the world.
That may be the main human source, but the main source in The Netherlands is measured as natural evaporation from deeper earth layers. The natural gas wells also are contaminated with a lot of mercury that need to be bounded with sulphur to get it out of the gas. That makes the largest deposit of mercury containing solid waste in The Netherlands…
So I wonder how much atmospheric mercury in the Arctic is of natural origin and how much is human made…

Tom Moran

Well done Engelbeen!

David L

Ice contains essentially no salt. What are they talking about?
Anyone can do the experiment, even Al Gore: put some salt water in the freezer. When a little ice forms, remove it, rinse it off, and taste it.

Louis Hooffstetter

Logic check:
This is the first time molecular chlorine has been measured in the Arctic.
(OK)
The level of molecular chlorine was as high as 400 parts per trillion.
(An amount so miniscule it’s extremely hard to measure accurately.)
These levels are ‘unprecedented’.
(Wrong. You just said they’ve never been measured before. There is no data for comparison.)
“We don’t really know the mechanism. It’s a mystery to us..,”
(OK, time to apply the scientific method.)
“But the sea ice is changing dramatically”… “There is definite climate change happening in the Arctic”… Conclusion: it’s from sea salt released by melting sea ice.
(FAIL!)
These are not scientists. These are climate clowns.

DirkH

Ferdinand Engelbeen says:
January 15, 2014 at 2:10 am
“Another, much larger source is CH3Cl, methylchloride or chloromethane, also 99% natural, made by fungi in their chemical pathway to make strong chemicals that are capable of cracking lignin, the chaotic structures that make the glue which binds cellulose together in all plants. Fungi need the cellulose as energy food, but lignin stands in the way.”
THANKS Ferdinand!!!

Trygve Eklund says:
January 15, 2014 at 1:48 am
At high school in Tønsberg (Norway) in 1962, in the chemistry course, we titrated for free chlorine in sea water samples from different places in the Oslo fjord. At that time, we were taught that free chlorine was generated by the action of UV light on sea water.
Interesting to see that, never thought it would happen in seawater too, as it should get extremely fast reacting with organics always present in seawater…
I was heavily involved in dioxin chemistry too, as working in a chlorine/PVC factory which was accused of high dioxin emissions, without a shred of evidence: it were the badly designed waste burning facilities which were the main source.
Dioxin formation also is a radical reaction where metals, especially copper, catalyse the transformation of chloride into chlorine radicals, which form dioxins in the temperature range of 300-600°C. The total amount of chloride is quite unimportant, but copper amounts and temperature are. Above the temperature range, dioxins are destroyed and below that the formation is too slow.
The design of the waste burning ovens nowadays is maintaining at least 800°C and fast cooling by quenching past the dioxin formation temperature range…
I had some contact with the Norsk Hydro PVC plant in Porsgrunn, not so far from Tønsberg and still have regular contact with friends in Krokstadelva, first met on top of the Galdhøpiggen in 1976…

Alan the Brit

As others have alluded to, how do they know it hasn’t always been like it, or at least for many hundreds or thousands of years?

DirkH

Link above gets me to a generic page; the press release text is here
http://www.news.gatech.edu/2014/01/13/high-levels-molecular-chlorine-found-arctic-atmosphere
And they really did say “Molecular chlorine, from sea salt released by melting sea ice,”.
That may be not the fault of the scientists but of the press release writer.

Can chlorine oxidize? Or does oxidization have to involve oxygen?
Sometimes the reporters make the scientists look like dopes. It is just one of those things scientists have to endure, to get funding.
Sea spray also liberates trace amounts of fluorine, bromine and iodine. Any element ending in “ine” reacts with ozone in the upper atmosphere, and big storms can suck sea spray right up past the tropopause into the stratosphere. Ozone holes may well be caused by sea spray.

knr

Given they simply don’t know what is going on would the fact they jumped on ‘climate change ‘ as the cause be becasue there is still buckets of funded avaiable to support ‘the cause ‘ and by doing this thay stated to others in ‘the team’ their true believers credentials ?

Some similar info(from 1998!) about “unexpected” levels of free chlorine in a coastal area of North America:
http://www.nature.com/nature/journal/v394/n6691/full/394353a0.html

John Marshall

If this is the first time that elemental chlorine has been measured then how can they claim that measured volumes are ”unprecidented”? It may be normal and happen every year during spring melt.
Another ”scare” we will end up paying for.

Ken Hall

Steve (Paris) 12:42. I am glad I read through the comments, before commenting, because I thought the exact same thing. The only time that they have measured, so they have no idea if this is an unusually high reading for that location, they have no idea how it is formed, so actually have no idea if it has anything to do with melting sea ice or not. This whole thing is a massive pile of work which can be summerised as
“nope, we don’t know jack about what’s happening, or if it is unusual or not, but I need my grant extending, so I’ll blame melting sea ice”

izen

@- Ferdinand Engelbeen
“So I wonder how much atmospheric mercury in the Arctic is of natural origin and how much is human made…”
Given that at least half of the background mercury levels we measure are human made, that is that anthropogenic sources have doubled the natural background level, {Munthe et al 2001} at least half the mercury measured anywhere must be from human activity releasing it from natural sequestration.

Leigh

Phew!
For a moment there I’d thought we’d wasted billions on global warming.

Jimbo

The study is the first time that molecular chlorine has been measured in the Arctic, and the first time that scientists have documented such high levels of molecular chlorine in the atmosphere.

Has there always been “high levels of molecular chlorine in the atmosphere” above Barrow, Alaska?
And now onto related news.

BBC – 15 January 2014
“Australia heatwave prompts fire alerts”
http://www.bbc.co.uk/news/world-asia-25723867
Last year was recently declared Australia’s hottest on record, further raising questions about the impact of climate change, our correspondent adds.

Get ready for “it’s a sure sign of global warming,” “the dice is loaded” blah, blah.

Mijnheer Engelbeen’s post is one of the finest. Dank.

Jimbo

It’s good to see that some people have been keeping an eye on chlorine in the air over Barrow since at least 1965.

Iodine, bromine, and chlorine in winter aerosols and snow from Barrow, Alaska
Robert A. Duce, John W. Winchester, Theodore W. Van Nahl
Abstract
Iodine, bromine, and chlorine have been determined in atmospheric aerosols and in snow collected in Barrow, Alaska, during January, 1965, by means of neutron activation analysis. Aerosols collected using both an aircraft collector by impaction and a ground-based 1.0 ? Type EA Millipore filter collector show concentrations of Cl to be much more variable than either Br or I, and I/Br points cluster at 0.1-0.2 gI/gBr for the filter samples. Cl varies from <0.02 to 4 ?g Cl/m3STP in the filter samples, and the aircraft concentrations agree with those taken by filter on the same days. Filter Br is 1–30 ngBr/m3STP and I is 0.3–10 ngI/m3STP, and the ratios I/Cl and Br/Cl increase sharply with decreasing Cl. Snow samples from the ground have Br/Cl somewhat greater than in sea water, although all halogen concentrations decrease with increasing distance from the sea up to 10 km. Assuming a mixture of undifferentiated sea salt and a more permanent atmospheric component, we estimate for the atmospheric component in the snows I/Br?0.2. Sea water, sea ice, and related samples were analyzed, and I/Cl = 4 times 10?6 gI/gCl is normal for sea water, although Br/Cl = 3.8 times 10?3 gBr/gCl stands a little high.
http://www.tellusa.net/index.php/tellusa/article/view/9630
http://onlinelibrary.wiley.com/doi/10.1111/j.2153-3490.1966.tb00232.x/pdf
DOI: 10.1111/j.2153-3490.1966.tb00232.x

Dodgy Geezer

Er…. does this mean that we can have our cheap, safe CFCs back now…?
Thought not….

Jimbo

The study is the first time that molecular chlorine has been measured in the Arctic, and the first time that scientists have documented such high levels of molecular chlorine in the atmosphere.

Here is another also reporting on high concentrations of molecular chlorine off Long Island. What mechanism could have caused this? Any chemists in the house?

Letters to Nature – Accepted 27 April 1998
Unexpectedly high concentrations of molecular chlorine in coastal air
C. W. Spicer1 et al
…..Here we report night-time observations of molecular chlorine concentrations at a North American coastal site during onshore wind flow conditions that cannot be explained using known chlorine chemistry. The measured Cl2 mixing ratios range from <10 to 150 parts per 1012 (p.p.t.), exceeding those predicted5 for marine air by more than an order of magnitude. Using the observed chlorine concentrations and a simple photochemical box model, we estimate that a hitherto unrecognized chlorine source must exist that produces up to 330 p.p.t. Cl2 per day. The model also indicates that early-morning photolysis of molecular chlorine can yield sufficiently high concentrations of chlorine atoms to render the oxidation of common gaseous compounds by this species 100 times faster than the analogous oxidation reactions involving the OH radical, thus emphasizing the locally significant effect of chlorine atoms on the concentrations and lifetimes of atmospheric trace species in both the remote marine boundary layer and coastal urban areas.
Nature 394, 353-356 (23 July 1998) | doi:10.1038/28584;
http://www.nature.com/nature/journal/v394/n6691/abs/394353a0.html

Tables and graphics
http://www.nature.com/nature/journal/v394/n6691/fig_tab/394353a0_T1.html
http://www.nature.com/nature/journal/v394/n6691/fig_tab/394353a0_ft.html

richardscourtney

izen:
I am bothering to answer your daft post at January 15, 2014 at 3:25 am to avoid any possibility of uninformed onlookers being misled by your nonsense.

@- Ferdinand Engelbeen
“So I wonder how much atmospheric mercury in the Arctic is of natural origin and how much is human made…”

Given that at least half of the background mercury levels we measure are human made, that is that anthropogenic sources have doubled the natural background level, {Munthe et al 2001} at least half the mercury measured anywhere must be from human activity releasing it from natural sequestration.

No, izen. It does not follow that the background level of mercury must be at least half from human activities EVERYWHERE merely because Munthe et al determined that is the case where they assessed it (even if Munthe et al were right). And the above report is about the Arctic region which had not been assessed before.
If you had a rational argument to refute Ferdinand then you would have provided it and not the nonsense you have.
I provide this link to Ferdinand’s fine post help those who missed it
http://wattsupwiththat.com/2014/01/15/high-levels-of-molecular-chlorine-found-in-arctic-atmosphere/#comment-1536483
Richard