From the “CO2 isn’t the master climate control knob after all” department and the AGU.
Air pollution reduces Arctic cloud lifetime, study suggests
WASHINGTON — Fossil fuel emissions from Asia and Europe may be cutting down the life expectancy of Arctic clouds, reducing the clouds’ ability to regulate temperatures in the polar region, according to new research.
A new study published in Geophysical Research Letters, a journal of the American Geophysical Union, suggests pollution plumes coming predominately from Northeast Asia and Northern Europe travel to the Arctic region and allow cloud droplets to freeze at higher temperatures.
This phenomenon triggers earlier than normal snowfall and can reduce the clouds’ lifetime, according to the new research. The shorter the clouds live, the less they are able to regulate temperatures at the surface, the study’s authors said.
Pollution has been known to disrupt Arctic temperatures by introducing greenhouse gases into the atmosphere, but the new finding suggests another process by which pollution from mid-latitudes can disrupt polar temperatures. This previously unquantified effect represents a valuable piece of the Arctic climate change puzzle, according to the study’s authors.
“The Arctic has a climate that is changing very rapidly, and the warming is more intense than the warming that we have in the middle latitudes,” said Quentin Coopman, an atmospheric scientist at the Institute of Meteorology and Climate Research at Karlsruhe Institute of Technology in Karlsruhe, Germany and lead author of the new study, which was completed while Coopman was a graduate student at the University of Utah and the University of Lille.
Along with increasing temperatures, the Arctic is experiencing record lows of sea ice extent in recent years according to the National Oceanic and Atmospheric Administration.
“We focused on the pollution and cloud interaction, but it is part of a bigger system including the sea ice and the atmosphere of the Arctic and (greenhouse) gas and aerosols for example,” Coopman added. “Our results will help modeling studies better predict the evolution of the climate in the Arctic.”
Not many sources of pollution exist in the Arctic but pollutants from combusted fossil fuels coming from other areas of the world can invade the region through atmospheric circulation patterns, Coopman said. Once the pollution arrives, it becomes trapped for weeks or months under a temperature inversion, where a layer of warm air rests above cooler air near the surface and prevents the pollution from escaping into the upper atmosphere or depositing on the surface.
Clouds can either cool or warm surface temperatures in the Arctic, depending on where they form and how much sea ice is present. Clouds above sea ice trap some of the sunlight reflected and heat emitted by the ice, which can warm the surface. But clouds above ocean water, which is much less reflective than ice, block sunlight and have a cooling effect. Collectively, these processes are key in regulating Arctic surface temperatures.
Previous research conducted by Coopman and his colleagues showed Arctic cloud properties are extremely sensitive to pollution. They found clouds in the Arctic were two to eight times more sensitive to air pollution than clouds at other latitudes.
The new study’s results suggest pollution plumes lower the amount of cooling needed for cloud droplets to freeze by about 4 degrees Celsius (7.2 degrees Fahrenheit), a much stronger impact than expected, Coopman said. This means cloud droplets can freeze at higher temperatures. When cloud droplets freeze more readily, snowfall occurs sooner, which can decrease the clouds’ lifetimes and inhibits their ability to regulate temperatures at the surface, according to the study’s authors.
In the new study, the researchers wanted to further investigate how air pollution affects Arctic clouds. They combined data from satellite images of Arctic clouds with atmospheric models used to simulate carbon monoxide, a by-product of incomplete combustion used as a tracer for pollution coming from mid-latitudes.
The new study did not examine how much this change in cloud formation is affecting surface temperatures but the study’s authors said previous work suggests a reduction of cloud lifetime would have an overall cooling effect on the surface and a warming effect in the upper atmosphere.
“Small changes can have very strong consequences in the Arctic region because the atmosphere is very dry, the temperature is very cold, and the clouds are at the edge of existence, so any addition of pollution will have a strong impact on the clouds,” Coopman said.
Marc Salzmann, a research scientist at the Institute for Meteorology at the University of Leipzig in Germany who was not involved with the new study, noted that although the study suggests combustion aerosols to be the cause of the change in freezing temperature, more research needs to be done to show what exactly about the plumes leads to this shift.
“Carbon monoxide is used as a marker for air pollution in this study, but it is obviously not the carbon monoxide itself that causes this,” Salzmann said. “It would therefore certainly be very interesting to find out which physical processes may cause this correlation.”
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This paper is open access for 30 days. You can download a PDF copy of the article by clicking on this link: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL079873
At grazing angles to the sun, it is hard to comprehend how the clouds have any detectable impact. They are driven by solar insolation, which marginally varies at the poles.
“The Arctic has a climate that is changing very rapidly, and the warming is more intense than the warming that we have in the middle latitudes”
Shameful propaganda that pretends the non-existence of the Pause.
Aside from actual satellite measurements, much of the Arctic warming comes from infilling a uniform temperature grid with calculated measurements.
More of the same that it is man that controls the climate. bunch of BS!
Any excuse to knock fossil fuels is a good one.
How about a steady ‘stream”
of dark soot falling
on the ice and snow,
from coal and wood burning
in the northern hemisphere
— an albedo change —
ramping up as China and India
started faster economic growth
in the 1970s —
which could explain
why there was
so much warming
in the Arctic,
and so little warming
in Antarctica?
My second theory involves aliens,
extraterrestrial craft, and heat from
the core of the Earth, which I saw
in a movie.
My third theory
is the general theory of science:
“No One Knows Why …
but that won’t stop the
scientists from wild guessing”.
My climate science blog:
http://www.elOnionBloggle.Blogspot.com
I like all 3 of them. But the Arctic sea ice responds to:
• The currents, both speed and temperature, but it will take extensive research to figure out which has more effect
• The amount of sunlight that reaches the ice, which can vary because of season, clouds and/or atmosphere, and variability of the Sun’s output
• Air temperature. And to a great extent, I think the air temperature is more a result of the first two plus SST than the other way around.
And furthermore, this study is really just another model output, using the output of other models (GCMs) as data for input, so another FAIL!
I see this repeatedly, but I have yet to see any supporting evidence. Can anyone show me a temperature change map of the Arctic that does NOT use ANY infilling? Show me only the 5 deg x 5 deg grid that has a thermometer in it, and if the grid cell has no thermometer IN it, it shows a gray for NO INFORMATION!!! I’m really afraid we our allowing ourselves to get caught up in the rising tide of “…we know it must be happening, all the models show it’s happening…” that I first read from Gavin Schmidt, to the point no one even LOOKS for the evidence anymore. Well, pretend I’m from Missouri, you gotta Show Me!
Good point Red. I remember when Gavin’s mob showed record heat occurring in Chad in Africa. Terribly alarming I’m sure, until you realised that they haven’t actually got any accurate thermometers there. The results are all down to modelling and infilling. And Chad is a huge country. But, what the hell, if it keeps the narrative going, the only people who are going to grumble are skeptics who get virtually no mainstream media traction anyway. That’s Goebell Warming for you, as Dellers would say!
The UAH satellite data shows the north polar trend is .25 C /decade which is double the global trend.
https://www.nsstc.uah.edu/data/msu/v6.0/tlt/uahncdc_lt_6.0.txt
Sorry, but UAH NoPol shows NO WARMING this century apart from the El Nino
Please don’t use transient effects as part of a non-existent trend, it is mathematical nonsense.
No satellite directly measures all the way to the poles.
“The new study did not examine how much this change in cloud formation is affecting surface temperatures but the study’s authors said previous work suggests a reduction of cloud lifetime would have an overall cooling effect on the surface and a warming effect in the upper atmosphere.”
Umm. So, which is it? This pollution examined (with no specifics, I saw, as to particulate or gases) is responsible for warming at the surface in the arctic or is not quite counteracting some other cause of surface warming. Is this conflicting info really in the paper?!? Or just a confused press release writer?
I personally think we haven’t yet truly fleshed out the net effect of more of less clouds on surface temperature. Much less by season/insolation rate.
At polar latitudes the angle of insolation and winter solar deprivation make clouds more a warming factor, if my information is correct. Warming of the arctic is very much SST dependent. That’s why it doesn’t get warmer than normal during summer lately. the extra enthalpy in summer has much less effect than when it is -30 C. A little RH% goes a long way at that temperature. Just look at NLCs during the summer. A little meteor smoke combined with a wisp of moisture that was carried above the tropopause to freeze into mother-of-pearl.
Honestly, who the hell cares if the Arctic, Antarctic and/or Greenland melt.
A few wealthy individuals with beach side or riverbank properties?
Lets get real here. If the planet warmed up enough to melt the poles (at 10’s of degrees C below zero by the way, 1.5 degrees C just aint going to do it) sea level would gradually rise, not a tsunami like rise, but a gradual rise over perhaps 1,000 years, and we would be left with at least two continents worth of productive agricultural land.
Oh dear, the weather might change. Big deal, we’ll cope with it.
What an unbelievable fuss over ice cubes that contribute nothing to humanity’s, or the planets well being.
Over it’s lifetime, the world has enjoyed 80% of it’s existence without frozen poles. Humanity is the unlucky sod that pitched up in the coldest period, with the lowest atmospheric CO2 content it has ever known.
Imagine what we could have achieved without that burden.
We’d still be living contentedly in the trees without a worry in the world. Humanity needs challenges.
8000 years ago Greenland started to melt and continued to melt for 3000 years. The temperature was 2C warmer than today. At the 5000 year ago mark, Greenland had lost about 20% of it’s ice mass. However the irony of it was not the 2 C difference in temperature that melted 20% of the ice mass but that the volcanic activity was more pronounced during that period, because Greenland melts from underneath.
This is sounding like utter nonsense to me.
The current warming in the Arctic is far more linked to a NH jet stream that has become more looping and unstable along with increased jet stream activity in the Arctic. What this change is causing is that there is now a greater movement of air masses flowing in and out of the Arctic and across the globe. As this more waving and unstable jet stream sets up weather patterns that aid to the movement of air masses over 1000’s of miles. There is currently a example of it going on in the N Atlantic. Where air from near the mid Atlantic is flowing up towards northern europe and into the Arctic. lts this sort of movement of air mass that is helping to cause the current warming of the Arctic.
So can dust from the Sahara Desert.
What’s the difference?
The sum of dust and pollution has a greater effect than dust alone.
The difference is…um, pollution.
Are they able to differentiate between natural pollution and anthro, or do they just assume that everything humans do is not “natural”?
Lets not forget the natural wild fires in Siberia;
https://siberiantimes.com/ecology/others/news/concern-over-raging-wildfires-as-smoke-from-siberia-crosses-alaska-and-canada-reaching-new-england/
Of more interest to me is the warm anomaly west of Siberia;
http://ocean.dmi.dk/satellite/index.uk.php;
Could we be seeing an increase of warm Pacific water entering the Arctic driven by an increase in deep water THC formation east and west Greenland due to the AMO turning negative? If so, then although warmer this water will cool in winter and as it less salty so will form sea ice much easier (radiating more latent heat into space). The Bering Strait is only shallow (50m) so this water should only form a slick on the surface.
https://frontierscientists.com/2015/06/discerning-ocean-currents-current/
Monitoring the warmer temperatures of the incoming waters to the Arctic would be a more productive exercise.
“Carbon monoxide is used as a marker for air pollution in this study…
So… they used a proxy. One that oxidizes readily in the atmosphere and is highly variable from natural sources.
Is this anywhere close to being reasonable? Not sarcasm here, actual question to anyone well versed in this. Is that a reasonable proxy for air pollution like particulates that are obviously long lived while carbon monoxide lasts, what, a couple of months?
David, not only did they use carbon monoxide as a proxy, then they modelled it with a computer program. I am thrilled to read all of the attentive Watts followers tear into this sham study. Warming in the Artic? What, from minus 30 C to minus 28 C? Somebody should take these dufus climate scientists to the Artic and turn them loose so they can enjoy the warmed-up Artic.
I agree that the warming is probably insignificant, but before calling a study a sham, I’d suggest you at least proofread your accusation so that you don’t misspell the word “Arctic” not once or twice but every single time you used it.
Thank you R Shearer, I stand corrected. I have actually been north of the Arctic Circle, just north of Circle, Alaska, and I should have remembered that. The study is a sham and not even fit for a Junior High School Science Project.
Now that was shur a “cutie”, …. R Shearer’s “badmouthing” of a vocal opponent of a pseudo-scientific publication that is obviously FUBAR ……. simply because Ron Long misspelled a word in his posted response.
In the UK, “artic” means an articulated lorry. That can be roughly translated as “tractor-trailer” or a “semi-trailer” for those of the transatlantic persuasion. Those darned artics warm up a lot when you leave them out in the hot sun. Must be the fossil fuel they’re using.
They used CO measurements from five stations in conjunction with their models. Yes, there is high variability as you state and that is a major contributor to the uncertainty of the results as the authors stated in their abstract. It appears that their approach is reasonable.
How can their approach be considered reasonable when they used models, used a proxy, and assumed from the beginning that the Arctic is warming ? This study is as bogus as a $3 bill.
They used CO measurements from five stations in conjunction with their models.
I read the abstract and there is no such statement in there as you state above.
In fact, further down in the paper, they do in fact talk about 5 stations, but it is in reference to another paper:
Coopman et al. (2017) performed a linear fit between modeled CO and measured CO from five Arctic stations and retrieved a slope of 0.8 with correlation coefficients greater than 0.68
So I bothered to look at THAT paper. From the abstract, bold mine:
Carefully controlling for meteorological conditions we find that the liquid water path of arctic clouds does not respond strongly to aerosols within pollution plumes. Or, not stratifying the data according to meteorological state can lead to artificially exaggerated calculations of the magnitude of the impacts of pollution on arctic clouds.
They then go on to claim that another paper supports the method:
Monks et al. (2015) compared 11 atmospheric models with chemistry and evaluated the simulated CO concentration in the Arctic: They concluded that CO concentration (χCO) retrieved by GEOS‐Chem showed better agreements with observations than χCO retrieved from other models.
Well “better than” does not mean “good”. From that paper (among other things)
Evaluation of 11- atmospheric models with chemistry shows that they generally underestimate CO throughout the Arctic troposphere, with the largest biases found during winter and spring. Negative CO biases are also found throughout the Northern Hemisphere, with multi-model mean gross errors (9–12%) suggesting models perform similarly over Asia, North America and Europe.
So the two papers they cite as showing that using CO as a tracer for aerosols basically don’t say what the authors claim they say. To be fair, I only read the abstracts of those two papers, but that’s what I got out of them. From THIS paper however, I note that it says in the abstract:
The relationship between anthropogenic plumes and the freezing transition temperature from liquid to ice remains to be explained.
So… they have a tracer of questionable accuracy possibly correlated with a physical observation for which they have no theory to explain. This isn’t even correlation is not causation. This is grant farming IMHO.
Very good detective work!
The arctic temperature varies a lot. It has been much warmer than it is now. Pollution has nothing to do with it. CO2 has nothing to do with it. link The idiots who write these speculative papers should first understand the arctic temperature record over geological time periods.
By defining CO2 as a ‘pollutant’, attention is diverted from the legitimate and genuinely toxic pollutants that adversely affect our health, the safety of our food supply, and the quality of our air, water and soils. There are corporations (pharmaceuticals and petrochemicals for example) happy for the reduced scrutiny.
“I see this repeatedly, but I have yet to see any supporting evidence. Can anyone show me a temperature change map of the Arctic that does NOT use ANY infilling? ”
Nothing resembling what was asked for. Just more stupid wiggly lines, not a map.
Seems you are well named my friend.
The only temp series that does not sample surface data is the satellite ones … and since denizens here only accept UAH (v6 of course as it’s by far the coldest of UAHs many ‘adjusted’ versions).
Shows a trend of 2.45C/cent.
For Baffin Island, there is no trend for last 80 years.
http://www.worldclimatereport.com/wp-images/baffling_fig1.JPG
Try posting the annual temp data.
Not just the summer.
Greatest warming is coming in the winter.
This is Resolute …..
https://data.giss.nasa.gov/cgi-bin/gistemp/stdata_show.cgi?id=403719240000&dt=1&ds=5
GissTemp….. after NCDC and NOAA “adjustments”
ROFLMAO. !!!
Oh absolutely!
Massive, massive “adjusted” warming.
Of the past…..
http://www.realclimate.org/images//GISS-adjustments.jpg
Inconvenient that eh?
Cue more conspiracy idiocy.
And even nature is in on the conspiracy.
Heck! ……
“Spring has already advanced in three-quarters of the 276 parks examined, and half of the parks are experiencing an “extreme” early spring that exceeds 95% of historical conditions as measured by first leaf index and/or first bloom index from indicator plant species. No parks are experiencing extreme delays in spring onset. Managers in the “extreme” early parks have thus already been working under relatively anomalous conditions for the past 10-30 years.”
https://www.nps.gov/subjects/climatechange/springonset.htm
Thanks, this is great, but I can’t seem to turn on the unadjusted series, or any of the other ones. I click on the series names, they get darker but nothing happens.
Interesting how they show the cooling leading up to the late seventies, before the warming trend. I would have thought that all the industrial activity during WWII and the rebuilding afterwards would have resulted in CO2 induced warming.
“Did you know? A new lawn mower produces 93 times more smog-forming emissions than a new car!”
CAR CHEMISTRY: WHAT IS A CATALYTIC CONVERTER AND HOW DOES IT WORK?
http://explorecuriocity.org/Explore/ArticleId/1779/car-chemistry-what-is-a-catalytic-converter-and-how-does-it-work-1779.aspx
Carbon Monoxide Vs. Carbon Dioxide: Let’s Compare
http://www.indsci.com/the-monitor-blog/carbon-monoxide-carbon-dioxide/
Arctic Ice Melt
Study suggests drilling for these fossil fuels is helping melt the arctic
“The flaring of natural gas is contributing more than 40 percent of the sooty black carbon in the Arctic, a level that raises new concerns about the link between energy production and ice melt, according to a new study.”
https://www.scientificamerican.com/article/oil-and-gas-production-drives-arctic-ice-melt/
You have linked another bogus study that again uses junk computer climate models. The number of gas flaring in Canadian Arctic was minimal and is now zero . Please look at this report.
https://www.beaufortrea.ca/wp-content/uploads/2012/03/NCR-5358624-v4-BREA_-_FINAL_UPDATE_-_EXPLORATION_AND_ACTIVITY_FORECAST-__MAY_2013.pdf
However the costs of drilling were so high that most of the companies backed out. To top it all off, both Obama and Trudeau banned the activity in 2016. So the study you pointed to was superceded by Trudeau and Obama.
Almost all of the pollution in the Canadian Arctic is coming from China or on the other side from Russia/Siberia drilling . So the bottom line is our politically correct western leaders ban exploration in the Arctic while Russia goes ahead full steam. A ruthless stone cold killer dictator like Putin doesnt care about any possible warming niceties from soot. He simply goes ahead and drills and then sells the gas to Europe. Meanwhile in Canada we still import a lot of oil from Saudi Arabia.
We’ve known for a long time that pollution reduces albedo and increases Arctic melt.
” said previous work suggests a reduction of cloud lifetime would have an overall cooling effect on the surface”
..so it makes it colder
and not one word about the positive AMO that’s been hosing straight in there for decades
We’re obviously going to have to ban market-economies, ban technology, and go back to stone tools, and even that may be bad for the environment. Plus be wery, wery careful about not starting fires. We only use it to cook meat, and there are plenty of tasty grubs if you dig around a bit like other animals do.
There aren’t enough caves for us to live in.
What the heck is “temperature disruption”?
This article is unscientific. Particles are “invading the Arctic”? Invading? Are these Ghengis Khan particles from Mongolian domestic heating of yurts or Attila’s particles from dacha fireplaces in the Urals? The text is sciency, but treats temperature measurements and weather forecasting into something closer to the “sociology of climate analysis”. It hawks feelings-based evidence.
In essence they are claiming that human activities are warming the Arctic (no direct evidence cited) while increasing snowfall, which removes clouds and greatly increases heat loss to space. As forest fire particles have always followed these patterns and forest fire incidence and severity are decreasing on a century basis, the core assertions are dubious.
The ICCI claims that these same particles (well, the BC component) are causing melting of the same snow that this article says is increasing. Add that to the thickening of the polar ice (at the pole), the increasing Greenland ice massand we have a divergence of opinion as messy as the ice chunks blocking access to the Cambridge Bay harbour.
Why don’t you seed the clouds if all else fails. This is a relatively new technology but non the less, successful. T
These guys are too lazy to do their homework and read the literature. Arctic ice melting is a consequence of the rearrangement of the North Atlantic surface current system at the beginning of the twentieth century that caused the north-flowing warm Gulf Stream water to send more of its warm water into the Arctic Ocean than tr did before. Read my paper in Energy and Environment that came out in 2011. There was a very warn water period in the twenties followed by thirty years of cooling which was followed finally by the present warning in the late sevenr\ties, That is what attracted the Arctic :experts” who had bo idea of the wo thousand year history that preceded it. And then they complain that th wqarming went twice as fast as rgeir models predicted. If you use the wrong model thaT IS WHAT YOU EILL GET.
“reducing the clouds’ ability to regulate temperatures in the polar region”
Except that isn’t air temperature
https://tambonthongchai.com/2018/08/04/does-global-warming-drive-changes-in-arctic-sea-ice/
Cloudy weather is dominant during the Arctic summer.
During winter clouds are more scarce, but clearly doing a lot to warm the cool Arctic.
As can be seen here: http://ocean.dmi.dk/arctic/meant80n.php
Can anyone explain this without clouds?
Less ice = more ocean heat escaping.
DMI shows no warming has occurred in the arctic summer. So how do clouds affect temperature … in the dark?
http://ocean.dmi.dk/arctic/plus80n/anoplus80N_summer_winter_engelsk.png
Mike
Good observation!
It is a gloomy weather to spend summer vacation in!
The same way clouds affect temperature overnight in your backyard in winter.
They reduce cooling to space.
More WV condensing in Arctic skies has been driving warmer arctic winters.
Leading to less max sea-ice formation by March.
More open waters in Autumn has also slowed the speed of ice- extent buildup ….
https://ocean.dmi.dk/arctic/meant80n.uk.php
I should have specified my remark was aimed at their reference to sunlight: “Clouds can either cool or warm surface temperatures in the Arctic, depending on where they form and how much sea ice is present. Clouds above sea ice trap some of the sunlight reflected and heat emitted by the ice, which can warm the surface. But clouds above ocean water, which is much less reflective than ice, block sunlight and have a cooling effect. Collectively, these processes are key in regulating Arctic surface temperatures.”
Per the DMI chart I posted above, there hasn’t been any change in arctic summer temperature at all in almost 60 years. If anything there has been a slight decrease in arctic summer temperature. Per the chart ALL of the warming there is happening in the winter when it is DARK so their mention of sunlight in that paragraph makes no sense at all.
There’s only one place heat can come from in the arctic winter and that is the ocean so a shorter lifetime of clouds due to pollution is going to enhance cooling by virtue of the observation that you made. “The same way clouds affect temperature overnight in your backyard in winter.
They reduce cooling to space.” Therefore, less clouds = more cooling to space.
But remember, the thousands of nautical miles which ice breakers plough through the ice margins, breaking the ice which melts first into smaller pieces, has no impact at all. And if the minimum ice extent doesn’t start decreasing again soon we’re going to need to launch three new ice breakers to go help study the ice.
Suffice it to say, it’s just more crap science pushing the “arctic is melting, and it’s our fault” meme.
This explains alot. If you look at charts of summer sea ice in the Arctic, you will see little ice melt over North America because there is very little air pollution. But there is lots of air pollution over northern Europe, Russia, and China. Furthermore, since no countries border the Antarctic, there is no ice loss problem there.
If it’s cold enough that the cloud droplets are freezing, then the amount of sun light is already very low.
Getting more water out of the air in this manner will result in more cooling, not more heating, as the drier air will permit more heat to escape to space.
A greater propensity to precipitate will mean more snow and hence ice, thus mitigating warming-driven ice loss. Good if you want more ice.
As i understand it, less cloud cover results in a cooler surface as radiation escapes more easily.
The heat released by condensation in clouds is dumped into the atmoshpere at a higher altitude than the surface. All other things being equal, such heat will escape into space more rapidly than if released at the surface.
The paper makes a clear statement about how settled the science is in this area:
“Measurements of ice nucleation rates from laboratory and field studies made over the past two decades can
differ by orders of magnitude (Jeffery & Austin, 1997; Pruppacher, 1995) making it difficult to bring ice nucleation theory into agreement with observations (Doutriaux-Boucher & Quaas, 2004).”
The paper cites one paper reporting that the correlation between aerosols and CO is strong near joint sources of both. It then cites several papers that have used CO as a proxy for aerosols, though it is silent on how far from the source those proxy inferences were. It is not stated how strong the correlation between aerosols and CO concentrations remains at the distance between the arctic and typical sources. How far are the major sources, namely bushfires and uncatalysed vehicle emissions, from the arctic?
CAGW skeptics will presumably see the paper as supporting their views as it implies increased heat loss and it reports considerable uncertainty.