The Discovery Channel has “shark week”. With all the Arctic news items on WUWT, this is beginning to feel like “polar week”. Here’s an article about aerosols having an impact on the arctic from a surprising source.- Anthony
From Universe Today, Nancy Atkinson
Since the 1890s, surface temperatures on Earth have risen faster in the Arctic than in other regions of the world. Usually, discussions on global warming tend to focus on greenhouse gases as the culprit for the trend. But new NASA research suggests about half the atmospheric warming measured in the Arctic is due to airborne particles called aerosols.
Aerosols are emitted by both natural and human sources. They can influence climate by reflecting or absorbing sunlight. The particles also affect climate by changing cloud properties, such as reflectivity. There is one type of aerosol that, according to the study, [reduces] rather than increases in its emissions seem to have promoted warming.
The research team, led by climate scientist Drew Shindell of the NASA Goddard Institute for Space Studies used a computer model to investigate how sensitive different regional climates are to changes in levels of carbon dioxide, ozone, and aerosols.
They found that Earth’s middle and high latitudes are particularly responsive to changes in aerosol levels. The model suggests aerosols likely account for 45 % or more of the warming measured in the Arctic since 1976.
Though there are several types of aerosols, previous research indicates two in particular, sulfates and black carbon, play leading roles in climate. Both are products of human activity. Sulfates, which come mainly from the burning of coal and oil, scatter sunlight and cool the air. Over the past three decades, the United States and European countries have passed clean-air laws that have halved sulfate emissions.
The models showed that regions of Earth that showed the strongest responses to aerosols in the model are the same regions that have witnessed the greatest actual temperature increases since 1976, specifically the Arctic. However in the Antarctic, aerosols play less of a role.
Researchers with the NOAA, the National Oceanic and Atmospheric Administration reported in the April 3 issue of the journal Geophysical Research Letters that Arctic summers may be ice-free in as few as 30 years.
The Arctic region has seen its surface air temperatures rise by 1.5 C (2.7 F) since the mid-1970s. In the Antarctic, surface air temperature has increased about 0.35 C (0.6 F). That makes sense, Shindell said, because the Arctic is near North America and Europe, highly industrialized regions that produce most of the world’s aerosols.
“In the mid-latitudes of the Northern Hemisphere and in the Arctic, the impact of aerosols is just as strong as that of the greenhouse gases,” said Shindell. “We will have very little leverage over climate in the next couple of decades if we’re just looking at carbon dioxide. If we want to try to stop the Arctic summer sea ice from melting completely over the next few decades, we’re much better off looking at aerosols and ozone.”
Aerosols tend to be short lived, staying in the atmosphere for just days or weeks, whereas greenhouses gases can persist for centuries. Atmospheric chemists thus think the climate may respond most quickly to changes in aerosol levels.
NASA’s upcoming Glory satellite is designed to enhance current aerosol measurement capabilities to help scientists reduce uncertainties about aerosols by measuring the distribution and properties of the particles.
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I think regardless of however you look at it the problem with the climate, whether It’s heating or cooling, rising or falling, sooty or clear the problem is Man. There are just too many of the aerosols, according to the leading aerosols on the planet.
Those Arctic mean temps tell nothing about the causes when we have enormous regional differences, e.g.
“…in the late 1930s with anomalous winter (DJFM) SAT, at Spitzbergen, of greater than +4°C….
…SAT in winter (DJF) and spring (MAM) for 2000–2007 show an Arctic-wide SAT anomaly of greater than +1.0°C and regional hot spots over the central Arctic of greater than +3.0°C.”
Ref: Overland, James E., Muyin Wang, and S. Salo, 2008. The recent Arctic warm period. Tellus A Vol. 60, No 4, pp. 589-597, August 2008, online http://www.pmel.noaa.gov/foci/publications/2008/over0682.pdf
They conclude: “Both periods suggest natural atmospheric advective contributions to the hot spots with regional loss of sea ice…The recent dramatic loss of Arctic sea ice appears to be due to a combination of a global warming signal and fortuitous phasing of intrinsic climate patterns.”
My favourite candidate for recent Arctic warming is 30 years of positive warm oceanic oscillations feeding warm water into the Arctic Circle via the North Atlantic resulting in a peak of ice melt in 2007 and now a likely slow recovery of ice following the arrival of a negative PDO and a cutting off of the supply of warm water.
The most obvious and simple explanation but the very one that AGW proponents cannot afford to consider so they scrabble about for ever less likely alternatives.
A bit OT:
northern Europe is getting an early spring “heat wave”, like almost every year since the beginning of the 2000s. today in Brussels, the temperature is 24C (approx 78 F), which is nothing but 11C above average. Since the beginning of Spring, the lowest daytime temperature we had here was “only” 4 degrees above average.
Justin Rollat the BBCs ethical man is in the USA (In this film Muskegon Michigan)
http://www.bbc.co.uk/blogs/ethicalman/2009/04/the_first_ethical_man_film.html
OT but thought it might be of interest.
I’ll translate from NASA to English:
Yes, we need to know more what aerosols do to our climate. Yes, we should have collected more data about this much much earlier. But the point they should be making is “we don’t know chickenshit” instead of running around arm-waving and declaring the end of the world as we know it. The last “help scientists reduce uncertainties” says it all, the rest of the article is dressing up these uncertainties.
What about this lot running around the North Pole all hot and bothered?
http://www.dailymail.co.uk/news/article-1168875/Im-just-run-North-Pole-marathon—I-time.html
I am sure I am missing something but where does the global temperature line come from. Looking at the Hadley global average temperatures http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh+sh/ I can see very little correlation as the big dip in the early 1900’s is completely missing
Flanagan
I was under the impression that you resided in the Central African Republic, do you have a town called Brussels there? According to! # weather underground,# the average temp. for Brussels Europe over the last 7 days was 12.15c slightly BELLOW normal.
None of the lines in that graph show a decade of recent cooling that is often refered to here, where is the decade of cooling?
Steady on. This is getting pretty close to blaming the warming on man and that is blasphemy.
Save the Antarctic, fry the Arctic.
Save the Arctic, fry the Antarctic.
To aerosol or not to aerosol, that is the question.
The Sun is nothing more than a big light bulb in the sky.
When Earth is lit, it activates the warming bacteria.
To solve Global Warming, turn off the lights when you go to bed.
All of them.
High Pressure Sodium Lights are evil invaders from Mars. Kill them all.
Hmmm. I prepared a post a few months ago that showed that ENSO and volcanic aerosols could explain most of the Arctic surface temperature volatility.
http://bobtisdale.blogspot.com/2009/01/enso-and-volcanic-aerosols-explain-most.html
The second title was “And High Latitude North Atlantic SST Anomalies Explain the Rest.”
It appears I need to replace EXCEL with a GCM.
Okay…where to start.
“We will have very little leverage over climate in the next couple of decades if we’re just looking at carbon dioxide. If we want to try to stop the Arctic summer sea ice from melting completely over the next few decades, we’re much better off looking at aerosols and ozone.”
Talk about shifting the goal posts. C02! C02! C0…errrrrrr…wha?…it’s getting colder?…err….ummmm….AEROSOLS! OZONE! AEROSOLS! OZONE!
And…I though there was another study a few months ago that said that giant hole in the ozone had nothing to do with us…and that a guy had the color of his eyes permanently change due to the hole in the ozone….and that…wha?….wrong pole?….shoot.
Looking at that graph…and polar-bear with me (I’m still on my first cuppa), but does that graph show that arctic surface temps rose pretty dramatically AFTER passing the clean air act?…looks like without that, temps were plummeting in the Actic??? Boy…did we screw THAT up or what?
More coffee…bbiab
JimB
I saw an ad for that and couldn’t roll my eyes enough (they’re still rolling). I suppose Justin swam to the US, and the cameras and electricity his production crew use are “all natural”… The Ethics Police can’t be far behind.
re: Arctic temps. Considering there are no temp measuring stations in important areas up there, any “arctic warming” is extrapolated from stations thousands of km away. That’s accurate, eh wot? And sat measurements don’t cover the Arctic well, where does that leave us for the so-called most rapid increase in temps?
Rimo Hämeranta,
“Those Arctic mean temps tell nothing about the causes when we have enormous regional differences…”
The paper you cite says exactly the opposite:
“Our main evidence is the spatial uniformity of the +1.0 ◦C or greater background SAT [Spring Autumn Temperature] anomalies across the Arctic … which are consistent with climate model projections from IPCC-AR4.”
http://www.pmel.noaa.gov/foci/publications/2008/over0682.pdf
Stephen Wilde,
“My favourite candidate for recent Arctic warming is 30 years of positive warm oceanic oscillations feeding warm water into the Arctic Circle via the North Atlantic…”
Your explanation is not consistent with this uniform warming, though undoubtedly such currents are not helping the situation. The paper above concludes:
“…a revised fast track estimate of summer sea ice loss before 2030 is reasonable.”
The failure of computer models to anywhere nearly reflect the real world draws this unfortunate conclusion: “The AGW campaign has resulted in a seething cesspool of deceit.”
And the pathetic refusal to acknowledge the failure casts each and every contributor to AGW, in a deep and darkening pall.
I think that we cannot have it both ways with these computer models.
Having examined the temperature outputs from these models when they play with CO2 I tend to think that they should be discarded and researched back to square number 1 .
To have someone come up fiddling with parameters in one of these dubious models and just because the output favors non CO2 warming to embrace it whole heartedly will be a big mistake, in my opinion. Until the models give an error band around their predictions, i.e. vary their caboodle of parameters by 1sigma and give us the true error band of their estimates, I am wary. It is still GIGO.
Are they saying they’ve erred with their CO2 assertion?
It’s out, and now it’s manmade aerosols?
Can someone kindly help to flesh out my thinking here?
1) Aerosols depress Arctic temperatures.
2) Some of the recent rise in Arctic temperatures has been due to the decrease in the amount of aerosols.
3) This leaves 2 possibilities:
a) This supports the idea that the sensitivity of temperature to Co2 levels is high because we are now able to see how powerfully aerosols dampen the increases due to Co2 etc.
b) This supports the idea that the sensitivity is low, because if we had not been producing aerosols the temperature would always would have been higher so the rise would have been smaller.
Can anyone tell me which it is?
pmoffitt (21:55:14) :
It is clear that sulfates are cooling- which aerosols are promoting the warming the carbon black?
Yes. From http://www.nasa.gov/topics/earth/features/warming_aerosols.html
“Sulfates, which come primarily from the burning of coal and oil, scatter incoming solar radiation and have a net cooling effect on climate. Over the past three decades, the United States and European countries have passed a series of laws that have reduced sulfate emissions by 50 percent. While improving air quality and aiding public health, the result has been less atmospheric cooling from sulfates.
At the same time, black carbon emissions have steadily risen, largely because of increasing emissions from Asia. Black carbon — small, soot-like particles produced by industrial processes and the combustion of diesel and biofuels — absorb incoming solar radiation and have a strong warming influence on the atmosphere.”
–Mike Ramsey
Im suspicious… the Co2 thing isnt going so well so they found another bad guy. Hey it worked before… Question is how do you cap and trade aerosols? Im tellin you guys saving the climate has nothing to do with the present administrations interest in the enviornment. Its all about cash flow. Without cap and trade how will they pay for everything?
OT:) Hey I didnt know you guys hired a proof reader:P hehehe
Paul R (22:44:14) :
There are just too many of the aerosols, according to the leading aerosols on the planet.
That would be my choice for quote of the week.
Stephen Wilde is of course correct. The simplest explanation for variations in Arctic ice is more warm water in the Arctic in the recent past which is now reversing.
Paul R is also right (if a little near the knuckle), we have to be made to believe the ‘problem’ is man made because that is the only way it can be taxed.