Naked Science Forum
Life Sciences => The Environment => Topic started by: Geezer on 23/04/2011 06:44:06
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There is some ongoing investigation to try to determine if soot deposited on the ice sheets is responsible for their rapid melting.
This is a very interesting theory. If there is a significant disparity between global temperature fluctuations and the rate of ice melt in the polar regions (I'm no expert, but it seems that way to me) the greater near term problem might actually be soot, rather than atmospheric CO2.
I'm not suggesting that it's a good idea to keep dumping millions of tons of CO2 into the atmosphere. To do so is clearly irresponsible and we better stop doing it, but we might need to focus our efforts on eliminating particulate emissions in the near term. If this is the case, we'll have to change our thinking in many areas.
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Hi Geezer , in my opinion we should indeed
.. focus our efforts on eliminating particulate emissions in the near term. ..
rather than wasting resources worrying about sequestering CO2 out of our emissions, but not only because of a possibility that soot on polar ice might or might not have any significant impact upon mean global temperatures. I understand that the Chinese are doing just that with their new “clean coal technology” power stations removing particulates (and other genuine pollutants) that present an established threat to human health.
Best regards, Pete Ridley
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Does that mean my old Diesel banger isn't as environmentally friendly as I thought? *humph!*
Actually as a keen & regular cyclist I would like to see much better handling of sooty emissions in cities anyway. Although w.r.t. climate change I am going to suppose that coal stations are by far the majority contributor globally (especially as the ejection height of the stacks serves to put particulates on longer-range trajectories) - I would ask also, just how clean is 'clean-coal' tech?
For a considerable time a large raft of legislation has concentrated on reducing NOx levels and good though this is, the cost in requiring other pollutants (and, in the case of CO2 that scientists never class as a pollutant, but rather as, rightly, a GHG) to be 'let-pass' instead seems a very risky strategy. That is, are the effects of, the now, relatively low NOx levels (in all but the most built-up cities) worth the cost of other damaging emissions worldwide? [oops! Hijack alert! [:D]]
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This article on “Ice Cores” (http://eo.ucar.edu/staff/rrussell/climate/paleoclimate/ice_core_proxy_records.html) has a note relating to the subject of this thread
.. Many types of aerosols (extremely fine particles), often carried to the polar regions from afar by winds, settle upon snow and become trapped within ice. These aerosols can include soot produced by burning (forest fires, slash-and-burn agriculture, industrial output from smokestacks, etc.), ash from volcanic eruptions, and dust from large-scale dust storms. ..
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It would be interesting to know how many of those .. millions of tons of CO2 into the atmosphere ..
that humans keep dumping actually get deposited on the surface of ice sheets and what proportion that is of the total of all other natural aerosols getting deposited there. Anyone have any idea?
While employed by AMEC Process & Energy Ltd. in the 1990s I worked in an office facing Tottenham Court Road, an extremely busy street in London with lots of the .. old Diesel banger ..
vehicles that peppercorn mentions. London Transport diesel buses and other vehicles stampeded along it all day. Any documents left on windowsills or desk surfaces near windows for several days ended up covered in soot. “90 hybrid buses drive into London's transport network” (http://www.energysavingtrust.org.uk/Resources/Energy-saving-news/Travel-Planning-Infrastructure/90-hybrid-buses-drive-into-London-s-transport-network) should make a big contribution towards sorting out that genuine atmospheric pollution problem. It will not only remove the direct problem from busy urban streets but also means that the polluting emissions from one of their main energy sources (electricity power stations) can readily be removed at source.
On the concerns over .. the rate of ice melt in the polar regions ..
you may be interested in reading this article on concerns expressed by Swedish geo-physicist Dr. Hans Ahlman about Arctic ice melt .. Dr. Hans Ahlman, the distinguished Geographer of Sweden, tells of startling climatic changes in the polar regions which he believes will affect the whole world. Speaking before the Geographical Institute of the University of California in Los Angeles, Dr. Ahlman said: "Northern oceanic waters are distinctly warmer than they were in 1900; waters in the critical Spitzbergen area have shown a 3-5 degrees F rise, arctic air temperatures have soared 10 degrees F in that period" -- an increase of temperature described by Dr. Ahlman as enormous. In the meantime the increase in the annual melting of the northern ice fields is causing an average rise in sea level of 1-11/2 mm each year. The professor points out that should the Greenland icecap, which is some 10,000 feet in depth, completely melt, large areas of coastal lowlands would be submerged, including many of the world's large seaports. Strangely enough, one result of the arctic conditions is found in the tropics, where a marked decrease in rainfall has been noted. ..
(http://www.theosociety.org/pasadena/sunrise/50-00-1/cy-stov.htm).
There’s an interesting graph “Global mean temperatures 18,000 years ago to present” presented there too.
Another article on this, by Steven Goddard, appeared on the Real Science blog ”Science is the belief in the ignorance of the experts" – Richard Feynman
(http://stevengoddard.wordpress.com/2011/03/21/1947-greenland-melting-sea-level-rising-at-a-dizzying-rate-speedy-international-intervention-needed/) – interesting date and interesting comments.
Best regards, Pete Ridley
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It seems like some think it would be a short time solution to reduce the warming globally but most agree that it's only a short term solution as I read it?
Take a look here Losing time, not buying time. (http://www.realclimate.org/index.php/archives/2010/12/losing-time-not-buying-time/)
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It seems like some think it would be a short time solution to reduce the warming globally but most agree that it's only a short term solution as I read it?
Take a look here Losing time, not buying time. (http://www.realclimate.org/index.php/archives/2010/12/losing-time-not-buying-time/)
Yoron,
Thanks for the link.
I'm not suggesting reduced particulate emissions would reduce global warming per se. However, it does seem that the ice sheets are melting at a rate that cannot be explained by atmospheric warming. If soot is the culprit, we better act quickly before a lot of land is innundated.
We may actually have two problems. Warming caused by CO2, and an even more immediate problem of ice melt caused by soot reducing the reflectivity of ice.
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Yeah, it's so many unknown still. Like water vapor in the stratosphere maybe influencing us, and soot and? The question is just what will give us the best result? And how far are we prepared to go to get that result? Like short term, slowing, and probably reducing the living standard we're used too.
And what about the developing Countries? China, India, South east Asia to name a few? They create the same smog that we did, us western countries in a hundred years, in mere decades? And it's us that invested in it too, cause they're 'cheaper' to produce in :)
It's a merry go round this one, dam*ed if I know how we ever gonna stop any global warming myself :) Maybe if we learned to see it in games. Seems that there are some people creating on-line games, don't you laugh now Geezer :) that you can play. In it they create different scenarios, like our oil disappearing and the people build communities and try to cope. The best solutions they save and show on-line as inspirations for others. And the idea isn't that new either, seem like the Sumerian's was the first to introduce it as they had a twenty years famine (a global cold-snap). They made RPG:s it seems and played them, and from those it developed into a strategy where I think (?) half of the population went out in search for better pastures whilst the other half stayed to survive on the meager rations they had. It was long thought to be just a story, but recent research have found Sumerian DNA in the Etruscan society, 200 BC suppressed and conquered by what later became the Roman Empire.
And in the story they let the game decide who to stay and who to go. Truly a impressive solution if the story is correct. So introduce those games to your kids and maybe? We will see different ideas taking hold. We're not counted out, yet :)
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My spelling sux..
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You may be interested in looking at some exchanges on this topic back in 2009 when I was discussing the article “FATAL ERRORS IN IPCC'S GLOBAL CLIMATE MODELS” by Jeffrey A. Glassman, PhD (http://www.rocketscientistsjournal.com/2009/03/_internal_modeling_mistakes_by.html) . Here’s an extract so that you can decide if it’s worthwhile visiting his thread.
Professor Keith Shine .. directed me to a 1995 paper by Professor Ramanathan .. For me, the important points made by Prof. Ramanathan are that: 1) CO2 is not a significant climate driver, 2) the aqua-sphere is far more significant, 3) the response of the continents to global temperature changes depends significantly upon ocean thermal inertia, 4) climate scientists have a poor understanding of ocean thermal inertia. ..
I was then directed to a 2008 publication .. in which .. Prof Ramanathan says there is enough CO2 in the atmosphere to warm the planet by 2-2.5C and that the reason the globe hasn't heated up so much as it should is because of human-made atmospheric aerosol pollutants, but we'll suffer when we clean up our emissions of these. .. his "Testimony to the House Committee on oversight and Government Reform" only one year earlier .. Professor Ramanathan testified on the "Role of Black Carbon in Global and Regional Climate Changes" saying "Thus, next to Carbon Dioxide (CO2), black carbon (BC) in soot particles is potentially the second major contributor to the observed twentieth century global warming". Then I was directed to .. in which Professor Ramanathan's abstract ends "the surface cooling effect of ABCs may have masked as much 47% of the global warming by greenhouse gases, with an uncertainty range of 20–80%.
These references suggest that Professor Ramanathan has changed his mind completely regarding the influence of aerosol pollutants from cooling to warming to cooling in two years.
I hope this helps.
Best regards, Pete Ridley
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I have to say that I find it hard to believe that soot, or other particulates, on ice sheets is a major cause of melting. It would be wrong to assume that the important ice sheets in remote parts of the world get to look anything like those we see in the middle of cities. It is usually the case that we see the rather dirty looking snow as it melts leaving the darker deposits to gradually accumulate on the surface. Where snow repeatedly falls, the surface gets continually re-whitened. In any case there are natural colorations that can occur in snow caused by algae (eg Watermelon snow). It is mainly visible as it accumulates during thawing, as would sooty deposits. It also thrives in sunlight and a higher CO2 atmosphere.
Having said this, I have to say that is just an opinion and I could convinced if there was good scientific evidence.
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There was a rather sooty event here in 1910. Three million acres of timber went up in smoke.
http://en.wikipedia.org/wiki/Great_Fire_of_1910
It might be interesting to try to determine a correlation between that event and historical melt rates, if there was any data available to do that.
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Those are from 2003 Graham. Don't really know how accurate they are found to be today though? But you made a very good point there. Still, if we assume that soot will get meshed into the snow the color should become darker, shouldn't it?
As Pure as Snow. (http://www.giss.nasa.gov/research/briefs/hansen_10/) But I have a lot of respect for the author though :) So?
And BLACK SOOT AND SNOW: A WARMER COMBINATION. (http://www.nasa.gov/centers/goddard/news/topstory/2003/1223blacksoot.html)
There are so many variables, but CO2 is one of the worst, due to the way it can cling in the air for hundred of years, conserving heat. Soot may help to melt the snow, freeing darker land and water, and so become a short term alternative for solving by us. That is, if we're not prepared to change our western way of living radically, but I agree in that it won't solve anything long term. It might give us more time though?
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This is what I said in the original post.
"If there is a significant disparity between global temperature fluctuations and the rate of ice melt in the polar regions"
Is there any evidence to suggest that there is a disparity, or is the melt rate consistent with temperature fluctuations? I had the impression that they are inconsistent, but I really don't know if that is the case.
Perhaps we should understand that before we try to draw any conclusions.
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Thanks for the references, Yor_on; I am much more convinced now. I was surprised by the statement by Hansen that even a small amount of soot can cause a 1% reduction in the reflected light. I guess it is another contributary factor.
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It's a very good question Geezer, and I don't really know that one?
"1989, Twohy et al. noted that "about 1000 times higher concentrations of soot are needed for clouds than for snow to cause a given albedo reduction." The reason is that snow crystals are much larger than cloud drops and a snow deck has greater "optical depth", i.e., it is more opaque. Thus, typical photons of visible sunlight are scattered hundreds of times within a snow deck, so they have a good chance of being absorbed by a soot particle before they can escape."
We need to know how much soot is produced, and where. We need to know how long they will stay in the atmosphere, their size(s) masses and shapes. We also need to have a accurate description of the earths atmosphere at all 'layers', relative humidity, temperatures and how they may 'drift' with winds, convection, clouds etc. It's a very hard question to answer, but what we might do is to look at different depths of snow-layers and try to correlate that to what we expect us to produce? As it is the Arctic, and in some ways also Antarctica, that seems worrying in the short time scenario. I will try to see if I can find something on it Geezer.
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Yeah, it's surprising :)
I will try to see if I can find anything more on it. But it's a added 'effect', directly applicable to places with lot of white stuff :) primary. Still, when that white stuff is gone the freed earth, water and rock will increase the warming noticeably, and the streams we know of, like the gulf stream warming parts of Europe, and parts of USA too, should then disappear. That there will be new streams is no doubt about but it will seriously disturb the underwater convection of cold and warm streams, creating a very different climate for us all.
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I've looked, but this is what I've found new & interesting, so far :)
Curbing soot could slow climate change. (http://www.reuters.com/article/2011/02/18/us-climate-soot-idUSTRE71H4N520110218)
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You may be interested in these comments from “Mitigating climate change through reductions in greenhouse gas emissions: climate science constraints on annual global emissions targets for 2020 and 2050:”
.. Different types of aerosols have different effects (e.g. sulphate aerosols are cooling, while black carbon has a warming effect), but the net effect is through to be negative) .. The effects of aerosols on climate are important, but are one of the largest sources of uncertainty in current climate projections ..
Considering the high level of uncertainty in current climate projections arising from the poor understanding of the processes and drivers of the different global climates it is no wonder that it is hard to find any definitive peer-reviewed papers on the significance of black carbon.
Best regards, Pete Ridley
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Thanks for the info everyone. I've been travelling, so I have a bit of catching up to do.
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Oh, but there are peer reviewed papers Peter, but those were in the links I cited first? Let me give you a direct link Soot climate forcing via snow and ice albedos; By Hansen and Nazarenko 2004. (http://pubs.giss.nasa.gov/cgi-bin/abstract.cgi?id=ha08900n)
What I mean is that I haven't found anything more, for the moment that is. As for definite? Yeah, that's a hard nut to crack. Like knowing it all :) That's not the way any science works. You make a proposition, you ground it on what we know already, then you create the experiment and proofs for how you expect your idea to work. Then you present it, that will be the peer review, if enough people in that field can test it and find it to be as you say we will have a new theory or idea at least for how something 'works'. It's like building a stair case, you have to have something under your feet to build on. Seldom there are people like Einstein, creating it out of his mind primarily, and first then searching for the validations mathematically and physically. Did you know he actually had to learn some of the math proving his ideas?
When it comes to the Earth and the Climate it's a non-linear dynamic system, with a lot of things going into each other creating a 'fluid reality' that makes it extremely hard to pre-cognize how the Earth will act. It's a little like the weather, nice to talk about but real hard to predict over any longer time periods.
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I definitively need a new keyboard. This one eeps losing the 'k' and 'o' :)