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    Soot Finally Gets Some Respect In Climate Change
    By News Staff | January 15th 2013 08:30 PM | 25 comments | Print | E-mail | Track Comments

    For two decades, carbon dioxide was touted as the silver bullet for halting climate change.  What about methane, what about NO2, and what about soot?

    Soot, that black carbon that causes smoggy skies (and has sent Beijing's Pollution Index right off the charts) is the number two contributor to global warming, second to carbon dioxide, according to a four-year assessment by an international panel that is not the Intergovernmental Panel on Climate Change. 

    The new study concludes that black carbon, the soot particles in smoke and smog, contributes about twice as much to global warming as previously estimated by the 2007 IPCC report.

    "We were surprised at its potential contribution to climate," said Sarah Doherty, a University of Washington atmospheric scientist and one of four coordinating lead authors. The good news for us all is that controlling soot can deliver more immediate climate benefits than trying to control carbon dioxide.


    Sarah Doherty (left) and Stephen Warren (right) taking snow samples in Greenland in summer 2010. Credit: S. Doherty, Univ. of Washington

    Some previous research had hinted that models were underestimating black-carbon emissions from such things as open burning of forests, crops and grasslands, and from energy-related emissions in Southeast Asia and East Asia.

    Black carbon's role in climate is complex, just like methane and CO2. Dark particles in the air work to shade the Earth's surface while warming the atmosphere. Black carbon that settles on the surface of snow and ice darkens the surface to absorb more sunlight and increase melting. Finally, soot particles influence cloud formation in ways that can have either a cooling or warming impact. The report surveyed past studies and included new research to quantify the sources of black carbon and better understand its overall effect on the climate. 

    Doherty was executive director of the International Global Atmospheric Chemistry Project in 2009 when policy groups were seeking better information on the benefits of reducing black-carbon emissions. The scientific body undertook a comprehensive assessment, supported by IGAC and the U.S. National Oceanic and Atmospheric Administration.

    "Because of a lack of action to reduce carbon dioxide emissions, the policy community is asking what else we can do, particularly to help places like the Arctic that are melting much more quickly than we had anticipated," Doherty said. "We hope reducing black-carbon emissions buys us some time. But it doesn't replace cutting back on CO2 emissions."

    While carbon dioxide has a half-life of 100 years, black carbon stays in the atmosphere for only a few days.

    The authors investigated various sources of black carbon to see which reductions might have the most short-term cooling impact. Regulating emissions from diesel engines followed by replacing some wood- and coal-burning household stoves, authors find, would have the greatest immediate cooling impact.

    "If you're just thinking about impact on climate, you would want to be strategic about which sources you cut back on," Doherty said. "We looked at the overall impact because some of these sources also emit associated particles that can have counteracting effects."

    Black carbon contributes to climate change in the mid to high latitudes, including the northern United States, Canada, northern Europe and northern Asia, as well as affecting rainfall patterns of the Asian Monsoon.

    The report incorporates data that Doherty and co-author Stephen Warren, a UW professor of atmospheric sciences, gathered between 2007 and 2009 to measure soot on Arctic snow. Calculating black carbon deposits in the Arctic is difficult, so data are essential for testing and correcting models.

    Citation: T. C. Bond, S. J. Doherty, D. W. Fahey, P. M. Forster, T. Berntsen, B. J. DeAngelo, M. G. Flanner, S. Ghan, B. Kärcher, D. Koch, S. Kinne, Y. Kondo, P. K. Quinn, M. C. Sarofim, M. G. Schultz, M. Schulz, C. Venkataraman, H. Zhang, S. Zhang, N. Bellouin, S. K. Guttikunda, P. K. Hopke, M. Z. Jacobson, J. W. Kaiser, Z. Klimont, U. Lohmann, J. P. Schwarz, D. Shindell, T. Storelvmo, S. G. Warren, C. S. Zender, 'Bounding the role of black carbon in the climate system: A scientific assessment', Journal of Geophysical Research: Atmospheres, DOI: 10.1002/jgrd.50171



    Comments

    Thor Russell
    Given that soot only stays around for a few days I don't really see what difference cutting down on soot now compared to cutting down on it in 30 years will do. Sure a little more heat will be trapped, but the temp in 2060 will probably be very similar whether soot is cut now or in 2040. The steady state temp won't be changed by cutting soot early. However that isn't the case with CO2, it is cumulative, an integral relationship. Any CO2 emission cut counts all the way past 2100 because most of that CO2 would stay in the atmosphere for that amount of time. Its only if cutting soot early can stop some tipping point that would otherwise NOT happen that it could potentially make a difference. If they can show that cutting soot can stop the arctic melting then they have a case, however I think that is very unlikely and that has already tipped.
    The business about immediate climate benefits seems a bit strange since AGW is going to be much more of a problem from 2050-2100 than from now to 2050, so I really don't see the point of action that could change things in the short term, but do very little in the long term. (e.g if you are concerned about the climate from 2050 on-wards then you may as well cut soot say 2040) If anything it could be counterproductive as it would make the case for action seem less, while not actually making it less.


    A similar argument applies to methane. It has a half life of 7 years, so cuts to methane now will less effect on a 100 year timescale compared to a 20 year one, 72 vs 25 times greater than CO2. I think it makes more sense to take a 100 year timescale or look at the maximum total warming in the next 100 years when comparing scenarios as that is more relevant to the total size of the problem than what happens in the next 20.
    (http://en.wikipedia.org/wiki/Greenhouse_gas)
    Thor Russell
    MikeCrow
    CO2 half life is about 5-10 years, atm level pretty much follow ocean temps.

    But here's an easy experiment for you to do, I presume you have the various home improvement stores with easy return policies (cause after you play with it a few days you can return it, so this doesn't even have to cost you a penny (US)), go buy a handheld IR thermometer and point it at the sky on a clear day.
    Actually it's winter here, I'm curious what you'll measure during the summer.
    For me, depending where it was pointed, on a 35F sunny day, it either max'ed out at 608F, or min'ed out at -40F, pointing at clouds ran from a little less than air temp, and colder.
    -40F is about 12.5u if, right fat where CO2 is suppose to be warming the planet. It didn't measure anything there, nothing, nada. Below 35F is also right where it's suppose to be causing the polar regions to melt
    I need to wait until it warms up some to try it at night (though I am going to see if anything is reflecting the solar 608 signal at night), cause it doesn't read any lower than -40.

    And remember night time cooling is pretty much the ratio between day and night, with some yearly averages gaining a slight bit, and some losing a slight bit.
    Never is a long time.
    Thor Russell
    I don't know how you get that 5-10 figure, you just seem to assume that all scientists studying it are idiots or something. Where is your reference for this extreme claim that pretty much everyone else has screwed up a simple calculation and measurement?
    CO2 has been increasing for >100 years and you can calculate where it has come from and where it is going etc. There is equilibrium between the atmosphere and the top layer of the ocean.

    Thor Russell
    MikeCrow
    If it walks, and quacks like a duck.

    http://www.skepticalscience.com/co2-residence-time.htm

    What I question about this answer is that we've dumped far more co2 into the atm than it's gone up, and the increases are following temperatures, not necessarily the other way around. Many of the ice cores show CO2 following temps, not the other way around.
    Deep oceans have the capacity of maybe 2000 times the entire carbon cycle, what's unclear is the hows and why it's transferring to deep water. The equilibrium is respiration out over warm tropical waters, and in at the cold polar oceans.

    http://www.sciencedirect.com/science/article/pii/0360544293900178 

    Abstract

    An atmospheric CO2 residence time is determined from a carbon cycle which assumes that anthropogenic emissions only marginally disturb the preindustrial equilibrium dynamics of source/atmosphere/sink fluxes. This study explores the plausibility of this concept, which results in much shorter atmospheric residence times, 4–5 years, than the magnitude larger outcomes of the usual global carbon cycle models which are adjusted to fit the assumption that anthropogenic emissions are primarily the cause of the observed rise in atmospheric CO2.

    The continuum concept is consistent with the record of the seasonal photosynthesis swing of atmospheric CO2 which supports a residence time of about 5 years, as also does the bomb C14 decay history. The short residence time suggests that anthropogenic emissions contribute only a fraction of the observed atmospheric rise, and that other sources need be sought.

    Never is a long time.
    Thor Russell
    That paper appears to come from 1993! A lot has happened since then. Based on measurements, the claim that the CO2 has come from somewhere else seems impossible. We have satellites that show CO2 being absorbed/emitted, we can see roads from space not by heat but by the CO2 trace left behind affecting the spectrum of the earth underneath. The measurements show CO2 going into the ocean because there is lower concentration there than over land. It is impossible for there to be lower concentration over a source, its like the bath water being colder than average just where the hot tap hits, when the hot tap is the only source of water hotter than average. The only possible source for such a large amount of CO2 that isn't us could be the ocean, or volcanoes, both ruled out by observation.

    Thor Russell
    MikeCrow
    Never is a long time.
    Thor Russell
    That doesn't look like the graph I have seen, wish I had the reference. Not sure that this graphs shows much, by mid-troposphere the wind could have disguised the source. Ground level would surely be better.
    Averaging over ground level for 1 year would tell you a lot more. Respiration causes a 1 yearly cycle that needs to be accounted for for a start. If you are claiming that CO2 has only a 5 year cycle because of the ocean, and that the ocean is the source, then integrating over the ocean at around sea level for 5 years should give you an average color of more yellow than that of over land.


    I still don't really see how that's supposed to work, you would need some deep upwelling ocean current carrying a massive amount of CO2 from deep waters to shallow waters, diffusion can't do it. That would surely leave its mark, making that part of the ocean very acidic and permanently out of equilibrium with the surrounding areas, permanently staying red in the satellite graph etc. We would see it surely. Even if that was the case, then what would be removing the CO2 we put in the atmosphere, because it is more than capable of producing the observer increase. 

    The only possible physical analogy, which I think has been ruled out by observation and perhaps logic is where you consider adding CO2 to the air like adding water to the ocean. You take a 1m^2 area of ocean, add enough water to raise the sea level by say 5cm, observe it raise by 2cm and say that you caused the 2cm, and 3cm went into a sink. In this case of course the 5cm rise is caused by the tide and if you added 20cm worth you still get 2cm rise etc. Now by analogy there would have to be some equivalent to the tide to remove CO2 from the atmosphere, and just diffusion in the ocean can't do it. The tide "sets" the water to be at a certain level, however an ocean current giving up CO2 doesn't "set" the world concentration to be say 450ppm it just adds CO2, doesn't remove what we add. Therefore even if there was an ocean current, what we added would still raise the atmospheric concentration by about what we put in, unlike pouring water into the ocean where it does nothing to affect the tide level.
    Thor Russell
    MikeCrow

    Figure 7.3. The global carbon cycle for the 1990s, showing the main annual fluxes in GtC yr–1: pre-industrial ‘natural’ fluxes in black and ‘anthropogenic’ fluxes in red (modified from Sarmiento and Gruber, 2006, with changes in pool sizes from Sabine et al., 2004a). The net terrestrial loss of –39 GtC is inferred from cumulative fossil fuel emissions minus atmospheric increase minus ocean storage. The loss of –140 GtC from the ‘vegetation, soil and detritus’ compartment represents the cumulative emissions from land use change (Houghton, 2003), and requires a terrestrial biosphere sink of 101 GtC (in Sabine et al., given only as ranges of –140 to –80 GtC and 61 to 141 GtC, respectively; other uncertainties given in their Table 1). Net anthropogenic exchanges with the atmosphere are from Column 5 ‘AR4’ in Table 7.1. Gross fluxes generally have uncertainties of more than ±20% but fractional amounts have been retained to achieve overall balance when including estimates in fractions of GtC yr–1 for riverine transport, weathering, deep ocean burial, etc. ‘GPP’ is annual gross (terrestrial) primary production. Atmospheric carbon content and all cumulative fluxes since 1750 are as of end 1994.

    From AR4

    And Henry's Law explains the solubility of CO2.

    Lastly RSJ
    Never is a long time.
    Thor Russell
    Well I can see that you can nit pick the details of various claims, however that was not what I asked. The article you have linked to at the end sounds confused to me, a picture is worth a thousand words.If you think the diagram above is incorrect, then provide an equivalent diagram that can explain the observations. I am saying that it is not possible without completely ignoring available data. The above diagram has human CO2 adding to the amount of CO2 in the intermediate ocean, the surface ocean and the air. In order for your claim to be correct, you need to show natural CO2 coming out of the intermediate/deep ocean into the surface and air AND show that the CO2 we emit is going somewhere other than the atmosphere. 
    Show me that this isn't impossible, with a similar diagram and physically realistic assumptions.


    Thor Russell
    MikeCrow
    It's pretty simple.

    Henry's law says depending on the temperature of water, it will hold some amount of CO2. Cold water will pick up CO2 from the ATM, as the picture shows. It also says as the water warms it will hold less CO2. Water near freezing hold the most co2, exposed polar waters are near freezing, and the ocean conveyer takes those cold co2 laden waters into the deep oceans which are also very cold. It's been doing this for thousands if not millions of years.

    Henry's law also says that co2 laden water that gets warmed will out gas co2. This means that CO2 is pumped out of the ocean based on temp. The AIRS image actually shows this cycle.

    A number of Ice cores have also shown that CO2 follows temps not the other way around.
    Never is a long time.
    Thor Russell
    No that doesn't work at all. For a start if the water is warming and releasing CO2 then it becomes less acidic, not more acidic as it warms. As far as I am aware that is directly contradicted by evidence showing that there is more CO2 dissolved in surface waters in spite of rising temperature. 
    Secondly it obviously means that the CO2 we add should still be in the atmosphere/shallow ocean, i.e. increasing the concentration there. If its just an equilibrium between the ocean/atmosphere changing then the CO2 we add will add the total CO2 to that atmosphere/shallow ocean equilibrium. If warming water is causing outgassing, then our CO2 will add to it, i.e. it will still increase the total amount of CO2 in the atmosphere/shallow ocean system and hence increase the atmospheric concentration above what it otherwise would be.

    Give you an analogy. You find you are $365 richer at the end of the year, and someone has been paying you $1 per day. It doesn't matter what else has been going on with your finances, it makes sense to say that you are $365 richer because of that payment. Its the same with CO2. we are emitting it, and unless you can provide a plausible mechanism where the CO2 we emit is completely removed from the air/shallow ocean equilibrium then you must conclude that what we add increases the amount of CO2 there.

    Even a skeptic thinks the ocean is absorbing not emitting CO2
    http://wattsupwiththat.com/2009/05/22/a-look-at-human-co2-emissions-vs-o...

    Also in this link page 41, the CO2 concentration is highest in the northern hemisphere and in the colder areas, not at all what you would expect if outgassing was occurring in the warmer waters.
    http://www.isprs.org/proceedings/2011/isrse-34/211104015Final00523.pdf

    Thor Russell
    MikeCrow
    Thor, it's real simple At 1 atm 0C water holds 1.337 (1000x mole fraction) of co2, at 25C it hold 0.614, at 40C 0.431

    We produce more co2 than the amount air has gone up, at the same time we've reduced the biomass on land. It has to be going some where, that somewhere is the (polar) oceans at some 90-110Gt/year, at the same time the (warmer) oceans out gas some amount less than it takes in.

    I think it is possible that the amount out gassed it controlled by water temps (as outlined above), not on the amount entering the oceans.
    Never is a long time.
    Thor Russell
    OK now you seem to have completely changed your position. Oceans absorbing about half of what we emit is the standard position that I think is correct. The amount outgassed depends on both temp and air concentration because that is how the equilibrium works. You seem to accept now that about half of what we emit raises the atmospheric concentration above what it otherwise would be by that amount which is of course my position.
    I'll give you one final simple example:
    Say you have a system with 10 units of CO2 in the air, 10 in the water in equilibrium. Now there are ways you can change this.
    1. You put an extra 10 units into the air, and wait till it reaches equilibrium of 15 in the air, 15 in the water. The 10 units added to the air caused an increase of 5 units in the air at equilibrium.
    2. You increase the temperature, the equilibrium shifts to 15 air, 5 water.
    3. You add 10 units to the air, and increase the temp by the amount in 2. The system now reaches equilibrium of 7.5+15=22.5 in the air, and 2.5+5=7.5 in the water. In this case the CO2 added to the air cause an increase of 7.5 units in the air above what it otherwise would be, and also showed that as temperature increases, carbon sinks become less effective. The fact that the water outgassed 5 units in scenario 3 in no way makes the 10 units emitted less significant, on the contrary it made it more so.

    Now if you still believe that we have not increased the atmospheric CO2 concentration above what it otherwise would be by about half of what we have emitted into the atmosphere, (and hence trapped extra heat above what otherwise would be trapped) then please think about how this possibly could be and give a complete physical explanation. I don't think one is possible.
    Thor Russell
    MikeCrow
    No, I didn't change my mind. First, atm lifetime is about 5-10 years. The sink into the ocean and the emissions from the ocean are not necessarily tied together, it's possible, or it's possible that emissions are tied directly to temps, which if that's the case equilibrium doesn't have anything to do with it. With raising temps from some natural source, we could expect CO2 to do exactly what it's doing with nothing to do with us. Ice cores say this is possible. I don't know if it is or not.

    But while temps are up, I see no evidence of a loss of cooling ability, which is how CO2 is suppose to be warming the planet, if there's no loss of cooling how exactly is co2 causing temps to rise?

    There's lots of evidence that CO2 AGW is wrong. There's no loss of nightly cooling, the temperature trend for the last 10-18 years (depending on which data set you use) are flat, something the GCM's says can't happen. And why does my IR thermometer read the sky at less than -40F? Where's the trapped heat?

    You're convinced, fine. But so am I.
    Never is a long time.
    Thor Russell
    I am sorry but there still seems obvious contradictions in your position. The cycle from atmosphere to shallow ocean may be 5 years or 5 secs unless it is taken to the deep ocean quickly which it isn't, that figure doesn't matter. Yes the ocean takes out half of what we put it which is fortunate and the ocean currents then take some to the deep ocean, effectively out of the picture, but unfortunately not fast enough.
    The sink in the ocean and emissions from the ocean add linearly. You don't seem to have got the point about my simple equilibrium example at all. Even if the oceans are releasing CO2 (direct evidence says it isn't anyway) that in no way stops the CO2 we are releasing from raising the concentration an additional amount. Why don't you seem to get this? It seems simple and logical to me.


    If you want to see loss of cooling ability, millions of satellite measurements showing the earth gaining heat and the emission spectrum changing slightly, as predicted by theory tells you far more than a single IR thermometer on earth. If you could pick up evidence for AGW from one instrument being waved around that easily we would have cooked long ago.
    Thor Russell
    MikeCrow
    You're just wrong.
    The global oceanic conveyer belt does exactly what you say doesn't happen.
    unless it is taken to the deep ocean quickly which it isn't

    The combined chilling of surface waters, evaporation, and sea-ice formation produces cold, salty North Atlantic Deep Water (NADW). The newly formed NADW sinks and flows southward along the continental slope of North and South America toward Antarctica where the water mass then flows eastward around the Antarctic continent (in the Antarctic Circumpolar Current). There the NADW mixes with Antarctic waters (i.e., AABW and AADW). The resulting Common Water, also called Antarctic Circumpolar water, flows northward at depth into the three ocean basins (primarily the Pacific and Indian Oceans).These bottom waters gradually warm and mix with overlying waters as they flow northward. They move to the surface at a rate of only a few meters per year.
    If you want to see loss of cooling ability, millions of satellite measurements showing the earth gaining heat and the emission spectrum changing slightly, as predicted by theory tells you far more than a single IR thermometer on earth. If you could pick up evidence for AGW from one instrument being waved around that easily we would have cooked long ago.

    The Satellites measure at the top of the atm, it's less than clear exactly what's happening between the surface and TOA. We also have no long term satellite record, as for waving around a ir thermometer, I'm measuring from the surface to space, through all of that co2, and just like the 100's of millions of nightly temperature measurements, it doesn't show anything. As for cooking, it doesn't sound like you understand what a IR thermometer is measuring, nor the wavelengths that CO2 effects, or the temperature of those wavelengths or the difference between the short waves radiating down from the Sun and the long wave radiation up from the surface.

    Even if the oceans are releasing CO2 (direct evidence says it isn't anyway)

    You might want to explain that to the IPCC which shows the oceans as a source of some 90GTons/year of co2 out gassing. BTW, near freezing deep water has a capacity of about 2,000 times the entire carbon cycle in co2.

    BTW, you do realize temp trends have been flat for near 18 years (satellite, 13-15 for surface stations), where this trend is falling out of almost all of the GCM model runs, Oops! It's so bad, NCDC and GISS are now routinely adjusting temperatures down for measurements made 60-80 years ago, at the same time adjusting recent temps up so they can keep making exaggerated claims of pending catastrophe.

    But, you're not going to change your mind, we'll see what happens over the next 5-20 years, I just hope we don't destroy the worlds economy before then, or too many people who can't afford needed energy freeze to death.
    But Hey, Al Gore sure made a bundle selling his climate change tv station to the oil sheiks didn't he lol!
    Never is a long time.
    Thor Russell
    You aren't reading what I am saying or understanding. I have said several times that the global conveyor takes out 1/2 CO2 of what we put in. You still clearly don't understand my position about outgassing either even though I tried to explain with a simple example. I fully understand that the ocean could absorb all our CO2 easily and have suggested artificially putting it there as a solution for climate change. 
    Thor Russell
    MikeCrow
    All you've been saying is that is that Anthropogenic generated CO2 exceeds the oceans(natures) ability to remove it (it's an equilibrium problem), and that's causing atm levels to rise.
    I said 2 things, one is that it takes 5-10 years for co2 to cycle out of the atm, and that ocean temps could be regulating atm CO2, not just human output.
    Dr Glassman does a better job of explaining how that might work than I did. But it's basically cold polar water pull co2 out of the atm, and warm waters out gas co2. And the Airs image shows lower levels around cold waters, and higher levels near warm waters.
    Never is a long time.
    Thor Russell
    No, I have been saying a lot more than that, but you don't get it so I give up.
    Page 41 here shows that CO2 concentration is higher in away from the equator, contradicting completely the theory about hot water outgassing.
    http://www.isprs.org/proceedings/2011/isrse-34/211104015Final00523.pdf


    Thor Russell
    MikeCrow
    I went back and reread all of your post. I don't see it.

    But, if you look at the AIRS image, that area you're talking about is down wind from all of the MidEast's oil refineries, as well as in the area of China's coal burning power stations. So that really proves me wrong.
    You might also notice that most of the warm ocean areas have high concentrations, and most of the cold areas have low concentrations. The 2 spots in S America, and S Africa are both fires.
    So there's no contradiction.
    Never is a long time.
    Thor Russell
    If you think I don't understand what you are saying properly, then provide a fully detailed model for the carbon sources/sinks like what was provided by the IPCC, but with your assumptions in it. Account for all the available data, (satellite, ice core, temp vs CO2 ocean temp, ocean acidity, conveyor measurements ) and show two scenarios.1. Where we don't emit CO2 and we get the air concentration we have now.
    2. We we do emit CO2 and STILL get about the same air concentration we have now.
    Only comparing these two scenarios will show that the CO2 we emit doesn't make a difference. A detailed model proving that our CO2 has not affected the atmospheric concentration significantly must give this result.
    Fill in all the details in a blog post and see if it withstands scrutiny, otherwise nothing else can come of this.
    Thor Russell
    MikeCrow
    Here you go The only difference compared to what I suggested might be possible, is the magnitude of the sinks and sources. And from this page, there are enough assumptions in their calculations to leave that still as a possibility (even if it's a small possibility). But I suspect it won't be the fully detailed model you so truly deserve.
    Never is a long time.
    UvaE
    Thor, here are some comments that accompany Mi Cro's graphic of CO2 concentrations in mid-troposphere.


    You might also be interested in http://www.isprs.org/proceedings/2011/isrse-34/211104015Final00523.pdf  It's an eight year  analysis of AIRS data ( which produced the graphic) and there's an annual growth rate of 2ppm(V) of carbon dioxide in the mid troposphere over industrial areas in China and across the globe. 
    rholley
    Many years ago, when snow was much more frequent than it is now in southern England, I noticed how patches where the snow had got dirty melted much more quickly, and realized that this was due to absorption of radiation from the sky.

    I then thought, why don’t the Russians spread soot over their land in early spring?  It would cause the snow to melt earlier so their land could warm up, and give them some extra days or weeks for agriculture, and it would also moderate the east winds that sometimes made our spring days rather miserable.

    Perhaps it’s just as well I didn’t have the opportunity to put that idea to them.

     
    Robert H. Olley / Quondam Physics Department / University of Reading / England
    UvaE
    When we were kids there was a snow dump about 5 minutes from our backyard. It was so dirty that it took us a a while to realize that it was made up of snow. The hill persisted until June at least, so it would be interesting to know much longer that snow would have been around if it had been virgin-white!