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Ozone impacts on climate change

Filed under: — gavin @ 27 July 2007

In a nice example of how complicated climate feedbacks and interactions can be, Sitch and colleagues report in Nature advance publication on a newly modelled effect of ground level (or tropospheric) ozone on carbon uptake on land (BBC). The ozone they are talking about is the ‘bad’ ozone (compared to ‘good’ stratospheric ozone) and is both a public health hazard and a greenhouse gas. Tropospheric ozone isn’t directly emitted by human activity, but is formed in the atmosphere as a result of photolytic reactions related to CH4, CO, NOx and VOCs (Volatile Organic Compounds like isoprene, benzene etc.) – the so-called ozone precursors.

It’s well known that increased ozone levels – particularly downwind of cities – can be harmful to plants, and in this new study with a carbon-climate model, they quantify how by how much increasing ozone levels make it more difficult for carbon to be sequestered by the land biosphere. This leads to larger CO2 levels in the atmosphere than before. Hence the ozone has, as well as its direct effect as a greenhouse gas, an indirect effect on CO2, which in this model at least appears to be almost as large.

Actually it’s even more complicated. Methane emissions are one of the principal causes of the rise of ozone, and the greenhouse effect of ozone can be thought of as an indirect effect of CH4 (and CO and VOCs). But while NOx is an ozone precursor, it actually has an indirect effect that reduces CH4, so that the net impact of NOx has been thought to be negative (i.e. the reduction in CH4 outweighs the increase of ozone in radiative forcing – see this paper for more details). This new result might prompt a re-adjustment of that balance – i.e. if the ozone produced by NOx has a stronger effect than previously thought (through this new indirect mechanism), than it might outweigh the reduction in CH4, and lead to NOx emissions themselves being a (slightly) positive forcing.

In a bizarre way this is actually good news. There are plenty of reasons to reduce NOx emissions already because of it’s impact on air pollution and smog, but this new result might mean that reductions wouldn’t make climate change any worse. It also, once again, highlights the role of CH4 (the second biggest GHG forcing), and points out a further reason (if that was required) why further methane reductions could be particularly welcome in moderating future changes in climate and air quality.


243 Responses to “Ozone impacts on climate change”

  1. 151

    #137 Timothy, Polar models failed to catch present Arctic Ocean all time low ice depletions, as they are known to be less than perfect, it is good to find out why (not to say that they are nevertheless awsome). I simply can’t reason with the same results as the models, an open Arctic Ocean will contribute to greater days with higher RH. On the opposite , fixed landscape scenario, an Increase in temperature in the desert would likely reduce RH (giving that no immediate moisture sources are around), in situ. highly localized effects of increasing temperatures change RH, it is that simple. Why would RH stay roughly the same then? I can imagine that this constant RH conclusion, should work if the entire planet was an ice free Ocean though, this may give a constant, but continents and ice provide the “roughly” (constant).

  2. 152
    Lawrence Brown says:

    I enjoyed Barton’s responses to Limbaugh’s inanities on global warming. Where do these pundits get their (self appointed) expertise on every subject known to humankind? If you ask Coulter, or Buchanan or Bob Novak or , any of them, a question on anything they never say “I don’t know enough about that subject.” ! How can that be?
    If one were to ask one of them…. If a cylinder with a piston and a mole of any gas,were fitted with a membrane through hydrogen could pass, what would the entropy be, if two thirds delta gamma equals one half delta p? ……… They wouldn’t say “I don’t know”, instead they would dance around it and give a nonsensical answer( just like the question).

  3. 153
    Timothy Chase says:

    wayne davidson (#151) wrote:

    #137 Timothy, Polar models failed to catch present Arctic Ocean all time low ice depletions, as they are known to be less than perfect, it is good to find out why (not to say that they are nevertheless awsome). I simply can’t reason with the same results as the models, an open Arctic Ocean will contribute to greater days with higher RH.

    I most definitely agree with you regarding the sea-ice being a serious matter. I expect the summers to free of sea-ice after 2020. This is according to projections based on current ice-loss. And from what I understand, much of the reason why the polar regions rise in temperature more quickly than the rest of the globe is due to loss of albedo. Not good – for a variety of reasons. Obviously something we need to work on. Aerosols are another area. Currently we are making a fair amount of progress on the later and working on the former.

    Regarding relative humidity, it is my understanding that the relative humidity due to ice tends to be greater than that of open water due to sublimation. There is a partial pressure to water vapor that extends well below freezing, and the partial pressure of saturation rises exponentially with temperature. But the loss of sea ice will no doubt raise temperatures simply as the result of the lost albedo.

    Regarding the continents, I believe what you point out is the key to a problem that has been puzzling me: why is it that the continental interiors will tend to suffer more from drought? The relative humidity will be lower. But this is something which is being captured by the models.

    Anyway, relative humidity is a useful concept, a normalized physical measure – which captures dew points, phenomena related to net evaporation, sublimation and condensation quite nicely. Which is why I like it.

    As for the models, obviously there are areas which are in need of work. It is an ongoing process of development, incorporation of the relevant physics. But when the models predict cooling in the stratosphere, the raising of the tropopause, the formation of hurricanes in temperate zones, the increased prevailence of droughts in the southern hemisphere despite the fact that temperatures there are rising more slowly, etc, I am impressed.

    Particularly when it is something which the models predict when why they do this is something that we can’t quite figure out, and yet they turn out to be right, or when the predictions seem especially counterintuitive, but are right nevertheless. Then again, Hansen’s prediction from 1988 was fairly impressive.

  4. 154
    B Buckner says:

    Timothy #153: I agree the accelerating trend in Arctic sea ice reductions since 1997 is troubling. You said you expect the ice to disappear by the year 2020, much quicker than most report. A couple of questions for you. Are you simply extracting the current trend out to 2020? Is it known what the global forcing would be from the decreased albedo resulting from ice free summers? It would seem this value would be low due the sun being low in the sky. Also, as the temperatures drop in the fall/early winter, the oceans would cool substantially more than if they were insulated by the ice cap, perhaps partially offsetting the albedo effects. I understand factors other than temperature also effect the ice, such as ocean currents that move thicker ice away from the pole to be replaced by thinner ice that melts quicker in the summer. Lastly, what do you think of the antarctic sea ice, which has been expanding over the same time period?

  5. 155
    Hank Roberts says:

    Which Antarctic sea ice would that be? It’d help if you’d tell us your sources instead of making claims that seem overbroad.

    Perhaps you’re referring to part of it described in http://www.gsfc.nasa.gov/topstory/20020820southseaice.html

    If so the change follows the general trend in temperature.

    “Overall, the area of the Antarctic with trends indicating a lengthening of the sea ice season by at least one day per year was 5.6 million square kilometers (2.16 million square miles), about 60 percent the size of the United States. At the same time, the area with sea ice seasons shortening by at least one day per year was 3 million square kilometers (1.16 million square miles).”

    Why the general trend? Look at the area involved — central to the Antarctic vortex. The ozone hole is persistent; it had been expected to be much reduced in size by now, before climate change produced extra cooling in that area. We know about it.

  6. 156
  7. 157

    Re #152 — Thanks. :)

    -BPL

  8. 158
    Timothy Chase says:

    B Buckner (#154) wrote:

    Timothy #153: I agree the accelerating trend in Arctic sea ice reductions since 1997 is troubling. You said you expect the ice to disappear by the year 2020, much quicker than most report. A couple of questions for you. Are you simply extracting the current trend out to 2020?

    Here are two articles on it in the newspapers:

    Arctic set to melt by 2020
    May 03, 2007 12:00am
    http://www.news.com.au/sundaytelegraph/story/0,,21660293-5009640,00.html

    Arctic ice cap melting 30 years ahead of forecast
    Tue May 1, 2007 3:11PM EDT
    By Deborah Zabarenko
    http://www.reuters.com/article/scienceNews/idUSN0122477020070501

    Although the figure of 2020 is not specifically mentioned in the technical paper, the claims are based on the analysis found in:

    Arctic sea ice decline: Faster than forecast
    Julienne Stroeve, Marika M. Holland, Walt Meier, Ted Scambos, and Mark Serreze
    GEOPHYSICAL RESEARCH LETTERS, VOL. 34, 1 May 2007

    From what I understand, this prediction is still regarded as somewhat extreme within the scientific community where I believe 2040 would still be considered mainstream. But it is based upon the most recent research and trends identified as the result of empirical studies. I believe I remember recently that the specific projection was based upon the average rate of percent rate of loss since 1979 having been 9%, the average net ice loss for the past several years as a linear trend, and the assumption that this would be roughly constant for the next 13 years.

    As such, this estimate is of 2020, although considered extreme could in fact be conservative since it does not take into account the fact that most of the feedback processes involved should be both positive. However, I prefer to stick with the figure of 2020 simply because we do not know enough about the positive feedback to make any better estimate.

  9. 159
    joel says:

    Maybe, instead of talking about computer models you might talk about real world data.

    How about commenting on the “Asian brown cloud” and how that affects climate. There is real world data on that.

  10. 160
    B Buckner says:

    Thanks for the reply Timothy. I apologize for not providing the cite regarding the growing antarctic sea ice. I got if from the web site “The Cryosphere Today” as mentioned on realclimate many times as documentation of the shrinking arctic ice.

    Does anyone have information quantifying the albedo effects of the arctic sea ice melting? Sorry to impose by I have not been able to find such info.

  11. 161
    Lynn Vincentnathan says:

    RE #141, most people I know are religous & consider themselves religious, some “very religious,” and only a tiny portion of those are concerned about global warming, and quite a few (even the “very very religious”) adamently object to the idea GW is happening or that it is caused by humans. I’ve gotten into some pretty strong fights with “religious” people over global warming. Even some from my own Carmelite order. It’s been extremely demoralizing for me, to say the least.

    OTOH I actually don’t associate with any atheists or non-religous people, so I don’t know if they might be the same — mostly opposed to any idea that GW is happening or that humans are causing it. Like I said, some study would have to be done to see if there actually is a difference.

  12. 162
    B Buckner says:

    Timothy et al, a December 22, 2006 post in the archive on this very weblog discusses the issues I raised in some detail regarding the melting ice and albedo. An interesting read.

  13. 163
    Timothy Chase says:

    B Buckner (#160) wrote:

    Thanks for the reply Timothy. I apologize for not providing the cite regarding the growing antarctic sea ice. I got if from the web site “The Cryosphere Today” as mentioned on realclimate many times as documentation of the shrinking arctic ice.

    The Cryosphere Today
    http://arctic.atmos.uiuc.edu/cryosphere

    Good site!

    I am glad you are taking time to look at it.

    Yes you are right: sea ice has been growing it the South Ocean this summer. Then again, our summer is their winter so this should come as no surprise.

    The following page gives a chart that is somewhat inconclusive:

    Southern Hemisphere Sea Ice Anomaly
    Anomaly from 1979-2000 mean
    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.anom.south.jpg

    It in fact seems rather variable – not much of a trend either way.

    But that is sea ice area.

    I would suggest that the actual mass of the Antarctic ice sheet may be more important…

    Using measurements of time-variable gravity from the Gravity Recovery and Climate Experiment satellites, we determined mass variations of the Antarctic ice sheet during 2002–2005. We found that the mass of the ice sheet decreased significantly, at a rate of 152 +/- 80 cubic kilometers of ice per year, which is equivalent to 0.4 +/- 0.2 millimeters of global sea-level rise per year. Most of this mass loss came from the West Antarctic Ice Sheet.

    Measurements of Time-Variable Gravity Show Mass Loss in Antarctica
    Isabella Velicogna and John Wahr
    Science 24 March 2006: Vol. 311. no. 5768, pp. 1754 – 1756
    http://www.sciencemag.org/cgi/content/abstract/311/5768/1754

    Of course, if and when a major sheet ice breaks off, that will mean more sea ice. So if you were to offer me a bet where I would win only if sea ice decreased the next one or five years, I probably wouldn’t take you up on it…

  14. 164
    Timothy Chase says:

    B Buckner (#162) wrote:

    Timothy et al, a December 22, 2006 post in the archive on this very weblog discusses the issues I raised in some detail regarding the melting ice and albedo. An interesting read.

    What you had stated (#154) is:

    Is it known what the global forcing would be from the decreased albedo resulting from ice free summers? It would seem this value would be low due the sun being low in the sky. Also, as the temperatures drop in the fall/early winter, the oceans would cool substantially more than if they were insulated by the ice cap, perhaps partially offsetting the albedo effects. I understand factors other than temperature also effect the ice, such as ocean currents that move thicker ice away from the pole to be replaced by thinner ice that melts quicker in the summer.

    Albedo loss would seem to be a significant problem, despite the latitude. Temperature drop in the fall? Well, what about temperature rise in the spring? I don’t see that much here. Partial offset? Perhaps.

    I remember someone arguing recently that an increased poleward warm ocean water flow due to stronger hurricanes is a negative feedback – and it clearly is – for hurricanes. But in terms of overall global warming it would seem to be a positive feedback which in the long-run would tend to increase the severity of hurricanes – at least for a while. Likewise, the smaller the Arctic sea ice gets, the farther north it seems the warm branch of the thermohaline must go before it sinks. This would seem to be a positive feedback.

    Nevertheless, it is worthwhile to examine and acknowledge the evidence regardless of whether it supports your view or tends to undercut it. The identification of reality must take precedence over any value, allegiance or political agenda. This is something which the contributors at Real Climate understand quite well.

    The post you are refering to…

    Not just ice albedo
    22 December 2006
    by Rasmus Benestad
    http://www.realclimate.org/index.php/archives/2006/12/not-just-ice-albedo/

    … is a shining example of that – where the author seeks to view the issue in terms of all the feedbacks, positive and negative. I hope this never changes. Then again, I rather doubt it will.

    My personal view is ultimately my own personal view. I wouldn’t ever claim to be an expert.

    However, since we have managed to push ourselves so well outside of the stable attractor, I expect the positive feedbacks to dominate – until we find a more stable attractor. That and the trends which I have seen so far lead me to expect the rate of loss to accelerate.

  15. 165

    [[Maybe, instead of talking about computer models you might talk about real world data.]]

    Since the computer models are constantly updated to reflect what is known about the relevant physics, and since that enables them to match historical climate data very closely, there’s no particular reason to distrust the models.

  16. 166
    Gareth says:

    If we’re talking about sea ice…

    Cryosphere Today doesn’t show much decline of sea ice in the long or short term – bouncing along above the mean at the moment. But ‘oop North, the picture is rather different. About 2 million km2 below mean. And the NCIDC sea ice index isn’t pretty sight for July. Albedo flip in action?

  17. 167
    Timothy Chase says:

    Barton Paul Levenson (#165) wrote:

    [[Maybe, instead of talking about computer models you might talk about real world data.]]

    Since the computer models are constantly updated to reflect what is known about the relevant physics, and since that enables them to match historical climate data very closely, there’s no particular reason to distrust the models.

    There is also the simple fact that data can’t tell you very much about the future. You can see a trend, but how do you know that the trend will continue? Ten years? Twenty years? Forty years? Perhaps what currently looks like a straight line will end up being a curve. Perhaps other factors will interact. What if we chose to reduce emissions?

    To the extent that we can incorporate the relevant physics, we are able to base our projections upon a far larger body of knowledge than just a few points on a graph – things as tried and tested as the laws of thermodynamics, the laws governing fluid motion, chemistry, the study or radiation in terms of the blackbody radiation, absorption and reemission – and even quantum mechanics.

    If I may quote from a different post:

    This is really part of the beauty of climate models – and at an abstract level, one of the most fundamental principles of climate modeling itself. It argues from general principles, typically fundamental principles of physics – although not strictly – as when the responses of organisms are incorporated into the models. It doesn’t allow the arbitrary element of curve-fitting. Such an approach would have little grounds for regarding its conclusions as applying to anything outside of what the curve was based on – and given the complexity of what we are dealing with, it would quickly evolve into a Rube Goldberg device which no one could understand the basis for – but which we would adopt merely like superstitious rats which are randomly rewarded – dancing about in the belief that some increasingly complex set of motions determines whether or not they get the reward.

    Green and Armstrong’s scientific forecast, comment 64

    The problem with the arctic ice cap which I mention above is that it is clear that we don’t know all of the relevant physics, at least not in the the form that would be necessary to incorporate it into the models. As such I believe there is some justification in making projections outside of the models based on some data points.

    But we are working on incorporating the relevant physics. As we do, we will know that the model will have a far greater range of applicability than simply the next thirteen years. It will apply to ice in the next forty or a hundred years, or the past billion years and beyond. It will apply to any given course of action we might choose to take – so that we can compare the alternatives and choose our actions based in part upon their consequences.

    The models have already proven themselves quite powerful, but they are a work in progress. The important thing is that, like the knowledge upon which they are based, it is cummulative.

  18. 168
    Lynn Vincentnathan says:

    RE #136 & what is the difference between holistic and loosey-goosey, anyway. Actually I subscribe to a holistic approach. It makes the best business cases for enterprises because it offers truth over accuracy. Unfortunately those cases are seldom accepted by executives because they are too “loosey-goosey”.

    If you mean a holistic approach is difficult to carry out, I agree. For instance, in social science we can only deal with several variables at a time. And if we get a moderate correlation….yeah!!! Because we know there are many many things impacting humans, & there are feedback loops. However, I keep the idea in mind that there are these many many other factors and dimensions (some in complex relations and feedbacks — as this post indicates was found for re ozone).

    So what we usually do is “hold the other factors (artificially) constant” & look at the 2 variables of interest. But that could be dangerous, if there are other variables involved and lives are at stake. So even if it is “loosey-goosey” in your opinion, it is good IMHO to keep as many known and potential factors in mind…to think out all the repercussions we can. (I guess we should have done that before inventing industrialization :) )

    Problem is we humans are fininte, limited beings in our thinking and science and technological aids. I understand that only with improving computer technology has climate science been able to advance as it has, including more and more variables in complex formulas.

    And still (I think) they don’t know how melting ice sheets will be acting & reacting, so they can’t even add that into the formula. And that seems to be an important factor. But if you can’t predict or quantify it, it gets left out. I wonder how many such (known and unknown) things are being left out of the formulas.

    There seems to be a trend in climate science of “we are now more certain” and “it’s worse than we thought.” Has anyone done a meta-study of climate science in this regard (I’m familiar with Oreskes’s study).

  19. 169
    Philippe Chantreau says:

    Tim has a good point about the Antarctic sea ice. A fast sliding ice sheet means possibly more sea ice but that will really not be good news, especially if the particles identified as a factor in a recent Sciam article can melt that sea ice extra fast. In any case, the current depletion of actic sea ice suggests to me that models might underestimate how fast it is going to disappear. And then Russia will move in to extract oil from the Arctic sea floor and reduce the price of oil…
    The more I think about the whole picture (and the more I read Rod B’s comments), the less I believe we will do anyting about this until consequences are so far reaching as to render any mitigation impossible. An interesting experiment, indeed. All because a few fat ogres would not have any of their enormous profits threatened. Curious species of ours really.

  20. 170

    Re #169 –

    I’m not convinced there is enough oil in the Artic, or the Orinoco, or up in Alberta, to make things as nasty as the worst (or even the middlest) warming scenarios.

    Also, don’t blame the corporate giants. There are a lot of not-so-fat ogres driving around in SUVs for no good reason. We’ve had the choice of fuel efficient vehicles for more than a decade now here in the States and the average car buyer is still buying on the high end of huge and wasteful. The United States could have been energy self-sufficient a decade or more ago.

    On the subject of the ozone hole and it not reducing as fast as expected. Is this being driven by CFC persistence that exceeded projections, or by climate change? And if the first (or why not answer anyway …) are the new coolants “safe” or just “safer”?

  21. 171
    Alan K says:

    #165
    Stating “Since the computer models are constantly updated…” is one of the reasons there is a scepticism about computer models. If they are constantly updated then the moment before they are updated they were presumably inaccurate.

  22. 172
    B Buckner says:

    I am not as pessimistic as many here, people are starting to come around. For instance, there was an article in the Wall Street Journal (or urinal as named by some) last week that talked of the demand for new coal electric generating stations in the US. Many utilities had been planning new coal stations to replace plans for natural gas stations as gas is becoming more expensive. The number of planned coal stations was 143 if I remember correctly. Well most of these coal station projects have now been canceled. Each and every new coal station is being stiffly resisted by the public because of global warming concerns. As a result, business, political and wall street interests are pulling their support as well.

  23. 173
    B Buckner says:

    Phillippe #169 The antarctic sea ice extent varies from about 2 million sq km in the summer to 16 sq km in the winter. This process is dominated by the seasonal freeze/thaw of the ocean, not the slow or fast sliding of the ice cap.

    You place blame for our current climate situation on a few fat cats who are more interested in profit than the well being of the human race. Please, name some names. Lets take Exxon Mobil. It has 5.5 billion shares outstanding, is half owned by 1500 mutual funds, and has millions of share holders. Who is the bogey man?

    Perhaps it is us. Large companies provide services and products to meet a market demand. The problem is not the fat cats, it is us. We could kill all the fat cats and it would not change a thing. The entire developed world heats and/or cools their homes, uses electricity for work, light and the internet, and owns a car. Blaming someone else is easy, but you are part of the problem. Everyone talks a good game here, but few of us (Lynn V comes to mind) actually walk the walk.

  24. 174
    Lawrence Brown says:

    Re Lynn’s comment #158, even with shortcomings in the models, like the lack of complete of understanding of clouds and the fact that the current speed of the fastest computers makes cells greater than 100 miles on a side impractical and limits atmospheric elevation divisions to 20 to 40 divisions they have a remarkable record of success. See the thread Hansen’s 1988 Projections posted on this site on 15 May by Gavin for example. In addition, climate models starting with past conditions successfully reproduce today’s climate. Future projections of different models using different assumptions of unknowns instances show consistency.
    There are uncertainties to be sure. This is true at the most elemental state of matter where a sub-atomic particle’s position and momentum can’t both be known. thank’s to Heisenburg’s principle. Even the queen of the sciences, mathematics has it’s Godel’s Undecidability Theorem.
    The success in predicting the world temperature that would follow the eruption of Mt. Pinatubo is another example of climate models reliability.

  25. 175
  26. 176

    Re #173:

    That happened here in Texas, and I’m not sure of the causality, but the electric utility I use was recently bought out by an environmentally friendly investment group. I was going to switch from TXU to Green Mountain for both environmental and cost reasons (Green Mountain (wind) is cheaper than TXU (goal, gas and nukes)), but with this buyout I may stick with them. Additionally, I suspect the rise in such things as CFL usage have got to be worrying the utilities, so I suspect they are seeing pressure from several sides –

    1). State mandates to begin producing renewable energy by some date in some amount.
    2). Environmentalist opposition.
    3). Consumer conservation.

    As regards long term change, the positive signs I’m seeing are shortages of many “green” products, or a surge in the number of “green” products on the market, and greatly increased discussion about climate change amongst the unwashed masses. This mirrors, to some extent, the discussions and behaviors I saw when “ozone friendly” products were starting to be produced ahead of the ban on CFCs. At this point in time, if consumer reaction to CFCs and ozone depletion is a guide, we’re just a few short years away from a major change in consumer attitudes.

    One really big event that I see on the horizon is the 2008 Olympics in China. From what I understand, China is going to restrict driving ahead of the Olympics in hopes it will reduce polution, but with the problem being as severe as it is, I suspect there will be a lot of focus on what Chinese and Indian development is doing to the environment. Which can only be a good thing.

  27. 177
    EW says:

    Archibald’s criticized graph of relationship of temp and sunspot cycle length in De Blij – probably derived from similar comparisons published for Armagh observatory:
    http://climate.arm.ac.uk/publications/global-warming-man-or-nature.pdf

    also in Butler and Johnston (1996), cited by Archibald.
    Butler, C.J. and Johnston, D.J. 1996.
    A Provisional Long Mean Air Temperature Series for Armagh Observatory,
    J. Atmosph. and Terrestrial Phys. 58, 1657

  28. 178
    Rod B says:

    a minor query re #170. Don’t CFCs persist in the stratosphere for years and tale decades to get into the stratosphere?

  29. 179
    Hank Roberts says:

    Just to veer back to the topic for a moment, the first post ends:

    “this is actually good news. There are plenty of reasons to reduce NOx emissions already because of it’s impact on air pollution and smog, but this new result might mean that reductions wouldn’t make climate change any worse. It also, once again, highlights the role of CH4 (the second biggest GHG forcing), and points out a further reason (if that was required) why further methane reductions could be particularly welcome in moderating future changes in climate and air quality.”

    This really is encouraging. It means that burning fuel in pure oxygen — rather than in air — is a win-win choice, for one thing.
    Any fire hot enough to oxidize nitrogen (any internal combustion engine, and as far as I know any current coal power plant) not only puts out nitrogen oxides, it also puts out a far greater total volume of exhaust gas since air is only 20 percent oxygen.

    Given this news that we can safely reduce nitrogen oxides without making climate change worse favors the more efficient, higher-tech idea of burning coal in pure oxygen and producing pure CO2 exhaust gas — using a closed system —- making the exhaust gas exactly what we need to sequester if we’re going to use coal at all.

    It suggests it makes sense to leapfrog the intermediate designs for “slightly cleaner” coal plants — the ones that would still be producing huge amounts of nitrogen oxide and be a big problem for separating out the CO2 — and going straight to plants that don’t release exhaust gas to the atmosphere at all.

  30. 180
    B Buckner says:

    RE: Hank #175
    So global warming warms the troposphere and cools the stratosphere. A cooler stratosphere effects atmospheric chemistry and reduces ozone. Stratospheric temperatures have cooled on a nearly linear basis since 1958, except for the blips provided by three large volcanic eruptions. For temp data I am relying on HadAT2 since 1958, and UAH and RSS since 1978. I am not aware of any pre-1958 data, and the UAH and RSS data pretty much fall right on top of the HadAT2 data.

    Stratosphere temps had been falling since at least 1958 at a constant rate of about 0.5C/decade. There is no evidence in the stratosphere temp record, however, of the 30 year cooling/flattening of the surface temps that occurred from the 40s to 70s. Why is that? Are they not directly related in that as the troposphere warms or cools, the stratosphere has to react accordingly to maintain the overall heat balance? Also, all three temp measures show a pronounced flattening of the stratosphere temps since 1993 or so. What is up with that?

  31. 181
    Timothy Chase says:

    FurryCatHerder (#170) wrote:

    On the subject of the ozone hole and it not reducing as fast as expected. Is this being driven by CFC persistence that exceeded projections, or by climate change? And if the first (or why not answer anyway …) are the new coolants “safe” or just “safer”?

    Well, the “hole” (which is actually a thinning) was of course put there by CFCs, but at this point, the cooling of the stratosphere and warming of the is leading to higher windsts as the result of the temperature differential. This is in large part because the stratosphere is closer to the surface in Antarctica than just about anywhere else. I believe Alastair may have more to say on this.

    In any case, the increased winds are carrying water vapor up into the upper troposphere and lower stratosphere – and water vapor destroys ozone. So yes, at this point it is being driven by climate change – and in part driving climate change as the destruction of ozone leads to increased cooling since, unlike other greenhouse gases, the largest part of the direct effect of ozone is to warm the atmosphere rather than cool it. But interestingly enough, CFCs are also greenhouse gases. No doubt it gets rather complicated.

  32. 182
    Lynn Vincentnathan says:

    RE #171 & Stating “Since the computer models are constantly updated…[#165]” is one of the reasons there is a scepticism about computer models. If they are constantly updated then the moment before they are updated they were presumably inaccurate.

    That’s the nature of science, in general; it keeps improving & refining & paradigm shifting. More predictive theories & better data collection and techniques replace older ones. However, I agree with #174 that the older predictions many times still hold up very well…including Arrhenius’s prediction over 100 years ago that industrial GHGs might cause anthropogenic global warming.

    OTOH, there ARE unknowns & (currently) unquantifiables. While climate science can nicely predict the effect of volcanos, such as Pinatubo, I don’t think it can predict whether or not there will be tremendous vulcanism in the future (to my knowledge it can’t predict that). I’m not saying we should worry about things not under our control, but we could do what we can to reduce our own GHGs. (Note that volcanos initially have a short run cooling effect because of the aerosols, but long term they have a warming effect because of their GHGs persisting much longer).

    I think the idea is that initial warming from extreme vulcanism (or some such other natural event) may have triggered the tremendous global warming at end-Permian extinction era (in positive feedback ways).

    We can probably hold that end-Permian extreme warming (and that of the PETM) as a bookend of what’s possible, and understand that some unknowns or unquantifiables may kick in and cause such a warming in this era (which is being triggered by initial warming from us). This might take hundreds or thousands of years before reaching those extremely high temps and causing massive extinction (we’ll all be long gone by then), but it’s morally untenable that we might be the cause of (pulling the trigger on) our progeny’s and other biota’s extreme suffering.

    OTOH, bookends have a way of toppling over when books aren’t set right, so who knows how hot it might get in a hysteresis type of event. A couple of years ago a poster here at RC suggested 6C higher than now as the absolute hottest is could possibly get (worst worst case), but then another poster suggested we don’t really know.

    We’re playing with fire.

    See, we just found out here re tropospheric ozone that what we thought was a negative feedback is actually a positive feedback. Science keeps changing….but for climate science the overall trend seems to be “it’s worse than we thought.”

  33. 183
    dhogaza says:

    Stating “Since the computer models are constantly updated…” is one of the reasons there is a scepticism about computer models. If they are constantly updated then the moment before they are updated they were presumably inaccurate.

    Next year if you step into a Boeing 787 after it enters commercial service, keep in mind that models used by the company to predict whether or not their products will fly are constantly being updated and refined.

    This means the model used during the design of the 787 was inaccurate.

    I presume your skeptism will cause you to turn tail and walk or drive to your destination?

  34. 184
    B Buckner says:

    Re:176 Furry Cat. It is even better than that. The buyout firm is Kohlberg Kravitz Roberts & Co, a huge private equity firm specializing in leveraged buyouts. This is not an environmentally sensitive firm, they are capitalist with a capital C, where profits always come first. If KKR saw benefits to going green, prospects for progress on the warming front just got a little brighter.

  35. 185
    Hank Roberts says:

    Since this thread’s about surface ozone and nitrogen oxides, rather than take it off topic, how about asking your stratosphere question in the Friday Roundup topic?
    Click here: http://www.realclimate.org/index.php/archives/2007/07/friday-roundup/

    I’m just a regular reader here like you. I’ll use the search tools and follow up if you will ask there, and others will try to help.

  36. 186
    Hank Roberts says:

    Back on topic, I really would appreciate comments about the implications of this study for actual practice. Did I guess right with “leapfrog the intermediate designs for “slightly cleaner” coal plants … going straight to plants that don’t release exhaust gas to the atmosphere at all”? What else might this finding change in practice?

  37. 187
    David B. Benson says:

    Re #186: Hank Roberts — Follow

    http://biopact.com

    for thoughtful and imformative posts about a variety of such implications.

  38. 188
    Hank Roberts says:

    Found this, which turns on the definition of “clean” (misposted the first time, reposting in appropriate topic)

    On arguments for clean coal, this has policy implications:

    http://www.iht.com/articles/2007/07/31/america/nuke.2-106441.php
    “The little-noticed provision in the Senate bill refines and expands the loan guarantee program that Congress passed in the Energy Policy Act of 2005…. the bill essentially allows the Department of Energy to approve as many loan guarantees as it wants for both new nuclear plants and those that use other “clean” technologies.”

    I’d like to think someone carefully limited the definition of “clean” for coal plants to mean only those run as closed cycle plants. But I’d fall over in a dead faint if that were true.

  39. 189
    See - owe to Rich says:

    Re #18, this is author’s response to ##19, 23, 27, 37, 41, 79, 82.

    First, a little about myself. I did not claim to be an “eminent” mathematician – that epithet was put into my mouth by #79 and reinforced by #82. And in fact I am not eminent; but I am still a practising mathematician, albeit not so much in statistics these days, and I believe that I am the sort of analytical person whom both sides of this argument should be trying to persuade. #23 says that my use of “CO2 brigade” ‘gives the game away’, despite the fact that I introduced the term “solar brigade” in the same paragraph, and despite the fact that I said “I am in two minds about…”. I really do see it as a fascinating scientific bust-up which I am trying to view impartially, and which would be funny if it wasn’t so important. (Actually, some of what I read on this is still pretty humorous anyway.) I am not sure whether to think of it as Montagues v. Capulets, or as David v. Goliath (because in terms of bulk, both number of scientists and number of newspaper articles, the CO2 brigade certainly seems to have the advantage).

    I regard myself as moderately ‘green’ – I usually cycle 5.5 miles each way to work, for health and reduction of pollution. Personally, as a cyclist, I hate diesel fumes and am sad about the increasing number of diesel cars on the roads, though no doubt someone will tell me I’m wrong to object to their smell and they’re really much better for the environment than petrol cars. But as said, regarding CO2 as a ‘pollutant’, I have still to make up my mind about that one.

    Re #19 (and the source of my 0.013), I am happy to apologize, at least as far upwards as the 0.016 C/y regression fit. My ’0.4C per 30 years’, only 1 significant figure please note, was taken by looking at a graph of HadCRUT3 data somewhere. I agree that that is a sloppy way of doing it, and apparently 0.5 per 30 years would have been closer to the mark. When at greater leisure I intend to analyze the figures more carefully, and may then comment further on the extra data presented by #19.

    Re #82, being a statistician I would rephrase it in terms of:
    Null hypothesis (H0) = no global warming from anthropogenic CO2 since 1970
    Alternative hypothesis (H1) = all global warming since 1970 is from anthropogenic CO2
    Then #82′s 1-4 become:

    1. False Positive = decide H1 but H0 is true = Type I error, with probability alpha
    4. False Negative = decide H0 but H1 is true = Type II error, with probability beta
    2. True Positive = decide H1 and H1 is true, with probability 1-beta
    3. True Negative = decide H0 and H0 is true, with probability 1-alpha

    Of course, life isn’t so simple, and the truth may lie somewhere between, hence my Q2:
    “how do we apportion this [1970.0-2000.0 warming] between CO2, the Sun, and other causes, and therefore how much is a doubling of CO2 worth?”

    I do have just one comment on #82′s statement in the False Positive that mitigation will save us money and strengthen the economy. When I see the amount of expenditure being proposed to combat global warming, I rather doubt this. Nevertheless I agree that evolutionary / revolutionary advances in technology may well have dramatic effects on CO2 output whether or not they are instigated by AGW politics.

    Turning now to #27, and the Archibald stuff, I’d like to point out that I did say “There are things I don’t understand about this, especially the time lag, so I am trying to follow up some of the references to understand more. Possibly Archibald is over-egging it…”, so I was certainly not taking it at face value, and I was especially worried that without epoch data one could not tell whether the better fitting points were older or newer or mixed. I have only seen the slides and not the full paper, so I thank #27 for pointing out things I should check when I find it. But the real point I was making was that if Solar Cycle 24 really does turn out to be as weak as predicted then the solar brigade will not have a leg to stand on if global temperatures continue to rise as per IPCC predictions. Therefore for the sake of settling the scientific argument I think a weak Cycle 24 will be a Very Good Thing. Of course, I realize that the CO2 brigade believes the argument has already been won incontrovertibly, and they are appalled that agnostics like me exist. Well, sorry, but I think, therefore I am.

    On the other hand, a weak Cycle 24 might be a Very Bad Thing. Because if temperatures drop, and the solar brigade wins the argument (or most of it, as its members mostly allow for a certain amount of CO2 warming), then we may discover that global cooling is devoutly less to be wished than global warming. For the sake of settling an argument we might have a worse world. But I believe that few readers on this site will be alarmed by this idea, as the majority will think it a false premise – and they may be right!

    In closing I’d like to thank correspondents for pointers to extra reading I should do. On the whole I prefer having been flamed to having been ignored :-)

  40. 190
    See - owe to Rich says:

    Re #65 and Gavin’s response, I know it isn’t cool on this site to mention heat, by which I mean the Sun, but regarding the January spike it should be pointed out that since Earth is at perihelion early in that month, the solar input is about 6.4% higher than in July. This comes from eccentricity ~ 1.6%, double that for (1+e)/(1-e) comparison of aphelion and perihelion, double again for the inverse square law of radiation.

    I think that’s right, but if not some friendly physicist will explain no doubt.

  41. 191
    Rod B says:

    Timothy (181), water vapor destroys ozone?? I never heard that; are you sure? I guess I don’t know. But why then doesn’t the overwhelming water vapor at ground level destroy the “bad” ozone?

  42. 192
    Michael says:

    Re 179 and 186. there are various NOx formation processes (eg fuel NOx, thermal NOx, prompt NOx) and varying oxygen and flame temperature, as well as burner structure and recirculation and various forms of catalysis can affect them. Increasing oxygen may increase flame temperature, resulting in enhanced thermal NOx, although some studies have shown that opposite effects can be seen. Different types of coal may influence fuel NOx formation processes in the early combustion reactions. Synergetic interaction between various NOx formation processes is complicated, especially as there may be hundreds / thousands of reactions taking place in the combustion process (or processes if these are multiply staged, eg through reburn).

  43. 193
    Hank Roberts says:

    Well, you can look these things up. It’s a useful skill worth learning.

    Pasting “water vapor destroys ozone” into the Google box:

    NASA GISS: Science Briefs: Reaction of Ozone and Climate to …
    Water vapor breaks down in the stratosphere, releasing reactive hydrogen oxide molecules that destroy ozone. These molecules also react with chlorine … http://www.giss.nasa.gov/research/briefs/shindell_05/

  44. 194
    Michael says:

    Re 108. It is odd why business leaders allow so much waste. Even more odd why Chief Financial Officers do not insist on a monthly waste account, providing tangible waste reduction figures delivered within the business each month (through energy conservation, water minimisation, waste minimisation, energy efficiency, product ecodesign, recycling, reuse, remanufacture, product repurposing, etc) . Climate change can be mitigated and the world economy can be shifted to an emissions profile which would limit warming to two degree C. It doesn’t require silver bullet technology solutions, because the solutions are already available. It requires a change in mindset and a change in attitude: a shift from destructive growth to one of restorative growth.

    Re 189. On the whole, implementation of mitigation within an organisation can provide considerable savings in direct costs (through utility bills, materials costs, logistics costs, process costs) as well as reductions in indirect costs (eg climate liabilities, brand damage, reduced competitiveness). However, the message hasn’t yet got home to business and industry of the urgency with which it needs to act. Emissions are still on an upward trajectory, which is of concern since there is only about 800 days to peak global emissions before we lose the chance to keep warming below 2 degree C. There is a window in which to limit warming to avoid dangerous climate change (when positive feedbacks are triggered). That window may close within the current business cycle (eg
    http://www.ippr.org.uk/publicationsandreports/publication.asp?id=501 ). When the window to limit warming to 2 degree C does close, what is currently perceived as a value-adding product or service, may switch to being viewed as a value-deducting (or climate liability laden) product or service. People’s notions or measures of what is a cost may then be thrown in the air as the world find itself on an uncontrollable trajectory. Costs of mitigation are small compared, for example, with the costs of a BAU trajectory that takes us, say, to sea level rises of 5 metres by 2100. For example see http://environment.independent.co.uk/climate_change/article2675747.ece and James Hansens article “Huge sea level rises are coming” at http://environment.newscientist.com/article.ns?id=mg19526141.600

    Assuming the sea level does rise by 5 metres in the coming decades, one can take representative supply chains through various sectors in the world economy and identify critical nodes in those supply chains and work out the potential for such supply chains to operate or function. Estimates can be made of rebuild costs as supply chains with attendent infrastructures are decommissioned, and moved / rebuilt inland. One can go through these scenarios self-consistently and backcast through the century to identify thresholds (eg indicative capex, risk contagion) and determine safety mechanisms or avoidance strategies that are required, etc. Costs may relate, for example, to rebuilding ports, rebuilding refineries, establishing new primary and secondary manufacturing plants, realigning transport and logistics infrastructure, as well as an array of reconfiguration, downtime, and hazard management costs. The supply systems involving chemicals are a case in point, as chemicals, particularly specialty chemicals, may be a critical element of multiple supply chain systems at higher levels of current-decade value-adding structures, such as may be found in pharmaceutical markets, electronics, IT and telecoms infrastructure markets. The chemicals may, however, be sourced from single points of synthesis on world markets, on account of complexity and costs of synthesis processes. Some of those single points of synthesis may be chemical plants next to present shoreline. Sea capture of industrial capability, much of which is next to the sea, may make it difficult to maintain continuous rebuild capacity as the sea level continues to rise.

    Re 58. There have been a lot of large-scale experiments done on plants (eg see work by Robert Jackson’s group http://www.eurekalert.org/pub_releases/2002-05/du-eo051502.php ) in which large enclosed areas have various gas mixtures (eg with varying levels of CO2) introduced. It is a very complex area of study as different plant species may react in different ways. Also, there are wild cards such as ways in which fungal and bacterial systems proliferate under the warming conditions and the effects these may have on other flora, which incidentally may undermine possibilities for biofuel and food-to-eat yields. There are also subtle interactions between insects, birds etc and how these may or may not be able to synchronise their life cycles in response to ecological confusion and seasonal pattern disruption as plants and trees also attempt to respond.

  45. 195
    Hank Roberts says:

    > clean

    As an aside — if closed cycle coal plants are used, there’s another immediate benefit to removing the nitrogen from the gas input, at least if it’s condensed out. One big hope is for superconducting power transport at liquid-nitrogen temperatures. It’d be great if the coal plant was able to put out electricity, liquid nitrogen, and CO2 to be sequestered.

    Need a distribution network? There’s nothing like a railroad right-of-way for long distance cross country. Bury the liquid nitrogen/superconducting cable alongside the tracks. Next, electric power for the coal trains ….

    Whether the energetics make sense, I don’t know. But it’d be a nice package.

  46. 196
    Timothy Chase says:

    Rod B (#191) wrote:

    Timothy (181), water vapor destroys ozone?? I never heard that; are you sure?

    Yep. Here is an article that deals with it over at NASA, although it doesn’t really get into the specifics.

    Wetter Upper Atmosphere May Delay Global Ozone Recovery
    Apr. 17, 2001
    http://www.giss.nasa.gov/research/news/20010417/

    The reason why I know about it is that it is one of the recent feedbacks creating problems in Antarctica…

    1. Ozone depletion in stratosphere leads to stratospheric cooling…
    2. Stratospheric cooling leads to temp diff between stratosphere and surface
    3. Temp diff leads to higher winds lofting more water vapor leading to more ozone depletion.
    4. Higher winds bring up nutrients from the deep leading to the release of methane and carbon dioxide.
    5. Methane and carbon dioxide lead to more greenhouse warming of surface.
    6. Warming of surface leads to more moist air convection which warms the troposphere.
    7. Temp diff between troposphere and stratosphere leads to higher winds.

    But why then doesn’t the overwhelming water vapor at ground level destroy the “bad” ozone?

    Not sure. Water vapor is supposed to act as a catalyst for some chemical reaction which may be dependent upon ultraviolet radiation, perhaps. But I will have to dig to find out.

  47. 197
    Hank Roberts says:

    > ground level
    See #193, now that it’s appeared.
    Yes, it’s the ultraviolet that breaks the H2o apart, then the ions of OH and O- react with the ozone.

    And the ozone decreases, and more UV gets through to lower levels.

    True, if we had no ozone layer, we’d have the higher energy UV cleaning up the ground level ozone pollution. But we’d have other problems.

  48. 198
    Alan K says:

    #183
    A Boeing jet will have been proven to fly. Computer models are making 100-yr predictions. Imagine a climate model was “updated” to correct, say, a 0.5% inaccuracy today. Imagine that error hadn’t been corrected. What would the magnitude of that inaccuracy be after 100 years?

  49. 199

    [[Stating “Since the computer models are constantly updated…” is one of the reasons there is a scepticism about computer models. If they are constantly updated then the moment before they are updated they were presumably inaccurate.]]

    That’s like saying evolution by natural selection is a conservative process, incapable of shaping new creatures, because it only eliminates the unfit. No. It eliminates the less fit, and that’s why natural selection is such a savage shaping process.

    Similarly, your last sentence above should read, “If they [the computer models] are constantly updated then the moment before they are updated they were presumably less accurate.” Not “inaccurate.” There’s a big difference.

  50. 200
    dhogaza says:

    A Boeing jet will have been proven to fly.

    And GCMs are checked against the real world, too.


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