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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. 51
    Nick Gotts says:

    re #47 [RE #37 – Nick Gotts Says:

    You are way off base. I do not deny the science of global warming in any respect, and see little in it to be very skeptical about.

    Animal populations that are not harvested tend to increase in size, so a vegetarian diet is likely to result in more enteric fermentation, not less. You have to kill a ruminant to prevent its production of methane.

    And my family has supported Al Gore’s family politically since Al Gore was his father’s snot-nosed kid.]

    Most of this is simply irrelevant, since I neither implied nor believed that you are a global warming sceptic, nor anything about your attitude to Al Gore. Rather, I think the rhetoric you’re coming out with on this specific issue shows marked similarities to that we repeatedly encounter among denialists.

    The vast majority of ruminant-derived methane production is from domestic animals, mostly cattle. Their huge populations are almost entirely dependent on human-provided food supply (this is largely true even of grass-fed range cattle, when we consider the destruction both of forests to produce ranges, of competitor species, and of predators). Domestic ruminants produce far more methane per head than wild ruminants, because they have been bred to maximise the rate at which they turn their food into meat and milk, rather than survival and reproduction under natural conditions. The populations of wild ruminants are of course limited by a combination of limited food supply and predation. If we decided to reduce the number of domestic ruminants, the only sensible course would be to continue to slaughter the existing animals for food, while reducing the breeding rate until the desired reduction in numbers was achieved.

  2. 52
    John Mashey says:

    re: #45 Nick
    “For reasons discussed previously on this site, biofuels are almost certainly not a good idea from a GHG emission perspective, but if the grain were used for ethanol it would at least not be producing methane.”

    I think this is an over-generalization, albeit a common one.
    Ethanol is ethanol.
    a) Brazil has done well with sugar cane.

    b) IMHO, corn-based ethanol is a transient approach. Corn wasn’t bred for this, and it’s seriously non-optimal, but the corn infrastructure is there, people are doing corn ethanol for a raft of different reasons, and the efficiencies are improving. If doing corn ethanol for a while helps get the distribution infrastructure in place, and induces a big increase in Flex-Fuel Vehicles, that’s a Really Good Thing.

    c) But, in the long-run, we’re likely to use other C4 crops, like my current favorite, miscanthus. We’ve had millennia of food crop breeding. We’re in for a period of intense design of fuel crops, as there is a lot of work to do, as we’ll need variants tuned to different climates and soils. We’ll have to build infrastructure, and likely optimize harvester design for this.
    [This says miscanthus looks about 2X more productive than switchgrass.]

  3. 53
    Nick Gotts says:

    Re #52. I’m sceptical, but certainly prepared to take another look at the biofuels issue. In the current context, if you’re right this would strengthen the case for a shift toward vegetable-based diets, since there would be competition for land between food and biofuel, and the amount needed for the former increases with the proportion of animal products eaten.

  4. 54
    Neil B. says:

    OK, it is good to see posts about GH gases other than CO2. What is confusing in reports about those, is claims like “X is N times more potent than CO2 in producing global warming…” but they don’t specify the calibration: Do they mean, comparing the same ppm by mass/vol., the same gas pressure, etc?

    [Response: The only calibration that makes sense is in terms of the radiative forcing – and usually the global mean number. See – gavin]

  5. 55
    Hans Henrik Hansen says:

    Re #37

    “(since the pattern seen in the oceans cannot be explained by solar forcing)” – could you possible elaborate a bit on that statement, e.g. which pattern and which kind of solar forcing??

  6. 56
    John Mashey says:

    re: #53 Nick
    Some of the negative press on biofuels derives from the famous Pimentel/Patzek paper,

    However, their negative results seem to be outliers compared to other studies.
    One meta-study is this one in Science:

    There’s a nice chart on p 18 of:

    and p.21 has nice photos of switch grass and miscanthus (this stuff grows like the bamboo that some previous owner planted on our property, i.e., indefatigable).

    p.26 has some nice charts from BP about expected cost reductions of biofuels.

    Bottom-line: unsurprisingly, there are plenty of disagreements about exact numbers for relatively immature technology, but some serious people (including some very smart local venture capitalists) think biofuels will be economic and important. In particular, from both farming & semiconductor experience, one always has to allow for learning-curve and volume improvements over time, and not get hung up on early-stage economics.

    As for methane, since many people wish to keep their beef & milk, at least people are starting to use approaches to lessen the amount of methane added to the atmosphere:

    and certainly people are generating electricity from cow-generated methane in poop-filled lagoons. Note: we eat mostly veggies, fruit, grains, and fish, so this isn’t me wishing to preserve cows :-)

  7. 57
    David B. Benson says:

    Nick Gotts — I recommend you follow

    for awhile to learn some approaches to sensible, even carbon-negative, biofuels.

  8. 58
    Gary says:

    I admit I have not read all of the above posts. But isn’t any one concerned that this article is about a computor modeled plants response to a computor modeled change in ozone levels. Best as I could tell no living plants were used in this study.

  9. 59
    Chuck Booth says:

    Re # 58 computer models
    Yeah, but the models are based on established scientific principles and documented responses based on actual experiments on plants. That is the nature of models – it is best to consider them hypotheses that need to be tested, either experimentally, or naturally over time. The problem is, if we wait to see how plants in their natural environments respond to increased CO2 and ozone levels for, say, a decade or two, and the models turn out to be correct, it may be too late to take corrective measures.

  10. 60
    Hank Roberts says:

    Er, Chuck, nope. You can look this stuff up. Field biologists have been doing this kind of experiment for a very long time with all sorts of different tweaks.

    Tell ya a story: When I was a kid in North Carolina, in the 1950s, some botanists decided to test the notion that Civil Defense was telling everyone, that a nuclear war would be survivable, wouldn’t hurt the plants much, the people would just have to stay in fallout shelters for a couple of weeks then come out and everything would be fine. They took a gamma source out into the piney woods (in a well fenced off area) and put it down a well and cranked it up and down to provide the same radiation dose in the immediate environment that was predicted for a one-shot atomic war. The results made the cover of Scientific American — a big, brown, dead circle of killed trees, killed grass, killed soil, around the source. Oops. It caused the whole notion of winning an atomic war to be reconsidered. Good thing, that. Nothing like actually testing what you’re being told to find out if it’s right.

    Similarly botanists have been putting big tents over all kinds of plants and environments and boosting carbon dioxide, varying humidity, and so forth, for years. The model study documents exactly which of that kind of study they looked at, to get an idea whether their model was getting it right.

  11. 61
    Bill Tarver says:

    Could someone please comment on James Hansen’s report in New Scientist (25 July) that the IPCC is far too conservative and that a business-as-usual scenario is more likely to give a sea level rise of 5m in the next 100 years.–unless-we-act-now.html

  12. 62
    Nick Gotts says:

    John Mashey, David B. Benson – Thanks for the refs. on biofuels, which I’ll follow up. I’ll send anything further on this to the “Friday roundup”.

  13. 63
    B Buckner says:

    Re: 59 Except of course that ozone levels have been falling for 20 plus years, at least in the US and Europe. Nox emissions are down as well, and methane in the atmosphere has leveled off. We are already taking the corrective measures and they are working.

  14. 64
    J.C.H says:

    Is there an accepted reason for why methane has leveled off (the corrective measure)?

    [Response: Not really. There has been speculation that it was related to the economic downturn after the collapse of Communism, and there are ongoing methane reductions through landfill management, flaring and reducing pipeline leaks, but there are too many uncertain terms in the total budget for a clear answer to emerge. Note however, that stabilisation only implies that the increased sources are balanced by increased sinks (atmos. oxidation), not that the sources are back down to pre-industrial levels. This Sci. Am. piece has more details. -gavin]

  15. 65
    B Buckner says:

    Gavin – OT, but looking at the monthly global temperature anomaly plots produced by UAH, GISS, RSS, HadCRUT3, and NCDC, almost all of the monthly high temperature spikes occur in January. Are you aware of a reason for this? It seems odd given the different methods of measuring temperature and the five databases involved. Thanks.

    [Response: Maximum usage of AC units obviously! Seriously though, you are probably seeing the impact of ice-albedo feedbacks on the NH land – warming is greatest there and during winter. You could make a case that direct CO2 effects are strongest during the coldest months and the effect of water vapour feedback more important in the drier periods. However, I haven’t seen that quantified. – gavin]

  16. 66
    Chuck Booth says:

    Re # 59 Hank,
    I think your clarifications were covered by my comment that:

    “the models are based on established scientific principles and documented responses based on actual experiments on plants.”

    The “mesocosm” experiments you described (“big tents over all kinds of plants and environments”) are still community-level experimental manipulations that don’t necessarily tell how an intact forest (or grassland, or whatever) ecosystem will respond over decade- or longer time scales. I’m not disputing the methods or conclusions of the Sich et al paper. But, I think Gary made a valid comment.

  17. 67
    Hank Roberts says:

    Gary “Best as I could tell …” can read online or download from the same page where the abstract appears the details he didn’t find about the plant studies. I tried a longer post quoting from them with pointers, but it’s not showed up.

    Gary: The models were evaluated compared to real plant studies. The supplemental material for the paper is online as a PDF file available to nonsubscribers, via links on the same page as the abstract.

    See that — it has descriptions and references.

  18. 68
    Vernon says:

    You do realize that if the temperature proxy being used is not actually measuring temperature or the instrumented readings for some reason are wrong, most of this discussion is meaningless?

    Briffa (2006) The spatial extent of 20th-Century Warmth in the Context of the Past 1200 Years ( clearly shows that the temperatures decreased from an early 20th century high and that the proxies and the instrumented readings do not match (or are even close).

    With the out the connection between abnormal warming now and increased CO2, then what does O2 matter? Without graphing on the instrumented reading to the proxies, then what is being shown is that the climate is not as sensitive as we were lead to believe and CO2 will cause some warming but not the warming that is being proposed.

    Please point out where I am wrong on this.

  19. 69
    Lynn Vincentnathan says:

    RE #33, the religious right’s denial of GW or that it’s harmful.

    This goes to both behavioral science & religious dimensions of GW. As for the social sci dimension (including the cultural, social, and psychological), people who consider themselves long ago “saved” or deeply religious might be less amenable to believing their GHGs could cause harm, than others who see themselves as less holy and more sin-prone. For instance, I became a GW activist around 1990, shortly after (or while) I was undergoing a conversion to a deeper spirituality — and I was already looking at my sins & ways to become a better person, so I was amenable to accepting my fault & responsibility re GW. I wonder if I had undergone that experience a decade earlier, if I would have been as open to accepting GW.

    In attribution theory, it is found that people have ways (cognitive manipulations) of downplaying their own failures and inadequacies, & magnifying those of disvalued others. Sort of like focusing on the speck in the other person’s eye, but failing to see the plank in one’s own. In highly complex situations (as in GW in general, and as in this post’s discussion of ozone complications), I think false (self-serving) attributions would surface up even more easily.

    RE the religious dimension of GW, I’m sure there’s a method in God’s madness — of allowing humans to cause GW, then deny it — though we can’t 2nd guess God. However, going beyond “GW is just further sign the Apocalypse upon us” attitude, it occurred to me that perhaps we have come to this era that requires us to truly convert and change, to truly establish a world of love & peace. Up till now it’s been a lot of preaching, & good practices on the part of a few saints here & there. All the previous world and personal problems (that God as allowed) have somewhat helped some to “convert,” turn to righteousness. But obviously not much, or not enough for this problem of GW at hand.

    So now to stop global harm from global warming, we all (or most of us) will have to mitigate and stop killing by turning to a more perfect life. That’s the only way. And if this conversion is profound (which I think it has to be to work – along the lines of a revitalization or social movement), people would reduce their meat consumption and live more simply not just to save lives by mitigating GW, but because of a desire for holiness, whole-ness, holism, and I’d think this would be a joy to do so, not just a drudgery.

    I’m thinking of my husband’s uncle — who was a parish priest in a boondocks village in India. He never thought of himself as a vegetarian & knew nothing about GW, but in his holy simplicity, he rarely ate meat, ate very little food, in fact (a strong wind would blow him away — but he lived up to 89), and had only 3 sets of clothing. He never had much money, and what he had, he shared with the needy. He also helped a religious order make a bio-gas pit, where the villagers put in dung and converted it to gas for cooking and electric generation for the few tube lights the village had.

    Perhaps GW could be the instigator for humanity of a true conversion to a truly holy lifestyle — not just a fake, self-righteous religiosity that serves to make one feel superior, and cover up one’s own flaws and sins.

    But the 1st step is accepting what we are doing is wrong (or at the least could be wrong). And that is a very difficult hurdle.

  20. 70
    Hank Roberts says:

    That’s almost a correct cite. It gets a 404 Not Found result.
    That means it’s wrong, but keep trying.

    This is a correct cite, that actually gets you to the page.

    You make some claims about what you believe is on that page.

    I don’t see what you claim to see.
    What are you talking about?
    Did you download the data file and do something with it?
    Did you read the actual Science paper?

  21. 71
    Hank Roberts says:

    Vernon, I gave you more cite help in the Friday Roundup thread where you were talking about this. Let’s not confuse the ozone thread.

  22. 72
    Petro says:

    Vernon said in 68:
    “Please point out where I am wrong on this.”

    You are wrong in this that you do read the actual articles you claim to support your opinions. By reading the articles it is very easy to see, that you distort their conclusions completely.

    Other posters here have educated you in detail, in what respect your opinions are based on the twisted denialist arguments. Please, do not degrade you by twisting the truth yourself.

  23. 73
    Timothy Chase says:


    If you want people to keep pointing out to you the same things and correcting the same errors as in the Friday Roundup, take it over there. I might even oblige you. Or perhaps not – I find repetition so… repetitive.

    Briffa (2006) The spatial extent of 20th-Century Warmth in the Context of the Past 1200 Years ( clearly shows that the temperatures decreased from an early 20th century high and that the proxies and the instrumented readings do not match (or are even close).

    You might want to find another link before posting it on the Friday Roundup: NOAA seems to have noticed you were trying to use the page and took it down.

    I suppose its part of that conspiracy… You know the one: they keep adjusting the temperatures upwards to a greater and greater degree in order to create the impression that temperatures keep rising. They are probably shining hot spotlights on the Arctic sea-ice and glaciers, too. Or perhaps they are just editing all those images. You might want to do some digging there, Vernon.

    Anyway, see you back at the Friday Roundup, perhaps.

  24. 74
    spilgard says:

    Re #68:

    “Briffa … clearly shows that the temperatures decreased from an early 20th century high and that the proxies and the instrumented readings do not match (or are even close).”

    A pdf of the paper is available at:

    Nowhere in the paper is there any graph of temperatures, proxy or instrumental. The paper performs a statistical measure of the geographical extent of historical variations of northern hemisphere proxies. The figures in the paper illustrate this geographical extent by displaying the relative fraction of proxy locations which show anomalous variation expressed as standard deviation from the normalized mean.

    The authors specifically point out that their results are indicative only of “periods of unusually high or low proxy values rather than as indicative of warm or cool periods”. The comparison with a similar analysis of instrumental records is used to support the argument that (italics added): “analysis of these proxy records is a useful indicator of Northern Hemisphere temperatures”.

  25. 75
    Lawrence Brown says:

    RE:54 There is an index called the Global Warming Potential, which might be used to facilitate trading of emissions reductions among countries and nation by nation rankings of individual contributions to climate change, would be a possible use.

    Back in 1992 The UN Framework Convention on Climate Change adopted the index called the Global Warming Potential ( GWP). It’s a weighting factor to allow comparisons between the global warming impact of 1kg of any greenhouse gas compared with 1kg of CO2, and includes a time horizon for which the impact will be felt. An example is that since the 20 year GWP for NO2 is 280, 1kg of NO2 emitted today will have 280 times the global warming effect over the next twenty years as 1kg of CO2 emitted today, or 1kg of NO2 emitted today will have the same effect as a release today of 280kg of CO2 over the next 20 years. A book titled “Introduction To Environmental Engineering and Science” 2nd Ed. by Gilbert M. Masters has some interesting comparisons using the GWP. Methane, for example has a GWP of 56 over a time horizon of 20 years, but decreases to 21 for 100 years.( above ref.- Table 8.6).The difference is due to the longer atmospheric lifetime of CO2.
    Here’s an interesting example given in the source cited above- In 1992 anthropogenic emissions of CO2 were approx. 24,000×10^9 kg per year, emissions of CH4 were about 375 X10^9 kg per year. A comparison over a twenty year time span shows:
    CO2: GWPx emissions= 1×24,000×10^9=2.4×10^13
    CH4: GWPx emissions= 56x375x10^9 =2.1×10^13
    In other words the impact on warming of methane is almost as much as CO2 over the next twenty years! But over longer time horizons, CO2 becomes the dominant greenhouse gas. The GWP for methane over a 500 year time horizon is only 6.5.

  26. 76
    James says:

    Re #69: [RE #33, the religious right’s denial of GW or that it’s harmful.]

    In respect of which, those inclined to believe on religious grounds that AGW can’t/won’t happen because “…He designed it and the universe to withstand just about anything humans could do” might want to reflect on the Biblical account of Noah and the Great Flood :-)

  27. 77
    Jim Eager says:

    Re 68 Vernon: “Please point out where I am wrong on this.”

    If at first you don’t succeed, try spamming another topic, eh Vernon?

    Your problem is that you have already reached your conclusion and are 1) looking for data points to cherry pick in support of it, and 2) looking for any _perceived_ chink in the real science in order to use it to discredit evidence that does not support your conclusion. Given that you repeatedly ignore those who make a serious attempt to answer your “questions” it is quite obvious that your sole purpose for posting here is to obfuscate and waste people’s time.

  28. 78
    dhogaza says:

    Vernon said:

    “Briffa … clearly shows that the temperatures decreased from an early 20th century high and that the proxies and the instrumented readings do not match (or are even close).”

    I chased his URL to the abstract page and saw no graph of temperature.

    Nowhere in the paper is there any graph of temperatures, proxy or instrumental.

    Guess this explains why.

    Vernon is representative of the people who are going to overturn the work of thousands of climate scientists?

  29. 79
    Florifulgurator says:

    On #18. A classic howler:
    “I am an eminent mathematician (string theorist, thermodynamic engineer,…) and I have some serious objections to the theory of AIDS (Climate, Evolution, …)”
    See e.g. Serge Lang (Lubos Motl, Stuart Burgess,…)

  30. 80
    Lynn Vincentnathan says:

    PBS had a piece on the end-Permian extinction last night (7/31/07) on Science Now (also here: )

    This could happen to us eventually over the following many thousands of years, but triggered by us in this time period. However, as some have pointed out here, life is now more resilient, so maybe only 70% of all life rather than 95% will go extinct this time around.

    I’ve also been reading about dead zones in Oregon & the Gulf of Mexico (the latter largely caused by nitrogen run-off from synthetic fertilizers, but also because the fresh water stays on top, bec there isn’t enough “roiling”?)

    I think (I may be wrong) that these synthetic fertilizers are also implicated in GW in several different ways, and the less roiling may be (if not now then later) caused by a slowing or halting of the THC ocean conveyor (which, by the way, no one is talking about how that might make the south a lot hotter, since people here say it won’t make the north a lot cooler, and the 1st law of thermodynamics says that GW heat has to go somewhere — like my home).

  31. 81
    dhogaza says:

    I am an eminent mathematician (string theorist, thermodynamic engineer,…) and I have some serious objections to the theory of AIDS (Climate, Evolution, …)”

    You forgot to add …
    “even though I’ve not bothered to take the time to understand the theory I object to”.

  32. 82
    Lynn Vincentnathan says:

    Okay, Mr. Eminent Mathematician, here’s how I deal with it, since I, too, don’t have time or the necessary post doctoral work in climate science to understand the finer intricacies of the matter….

    (Of course, I already knew a little about the natural greenhouse effect (that it warmed the earth enough so life could exit) before I learned about anthropogenic global warming… perhaps I did have some background that made it easier for me to understand. Too bad others didn’t have such good science classes in high school, or fell asleep during that part.)

    Let’s assume for a moment that we are back in 1990, before 1995 when the first climate science studies started coming out at .05 significance on AGW, or before today, when virtually all bonafided, honest climate scientists are now (if not 15 years ago) highly confident AGW is indeed happening, and most agree many consequences and effects are and will be harmful to people (not to mention to much of biota).

    So in this heuristic world there are only theorists, neither side with conclusive evidence, debating whether or not AGW (with negative consequences for people) is happening or will happen. Take Pascal’s model (being a statistician, you may have heard of him), and look at the following scenarios to help you decide what to do (mitigate or fail to mitigate):

    1. THE FALSE POSITIVE: If AGW is not happening, and we think it is and we mitigate, that will save us money and strengthen the economy, without lowering living standards or productivity …. at least down to reducing GHGs by three-forths with known technology; perhaps there could be further reductions with future tech. We also reduce many many other problems associated with emitting GHGs (e.g., other pollutants, wars for oil, taxes for roads damaged by Hummers and SUVs, etc). Making AGW perhaps be the best fallacy we ever believed in. (Just remember to divest from Exxon early on, and you should be fine.)

    2. THE TRUE POSITIVE: AGW is happening & we mitigate. All the benefits above, plus we reduce a serious problem and avoid the worse.

    3. THE TRUE NEGATIVE: AGW is not happening and we don’t mitigate. Well, we don’t have problems from GW, but we do run into economic, financial, and political (war) disaster (not to mention all sorts of other environmental harms) from our proligate, wasteful, gluttonous use of energy and resources.

    4. THE FALSE NEGATIVE: AGW is happpening, but we fail to mitigate because mathematical statisticians have convinced us not to do so. Not only do we have all the problems listed in #3 from failure to become resource/energy conservative/efficient, but we cause tremendous death and suffering through AGW for people and much of biota after passing the tipping point where nature in response to the warming causes a lot more warming over the next many thousands of years. Of course, when the water warms and oceans go superanoxic leading to massive hydrogen sulfide outgassing, humans can wear gas masks (assuming we’ve saved a few resources to make those gas masks), but gas masks and oxygen tanks for crops in the field, I don’t know about that (see: ).

    Oh yeh, that’s right, we haven’t achieved 95% scientific certainty yet on the hydrogen sulfide outgassing mass extinction scenario. It’s just a theory, based on known chemical/biological principles.

  33. 83
    Ray Ladbury says:

    Re 68. Vernon, I have to say that your interpretation of Osborn and Briffa 2006 is certainly creative. Most of the graphs I see show significant positive anomalies late in the 20th century. In particular, I wonder if you read the abstract, which says: “but comparison with instrumental temperaturesshows the spatial extent of recent warmth to be of greater significance than that during the
    medieval period.” What is more, I’m going to trust the instrument readings where we have them over the proxies. Certainly they show no reason to believe things are cooling significantly. Moreover, note that O&B specifically smoothe most of their graphs to eliminate trends less than about 20 years. I must say, you work very hard to justify your preconceived notions.

  34. 84
    Lawrence Brown says:

    On my post #75 I unforgiveably didn’t put in the units of the last GWP calculations.
    The lines showing the 20 year comparison of CO2 and CH4 should read:
    CO2: GWPx emissions= 1×24,000×10^9=2.4×10^13 kgCO2
    CH4: GWPx emissions= 56×375×10^9 = 2.1×10^13 kg as CO2
    first mistake I ever made(not!)

  35. 85
    J.C.H says:

    [Response: Not really. There has been speculation that it was related to the economic downturn after the collapse of Communism, …”)

    Well, I guess perhaps the cowmoonists ceased rumination after the collapse.

  36. 86
    Tavita says:

    Off topic: I need to find the emissions of diesel per kilwatt hour for Nox and CH4. I’m writing a grant to put solar panels on a school and I want to boast about the amount of emissions we’ll be offsetting. I will appreciate any assistance from the brain trust here.

  37. 87
    Hank Roberts says:

    What specific fuel and model of diesel generator is the school using, Tavita? Probably the manufacturer of the generator will have the info.
    (Assuming you don’t mean you’re using an electric utility that burns diesel, but if you do, the utility should have the info.)

    Diesel is a type of engine, and they can run on all sorts of fuel. If you’re using a diesel generator running on biodiesel, for example, that’s going to be very different than one running off of high sulfur #2 diesel typically used for home heating oil.

  38. 88
    Timothy Chase says:

    Lynn Vincentnathan (#80) wrote:

    I’ve also been reading about dead zones in Oregon & the Gulf of Mexico (the latter largely caused by nitrogen run-off from synthetic fertilizers, but also because the fresh water stays on top, bec there isn’t enough “roiling”?)

    Actually the problem in Oregon isn’t the fertilizers – with most deadzones which are occuring at present it is, but not in Oregon. In Oregon the problem is that at certain times of the year, the coastal lands warm much more quickly than the coastal waters – and of course there is that lag in the ocean due to its thermal inertia – and the temperature differential should greater the more prolonged the warming trend. The higher temperatures over land result in a low pressure near the coastline – and thus roiling near the coastline.

    The roiling dredges up nutrients from below causing a burst of algae growth – giant “blooms” must like those one gets from sewage and fertilzer – but which have been common at certain times in the distant past during earlier instances of rapid global warming. When these die off, their organic decay takes all of the oxygen from the surrounding water – creating the hypoxic conditions which – in the case of Oregon at least – kills off everything except some of the heartiest species. So far, starfish have survived, but even the crabs are dead – for as far as they looked.

    The vertical coastal roiling may also warm the shallow water methane hydrates – one of those things we should try and avoid. But the vertical roiling along the coasts will also disturb the oxycline – the boundary between the normally oxygenated waters and the anoxic layer of the deep where one finds the anaerobes – including the sulfate reducers – which also have the ability to render the waters more anoxic.

    We have seen thick mats of anaerobes whose growth is promoted both by the increased conditions of anoxia and the nutrients from the algae blooms of the Oregon coastline. They were described as being white – which would be suggestive of sulfate reducers. More recently the Oregon deadzone has been extending into Washington State waters. If I stay here long enough I will probably see it. And I can’t really imagine living anywhere far from the coasts. I love the sea and the port cities too much.


    Normal ocean circulation and turnover which carries water from the lower latitudes to the higher latitudes is generally good – and currently it has become even more pronounced. Its driven by the temperature differential of between the waters of the higher latitudes and the equatorial latitudes. But there are a number of reasons you want to avoid especially pronounced vertical roiling along the coasts.

  39. 89
    wildlifer says:

    RE: 76

    Re #69: [RE #33, the religious right’s denial of GW or that it’s harmful.]

    In respect of which, those inclined to believe on religious grounds that AGW can’t/won’t happen because “…He designed it and the universe to withstand just about anything humans could do” might want to reflect on the Biblical account of Noah and the Great Flood.

    One of the godbotherers (again from that since he didn’t know the mind of his god, he couldn’t be certain his god didn’t want man to warm the earth ……… That this was all part of “THE PLAN.”

  40. 90
    Tavita says:

    Hank it’s a diesel generator that the utility uses. The fuel is diesel No. 2 and the generator is a 4 stroke diesel engine made by Deutz Mannheim, Germany.

    Thanks for your assistance.

  41. 91
    mzed says:

    Is there a simple explanation for the vertical leading of warming in the lower troposphere? Or at least a basic statement of the dominant physical mechanism for it? And is this leading only expected in the tropics, or is it expected at all latitudes?

    [Response: Yes. It’s the moist adiabat. This is independent of the mechanism of warming and works for solar driven changes as well as for GHGs. The enhancement of the warming aloft is seen purely as a function of the surface warming and a relative humidity that is roughly constant. Since the humidty is a nonlinear function of temperature the amount of latent heat available for moist convection increases strongly as temperature rises – as that latent heat is condensed in the tropopshere it will increase the temperatures aloft by more than the surface warms. Since moist convection (and the moist adiabat) are predominantly tropical issues, this will be true in the tropics only. – gavin]

  42. 92
    Hank Roberts says:

    Tavita, this site might have the answer for you (though some of their info is just promised but not yet available online):

  43. 93
    S. Molnar says:

    Re #79: I hate to defend a man whose Algebra book caused me so much pain many years ago, but as far as I am aware Serge Lang never suggested that anything he said about either mathematical or non-mathematical topics should be believed on the basis of his prior work. An appeal to lack of authority is every bit as fallacious as an appeal to authority.

  44. 94
    Timothy Chase says:

    Re: The Attitudes of the “traditionally religious” towards climate change

    My last post on this topic for a bit, but…

    I would be careful about generalizing too much in this area. There are those who believe that God made the world resilient enough to withstand anything we might throw at it, and thus we couldn’t possibly cause dangerous climate change, there are those who believe that climate change may very well be part of the End Times, but there are also those who believe that this world is a gift which we should cherish and take care of, that we are responsible for taking care of it.

    This last attitude is growing even among the Evangelicals. I have seen at least a couple of different evangelical organizations promoting this sort of an approach – and I haven’t been looking but just noticing when I bump into them on the net.

    As for myself, although not being traditionally religious, I have always liked the view of the priest in the original Poseidon Adventure – he thought that God wanted and intended for people to do everything the could in the face of any disaster. Then again, he was a bit of a rebel. I think he and I would have some serious differences in politics – but that is probably another topic I should try and avoid.

  45. 95
    Rod B says:

    Lynn (82), I appreciate your logic structure, but your certainty leads to not well-developed conclusions.
    Your conclusion that the world economy will be just peachy if we mitigate GHGs, whether we have to or not(!!), is way obviously blithe and pat, and evidently stems from your view that mitigating AGW will produce a world and economy that you would choose for everybody else so therefore must be great.

  46. 96
    Hank Roberts says:

    Rod, you’re aware the same people expressed the same doubts about controlling chlorofluorocarbons. Lead. Asbestos. Many other industrial byproducts. And they were wrong. So far they’ve been wrong every single time the business and market people have argued against the health and science people.

    If we use the linear trend method of forecasting, assuming things will go on the same as always, you can see it’s most likely the scientists are right this time too. (That’s irony.) The evidence isn’t arguable, though it will always be deniable by individuals who can’t imagine the world could be different than their politics allows them to imagine. Dustbin of history, awaits such believers.

  47. 97
    Jim Eager says:

    Re 96 Hank Roberts: “Rod, you’re aware the same people expressed the same doubts about controlling chlorofluorocarbons. Lead. Asbestos. Many other industrial byproducts.”

    Not to mention even the Paris sewer system.

  48. 98
    Joseph O'Sullivan says:

    I could not read the entire paper so I don’t know exactly what the researchers said. How big an issue is this? How much effect will it have on the biosphere’s ability to absorb CO2?

    Ozone is present when air pollution reaches certain levels. These area are generally urban areas where there is little vegetation. Ozone does drift down wind into non-urban areas but how big are these areas? If am right ozone is very reactive so doesn’t have a long residence time, so how much vegetation will be subject to the negative effects of ozone? If ozone harms a large amount of plants a large amount of CO2 will not be sequestered, but if ozone harms only a relatively small number of plants then only a small amount of CO2 would not be removed from the atmosphere.

    Rod B. the claims of economic catastrophe that environmental regulation would have have been proved wrong time and time again. The National Academy of Sciences has researched the costs and benefits of laws that reduce air and water pollution and concluded that the monetary costs of reducing pollution have had substantial positive monetary benefits.

    There have been some in the US business community that have come out in favor of laws that will require GW pollution reduction in the US. They think that this will encourage US companies to develop technologies that will make them better able to compete in a global economy that is trying to reduce greenhouse gas emissions.

  49. 99

    Re 96 —


    The problem is that the linear models were accurate at a time when the economics and resource availability made linear models feasible. That’s no longer the case — gasoline prices are at record levels (actually, just below all time inflation adjusted record levels) and supplies are exceedingly tight. That’s not an environment that would tolerate linear growth in fossil fuel consumption.

    As regards the “health” argument, I’d argue that increasing life expectancies demonstrate that the “marketing” people were right, and the “science” people were wrong. So long as the increase in lung cancer deaths is less than the decrease in fire-related deaths, “asbestos” was a decision that made sense.

  50. 100
    dhogaza says:

    Not to mention even the Paris sewer system.

    Or the mandated installation of seat belts and (later) airbags in new automobiles.

    Or the mandated installation of catalytic converters which was necessary to ban lead from gasoline.

    All of which were destined to lead to the collapse of the auto industry, the consequences of which would be … hmmm … I was never clear on the concept. The return to the horse-and-buggy era?