RealClimate logo


Technical Note: Sorry for the recent unanticipated down-time, we had to perform some necessary updates. Please let us know if you have any problems.

Is the ocean carbon sink sinking?

Filed under: — david @ 1 November 2007 - (Español)

The past few weeks and years have seen a bushel of papers finding that the natural world, in particular perhaps the ocean, is getting fed up with absorbing our CO2. There are uncertainties and caveats associated with each study, but taken as a whole, they provide convincing evidence that the hypothesized carbon cycle positive feedback has begun.

Of the new carbon released to the atmosphere from fossil fuel combustion and deforestation, some remains in the atmosphere, while some is taken up into the land biosphere (in places other than those which are being cut) and into the ocean. The natural uptake has been taking up more than half of the carbon emission. If changing climate were to cause the natural world to slow down its carbon uptake, or even begin to release carbon, that would exacerbate the climate forcing from fossil fuels: a positive feedback.

The ocean has a tendency to take up more carbon as the CO2 concentration in the air rises, because of Henry’s Law, which states that in equilibrium, more in the air means more dissolved in the water. Stratification of the waters in the ocean, due to warming at the surface for example, tends to oppose CO2 invasion, by slowing the rate of replenishing surface waters by deep waters which haven’t taken up fossil fuel CO2 yet.

The Southern Ocean is an important avenue of carbon invasion into the ocean, because the deep ocean outcrops here. Le Quere et al. [2007] diagnosed the uptake of CO2 into the Southern Ocean using atmospheric CO2 concentration data from a dozen or so sites in the Southern hemisphere. They find that the Southern Ocean has begun to release carbon since about 1990, in contrast to the model predictions that Southern Ocean carbon uptake should be increasing because of the Henry’s Law thing. We have to keep in mind that it is a tricky business to invert the atmospheric CO2 concentration to get sources and sinks. The history of this type of study tells us to wait for independent replication before taking this result to the bank.

Le Quere et al propose that the sluggish Southern Ocean CO2 uptake could be due to a windier Southern Ocean. Here the literature gets complicated. The deep ocean contains high concentrations of CO2, the product of organic carbon degradation (think exhaling fish). The effect of the winds is to open a ventilation channel between the atmosphere and the deep ocean. Stratification, especially some decades from now, would tend to shut down this ventilation channel. The ventilation channel could let the deep ocean carbon out, or it could let atmospheric carbon in, especially in a few decades as the CO2 concentration gets ever higher (Henry’s Law again). I guess it’s fair to say that models are not decisive in their assessment about which of these two factors should be dominating at present. The atmospheric inversion method, once it passes the test of independent replication, would trump model predictions of what ought to be happening, in my book.

A decrease in ocean uptake is more clearly documented in the North Atlantic by Schuster and Watson [2007]. They show surface ocean CO2 measurements from ships of opportunity from the period 1994-1995, and from 2002-2005. Their surface ocean chemistry data is expressed in terms of partial pressure of CO2 that would be in equilibrium with the water. If the pCO2 of the air is higher than the calculated pCO2 of the water for example, then CO2 will be dissolving into the water.

The pCO2 of the air rose by about 15 microatmospheres in that decade. The strongest Henry’s Law scenario would be for the ocean pCO2 to remain constant through that time, so that the air/sea difference would increase by the 15 microatmospheres of the atmospheric rise. Instead what happened is that the pCO2 of the water rose twice as fast as the atmosphere did, by about 30 microatmospheres. The air-sea difference in pCO2 collapsed to zero in the high latitudes, meaning no CO2 uptake at all in a place where the CO2 uptake might be expected to be strongest.

One factor that might be changing the pressure of CO2 coming from the sea surface might be the warming surface waters, because CO2 becomes less soluble as the temperature rises. But that ain’t it, as it turns out. The surface ocean is warming in their data, except for the two most tropical regions, but the amount of warming can only explain a small fraction of the CO2 pressure change. The culprit is not in hand exactly, but is described as some change in ocean circulation, caused maybe by stratification or by the North Atlantic Oscillation, bringing a different crop of water to the surface. At any event, the decrease in ocean uptake in the North Atlantic is convincing. It’s real, all right.

Canadell et al [2007] claim to see the recent sluggishness of natural CO2 uptake in the rate of atmospheric CO2 rise relative to the total rate of CO2 release (from fossil fuels plus land use changes). They construct records of the atmospheric fraction of the total carbon release, and find that it has increased from 0.4 back in about 1960, to 0.45 today. Carbon cycle models (13 of them, from the SRES A2 scenario) also predict that the atmospheric fraction should increase, but not yet. For the time period from 1960 to 2000, the models predict that we would find the opposite of what is observed: a slight decrease in the atmospheric fraction, driven by increasing carbon uptake into the natural world. Positive feedbacks in the real-world carbon cycle seem to be kicking in faster than anticipated, Canadell et al conclude.

There is no real new information in the Canadell et al [2007] analysis on whether the sinking sink is in the ocean or on land. They use an ocean model to do this bookkeeping, but we have just seen how hard it is to model or even understand some of the observed changes in ocean uptake. In addition to the changing ocean sink, drought and heat wave conditions may change the uptake of carbon on land. The infamously hot summer of 2003 in Europe for example cut the rate of photosynthesis by 50%, dumping as much carbon into the air as had been taken up by that same area for the four previous years [Ciais et al., 2005].

The warming at the end of the last ice age was prompted by changes in Earth’s orbit around the sun, but it was greatly amplified by the rising CO2 concentration in the atmosphere. The orbits pushed on ice sheets, which pushed on climate. The climate changes triggered a strong positive carbon cycle feedback which is, yes, still poorly understood.

Now industrial activity is pushing on atmospheric CO2 directly. The question is when and how strongly the carbon cycle will push back.
 
—–

Canadell, J.G., C.L. Quere, M.R. Raupach, C.B. Field, E.T. Buitehuis, P. Ciais, T.J. Conway, N.P. Gillett, R.A. Houghton, and G. Marland, Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks, Proc. Natl. Acad. Sci. USA, doi 10.1073, 2007.

Ciais, P., M. Reichstein, N. Viovy, A. Granier, J. Ogee, V. Allard, M. Aubinet, N. Buchmann, C. Bernhofer, A. Carrara, F. Chevallier, N. De Noblet, A.D. Friend, P. Friedlingstein, T. Grunwald, B. Heinesch, P. Keronen, A. Knohl, G. Krinner, D. Loustau, G. Manca, G. Matteucci, F. Miglietta, J.M. Ourcival, D. Papale, K. Pilegaard, S. Rambal, G. Seufert, J.F. Soussana, M.J. Sanz, E.D. Schulze, T. Vesala, and R. Valentini, Europe-wide reduction in primary productivity caused by the heat and drought in 2003, Nature, 437 (7058), 529-533, 2005.

Le Quere, C., C. Rodenbeck, E.T. Buitenhuis, T.J. Conway, R. Langenfelds, A. Gomez, C. Labuschagne, M. Ramonet, T. Nakazawa, N. Metzl, N. Gillett, and M. Heimann, Saturation of the Southern Ocean CO2 sink due to recent climate change, Science, 316 (5832), 1735-1738, 2007.

Schuster, U., and A.J. Watson, A variable and decreasing sink for atmospheric CO2 in the North Atlantic, J. Geophysical Res., in press, 2007.


680 Responses to “Is the ocean carbon sink sinking?”

  1. 301
    Matt says:

    #269 Majorajam: Here’s a little factoid- the 1970’s with their huge forced mitigation due to the oil embargos experienced significantly higher global GDP growth than the 80’s or 90’s which had extremely cheap energy by comparison. Is that consistent with the assumptions you’ve just made? This decade’s global GDP growth has been faster than the last, with much more expensive energy. How’s your theory holding up

    Let’s look at it this way: How have emerging markets made a name for themselves in the last 50 years? By doing something cheaper than an established market. Usually, to date has been focused nearly 100% labor cost, with contributions from governments at times to lure businesses. Consider that energy costs are 20% of an airlines expenses. Consider energy costs are under 1% of a SW company’s expenses. But there are a host of products, such as LCD TVs, in which energy costs related to production are non-trivial–in some cases 4-5%.

    If a country with near zero infrastructure today opts to avoid legacy constraints that the US or EU might have (as related to power generation), and finds a way to trim that 4-5% energy cost to 1-2% ON TOP OF offering a labor pool that will do the same job for 10% less than the next highest bidder, then the world will beat a path to their door.

    We watched the world movemanufacturing to Japan, then back to US, then to Mexico, then Taiwan, then China, Malaysia, Vietnam, and then ??? all over reduced labor costs.

    Give owners time to mitigate? What, costal property owners will single handedly reduce CO2 concentrations to such a point as to impact global climate? Or what, sell? Sell to…? I know, the guy who wants to live under water.

    Assume I have ocean front property today worth $1M today for the land, and $500K for the house. Houses get moved all the time. The land today is worth $1M. The land in 40 years is worth about half that. When the water rises in 80 years, it’s obviously worth zero. Things get depreciated all the time. Without AGW it’ll be worth 0 in 400 years. What’s 320 years? One might also note that those living this close to the water are already costing society a disproportionate chunk of change.

    I find it intriguing that you believe that erecting massive sea walls around tens of thousands of miles of coastline (together with concomitant environmental damage) will be cheaper than CO2 mitigation. Is that a back of the envelope calculation perhaps?

    Again, it’s not needed everywhere. Put a stick in the sand, tell folks this will probably be under water in 80 years what do you want to do? If you want us to protect it, here’s the cost. If you want to sell it, now is the time.

    Again, it would have happened in 320 years anyway if man wasn’t even on the planet. It’s nature.

    I’m sure you’re not scared, even as you’re keenly aware of the staggering amount of energy required to move water.

    100 years ago do you know how daunting the task must have seemed to produce the 3.6T KWH the US needs today each and every year? And yet we did it. See my other post. It’s entirely reasonable energy could cost 1/10 in 50 years of what it costs today. Outside of minor blips and burps, the cost for energy falls so quickly folks really fail to grasp it. A paper in SCIENCE in 1981 predicted that it would require more than a barrel of oil’s worth of energy to extract a barrel of oil. Spectacularly wrong.

    Moving water is a problem if energy is expensive. Fresh water is a problem if energy is expensive. Both are managable if energy is cheap.

  2. 302
    J.S. McIntyre says:

    re 291

    J.S. McIntyre (275), I think this was a cogent analysis, but I have one disagreement. The cost of producing oil is no way the driving force behind $100/bbl pricing, and there is major leeway between the $100/bbl and the cost of production, transport, refining and delivery (the latter two a near zero factor in the $100 figure) — all from what the folks at OPEC, e.g., simply think they can charge.
    =============

    Nor did I say it was, specifically, only using the figure to underscore a point – that this is a commodity that will invariably continue to rise in cost. The estimated true cost of oil right now is closer to $70.00 a barrel, not $100.00. Adjusting for inflation, I believe at $70.00 a barrel it is cheaper than during the oil crisis of the 70s. That price is being pushed by nervous traders looking for something, anything, to keep an ailing market moving. It may decline, it may not…there are many factors at play.

    And it is not the “folks from OPEC”, though they contribute. There are a multitude of factors, such as 1) the ill-advised invasion of Iraq coupled with the mismanagement, corruption and painful incompetence that has marked our presence there, 2) the continued saber-rattling over Iran, 3) the ongoing problems with refineries being taken off-line for repair and maintenance, 4) the loss of production from Mexico 5) the growth of energy consuming economies that more and more are helping to drive the cost of oil up and so forth. And let’s not forget Big Oil, who have a stake in keeping the money flowing.

    “Neither will the cost of production see large continuous increases in the future.”

    I disagree. “Easy” oil production is becoming more a thing of the past – witness the scramble of the East Asian countries and India to compete with the U.S. and Western Europe to lock up oil from a variety of countries. The newer fields are in harsh climes, in deeper water, or increasingly unstable regions of the world, politically and militarily. Getting oil out of these places will be increasingly expensive, both in terms of inflation and real cost. Consider Iraq: even if we hold on to a presence there and somehow get production flowing, we already thrown multiple billions of dollars at the problem for no return. And once the oil is produced, there is no guarantee it is “ours” – it gets turned over to companies that refine and ship it to the highest bidder. What are we going to do – levy a tax on the oil before they can have it? If so, that will only raise the cost of production.

    “I would not be surprised if the producers, if so inclined, could drop the spot/futures price to $50 overnight and feel nary a twinge.”

    Unlikely to an extreme, and even if it did, it would likely be little more than the last gasp of a bygone era. The world has changed, Rod. There are more consumers than consumables. In such a world, it’s a seller’s market.

  3. 303
    J.S. McIntyre says:

    re 293

    #275 J.S. McIntyre: But the price of producing, refining and delivering oil will not change in any appreciative fashion.

    50% of gas is oil costs according to (1). US, EU are 44% of world oil consumption. If US and EU manage to get substantially off oil (say, 90% reduction) over 50 years, do Saudi Arabia et al simply live with half as much revenue? Do they double the price and accelerate emerging nations shift to non-oil use, or do they halve the price and make it easy for emerging nations to use all the old technology (IC engines), that the rest of the world quit using a while back?”

    Oil is a finite resource. The U.S. hit peak oil decades ago. The Middle East hit or will hit peak oil soon. There are not enough new fields coming on line to substantially change production levels – what is there is there, and in many places production is in decline. Given the increased demand, even short term, by the time Western (and hopefully Eastern) economies wean themselves off fossil fuels, it is unlikely there will be a dramatic lowering in price. Why? Factor in the understanding that as countries develop and seek to exploit renewables the produce they are going to undermine any attempt by oil producing countries to take advantage of your fairy-tale scenario by underselling. It’s smart business, both for the seller and the buyer.

    Again, the more renewables grow, the cheaper they will become to produce. Add to that the understanding that beyond one-time costs of production and installation and invariable maintenence(which you are not addressing) the cost advantage of alternatives outweigh the constant maintenece of an oil-based economy.

    And, of course, you fail to address the ecological and health advantages…but then, you really can’t, now can you?

    Here’s the real bottom line … we’re going to be forced off of oil-based economies sooner or later. The real question is whether we do it now, or are forced to do it when, as discussed here quite a bit, it will probably be too late. But once alternative energy solutions come on line in large quantities, become cheaper, and lifestyles change – and they will – the odds are there will be a major shift in how the world consumes energy.

    Those small, impovershed nations you like to talk about will probably adapt well, if allowed. It’s countries like the U.S., consuming 25% of the world’s energy, that is going to have a rough go of it.

    Put another way, this is going to be one heck of a diet.

  4. 304
    Hank Roberts says:

    DanG — don’t include the period after the ‘org’ in the link you ask for, as you did in your posting. Anything with ‘www’ or http:// in front of it will be hilighted and clickable (it will “look alive), but the rest of the URL has to be right for it to connect.

  5. 305
    James Annan says:

    Marjorajam,

    Well I would guess I am in a small minority, being a climate scientist who actually does have a formal qualification in economics – not that I am going to cross swords with Weitzman on that score :-)

    Weitzman’s result is essentially due to how he handles the infinitesimal probability of an infinitely large catastrophe. Even if one accepts his probabilistic paradigm (which I do not) it is important to realise that he is not just saying that (eg) 2xCO2 is a catastrophe with unbounded cost, his analysis shows that +1ppm of CO2 is equally a catastrophe with unbounded cost, and I bet his method would also say that the risk of a future flu epidemic is a catastrophe with unbounded cost (consider the number of people killed as an uncertain multiplicative parameter just like climate sensitivity). So it seems that at best he has shown that this sort of analysis cannot provide usable results – how are we supposed to allocate resources to such things as CO2 mitigation and disease control if we face an infinite future cost for all possible choices?

  6. 306
    Martin Vermeer says:

    > Wiki says there are 10,000 miles of dykes protecting the Dutch. TEN
    > THOUSAND MILES OF DYKES. Holy cow.

    Matt, not all dykes are created equal. Most of those are “internal”
    dykes, part of a hierarchical system aimed at removing excess water in
    steps. Others are river dykes, which have recently been under threat
    also as the Rhine has been flooding more abundantly due to environmental
    changes upstream (which may be partly climate related too).

    The dykes (and dunes!) protecting the Netherlands from sea level
    extremes are no more than a few hundred kms long. It includes the
    ‘afsluitdijk’ behind which the Zuyderzee polders are located (each with
    its own dykes), and the Zealand storm surge barrier. Both these were
    specifically aimed at shortening the coastline exposed to the sea.

    In the North there is the Waddenzee, a tidal plain serving as a
    stop-over for many (most?) migrating birds of W Europe. That’s going to
    disappear too, no way to save that with dykes. Same for the salt water
    ecosystem behind the storm surge barrier, which was designed (at great
    cost) to preserve it.

    The Dutch are spending as much money on their sea defences as most
    nations on their military. It would (will?) increase drastically with
    sea level rise as projected. Mitigation costs are (would be?) modest by
    comparison, cf. the IPCC report of WG3.

    I am from the Netherlands originally, the part protected by these works.
    If all your arguments are as facts based as this one, I am not
    impressed.

  7. 307
    Martin Vermeer says:

    BTW the learning process of the Dutch was very similar to what we can
    observe as ongoing now for climate change: first disaster strikes, and
    then you learn — and spend. In 1953, my cradle stood behind one of
    those lowly “internal dykes”, mere kilometres from the flooded area.

  8. 308
    Timothy Chase says:

    Dan G (#295) wrote:

    Off topic — sorry! I’ve had a difficult time finding this website, which Google no longer seems to list, even as I ask for http://www.realclimate.org. Can anyone tell me what’s happening? I normally connect almost daily.

    http://www.google.com/search?hl=en&safe=off&q=site%3Awww.realclimate.org&btnG=Search

    Zero pages returned. As far as the Google index is concerned, not a single web page at Real Climate exists.

    Someone apparently found a trick to flush it from Google. Something similar was done to Panda’s Thumb a while back by creationists. Science under attack — again.

    The good news is that there are plenty of sites that link here, but all of the posts and comments should be generating their own traffic, showing up as results in the Google searches. A large part of what makes it a real resource.

  9. 309
    Hans Kiesewetter says:

    re 294: “there are 10,000 miles of dykes protecting the Dutch”.
    Yes indeed, however most of them are old inland dikes. The main coastline is around 50% dikes, 50% natural dunes (personal guess). But we (I live there, my house stands 2 meters below see level.) have dikes along rivers, and the most of that 10.000 km are dikes remaining from the time we made polders, reclaimed the land from sea, bit by bit. http://en.wikipedia.org/wiki/Polder.
    For SLR we need to enforce the 500 km coastline, but also have to take care of the river water, coming from Germany and Belgium. With a few meters SLR it will not flow, and we will have to pump and enforce the dikes along that rivers. And to keep my personal feet dry we now have to pump up the water 2 meters, and that will be a bit more in the future (or much more.) It is not only water from rain that has to be removed, ground water is coming up and this water is becoming saltier. Some farmers near the coast already have problems…
    In our local news today and yesterday: plans to make new islands in front of the coast (Dubai didn’t figure out Palm Islands all by themselves. We have a proposal of a tulip.) Main purpose: we need (??) space (including new airport?) and nature for recreation… No stupid decision taken yet, but I do not understand it at all. Why make more land that we will have to protect this coming age?? And how long will we try, before we retreat? 1 meter SLR? No problem, we will build dikes and new (energy consuming) pumps. 5 meters? Some time this or coming century we will loose this expensive battle.

  10. 310
    Joe Duck says:

    Thanks to all for the spirited opinions above.

    You are proposing that Lomborg understands population biology and climate science better than the published professionals in these fields. You’re telling me to believe Lomborg over E.O. Wilson, and Lomborg over Hansen, correct?

    No, of course not. I think he has many reasonable ideas for how to prioritize global problems and correctly suggests that we avoid alarmism or risk spending money and allocating time ineffectively.
    Lomborg actually agrees with mainstream scientific assessments on almost every issue of substance. Can you give an example where he does not do that? No. He pisses people off because he regularly and assertively suggests – reasonably in my view – that there is a lot of hype and alarmism about AGW and other environmental issues that misuses the science. Here at RC that notion is very objectionable because people seem to feel strongly that there is not much alarmism in the media (e.g. An Inconvenient Truth was objective science rather than subjective hype). Alarmism is a subjective opinion and thus can’t be labelled “true or false” so I doubt we’ll make much progress debating “alarmism”.

    Above some correctly noted I should NOT have used the term “simplified”, which is what I think Lomborg usually does, to characterize scientists feeling and saying he *misrepresented* their science, which is what many scientists suggest he does.

    I saw few references to actual Lomborg points that people disagree with. Some above even seem to think he is an AGW skeptic when Lomborg has consistently used IPCC data even years ago when he first started writing.

    I did NOT say Lomborg cherry picked, rather I was noting he was accused of that in The Skeptical Environmentalist. Of course cherry picking is not scientific and is misleading. He may be guilty of a small amount of that (I have only seen a handful of trivial examples from the SciAm articles). Nothing that would discredit any of his main points about allocating resources more effectively and recognizing that catastrophe is unlikely to be looming.

    The price of oil quote as a sign he’s not credible or a “liar” is so ridiculous I don’t know how to respond. Lomborg is made an oil price prediction that did not come true. Wrong predictions are not lies though you’d be right to question his credibility if he made a lot of predictions that did not come true. He has not done that. Nobody can predict oil prices accurately except perhaps OPEC because they can set them.

    Mary – several times you note that you *agree* with specific things he said, then go on to elaborate on topics where you don’t know what he thinks. I’m not saying that is all you did, but could you find something substantial and specific Lomborg says that you think is a lie or inaccurate? Not opinions because I agree you should not be a Lomborg fan. It’s clear that compared to me you assume there is a higher chance of climate change that will create catastrophic conditions. Several people here seem to think catastrophic sea level rises this century are – let’s say for sake of reasoned debate – more than 10% likely, probably as a result of the type of feedbacks Hansen is concerned about that could cause much faster Greenland melting than had been previously considered likely. If you believe Greenland has a reasonably liklihood of melting soon you are completely right to feel Lomborg is a sort of pied piper, luring us into a false sense of security.

    If, on the other hand, you assume catastrophic conditions are extremely unlikely (on the order of less than 1%), as I do, you see Lomborg as offering reasonable approaches to mitigation and other global problems – placing more urgency on immediate benefits.

    In my opinion discussing these issues as if Lomborg was the issue detracts from the very important questions of the day – how much mitigation, how we do it, how do we minimize the cost and maximize the impact. Attack the problems, not the people.

  11. 311
    Roly Gross says:

    #294 Wiki says there are 10,000 miles of dykes protecting the Dutch. TEN THOUSAND MILES OF DYKES. Holy cow.

    Maybe that shows just how difficult it would be to protect all the vulnerable coastline on the planet.

  12. 312
    Goffers says:

    Can anybody tell me what the latest level of atmospheric CO2 is, seasonally adjusted if possible?

    Every figure I see is about 2 years old. All I see of recent readings is comment on percentage growth in emissions, and not the result of the increase on actual levels.

  13. 313
    Joe Duck says:

    Extensive analysis of Lomborg criticisms:
    http://www.stichting-han.nl/lomborg.htm

  14. 314
    pete best says:

    Regarding OIL production. OPEC countries produce 42% of world demand but have 60% of proven reserves. Russia for instance produces a lot of Oil but does not have much left hence I guess their recent activities in the Arctic. However Oil in the Arctic is probably 4 miles down and drilling for Oil has never taken place at such depths before. The UK recently put in some requests for Antartic space most likely for Oil reasons and Canada and the USA through Alaska will probably become interested in the Arctic to.

    Lets get this straight, consumption of oil is increasing but the world currently due to drilling issues and lack of new investment cannot pump it even if it is there to pump. There have been 1 trillion barrels of Oil used since 1850 and one trillion is known about left to drill. However these proven reserves figues have remained unchanged since the 1980′s and OPEC countries do not disclose their reserves willingly or accurately. Another trillion barrels of heavy oil might exist in the Antartic and Arctic and places such as venezuela (orinicho belt etc) and tar sands and shale but these oils are not limited by cost but by technology and the availability of natural resources.

    A new movie/dvd called A Crude Awakening explains this situation and examines in consequences.

    Peak Oil appears to be real and worrying as china and India seek more of it. It just serves to keep the price high. It may well be that for a short time prices will come down as more oil can be pumped but by the IEAs own admission long term oil production is a worry simply because of the cost of new exploration and limited returns.

    We defo need to find something else within 20 years and its either second generation ethanol or hydrogen. Time is against us thats for sure.

  15. 315
    J.C.H. says:

    There are 10,000 kilometers of dikes (much of it river and canal dikes) that protect the Dutch from the SLR of the past, not the future.

    I guess they’ll call it the Lomborg Sea.

  16. 316
    Lowlander says:

    Matt 294
    “Wiki says there are 10,000 miles of dykes protecting the Dutch. TEN THOUSAND MILES OF DYKES. Holy cow.”

    You need to brush up your Geography and History. Most of those dykes are actually inland to control the flow of rivers, they are not coastal defenses, plus they have been built ever since Midle Age.
    The biggest coastal defense in Holland as mentioned somewhere above is actually a storm defense, a direct result of the great storm of 1958 (which also caused devastation in the coast of East Anglia, thats England), it defends the mouth of a gulf which is exposed to the North Sea and it took decades to finnally be completed and declared fit to counter a storm equivalent to 1958.

  17. 317
    Cobblyworlds says:

    #298 Majorajam,

    I’m just an amateur reader of the science, but for what it’s worth:

    I agree with James Annan with regards climate sensitivity being of the order of 3degC – I get the impression his stance on this is within the consensus, and the long tail lobby are not. And I agree with him in that I think we can largely dismiss claims of long tail high sensitivity.

    But saying we can expect 3degC committed global average temperature increase for a doubling of CO2 levels above pre-industrial does NOT amount to “no need to worry”.

    To read someone as noteworthy as David Archer stating “taken as a whole, [the studies] provide convincing evidence that the hypothesized carbon cycle positive feedback has begun.” That was chilling, partly because I was hoping he’d say the opposite. The point being that CO2 feedbacks, even with a 3degC Climate Sensitivity can still produce the sort of overall impacts one might have associated with a higher Climate Sensitivity.

    Take an emissions profile (the SRES data used by IPCC) and with a Climate Sensitivity of 3deg C you may expect a certain evolution of global average temperature. BUT if the carbon cycle acts to “amplify” emissions more than expected (as it seems to be), the actual atmospheric CO2 build-up associated with that SRES scenario can still proceed ahead of projections. The end result (very simplistically speaking) could be a warming progression similar to a projection with a higher Climate Sensitivity than 3degC.

    So whilst I agree with Annan’s dismissal of a long tail to Climate Sensitivity. I don’t think that this can be carried through to the actual warming associated with a given emissions path – that pdf tail is not so certain and cannot be bounded as Annan/Hargreaves have done.

    (It has been very interesting to compare the Roe/Baker paper’s discussion alongside this posting by David Archer.)

  18. 318
    SecularAnimist says:

    Mary C wrote: “I get so sick and tired of hearing about how Kyoto will make people poorer ..”

    The rapid phase-out of fossil fuels that is necessary to avert the worst consequences of anthropogenic global warming will make Exxon-Mobil “poorer”, which is to say it will transfer some of the trillions of dollars in profits that they would otherwise receive over the next 10 to 20 years to other sectors of the economy.

    To the already unimaginably rich fossil fuel corporations, that’s an unacceptable “cost” of global warming mitigation, and it is the real impetus behind all the fraudulent Lomborgian propaganda about how global warming mitigation will “hurt the poor”.

  19. 319
    tamino says:

    Re: #312 (Goffers)

    As of September 2007 the monthly average CO2 concentration from Mauna Loa is 380.58 ppmv. Seasonally adjusted, it’s 383.57.

  20. 320
    Lynn Vincentnathan says:

    #317 & David’s statement “taken as a whole, they provide convincing evidence that the hypothesized carbon cycle positive feedback has begun.”

    Does this mean we just might have already reached that tipping point I’m most concerned about (that no matter how much we reduce our GHGs now, nature will take over and keep on increasing the warming, in the most part by its own GHG emissions)?

    I’ve read Mark Lynas’s SIX DEGREES, and based on his best assessment of the scientific studies a couple of years ago when it was sent for publication, he suggested that a 3C degree increase in warming would push us past that point of no return tipping point (at least for many 1000s of years), that 3C would ensure we get to 4C, which would ensure we get to 5C, that would ensure 6C (at least that’s how I read it). And BTW his vision of a 3C increase scenario is pretty horrible in my books, even if he is wrong about it being the tipping point.

    A few years earlier, I think the idea was if we reach 6C warming (the high projection for 2100), that would be the tipping point.

    My gut sense is that we really don’t know. 3C makes it more sure than 1C, and 6C is pretty high certainty, but we really don’t know.

  21. 321
    Ray Ladbury says:

    Joe Duck, Re 313. Let’s look at some of the other sites your HAN_NL site links to:

    globalwarming.org, Hudson Institute, Johndaly.com, OISM, and Fred Singer’s SEPP. And that’s just a start. Hmm, thanks, Joe. I’ve seen enough. With friends like this, Lomborg is damned just by the company he keeps. The fact of the matter is that Lomborg’s opinions are based on ideology, and a misunderstanding of the science informed by that ideology.
    Joe, why is it hard for you to understand why scientists are outraged by someone who distorts the science and then calls the scientists “alarmists” based on that distortion? Scientists have been trying to get people to pay attention to this for over 20 years. They have been rewarded by being called “chicken littles”, alarmists, frauds and worse by ignorant, greedy food tubes who don’t understand the science. Do you wonder that their skin on that issue might have worn a little thin?

  22. 322
    J.S. McIntyre says:

    re 310

    “I saw few references to actual Lomborg points that people disagree with.”

    ======================

    With all due respect, reviewing the contents of the post referenced, you are either ignoring what has been provided/not paying attention or, as I pointed out on another thread, you are wasting everyone’s time.

    I tend to continue to support the latter position.

  23. 323
    tamino says:

    Re: Joe Duck

    I disagree with you, but thanks for a rational and civil statement of your position.

    Here’s an analogy: global warming is like lung cancer. Right now it’s just a tiny little dark spot on your chest x-ray. It doesn’t affect your life dramatically — yet — you only have a little cough from time to time and a wee bit of shortness of breath. Your uncle Lomborg comes along and says, “If you spend all that money to treat lung cancer, it’ll take away from your budget for food and rent. Even your “extra” money would be better spent elsewhere — like sending some cash to our poor cousin living in poverty in Bangladesh. Besides, chemo and radiation therapy are likely to have only a minor effect on the progress of your cancer.”

    Your *doctor* (let’s call him Dr. Hansen) says that without an aggressive treatment plan things are going to get a lot worse. He also tells you right up front that things will get worse even *with* that agressive treatment plan. Most of all, he emphasizes that every minute of delay in treatment makes the problem worse. A lot worse. He further says that you must quit smoking, and beside, it’ll save you money.

    Meanwhile your wife tells you, “For the love of God, quit smoking!!!” She also says your uncle Lomborg is a detestable worm.

  24. 324
    Matt says:

    #303 J.S. McIntyre Here’s the real bottom line … we’re going to be forced off of oil-based economies sooner or later. The real question is whether we do it now, or are forced to do it when, as discussed here quite a bit, it will probably be too late. But once alternative energy solutions come on line in large quantities, become cheaper, and lifestyles change – and they will – the odds are there will be a major shift in how the world consumes energy.

    I think we are at total agreement here. As I’ve said previously, Bush should have said to the country on September 12 2001 that we were going to speed our migration off of oil like nobody has seen before.

    My guess is where we do diverge is that I’m keen on nuclear, and you aren’t (true?). That’s really a separate discussion that I think was collectively mined out in another thread a while back.

    BTW, it’s the refusal to speed the migration to nuclear that will ultimately cause us to remain stuck on oil. Everything else in the near term just doesn’t deliver the scale we need to make a quick transition, and in those times the status quo always wins.

  25. 325
  26. 326
    Jim Galasyn says:

    Joe agrees that Lomborg does not understand population biology and climate science better than published researchers, which is cool, but then Joe asks, “Lomborg actually agrees with mainstream scientific assessments on almost every issue of substance. Can you give an example where he does not do that? No.”

    Yes. Lomborg told me, in person, that “biodiversity loss is not a catastrophe.” I don’t know what would rise to the level of catastrophe for him, but I call wiping out entire ecosystems catastrophic.

    For example, great sharks, the top of the food web in many ocean ecosystems, have been fished nearly to extinction. If you remove the apex predators from an ecosystem, the system unravels in a trophic cascade. See recent research on the destruction of the N. Carolina scallop industry:

    Cascading effects of the loss of apex predatory sharks from a coastal ocean

    Here’s another example: Most of the N. Atlantic fisheries have collapsed due to overexplotation. This grim development is part of a global crisis in ocean biomass. For published work, see UBC Fisheries research.

    In both of these cases, “environmentalist” Lomborg denies there’s an issue; as long as we have some aquaculture to farm fish for human consumption, all is well. And in both cases, Lomborg’s opinion flies completely in the face of mountains of peer-reviewed research.

    Furthermore, when I pressed him on this very issue, he tried to switch the conversation to forestry, but I didn’t let him. I said, “We’re not deploying factory trawlers and longliners into the forests.” My point was that we don’t allow hunters to place 30-mile trap lines in Yellowstone; imagine the outcry, as bears, cougars, deer, raccoons, squirrels, and all manner of furry creatures would be very visibly caught to die slow, agonizing deaths. But that’s what we do in the oceans, and the result is to remove entire trophic levels from the ocean ecosystems. To Lomborg, that’s just “removing the oldest fish from the population” (his exact quote to me). I doubt that Lomborg knows what a “trophic level” is.

  27. 327
    J.S. McIntyre says:

    re 288

    “Matt (249) and Joe (276) – What is about Lomborg that you two find so admirable and credible? I really, really don’t get it.”

    I often ask myself this same question about one-issue voters, the kind of people who will support any candidate as long as they claim to be against abortion or homosexuality or favor prayer-in-schools.

    It strikes me there will always be a segment of society that will want the world to be a certain way and to hell with the consequences, or the evidence.

    This sort of behavior reminds me of a quote from David Brin:
    ===============

    What are the most common traits of nearly all forms of Mental Illness?

    Nearly all sufferers lack…

    …flexibility – to be able to change your opinion or course of action, if shown clear evidence you are wrong

    …satiability – the ability to feel satisfaction if you actually get what you wanted, and to transfer your strivings to other goals.

    …extrapolation – the ability to realistically access the possible consequences of your actions and to empathize, or guess how another person might think or feel.

    David Brin.

  28. 328

    Re #312 & #319

    The latest Mauna Loa trends can be found at http://www.esrl.noaa.gov/gmd/ccgg/trends/

    HTH, Alastair.

  29. 329
    mg says:

    #324 Surely the world is going is going to decommission nuclear reactors as quickly as possible because of SLR. A good majority of them are sitting at current sea level at the coastline and would be engulfed by the sea if it rises much more than the IPCC SLR estimates. The disintegrating ice sheets and the nuclear reactors need to be viewed as a single, coupled system. Perhaps if the IPCC is correct, it is just a question of storm surges. But if the IPCC has a shread a doubt in its collective mind about its few-centimetre SLR estimates for BAU SLR then it ought to get back and start discussing SLR properly … and pronto.

  30. 330
    J.S. McIntyre says:

    re 324

    “My guess is where we do diverge is that I’m keen on nuclear, and you aren’t (true?).”

    No, I’m not. Having worked with nukes, and spent a fair amount of time studying the problems associated with the use of nuclear energy as a solution to energy problems, I have a very strong aversion to most things nuclear.

    I would suggest you read the interview with Dr. Brice Smith in the Bulletin of the Atomic Scientists (Nov/Dec) and then get back to me.

    http://thebulletin.metapress.com/content/06276q2j38877333/fulltext.pdf

    (Note: It might load a little slow, but it will load)

    As he discusses, nuclear is a short-term solution, a band-aide that treats the symptom, not the disease, to use a medical metaphor.

    He points out there are three classic risks:

    1) the association between the fuel cycle and weapons production;
    2) reactor accidents; and
    3) disposal.

    He also points out that while the risk of accidents – low probabilities mixed with very high consequences.

    There are also two very good discussions of Climate Change to be found in this issue, found here:

    http://thebulletin.metapress.com/content/u51191350533/?p=3d88486ade784dff9a5d4f7604f058c2&pi=0

    I would also recommend Alan Weisman’s “The World Without Us”. His discussion of what we know about disposal issues is nothing short of nightmarish.

    “…it’s the refusal to speed the migration to nuclear that will ultimately cause us to remain stuck on oil.”

    There is no real data to support this opinion.

    But seeing as you brought up the pie-in-the-sky solution, let me offer another: “Mining the Sky” by John S. Lewis, a book that offers some long-term and potentially sustainable non-nuclear solutions to our energy problems, and to my thinking, a wiser solution than the nuclear option.

    http://books.google.com/books?id=k9hwi3ktye8C&dq=mining+the+sky&printsec=frontcover&source=web&ots=ph8ZfRQrTk&sig=W5XEj2iKuRLVzOamkFqsSiexwWM

  31. 331
    Matt says:

    #306 Margin Vermeer:If all your arguments are as facts based as this one, I am not
    impressed.

    I’m just merely pointing out that it floods in 320 years naturally anyway. Because of man, it might flood in 80 years. From a planning perspective, both are long term projects. Here in Seattle we can’t even get consensus on whether or not to build new bridges that are supposed to fall down in the next big earthquake. If we can’t agree on that 20 year event, what is the difference between an 80 year SLR with 10% certainty and a 320 year SLR with 100% certainty?

  32. 332
    J.S. McIntyre says:

    re 324

    “it’s the refusal to speed the migration to nuclear that will ultimately cause us to remain stuck on oil.”

    I wrote there was no data I was aware of to support this.

    I should have elaborated. There is nothing to suggest this is limited to an either/or situation, as your statement suggests.

  33. 333
    Matt says:

    #318 SecularAnimist: To the already unimaginably rich fossil fuel corporations, that’s an unacceptable “cost” of global warming mitigation,

    XOM has GM of 43.5%, op margin of 42%, 41.4% tax rate, 10.5% net on sales.

    AAPL has GM of 29%, op margin of 43%, 29.4% tax rate, 10.3% net on sales.

    MSFT has GM of 79.1%, op margin of 45%, 30.0% tax rate, 27.5% net on sales.

    GOOG has GM of 60.2%, op margin of 55.6%, 23.3% tax rate, 29% net on sales.

    I’m not sure what “unimaginably rich fossil fuel corporations” you are using, but XOM isn’t a great looking business from teh numbers. They are about the same as Apple, with a 12% higher tax burden. MSFT and GOOG do, in fact, meet the measure of “unimaginably rich corporations”.

    Labels need to mean something to actually stick.

  34. 334
    Nick Barnes says:

    Matt @ 324: One difference between J.S.McIntyre and yourself is plain in this post. When McIntyre says “we’re going to be forced off of oil-based economies sooner or later”, he doesn’t just mean the US. He also means the rest of us. There are of course national security reasons to reduce US dependence on imported oil. But even if the US had a gazillion barrels of home-grown oil, it should still be reducing fossil fuel dependence, because (a) the atmospheric CO2 will do for you just as surely as it does for the rest of the world, and also (b) latecomers to the energy-efficiency game will buy their solutions from the early adopters.

    [In fact, the US does have a gazillion barrels of oil underground, in the form of coal, which can be converted to gasoline etc at a price equivalence of about $50/barrel, once the conversion plant is constructed].

  35. 335
    Konstantin says:

    Re:324

    Matt, if you think nuclear is a solution you need to read

    http://nsl.caltech.edu/energy.html

    Sorry if this is off topic!

  36. 336
    Lowlander says:

    Zero pages returned. As far as the Google index is concerned, not a single web page at Real Climate exists.

    Someone apparently found a trick to flush it from Google. Something similar was done to Panda’s Thumb a while back by creationists. Science under attack — again.

    Timothy Chase wrotte (308)

    “The good news is that there are plenty of sites that link here, but all of the posts and comments should be generating their own traffic, showing up as results in the Google searches. A large part of what makes it a real resource.”

    I imagined something like that, so it’s on my favourites list now.
    It reminds me of Reasic blog which as well one day simply disapeared from the web. It is impossible to access it and technocrati without much surprise reports that visits from one day to the next dropped from a few hundred a day to nil.
    Natural variation some would say… nothing to worry about.

    [Response: Actually, this is not what you think. We are talking to google and hope to have normal service restored soon. - gavin]

  37. 337
    Matt says:

    #322 J.S. McIntyre: With all due respect, reviewing the contents of the post referenced, you are either ignoring what has been provided/not paying attention or, as I pointed out on another thread, you are wasting everyone’s time.

    It remains a fair question. I’ll note that while Lomborg was suitably taken to task on extinction, nobody here really faulted the other that were MUCH MORE WRONG about extinction rates. Gore, Wilson, Ehrlich, Lovejoy all claimed extinction rates much much much higher than anyone is seeing. And, for all the grief he took, at the end of the section in SE, Lomborg’s position is 0.7% species lost over 50 years (if 30M species, that’s 4,200 species/year). The UN predicts 0.1 to 1% over 50 years. So for all the arm waving, Lomborg was in line with UN estimates.

    Lomborg? ~4000 species per year. Within UN range.

    Gore? 40,000 species per year. ~10X higher than UN.

    Lovejoy? 15-20% of all species dead by 2000. ~100X higher than UN.

    Ehrlich? Everything dead by 2020.

    So, in the end, who was bending the truth a bit?

    Of all the players, I think Lomborg was being most truthful with the readers. Could he have been more clear? Sure. But if you want to fault Lomborg, then you also need to hold the other names above in a similarly dimmed light.

    [Response: Everyone's actual statements are fair game - but the problem with much of this analysis is that you are quoting biased paraphrases of what was actually said. http://www.lomborg-errors.dk/chapter23.htm (p249 comment). If you want to get to the bottom of anything and make the appropriate comment - check your sources! - gavin]

  38. 338

    Re #305 Where James Annan wrote:
    Well I would guess I am in a small minority, being a climate scientist who actually does have a formal qualification in economics – not that I am going to cross swords with Weitzman on that score :-)

    James,

    James this thread is not about economics, nor is it about a climate sensitivity, or even Bayesian statistics. It is about the oceans saturating with CO2, which if global warming continues will result in their emitting rather than absorbing CO2. This will result in a positive feedback which could end up in a runaway situation!

    If, as you have done, you go over past trends and average them out, then you can come up with a climate sensitivity which is smooth 3K change. But that is because you have smoothed it out by taking an average! The recent (last 100,000 years) climate record for the northern hemisphere shows that the climate changed abruptly, not smoothly. During the last major change, at the end of the Younger Dryas, the UK average temperature rose by 5 K in perhaps only three years. See Richard Alley’s “Two Mile Time Machine.”

    The Russian scientists now estimate that the Arctic ice will disappear withing three years. After it has gone perhaps global temperatures will only have risen by 3 K. But how will that affect the forests in California, Greece, Turkey, and Australia. How will that affect the droughts in the Southern sttes of the US, or the flooding in the northern tropics of Africa and south America?

    Recently we have seen that the Earth can behave catastrophically, both with the Boxing Day Tsunami, and with the Katrina in New Orleans. How big a disaster will it take before you realise that you cannot predict the behaviour of the Earth system using a spread sheet.

    The Earth system is not a mathematical model. It is a real system which if pushed too hard will explode!

  39. 339
    Joe Duck says:

    Annan above: Very insightful. I’m unfamiliar with that particular issue but I find it extremely helpful when climate issues are discussed in terms of probabilities. Without this, policy decisions are poisoned from the outset by emotion and politics. The concept of “unbounded risk” seems to be invoked here at RealClimate often and I think lies at the heart of many of the points of contention.
    *
    Tamino – thanks, I appreciate that.
    *
    Concernd that Lomborg, rather than his ideas, are held up as the climate issue though I suppose it’s in line with how skeptics have treated Gore for his policy suggestions. IMO both Gore and Lomborg are sincere advocates for very different points of view.
    *
    Ray I agree that it makes sense that many scientists are angry at Lomborg for what often seems to be an arrogant disregard for complexities. Also those scientists feel he has misrepresented and mischaracterized many issues as “not problems” or “small problems” when those scientists see the complexities as creating “big problems”. However, when I actually go read Lomborg I find little to disagree with. You (Ray) criticized the Danish website referenced above based on links to sites you say are just confusing the debate. Not sure how to counter that point, since it devolves into a discussion of things that, to me, are unrelated to whether Lomborg has been treated fairly by critics.
    *
    J.S. – reviewing the contents of the post referenced, you are either ignoring what has been provided/not paying attention
    Hard to address your concern J.S. I’ve reviewed this post and spent a lot of time earlier at the AIT discussion. Most of the discussion seems to simply lash out at Lomborg as not credible rather than quote him and then provide an alternative interpretation (this is because Lomborg usually is in agreement with mainstream science assessments – he disagrees with how policy and resource allocation should flow from the science). Here is a quote made a couple of times above attributed to Lomborg. But this would be general opinion and, ummm, it’s not even a Lomborg quote at all!

    “…make the rest of the world as rich as New York, so
    that people elsewhere can afford to do things like shore up their coastlines and buy air conditioners.”
    *
    Here is a real Lomborg quote about a point of substance where he’s making the point that alarmism is focusing attention on heat deaths and simply ignoring deaths from cold:

    For Europe as a whole, about 200,000 people die from excess heat each year. However, about 1.5 million Europeans die annually from excess cold.

    Does this suggest warming is not a problem? No. Does it suggest we are failing to view climate-related death in a rational manner? To me, it does.

  40. 340
    dhogaza says:

    Lomborg actually agrees with mainstream scientific assessments on almost every issue of substance. Can you give an example where he does not do that?

    Yes. Today’s rate of species extinction, and the number of past extinctions, attributable to human activity.

  41. 341
    Aaron Lewis says:

    re 325
    Very Good! (As Usual)
    Better! :http://www.esrl.noaa.gov/gmd/aggi/
    and scroll down

  42. 342
    Nick Gotts says:

    Re #197 (Matt) Since I wasn’t defending either Erlich’s or Myers’ numbers, your response is entirely beside the point, which is that “known extinctions” and “extinctions” are entirely different things. Any discussion of extinction that does not acknowledge this is, as I said, either ignorant, mendacious, or both.

    Re #331 (Matt) “I’m just merely pointing out that it floods in 320 years naturally anyway. Because of man, it might flood in 80 years. From a planning perspective, both are long term projects.”

    First, I’m truly gobsmacked you can’t see it might be easier to deal with a given SLR over 320 years than over 80. Second, what’s your source for the 320 year natural flooding claim?

  43. 343
    Nick Gotts says:

    Re #339 (Joe Duck) Joe, despite the number of times you’ve repeated it, it simply is not true that Lomborg is usually in agreement with mainstream science assessments. On p.277 of TSE, he says (this is from Kare Fog – I don’t have a copy of TSE handy): “This theory [the sunspot theory] also has the tremendous advantage, compared to the greenhouse theory, that it can explain the temperature changes from 1860 to 1950, which the rest of the climate scientists with a shrug of the shoulders have accredited to `natural variation´”. This is a gross mischaracterisation of the mainstream view, and also a fine example of Lomborg’s use of false dichotomies, suggesting that solar and anthropogenic causes for temperature change are mutually exclusive possibilities. On extinction, you’ve already been referred to E.O. Wilson’s response to Lomborg. Here’s a quote from Wilson: “His estimate, “0.7 percent over the next 50 years” — or 0.014 percent per year — is an order of magnitude smaller than the most conservative species extinction rates by authorities in the field.”

  44. 344
    J.S. McIntyre says:

    re 339

    “I’ve reviewed this post and spent a lot of time earlier at the AIT discussion. ”

    Obviously we – and the record of your responses in relation to what has been said – disagree.

    I’ll leave it at that.

  45. 345
    Jim Galasyn says:

    Re flooding in 320 years, doesn’t this turn the usual denialist claim on its head? I thought AGW was good, because it’s forestalling the next ice age and the concomitant falling sea level.

  46. 346
    Cobblyworlds says:

    #320 Lynn Vincentnathan,

    All I am saying is that whilst I am with Annan on the lower end climate sensitivity I don’t find this too comforting in light of results such as David Archer outlines. From my (limited) understanding, if we accept the Permian/Triassic Extinction as the best analogy for what could happen, it’s when we get to the >5degC range that there is a risk of clathrate outgassing which will then produce a substantial outgassing. I think this is where the ~6degC you refer to is sourced from.

    I certainly don’t think we’re anywhere near being committed to catastrophic warming based on the physics and earth-system side of things.

    [Human evolved behaviours + 5000Gtons of extractable carbon equivalent fossil fuels] is a totally different equation. IMHO we’re committed to re-running the Permian/Triassic unless the intermediate process acts as a negative feedback on our activities.

  47. 347
    Majorajam says:

    James Annan,

    Thanks for your response. You say, “Weitzman’s result is essentially due to how he handles the infinitesimal probability of an infinitely large catastrophe.”

    As I understand and possibly misunderstand it, Weitzman’s result is due to the fact that the probability of catastrophe is not infinitesimally small, (or, more to the point, does not decay faster than utility burgeons), or cannot be inferred to be such as a result of uncertainty in the scale parameter. If on the other hand that parameter is drawn from a known pdf, you do get infinitesimally small probabilities of catastrophe and therefore DT does not apply- the tails of the posterior pdf in that case decay exponentially. As I understood the manuscript, only when damages from a catastrophe are unbounded, (which they’re not in DT, given that have only one life to give for our CBA), and S must be inferred by inductive reasoning from empirical data, (i.e. has power-law tails), do you get the result that the utility of an extra sure unit of consumption is infinite.

    “Even if one accepts his probabilistic paradigm (which I do not) it is important to realise that he is not just saying that (eg) 2xCO2 is a catastrophe with unbounded cost, his analysis shows that +1ppm of CO2 is equally a catastrophe with unbounded cost”.

    This is a misreading. His result does not say that +1ppm has catastrophe- it says that the utility of mitigation in a two stage model (present and future) is infinite if and only if deep uncertainty exists and the expected loss from a catastrophe assuming it occurs is unbounded. Again, that is not the model presented, as Weitzman introduces the value of statistical life as the lower bound on catastrophic damages in the outermost regions of f(y). In any case, the result is marginal- so it holds for 1ppm most closely, while a doubling is not explicitly demonstrated. I would presume it will hold for extra sure units of consumption until the tradeoff between bad tail behavior in f(y) and the utility of current consumption come into balance, presumably when mitigation spending is large. I have to ask though, would it make sense for the utility of significant savings/mitigation to be infinite but small scale savings/mitigation not to be? It wouldn’t to me.

    A better way to illustrate absurdity is not to scale the mitigation down but up (as Weitzman does when he asks rhetorically whether it was optimal to undergo the industrial revolution). It is not the case that Weitzman doesn’t perceive the strength of this result- as illustrated- it is that that alone does not invalidate the poignancy of what he’s pointed out: that in situations where DT applies, the degree of uncertainty in the scale parameter and upper bound on damages in tail events can dominate assumptions of discounting and of middle of the distribution costs and benefits. Clearly a strong implication worthy of further inquiry.

    “I bet his method would also say that the risk of a future flu epidemic is a catastrophe with unbounded cost (consider the number of people killed as an uncertain multiplicative parameter just like climate sensitivity).”

    Weitzman points to a number of potential other circumstances where DT may apply, though I don’t see that it would here (a death is a damage, not a scaling parameter. A closer analogy would be something encapsulating the virulence and communicability of the mutated virus, but the uncertainty here extends in both directions not to mention to the virus generating process, the meaning of an extra sure unit of consumption in such a context is not obvious, and, clearly, the scope of potential catastrophic damage is far smaller than a temperature change of 10ºC). Either way, the applicability of DT to other circumstances is not prima facie meaningful. It is after all a mathematical finding.

    “So it seems that at best he has shown that this sort of analysis cannot provide usable results – how are we supposed to allocate resources to such things as CO2 mitigation and disease control if we face an infinite future cost for all possible choices?”

    Even if all his paper showed was that this sort of analysis cannot provide usable results, (which I don’t accept), this would be well worth a manuscript. And that of course is a major thrust of his piece- that conventional cost benefit models of climate change should be affixed with a caveat: oh by the way, we’re assuming things that the science and statistic do not support, so while the simplified parallel world that our model describes should do X, it says nothing about what we should do. This is a rather big deal, wouldn’t you agree? What room that leaves for economics to add to the discussion is frankly, at best, a secondary concern. Relying on an informationless compass to lead you out of the desert because it’s all you’ve got won’t get the job done.

    In my view though, this is actually quite a constructive step as all works that point to critical flaws in existing scientific practices are. It is a point of departure for a field where there are smart people to make its tool set more relevant, (and hopefully to better fit empirical data where before their performance has been dismal to put it mildly). Weitzman suggests ways we can reduce the pertinence of DT by learning more about geo-engineering steps that may truncate the catastrophic tail. That is a constructive result. Others may look to better articulate sensitivity analysis or Monte Carlo simulation, etc. that add to the knowledge. I don’t see how these developments could be construed as anything other than constructive.

    PS I won’t ask you about the climate sensitivity debate despite your expertise because having published on it you are a stakeholder. I would however like to know more about what I read on your blog- namely that if climate sensitivity was inferred from observations on other planets and then ported to Earth that it could be seen as arising from a distribution. This point is irritating me because the basic physics of radiative transfer will be the same in either case as it will have always been on Earth- but other major things will not be in both cases, while with Earth-only observations there are more factors that have to be kept constant, (e.g. rough distance from the sun, diameter, basic magnetic properties, etc.). Are you saying that you can attribute the fact that variation in sensitivity cannot be expected of climate sensitivity because of these factors but cannot be for those that time vary on Earth? This is only a somewhat pointed question in that I enter into it in full appreciation of my ignorance of the subject.

  48. 348
    Ray Ladbury says:

    Joe Duck, your quote by Lomborg suggesting a warmer world will decrease death rate is precisely the sort of deceptive simplification that typifies his lines of argument. Look at a single limited facet that illustrates your point rather than looking at the totality of deaths and economic impact from climate change. Do a google search on Lomborg, hotter climate, deaths and look at the crap that floats to the top. Lomborg is an apologist for complacency. However, his worst sin is to present global environmental and economic challenges in terms of competition, when there exist common solutions–or at least remediations–to many of them. Presenting challenges to sustainability as a “multichotomy” and forcing people to choose which concerns are addressed is simply a recipe for fracturing consensus to deal with any of them. It is a strategy of divide et impera in a pseudo-democratic guise.

  49. 349
    Joe Duck says:

    Nick – thanks for those specific examples, I want to review those points and will respond here tomorrow, though I think a separate “Lomborg” thread is called for here to keep the rabblerousers on topic. Better would be a mitigation thread to discuss a highly relevant topic of great concern to all of us.
    *
    Moderators – if the RC pages don’t reappear in Google I can help get them back – suggest you review and/or email me with any changes you recently made to robots.txt or server 301 redirection or use of “NOFOLLOW” tags here at the site – those are the most likely culprits. A reinclusion request is probably needed at Google and I may be able to expedite that process.
    *
    J.S. What are the most common traits of nearly all forms of Mental Illness?
    I think you forgot to add “regular participation in this comment thread”. Maybe we can agree about that one.

  50. 350
    Timothy Chase says:

    Gavin wrote in response to RealClimate getting dropped by Google:

    Response: Actually, this is not what you think. We are talking to google and hope to have normal service restored soon. – gavin

    Lovely.

    I wish I had checked back again prior to making some calls. Fortunately I was put on hold and checked back just prior to being transfered somewhere else. It took PandasThumb quite a while to get back — and I didn’t want the same thing happening to you guys.

    Anyway, keeping busy with interviews. But reading.


Switch to our mobile site