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  1. Gavin writes “With respect to sea level, the Thames Barrier is a concrete example that has been frequently raised.” I don’t know if the phrasing was intended to amuse, but I burst out laughing. One quibble, however: it’s actually concrete and steel.

    [Response: Pedant! ;) – gavin]

    Comment by S. Molnar — 27 Dec 2007 @ 6:02 PM

  2. The Environment Agency has just completed a comprehensive review of some of these issues, pulling together GPS, tide gauges, absolute gravimeters and InSAR data. It shows London continues to subside at 1-2mm a year. With waters rising in the region by about 1mm a year, the combined effect is a 2-3mm a year rise in sea level with respect to the land. With some slight modifications, the barrier is good for a number of years yet. The engineers who built it were very far-sighted. I’ve written about it at:

    Comment by Jonathan Amos — 27 Dec 2007 @ 6:23 PM

  3. I’ve seen the Thames River Barrier, but impressive as it is, some very large lurking problems of climate change are harder to envision.

    While the concerns of rising sea levels due to thermal expansion and melting polar glacial ice are very provoking, my primary concern of anthropegenic forcing remains disruption of bio-geochemical cycles.

    Not to sound like a broken record, but, the food chains of the oceans have been polluted and gutted by overfishing; the result of these pressures is a weakening adaptive ability to climate change of any kind.

    Huge swaths of terrestrial biomes in have been placed in service to agriculture.

    In both cases, the destabilizing loss of diversity, and the commensurate diversion of energy, space, and life activity, to sustain humans is more than dangerous.

    Given that we are in the midst of massive unprecedented changes in the chemical makeup of the atmosphere, one can see how James Lovelock arrives at such pessimistic conclusions. Natural systems may break rather than adapt.

    I am not one to give up hope, but given the politics at hand, we might just end up watching the end on TV.

    Comment by Jim Redden — 27 Dec 2007 @ 6:37 PM

  4. Re#1, Ah Mr Molnar, you beat me to that one, I too laughed out loud at the ebb and flow of the puns in that phrasing.

    Comment by Fernando Magyar — 27 Dec 2007 @ 7:34 PM

  5. In the U.S., a barrier to understanding global warming was created by misinformation from agencies in NOAA on weather, climate change and hydrology. Examples at:

    Comment by Pat Neuman — 27 Dec 2007 @ 8:55 PM

  6. Regarding the Thames, increasing river flows in many regions of the world suggest that the frequency of Thames Barrier closings may be a result of increases in river flow.

    Photos and graphs of recent heavy runoff in the Midwest are at:

    Comment by Pat Neuman — 27 Dec 2007 @ 9:25 PM

  7. I too am pessimistic. Population growth has to be considered as a major factor in climate change, given the technologies available. The human race must forget about the Biblical injunction to be fruitful & multiply. Fertility rates everywhere must be given incentives to become less than 2 children per woman. A rational approach to this can be found at–Negative Population Growth.

    Comment by Bird Thompson — 27 Dec 2007 @ 9:29 PM

  8. [ It shows London continues to subside at 1-2mm a year. With waters rising in the region by about 1mm a year ]

    Didn’t know that London was sinking into the ocean, and at twice the rate of any climate change.

    Comment by BlogReader — 27 Dec 2007 @ 9:41 PM

  9. Re N°8 : Yes, London is sinking, while Scotland is rising (a souvenir of the end of the last glaciation).

    Comment by Marchand — 27 Dec 2007 @ 11:14 PM

  10. Since GW has already been proven beyond a 5% doubt, attribution of single events is more like “deconstructing” the statistical level of climate, and getting back down to the micro-level.

    I’m thinking like this. We live in a globally warming world. Events that are expected in such a world could be attributed to GW, with the idea it would be up to the skeptics or scientists to prove at scientific certainty the event is in no way impacted by GW (e.g., by finding other factors that more greatly overshadow any GW effect). So from a layperson’s perspective (one not out to sue for damages), I feel OK with linking single events expected in a globally warming world to GW. Afterall, the stats are just a collection of many such above average or above baseline events.

    Comment by Lynn Vincentnathan — 28 Dec 2007 @ 1:03 AM

  11. Sea level rising in millimeters and temperature rising in degrees are too small. At the other end, the collapse of civilization and the extinction of Homo Sap are too big and evoke surrender. Perhaps the drought in Atlanta, Georgia, California, Australia, Greece, Turkey, the Sahel, China and other places would be closer to the right size. Changes in soil moisture affect crop yields, and everybody knows this. Both Jared Diamond and Brian Fagan, the author of “The Long Summer,” blame minor climate changes for the collapse or as a factor in the collapse of many civilizations. Jared Diamond points out that present time environmentally stressed countries are the same countries that are suffering breakdowns of government, genocide, terrorism, and so on, because the citizens of those countries are hungry or starving. Food is the issue to communicate to the masses. If it doesn’t rain in Iowa, what are Americans to eat?
    Another thing you have going against you is religion. In “Collapse, How Societies Choose to Fail or Succeed,” Jared Diamond discusses how religion has played a role in the collapse of some civilizations. Christianity contributed to the collapse of the Greenland Viking civilization. Religionists will, of course, resist any change in values regardless of the fact that a change in values is necessary for survival. This is an issue of the preachers’ income. In the end, the preachers may be eaten, but it is too late by that time. Yes, “Collapse” has its gory points.

    Comment by Edward Greisch — 28 Dec 2007 @ 3:44 AM

  12. Thanks a lot for that one, Gavin. Understanding what can be linked directly to AGW and what can’t is very important in the political debate. Blaming AGW for everything and seeing “evidence” everywhere would not lead to more public awareness – in the long run it would be rather the opposite. Personally, I would have liked to see somewhat more of this in the “Gore” thread… but never mind. ;-)

    Comment by henning — 28 Dec 2007 @ 5:09 AM

  13. I’m surprised the article made no mention of the UK government’s (recently retired) Chief Scientific Officer Sir David King, who has frequently used Thames Barrier statistics as an example of real-world evidence for AGW. (See for instance this 2004 address to the AAAS, and Google has many more examples.)

    Comment by A. Simmons — 28 Dec 2007 @ 7:17 AM

  14. Scotland, Norway, Sweden, Finland and many other places are rising and pushing away water from their coasts. Where is all that water going ?

    Comment by Akseli — 28 Dec 2007 @ 7:27 AM

  15. #5 Very interesting info.
    I’ve had my own doubts about my local NWS in New York. They always seem to be understating the actual temperatures we experience here, especially during the Winter.

    Comment by rick — 28 Dec 2007 @ 8:20 AM

  16. Mount Kilimanjaro seems a poor example.
    “Kilimanjaro’s ice has been melting away for more than a century, and most of that melt occurred before 1953, prior to the period where science begins to be conclusive about atmospheric warming in that region, according to Philip Mote of the University of Washington and Georg Kaser of the University of Innsbruck in Austria. “

    [Response: This is precisely what my bigger point was. Kilimanjaro, like almost all other tropical glaciers, is receding fast. These glaciers have existed continuously for 1000’s of years, and now the one on Kilimanjaro is disappearing (and it really is). The important point is that tropical glaciers are receding everywhere (see our previous post) and that is much more easily attributable to global climate change than any one glacier. However, Kilimanjaro is a great example of tropical glacier retreat, even if on it’s own it is not proof of the attribution. What gets lost in these discussions is the whole balance of evidence from other sources. – gavin]

    Comment by Ricks — 28 Dec 2007 @ 10:03 AM

  17. response to Bird Thompson
    Actually, population growth is trending the right way.
    Global rates of growth, though still positive, are falling. Averaged over all of humanity, fertility rates were about 6 children per woman 35 years ago; now the number is less than 3. We have a huge task ahead of us in feeding 6 billion people now and probably about 9 billion before the total number starts to fall. Certainly GW will make feeding the world much more difficult, and the knock-on effects of secondary pollution will aggravate environmental damage Most overall growth is now in the age structure rather in the number of children per woman. The contribution to greenhouse gases is small among peoples with the highest growth rates. Burning the coal for air conditioning in the southeastern US probably contributes more CO2 to the atmosphere than does Africa and the parts of Asia and the Middle East where poverty and high birth rates are found. GW will harm these impoverished people much more than they will contribute to global warming.

    Comment by Don — 28 Dec 2007 @ 10:07 AM

  18. Edward Greisch posts:

    [[Another thing you have going against you is religion. In “Collapse, How Societies Choose to Fail or Succeed,” Jared Diamond discusses how religion has played a role in the collapse of some civilizations. Christianity contributed to the collapse of the Greenland Viking civilization. Religionists will, of course, resist any change in values regardless of the fact that a change in values is necessary for survival. This is an issue of the preachers’ income. In the end, the preachers may be eaten, but it is too late by that time. Yes, “Collapse” has its gory points.]]

    And yet the Pope has said that global warming is a serious problem and 83 leading evangelicals have signed a statement saying Christians need to act to prevent global warming. How about that?

    [Response: No more discussion of religious issues please. – gavin]

    Comment by Barton Paul Levenson — 28 Dec 2007 @ 10:25 AM

  19. Re #18, what would the pope know on this issue really. Although AGW is a serious problem I doubt that it is the main threat in the near term for the first world is some decades off. No, that accolade goes to peak oil, the cost of oil and its global availability. Come 2020 we are really going to be struggling with adequate supply. All IPCC climate models vastly overestimate global fossil fuels reserves and hence peak fossil fuels will come first with oil happening first of all.

    Maybe we can delay the onset of peak oil by a decade by mining increasingly energy poor oil reserves but the writing is on the wall. Once oil peaks extracting coal and gas becomes very difficult so its doubtful they will scale.

    21st century issues eh

    Comment by pete best — 28 Dec 2007 @ 11:32 AM

  20. I don’t understand, how even all glaciers put together (or all tide barriers or whatever) could possibly provide “proof” for global warming. We measure temperatures using termometers, we measure percipitation using a bucket on a stick and we measure gas concentrations and radiation using sophisticated sensoring. Obviously, filming a termometer slowly rising by .2C per decade for 90 minutes won’t win you an oscar – but when you want to find out, how the temperature behaved during the last couple of decades, you fire up GISTEMP – you certainly don’t hike up the Kilimajaro with a yardstick or penetrate your garden with a core-driller, right?

    Comment by henning — 28 Dec 2007 @ 11:33 AM

  21. Just a point of detail. The floods in 1953 referred to in the article did not actually reach the City of London, only going as far as dockland and the east end. The 307 deaths were all along the east coast of England from Northumberland to Essex. (Central London is about 25 miles in-land).

    This is something of a technical point because it is certainly true that the people of London were very worried by the 1953 floods and that the case for a Thames Barrier was made, but as far as I can tell there were few, if any, casualties in 1953 up-river of the site of barrier.

    Comment by Martin — 28 Dec 2007 @ 11:40 AM

  22. Aleksi #14 kirjoitti:

    Scotland, Norway, Sweden, Finland and many other places are rising and pushing away water from their coasts. Where is all that water going ?

    Well, to London, for instance. :-)

    Seriously, for every post-glacial uplift area there is a “remote zone” that’s downlifting, very slowly. For Fennoscandia it includes Central Europe.

    BTW Gavin, the Eastern Schelde Barrier in the Netherlands may be interesting to look at, as it is a cleaner example (and a longer time base)

    Comment by Martin Vermeer — 28 Dec 2007 @ 11:46 AM

  23. Henning, Actually, Gavin’s point is very important. The balance of evidence or the aggregate of the evidence is crucial. Drawing conclusions based on data from multiple independent lines of evidence and reasoning makes it much less likely you’ll draw erroneous conclusions. So it is not the thermometers or the yard sticks or the laser altimetry by themselves that make us so confident about our conclusions, but rather all of them together.
    Likewise in evolution, it is not any particular fossil that establishes evolution, but the aggregate of the entire fossil record.

    Comment by Ray Ladbury — 28 Dec 2007 @ 12:00 PM

  24. Sorry, that should have read:

    Full(ish) details on the UK 1953 floods can be found at the Met Office.

    Comment by P. Lewis — 28 Dec 2007 @ 12:04 PM

  25. Pete Best,
    Oh, I suspect we will find a way to use the coal–plenty of that for decades to come. Then there are the clathrate deposits at the bottoms of the oceans–already looking into how to use that. Humans have plenty of ingenuity to release all the carbon we need to cook our own goose. The question is whether we will have the wisdom to apply our ingenuity to making the situation better rather than worse.

    Comment by Ray Ladbury — 28 Dec 2007 @ 12:06 PM

  26. Re #20: [I don’t understand, how even all glaciers put together (or all tide barriers or whatever) could possibly provide “proof” for global warming.]

    It’s a cold morning, your outside thermometer says 20F. You want to know if it gets above freezing while you’re away at work (and you have a bunch of skeptics claiming your thermometer is out of whack), so what do you do? Simple: put an ice cube outside. Go to work. If the ice cube’s melted when you get home, it’s a pretty good indication that the temperature got above freezing, isn’t it? If you want to get a bit fancier, you could measure how much of the ice had melted, do a little math, and come up with a figure for degree-hours.

    So that’s glaciers: handy natural sensing devices that integrate temperature and precipitation for you :-)

    Comment by James — 28 Dec 2007 @ 12:12 PM

  27. Likewise in evolution, it is not any particular fossil that establishes evolution, but the aggregate of the entire fossil record.

    Stronger still: the fossil record, and Linnaeus’s family tree, and molecular genetics: several methodologically different lines of evidence, all telling essentially the same story.

    Comment by Martin Vermeer — 28 Dec 2007 @ 12:48 PM

  28. Re #25, that just not reality if you study the subject Ray. There are many interpretations but the IPCC projections for fossil fuel energy reserves are extreme best case scrnarios (worse case really) and not reality (well in many peoples eyes anyway).

    You see OPEC all bumped up their quotas in the 1980’s in order to be able to pump more oil. Those rises were not real, they were economic and since then many billions of barrels have been used by their proven reserves remain the same. However the IPCC took data from these reserves and more besides in the ultimately recoverable reserves range.

    No, peak oil or economically more expensive oil is going to be a major destabaliser and if we somehow do find enough oil then climate change will be worse than I expect.

    Comment by pete best — 28 Dec 2007 @ 12:59 PM

  29. Re 27. Exactly! A single fossil or measurement can mislead. A single trend can be misinterpreted. However, when all the data are telling you anthropogenic CO2 is behind the warming, it’s bloody unlikely that all the people analyzing all these data are making mistakes in the same direction. That seems to be what denialists–of anthropogenic climate change or of evolution–seem to miss.

    Comment by Ray Ladbury — 28 Dec 2007 @ 1:02 PM

  30. Pat Neuman Re #5…

    A particular climatic event like the 1993 Midwest Flood in itself isn’t proof of anything. There has been paleoclimatic research published on such events (Midwest River Floods) and many such events have occurred in the last 1000 years before significant human arthoprogenic climate forcing. Some of those events were much more severe than what was experienced in 1993. So how can you be so sure that the 1993 Midwest Floods was not a natural event?

    Yesterday, I read a paper in the journal Earth-Science Reviews: Cook et al (2007) North American drought: Reconstructions, causes, and consequences. In the abstract, this paper notes: “Of central importance to drought formation is the development of cool “La Nina-like” SSTs in the eastern tropical Pacific region.” So if persistant La Nina conditions causes drought over significant portions of the United States, then could it be that persistant El Nino conditions causes floods over significant portions of the United States? Going back to the ENSO record during that time, Neutral to Moderate El Nino conditions was present over the equatorial Pacific from 1990 to the onset of the 1993 Midwest floods. I wonder if such a connection has already been made in published research?

    The point here is that while the National Weather Service sees it’s mission to publicize major climatic events as they happen, they don’t have the research published in journals available to them that tells them if the climatic event is human caused or natural caused. Such research only gets published years after the event. Many NWS offices have chosen to take the conservative approach in this area to preserve credibility and trust rather than in enguaging in non-peer reviewed speculation on the causes of climatic events.

    Comment by VirgilM — 28 Dec 2007 @ 1:36 PM

  31. “However, when all the data are telling you anthropogenic CO2 is behind the warming…”

    Does it? A rise in sea-level is just that – a rise in sea-level. It can be measured and it can be broken down to various contributions by further investigation. The frequency of the closing of some human controlled barrier surely does not even remotely clarify whether there is a rise in sea-level, let alone that it’s cause lies in the warming of our planet and even less so when it comes to the question of what caused this warming. You don’t have to be a denialist to see that you can stretch an argument only so far.

    Comment by henning — 28 Dec 2007 @ 1:52 PM

  32. Pete, I don’t doubt that Peak Oil will be a factor, but it will be short term. I have greate faith in human ingenuity. I’ve seen it work time and again–mostly digging us deeper and deeper into a hole. Peak oil means there’s more incentive to find new ways to use other energy resources. Now those resources could be renewables, or they could be coal, and clathrates and nukes, etc. Indeed, there may be only a tiny difference in cost between them. But that tiny cost multiplied by billions of consumers will make somebody very, very rich.
    Look at India. When the wood was gone, they went further and go more wood. When that was gone, they used the stubble from their fields. Now they use animal dung. There’s a whole industry processing animal dung for use in cook stoves. Economics doesn’t stop when things get expensive, or even when things are used up. It goes on as long as there are sufficient resources to support life–just like bacteria in a bottle.

    Comment by Ray Ladbury — 28 Dec 2007 @ 2:21 PM

  33. Henning, Yes, a rise in sea level says little in and of itself. However, if a theory predicts a priori that sea levels will rise, the rise is evidence that favors that theory over those that predict no rise or falling sea levels. Moreover, if the theory predicts the rise quantitatively within errors, the support for the theory is stronger.
    Similar arguments apply to melting glaciers and sea ice. Likewise if one model predicts that night-time temperatures will see greater effects than daytime temperatures–that favors said model. You cannot look at an isolated result or line of reasoning. However, if you have lots of favor a particular theory moderately strongly, the result is no less convincing–and maybe moreso–than a single smoking gun.

    Comment by Ray Ladbury — 28 Dec 2007 @ 2:40 PM

  34. re: #28 peak Oil

    1) I recommend the recent paper by Kharecha & Hansen, “Implications of “peak oil” for atmospheric CO2 and climate”, which is submitted (so its name may change), but rather than talk about that here, perhaps RC might start a thread for it?

    2) As far as I can tell:

    a) IF that paper is reasonable.

    b) IF The Ayres+Warr work is reasonable, i.e., that GDP growth is more dependent on exergy = efficiency * energy-used than any other factor, i.e., the “Solow residual” isn’t jsut “technology”.

    c) THEN the idea held by many economists that one can defer climate change mitigation because people in 2100, 2200… will be much richer and they can do it (i.e., sometimes described a positive discount rate) … is seriously wrong.

    d) In particular, no matter how cheap an iPod with a Terabyte of memory gets, things that actually require energy in the real world won’t, especially when there’s effectively no petroleum left:
    – Water
    – Nitrogen-based fertilizer [natural gas]
    – Food (The Economist: “The End of Cheap Food a week or two ago)
    – Required transport of food & needed materials
    – Concrete & steel
    – Building dikes and sea-walls, earthmoving in general

    As economists would say, iPods are not substitutes for these goods. [Of course, we can get more efficient, we can electrify, use biofuels for the necessary transport, stretch the oil&gas longer (to avoid coal-to-liquid and burning a lot more coal), and maybe it won’t be worldwide depression, but it’s just hard to see how there is *not* going to be a negative discount rate during much of the next century.

    Anyway, the article mentioned above is very useful.

    Comment by John Mashey — 28 Dec 2007 @ 2:52 PM

  35. Oops, sorry, the URL for previous post was:

    Comment by John Mashey — 28 Dec 2007 @ 3:04 PM

  36. Re 22: the Eastern Schelde Barrier in the Netherlands may be interesting to look at, as it is a cleaner example (and a longer time base)

    Not interesting (sorry). Had a quick look, see: Wiki NL”

    Construction finished in 26 june 1986.
    Number of closures period 1986-1995: 13.
    Number in period 1996 – 2007: 5.
    (Counting two closures on same day, or following day as one.)

    Also in this case weather is dominant. Climate change is (still) of minor impact. Only a few cm SLR in this period.

    Comment by Hans Kiesewetter — 28 Dec 2007 @ 3:13 PM

  37. There is quite a bit of discussion in RC comments about short vs. long term trends. Mostly with persons cherry picking short term data to justify arguments against long term climate modeling. Can someone answer at what durations could temperature observations contrary to predictions begin to represent real issues? For example SST.

    Comment by Tom M — 28 Dec 2007 @ 3:52 PM

  38. Actually temperatures dont necessarily get through to people like other markers do. But it seems people in these cities do get the point. This website lists the greenest cities in the US. This shows that municipalities care about climate change. I guess the general population cares about the environment and global warming. My score on their calculator was 400 but at least I am trying. Here is the link to the website that published the list of cites and where the carbon calculator can be found: The test took me like 5 minutes tops, and then maybe another 2 minutes to find the pledges I wanted. Pretty cool application.

    Comment by Stu1211 — 28 Dec 2007 @ 3:56 PM

  39. On a different note, I found this article ( listing the greenest cities in the US. This shows that municipalities care about climate change. I guess the general population cares about the environment and global warming. My score on their calculator was 400 but at least I am trying. Here is the link to the website that published the list of cites and where the carbon calculator can be found: The test took me like 5 minutes tops, and then maybe another 2 minutes to find the pledges I wanted. Pretty cool application.

    Comment by Stu1211 — 28 Dec 2007 @ 3:57 PM

  40. Britain’s CRU data show the following. Global temperature in Nov 2007 was 0.22 degrees colder than in Nov 1997. Warming peaked in 1998. Granted that year was unusually hot, 2006 was still cooler than 2002,2003,2004 and 2005 . This year 2007 is going to end up cooler than 2006. During this period CO2 rose by >5%. There has been no net warming during this 10 year period.
    Many investigators conclude that the sun is the main climate driver and that we may be entering a cooling period for the next 20 years and perhaps until mid century.
    I would like to pose a serious multiple choice question to the Realclimate people. How many more years of rising CO2 and flat or falling temperatures would it take to make y’all begin to question the Anthropgenic CO2 – warming paradigm? A 2, B 3, C 5,D 10 E 15.
    I would seriously like to hear your considered response to this question Regards Norman Page.

    [Response: How many times do we need to say that short term trends are too noisy and cherry picking start dates is a no-no? CRU trends are all positive for this period, but they are noisy. 1998-2007 (crutem3v) is 0.12+/- 0.3 C/dec. Note the error bar. Why is this so hard to do for your self? – gavin]

    Comment by Norman Page — 28 Dec 2007 @ 5:07 PM

  41. I think indisputable effects of sea level rise are only a few years away. For example a nearby fresh water intake to a pumping station is about 20km from a river mouth. Recent salt water incursions have come within a kilometre or so. When they have to move the intake further upstream there can be little doubt.

    Some concrete walkways at boat marinas are barely a centimetre or two above mild surge levels; they will have to be rebuilt.

    Comment by Johnno — 28 Dec 2007 @ 5:11 PM

  42. Gavin. I really would like a response to the question I posed.I will rephrase it.By what year would you reconsider the CO2 – Warming paradigm if the CRU Global annual mean temperature is cooler than 2005 – 2009, 2010 2012 ,2017 or 2022.?
    Regards Norman Page

    [Response: Long term trends from the forcing are expected to be around 0.2 – 0.3 deg/decade. Therefore you need to be able to get uncertainties down to well below those values in order to find a clear discrepancy. Judging from the last thirty years, that period is around a decade. All trends starting before 1996 are unambiguously positive and significant. But so is starting from 1999 or 2000 – 0.31+/-0.22 and 0.34+/-0.29 (95% confidence). Therefore the only significant trends you can find are spot on projections. Even the non-sig trends are still positive and with uncertainties that encompass the predictions. We would start to worry if that didn’t stay true, but there is no sign of it. It’s never going to be about a single month or a single year. You need a greater than a decade non-trend that is significantly different from projections. Going from the numbers recently, that isn’t even plausible in the next 5 years (and I don’t consider it likely at all). – gavin]

    Comment by Norman Page — 28 Dec 2007 @ 6:09 PM

  43. Re #33

    The important part is make the predictions before searching for the evidence, the more odd the better.

    For instance, because of the indirect and nonlinear nature of climate/weather, I as an amateur that does not know better, thinks it is pretty obvious that ‘necessary but not sufficient’ single event teleconnections does not exist.

    Comment by per — 28 Dec 2007 @ 6:34 PM

  44. Re #33, you misunderstand me Ray. Peak oil will make us forget climate change. So many things are made from oil, it will depress our first world economy far too much. We may however create plastics from something else or find additional oil reserves but soon that AGW comes the economic crash or peak oil.

    Comment by pete best — 28 Dec 2007 @ 7:12 PM

  45. pete best (44) — There are already bioplastic products on the market. More coming soon. So I deeply doubt that lack of petrochemical feedstocks will ever be an issue.

    Comment by David B. Benson — 28 Dec 2007 @ 7:30 PM

  46. Rick #15 if you are talking about NYC the Central Park weater station is in a shaded grove protected from wind. is a picture. The station is maintained in this location because the NWS does not want to break a long historical series

    Comment by Eli Rabett — 28 Dec 2007 @ 10:03 PM

  47. Gavin:

    You write at comment 42:

    “You need a greater than a decade non-trend that is significantly different from projections.”

    OK, lets start with 1998. There is a significant cooling over the past 10 years:

    You suggest that trends from 1999 are appropriate to interpret, how about 1998?

    [Response: Oh please. Almost by definition, if you only get a negative trend by picking one specific start date that means that the trend will not be significant. Plus, all the surface records even have positive (non-significant) trends, even starting from then. The issue is significance . – gavin]

    Comment by Daniel Klein — 29 Dec 2007 @ 1:17 AM

  48. RE46 Since “Eli Rabett” is fond of referencing a picture of the NYC weather station, but didn’t actually have one to share, I thought I’d help him out by offering these pictures:

    Comment by Anthony Watts — 29 Dec 2007 @ 3:00 AM

  49. Re #45, I doubt that they scale as yet. It is all about scale and I would imagine that Oil provides nearly 100% of the volume required for all plastics and petrochemicals.

    It is early days for all alternatives to oil such is its grip on the market.

    In fact recent work by a caltech professor seems to demonstrate that peak fossil fuels will become an issue much sooner that climate change becomes one. Although both are linked to alternative sustainable energy sources, there is still a huge gap between what people propose and reality.

    Comment by pete best — 29 Dec 2007 @ 5:19 AM

  50. #36 thanks!

    Construction finished in 26 june 1986.
    Number of closures period 1986-1995: 13.
    Number in period 1996 – 2007: 5.
    (Counting two closures on same day, or following day as one.)

    So using a cleaner data source than London gives a null result :-)

    Not only is the closure data very noisy due to the weather, it is also not properly reduced for, e.g., the lunar declinational tide (saros period, 18.03 a) and who knows what. Sounds like a hopeless exercise.

    I calculated for the heck of it the percentage of closures where the “trigger” of 3.00 m over NAP actually materialized. 69% and 70%, respectively, for both periods. Doesn’t seem they are getting any better at predicting…

    Comment by Martin Vermeer — 29 Dec 2007 @ 5:53 AM

  51. Re Gavin in 42: “Even the non-sig trends are still positive and with uncertainties that encompass the predictions. We would start to worry if that didn’t stay true…”

    Again, I have a question about the emotional side of this: Why would you “worry”, if temperature trends would change their sign? Is it because you like global warming an sich, or because you have invested so much intellectual capital in the warming scenario?

    [Response: Don’t be ridiculous, no-one wants this to be happening. We are always worried that we might be missing something in our understanding, but that is complete separate from my worries about what it all means. – gavin]

    Comment by Dodo — 29 Dec 2007 @ 7:00 AM

  52. Norman Page writes:

    [[Warming peaked in 1998.]]

    1998 was the hottest El Nino year on record. The trend is still up, not down or flat.

    [[ Granted that year was unusually hot, 2006 was still cooler than 2002,2003,2004 and 2005 . This year 2007 is going to end up cooler than 2006. During this period CO2 rose by >5%. There has been no net warming during this 10 year period.]]

    You don’t know how to do a linear regression, do you?

    [[Many investigators conclude that the sun is the main climate driver and that we may be entering a cooling period for the next 20 years and perhaps until mid century.]]

    The sun is not the main climate CHANGE driver because it hasn’t put out significantly more or less sunlight in 50 years. And nobody can accurately forecast what the sun will do in the future.

    [[I would like to pose a serious multiple choice question to the Realclimate people. How many more years of rising CO2 and flat or falling temperatures would it take to make y’all begin to question the Anthropgenic CO2 – warming paradigm? A 2, B 3, C 5,D 10 E 15.]]

    How many years would it take for you to question relativity, evolution, or the theory of gravitation? Carbon dioxide was shown to be a greenhouse gas back in 1859, by John Tyndall. The “Anthropgenic [sic] CO2 – warming paradigm” isn’t based on temperature trends, it’s based on radiation physics.

    Comment by Barton Paul Levenson — 29 Dec 2007 @ 7:01 AM

  53. Pete Best,
    Oh I agree that we’ll forget about climate change in our quest to keep our economy distorted by cheap energy. We will spend trillions of dollars trying to develop alternative energy sources so that I can buy tropical fruits more cheaply than local produce. The thing is, I think we will largely succeed. Not that we may not have some rather difficult and tense times for awhile. Golly, we might even have to raise fuel efficiencies an mpg or two as the (not so) Big 3 wail and gnash their teeth. But there is lots of fossil fuel out there, and it is owned by powerful interests, and it will be competitive with renewables, and people will panic about Peak Oil. Then we’ll have business as usual until A)all the fossil carbon is back in the atmosphere and we are back to Jurassic atmosphere, or B)it becomes obvious to even the most blinkered, self-interested, complacent food tube (since this seems to be who we elect) that we are altering the climate to our detriment. Alternative B) above would take something like a yearly visitation of a Cat 5 hurricane to Boston for a decade.

    I have tremendous faith in human ingenuity to confront and solve the problems we face immediately. I have zero faith in our wisdom to prioritize and look at resolving the problems we will face a decade or so hence.

    Comment by Ray Ladbury — 29 Dec 2007 @ 7:34 AM

  54. Norman Page, If the Sun dims (as it may, slightly), of course temperatures will not rise as quickly as they might otherwise. And if China spews gigatons of aerosols into the air, that too may slow warming for awhile. However, the solar output will increase eventually–on a timescale of decades. Aerosols will rain out of the skies eventually. And greenhouse gasses will still be there trapping IR radiation, and warming will return with a vengeance. CO2 stays in the atmosphere for hundreds to thousands of years.
    You contend warming has stopped. Yet we still see ice melting in record volumes in Greenland, the WAIS, and in the Arctic. That doesn’t sound like a cooling world to me. Norman, if you get past all the mechanisms and talk of blackbody and greybody radiation, the physics comes down to conservation of energy. Increasing greenhouse gasses decreases the energy that leaves the planet. That energy has to warm things up. I’m afaid it will take a lot of evidence before I give up on conservation of energy.

    Comment by Ray Ladbury — 29 Dec 2007 @ 8:07 AM

  55. There are already bioplastic products on the market. More coming soon. So I deeply doubt that lack of petrochemical feedstocks will ever be an issue.

    Unless of course we are unable to grow the necessary crops due to global ecological catastrophes resulting from the effects of climate change…

    Comment by Fernando Magyar — 29 Dec 2007 @ 8:54 AM

  56. Gavin: Are you sure about this comment you leave at number 47?

    “Plus, all the surface records even have positive (non-significant) trends, even starting from then [1998].”

    With 1998 remaining the record, and 2007 is the lowest since 2001 (UKMET) you certainly won’t have a positive trend (significant or not) in that record at least.

    While I agree with your comment that picking a single starting date is not good statistics, I am curious as to the meaning of your assertion, “You need a greater than a decade non-trend that is significantly different from projections.” One does need to start somewhere.

    Let me rephrase the question then. How long would it need to be for the 1998 record global temperature to not be exceeded (or if you prefer, a “non-trend” beginning at that date) for you worry that something has been missed in your understanding? 2010? 2015? 2020? 2030? A single year as an answer would be appreciated.

    I am simply curious and mean no disrespect with the question.

    [Response: Trends are not determined by picking two dates and looking at the difference. Trends instead are (usually) least squares fits to all the data – this is much more robust and why it is preferred to cherry-picking start dates. I’m pretty sure excel or other common software allows you calculate linear regressions and their uncertainty, and I suggest you find some software to try it out so that you can follow what is being discussed. 1998 was roughly 0.2 deg C above trend. If the trend is around 0.2 deg C/dec, that implies that the mean level about 10 years later would be expected to match. But the weather noise is about 0.1 deg C in any individual year and so you might need to wait awhile. Much of this is already moot though – although the differences are small, both 2005 and 2007 beat 1998 in the GISS and NOAA analyses, more importantly, the more robust longer term averages (say over 5 years) are still increasing. To answer your question though, 1998 will likely be exceeded in all the indices within the next five years – the solar cycle upswing into the next solar max will help, and the next big El Nino will probably put it over the edge. -gavin]

    Comment by Daniel Klein — 29 Dec 2007 @ 10:54 AM

  57. OK, simply to clarify what I’ve heard from you.

    (1) If 1998 is not exceeded in all global temperature indices by 2013, you’ll be worried about state of understanding

    (2) In general, any year’s global temperature that is “on trend” should be exceeded within 5 years (when size of trend exceeds “weather noise”)

    (3) Any ten-year period or more with no increasing trend in global average temperature is reason for worry about state of understandings

    I am curious as to whether there are other simple variables that can be looked at unambiguously in terms of their behaviour over coming years that might allow for such explicit quantitative tests of understanding?

    [Response: 1) yes, 2) probably, I’d need to do some checking, 3) No. There is no iron rule of climate that says that any ten year period must have a positive trend. The expectation of any particular time period depends on the forcings that are going on. If there is a big volcanic event, then the expectation is that there will be a cooling, if GHGs are increasing, then we expect a warming etc. The point of any comparison is to compare the modelled expectation with reality – right now, the modelled expectation is for trends in the range of 0.2 to 0.3 deg/decade and so that’s the target. In any other period it depends on what the forcings are. – gavin]

    Comment by Daniel Klein — 29 Dec 2007 @ 11:40 AM

  58. Bush finally warms to warming

    At end of term, in search of a greener legacy, president highlights warming

    By Peter Baker
    Friday, Dec. 28, 2007

    …For years, Bush bristled privately at what he considered sky-is-falling alarmism by the liberal, elitist Hollywood crowd. The clatter over climate change, according to friends and advisers, seemed to him more like a political agenda than a rational response to known facts. But ever so gradually, they say, Bush’s views have evolved. He has found the science increasingly persuasive and believes more needs to be done, especially after a set of secret briefings last winter. A former aide said Bush’s staff even developed models for a market-based cap on greenhouse emissions.

    Comment by Jim Galasyn — 29 Dec 2007 @ 12:54 PM

  59. Re #42: [By what year would you reconsider the CO2 – Warming paradigm if the CRU Global annual mean temperature is cooler than 2005 – 2009, 2010 2012 ,2017 or 2022.?]

    In fairness, it seems that you should also answer the converse question: how many more years of rising temperatures matching model predictions (when all factors such as aerosols, volcanic erruptions, and the like are included) would it take before you’ll consider that the theory does represent the real world?

    Comment by James — 29 Dec 2007 @ 1:13 PM

  60. Re: #40 (Norman Page)

    “How many more years of rising CO2 and flat or falling temperatures would it take to make y’all begin to question the Anthropgenic CO2”

    and the answers to it by Gavin and

    # 52 (Barton Paul Levenson)

    which I agree with completely.

    Trivial point.
    In view of #52 and Gavins’s reply we have to take Norman Page’s question as a hypothetical one rather than one based on the evidence so far. In that case the question should not be dismissed. The simple answer might be that the theory would have been falsified and goodness knows what might be wrong. That is what the Popperians claim could happen to any scientific idea.

    Non-trivial question.
    Some time ago I read a paper by Schlesinger and Andronova which I seem to have lost. It was about unforced fluctuations (cycles) of various kinds. The summary which is at

    includes the headline

    “Protracted cooling could camouflage effects of global warming”

    Is this relevant? Could it be relevant to the answer to #40?

    Comment by Geoff Wexler — 29 Dec 2007 @ 1:41 PM

  61. re: #56, #57 Daniel

    In Excel:
    SLOPE gives you the simple linear regression slope.
    LINEST gives you the statistical measures.

    Comment by John Mashey — 29 Dec 2007 @ 4:26 PM

  62. Do we – that is scientists – have a handle on the worst case rate of sea level rise. It seems clear that the science regarding melting of the Greenland and West Antarctic ice caps is still at an early stage, and that recent melting has been somewhat faster than predicted – predictions were essential based on thermal conduction models. Melting in fact seems to be accelerating.

    Based on the following figures sea level at times rose by 20cm to 30cm per decade (20-30metres per millenium) during the Holocene:

    Is this the worst we can expect?

    I have seen estimates (I can’t remember where) of rates of sea level rise of 1 metre per decade. Such a rate would make adaptation challenging to say the least.

    Is it possible to place an upper limit on sea level rise (other than 70 metres by next Tuesday)?

    Comment by Bruce Tabor — 30 Dec 2007 @ 7:16 AM

  63. General: Again, a single example has many complicating factors: storm surge, tide, periodic increases in rainfall, etc.

    40 & 56: Using 1998 as a starting point for trending recent temperatures might be cherry-picking, since 1998 was an El Nino year, but 2006 was also an El Nino year and there’s still a downward trend.

    Using the late 1970s as a starting point for a trend is cherry-picking, too, as it absorbs the AMO and PDO shifts into the equation.

    52: Another way to phrase it: The sun drives climate; it does not drive AGW.

    Enjoy the New Year.

    Comment by Bob Tisdale — 30 Dec 2007 @ 7:42 AM

  64. Gavin in 51: “We are always worried that we might be missing something in our understanding, but that is complete separate from my worries about what it all means.”

    I’m sorry for the sarcastic tone in my question. I just think it is not wise to attach much emotion into the success or failure of predictions. But then again, maybe it belongs to the scientific endeavor: understanding nature is a fine motive, but clearly second to the urge to belong to the group that was right.

    Thanks for the 1998-2012 prediction you made in comment 56. I’m sure it will be remembered. Let’s all hope (dispassionately) that Gavin and the whole RC group are indeed missing something.

    Comment by Dodo — 30 Dec 2007 @ 7:49 AM

  65. Dodo, I think that it may be you and others that are missing something. The greenhouse effect is established physics. The radiative behavior of ghgs is established physics. Even if we were to find some glaring omission in the models, it is unlikely that our understanding of the greenhouse role in climate models would be significantly changed. And since CO2 is the gift that keeps on giving–for centuries–in climate, at best this would delay the problem (a welcome event to be sure) rather than negate it.
    Indeed, the only way I could see out of this problem would be for there to be some sort of negative feedback that has not been taken into account, and the paleoclimate and other lines of inquiry provide no evidence for this. There simply is not much cause for hope that this problem will go away.

    Comment by Ray Ladbury — 30 Dec 2007 @ 11:39 AM

  66. VirgilM (in comment #30) made comments about the 1993 Midwest Flood.

    However the main point brought out in comment #5 was that the U.S. National Weather Service downplayed and kept climate change and global warming out of the U.S. local and national U.S. news for more than 13 years by their refusing to allow it to be discussed.

    Global warming was a serious concern to many scientists in before 1993, during 1993 and after. NWS staffers have had free access to climate and hydrologic records but NWS management forbid it’s staffers from using those records to tract regional changes in temperature and snowmelt runoff.

    NWS management downplaying and refusal to allow staffer research on climate and hydrologic change was severe, mainly behind the public eye. Although NWS staffers who spoke out skeptically on climate change and global warming were not punished the staffers who did the research and who tried to show their findings that regional climate and hydrologic changes were happening were punished severely.

    Comment by pat n — 30 Dec 2007 @ 3:46 PM

  67. Getting back to the Thames barrier, I’m wondering if as scientists, the authors have sought detailed data with regard to the changed maintenance schedules for the barrier. There was a news item in the London press earlier this year about how the barrier had been raised more frequently, and how it had been linked to ‘Global Warming’ being an indicator of rising sea levels. An unscientific independent individual asked the operators of the barrier for comment on the increased raising of the barrier. They were able to explain it as implementation of a new maintenance policy only. Real Mechanics.

    [Response: source? -gavin]

    Comment by Derek — 31 Dec 2007 @ 3:21 AM

  68. Bob Tisdale posts:

    [[Using 1998 as a starting point for trending recent temperatures might be cherry-picking, since 1998 was an El Nino year, but 2006 was also an El Nino year and there’s still a downward trend. ]]

    There is not a downward trend:

    Comment by Barton Paul Levenson — 31 Dec 2007 @ 6:00 AM

  69. In #67 Derek Said “Getting back to the Thames barrier,” …

    However, the discussion in #66 about the 1993 Midwest Flood, which broke historical record crests by 5-6 feet after the levees failed may indeed be pertinent to Thames River flood frequencies and other flooding events involving heavy runoff from rainfall from the mid 1970s to recent, as part of a larger trend in mid-latitude Northern Hemisphere flooding due to increasing rainfall intensity.

    For example, rainfall driven flooding in the Midwest from the mid-1970s to recent included:

    a.) mid-late 1970s flooding:
    Big Thompson River (near Estes Park, CO), Brush Creek (Kansas City, MO), Red River (Grand Forks, ND)

    b.) 1980s flooding:
    Sagninaw river (central Michigan), Mississippi River (Missouri, Illinois), flash flooding in east central Minnesota (Twin Cities), Red River (Breckenridge, MN)

    C.) 1990s flooding: Great Mississippi River basin Midwest Flood, Midwest (MN, WI, IA, IL, IN, NE, KS, MO), 1997 Red River Flood (SD, ND, MN and Manitoba), 1999 Devil Lake (ND)

    D.) 2000-2007 flooding: 2001 Upper Mississippi River flood (MN, WI, IA, IL), 2002 Illinois River flood, 2004 Illinois R basin (WI, IL), 2005 Illinois River January Flood, 2007 Upper Midwest Flash Flood (southeast MN, southwest WI).

    From the article above (A barrier to understanding?) … “Is this a sign of increased sea level, increased storminess, increased river flow, or changes in river management policy?”

    The Midwest has shown a trend in recent decades of increased storminess and increased river flow. Not having Thames river flow data back 100 years, I’m not able to comment specifically on Thames runoff. I have seen flow data for the last 100 years for several major rivers in the Upper Midwest which shows increasing runoff. Massive widespread levee failures and minimal changes in land use over the majority of the drainage areas indicate the increased flooding is being driven by climate change. The culprit is increasing rainfall intensity with increasing soil erosion.


    Heavy rainfall events on the increase, advocacy group says
    John Myers, Duluth News Tribune
    Published Wednesday, December 05, 2007

    … “Instead of slowly soaking into the ground to recharge groundwater,
    streams and lakes, downpours tend to wash off the land, bringing
    sediment into streams and lakes and reducing benefits to the land.

    Frequency of Extreme Rain Up 24% in U.S.

    Comment by pat n — 31 Dec 2007 @ 1:08 PM

  70. pat n,

    I grew up in one of the areas you talk about – NE South Dakota. In the 1990s, I think last half, they experienced widespread ponding in low areas of fields. Many farms lost a great deal of land for the entire growing season. The state lost a lot trees to water damage. There was a French trading post along the James SE of our home where I used to hunt as a kid. It had huge trees. Almost all of them died in the continual flooding.

    Most of those ponds have since dried up.

    Comment by JCH — 31 Dec 2007 @ 1:35 PM

  71. JCH,

    Thanks for reminding me of that. Severe flooding occurred in 1997 in both the James River basin in SD and the Red River basin in ND/MN in 1997, from snowmelt and rainfall runoff. Runoff from snowmelt and rain froze up by a cold spell in late March, then all H. broke loose with a rapid warm-up combined with additional heavy rainfall in April.

    Regions in Greenland and Antarctic will experience similar episodes of lull and gush of flows with ice break-up, as happened when Lake Agassiz, Pleistocene epoch, gave way.

    Comment by pat n — 31 Dec 2007 @ 2:18 PM

  72. Regarding feedbacks. (65)
    I don’t believe the paleo record really explains whether the current pattern will or will not generate negative or positive feedbacks or none at all. Something like a significant, positive feedback seems unlikely because climate never really warmed through the roof like you’d expect if there was a runaway effect – but of course nothing in the paleo record can really be compared with what we’ve got here today. From my (climate) layman perspecitive, the long-term temperature record rather points towards positive feedbacks and a small reversal sensitivity on cooling and no feedbacks plus a bigger reversal sensitivity on warming – but the curves I usually look at describe mechanics, not temperatures.

    Comment by henning — 31 Dec 2007 @ 3:13 PM

  73. Ref: Message 67, and hopefully supply Gavin with a little more:

    I believe there has been a change of policy on maintenance schedules, though at present I am unable to locate an exact reference. However;
    There is an exchange between the Government’s scientific advisor Dr David King and Joan Ruddock in the House on 25th October 2004:

    Q272 Joan Ruddock: “I was going to ask a number of things about sewers and flash flooding and all those sorts of jolly items, but I think you have touched on a number of the things that I might have asked. You said in a previous answer that it was not the case of another Thames Barrier. As a London Member, could I ask you just on that specific issue? The GLA told me that the barrier had been raised 19 times in January? This sounds to be a really grave problem and we of course had those amazing scenes in Dulwich recently of tremendous flooding there which occurred very, very suddenly. Can you say something specifically about London? Again, you indicated that there is a range of possible measures; what are the measures you think that we need and why is it not a second Thames Barrier?”

    Professor Sir David King: “The first thing to say is that the use of the flood barrier is an indication of the influences of global warming. However, we have to be careful to distinguish the uses in anger, that is to prevent flooding— ”

    Q273 Joan Ruddock: “I thought you meant there was a difference of degree.”

    Professor Sir David King: “. . . from the attempts to see what happens if we store up water. So they have been doing a lot of work in the Thames Barrier, raising the barrier for other reasons than risk reduction. So the figure I gave you of around six or seven times a year is a better indication of how things have got worse; but, remember, it used to be once every five years, so it is a 30-fold increase in use to prevent flooding. One flood, £30 billion worth of damage to London, the damage to the economy considerably greater; we would anticipate flooding the Underground, we would anticipate losing a few power stations. So it would be very, very severe. We are, through the Environment Agency, maintaining the barrier quite well, Chairman. I have not really answered the question fully nor would I be able to in the time. London obviously is a point of focus. The Environment Agency is starting a new study of the Thames Barrier with a view to updating the defences provided by the barrier out to the year 2030. It is my understanding, but we will be waiting to see with interest the results and outcomes of their study, that the barrier is good to 2020. It is a wonderful piece of civil engineering, it is also such an attractive piece of architectural engineering, and it really is a matter of British pride that that barrier has worked without fail on every flood occasion. We can anticipate that small adaptations to the barrier will allow us to extrapolate forward to 2020. There will have to be added flood defences around the barrier over that period of time, but all of this can be done. Extending it beyond that period will take a substantial piece of civil engineering and planning.”

    [Please note: J Ruddock stated that the Greater London Authority (GLA) advised her the barrier had been raised 19 times in January. The following table shows the barriers closing frequencies. For the year 2004 it was 1. Also, Sir David has made errors before]

    Mr. Drew: “To ask the Secretary of State for Environment, Food and Rural Affairs how many times the Thames Barrier has been closed in each year since its construction.”

    Mr. Morley [holding answer 18 October 2004]: “The Thames Barrier has been closed as following since it was first used in February 1983”:

    [I’m afraid this table may not transfer clearly – first column is year; second closures against tide; third, closures for fluvial retention; last, total].

    Tidal. Fluvially dominated. Total.

    1983 1 0 1
    1984 0 0 0
    1985 0 1 1
    1986 0 0 0
    1987 1 0 1
    1988 1 0 1
    1989 0 0 0
    1990 3 3 6
    1991 0 0 0
    1992 1 0 1
    1993 5 4 9
    1994 1 0 1
    1995 3 2 5
    1996 4 0 4
    1997 0 0 0
    1998 3 0 3
    1999 3 3 6
    2000 6 4 10
    2001 11 4 15
    2002 2 2 4
    2003 8 11 19
    2004 1 0 1
    Total 54 34 88

    Actual closure dates are available on the Environment Agency’s website,.

    The reference to “tidal” closures are where the barrier was closed to prevent flooding or overtopping of the defences upstream of the barrier.

    The “fluvially dominated” closures refer to occasions where closing the barrier has stopped the tide and allowed unhindered fluvial/rainfall flow to continue over Teddington Weir, which has thereby reduced the risk of flooding just upstream of the weir. [Therby leaving the reach between Teddington and the barrier as a temporary reservoir].

    My previous comment on the number of closures for maintenance, stems from a BBC Radio 4 program broadcast in January 2007:
    Simon Cox and Richard Vadon, BBC Radio 4, ‘The Investigation of the Stern Report’ BBC radio 4, 20:00 25th Jan. 2007.

    In the program, it was stated that the Thames barrier had to be raised 55 times in the past five years, as opposed to 12 times in the previous five years, supposedly indicating the ever increasing threat of raised tide levels associated with ‘Global warming’. The investigator then visited the barrier and interviewed the man in charge. They had been raised 31 times in the last five years, and 35 in the previous five, he claimed no knowledge of where the other figures may have come from.

    It is known that the barrier is raised on a monthly basis for test purposes. It is not known if the figure of 55 is including these or not. Currently, the barrier has been raised for the 100th time according to the Environmental Agencies website

    During November 2007, the barrier was raised three times (it is raised on average 5 times a year).


    It should also be noted, and I quote from the ‘Thames Barrier Project Pack’ :-

    In London, records show that the high water level at London Bridge has risen by about 75cm each century.
    Locally, the British Isles is tilting towards Europe, causing the south of England to sink at an estimated rate of 30cm per century. This is a natural geological process, also contributing to rising river levels in the Thames.

    [Response: I don’t think the definition for the ‘tidal’ and ‘fluvial’ accords with what I was told more recently. The ‘fluvial’ closings are when the river flow over Teddington weir is a dominant factor in deciding whether the tide will cause flooding or not. In times of very strong river flow, the tides at Southend don’t need to be particularly high to potentially cause problems. The definition you quote from makes no sense – levels upstream from Teddington are not affected by tides. None of the stats in your table or in the linked file in my post include test raisings. I’ll make a guess as to where the quoted numbers come from. I suggest there was either a) a confusion of the term ‘five year’ closings (it was 55 in 2000-2005 (combined causes) which is six years, not five), or b) they were thinking about winter seasons (ie. fall 2001 to spring 2006) which had 56 closings. The previous five years in the first case had 18 from 1995-1999, or 14 in the previous 5 winter seasons. The alternate numbers are also supportable: total closings are 31 for the calendar years 2002-2006, and 34 in the previous 5 calendar years. The big change is because of 2001 was the standout year, mainly because very strong river flow. The total for calendar year 2007 is 11 closings (I think). I think this just demonstrates the potential for end-year effects in short and very noisy data series. The longer term trends are however clear – what isn’t clear is attribution, not the increases in use. – gavin]

    Comment by Derek — 31 Dec 2007 @ 4:09 PM

  74. Mr Neuman…Re #66…

    First off, congratulations on all the awards you received as an employee of a NWS River Forecast Center. Hydrology is not simple in Minnesota and Eastern North Dakota and there have been some challenging events during your career.

    I am going to quote one statement that your NWS bosses deleted from your proposed statement to issue to the public on March 23, 2000…

    “Lowering of the lake level for Devils Lake, North Dakota – Due to reduced length of time that the lake is ice covered, each year – with increased late fall and winter open water evaporation.”

    That is quite the bold prediction. How has the level of Devils Lake done since 2000?

    Historical Crests
    (1) 1449.20 ft on 05/09/2006
    (2) 1449.18 ft on 06/17/2004
    (3) 1449.17 ft on 08/02/2005
    (4) 1448.92 ft on 03/05/2005
    (5) 1448.01 ft on 08/09/2001
    (5) 1448.01 ft on 07/22/2001
    (7) 1447.56 ft on 07/17/2002
    (8) 1447.52 ft on 05/19/2003
    (9) 1447.48 ft on 07/11/2002
    (9) 1447.48 ft on 07/10/2002

    It has been seven years, since you made this prediction. Granted, you may be eventually right, but the people who live near Devils Lake wouldn’t think you have any credibility given that the levels of Devils Lake have hit record or near record highs each of the last 6 years. Many NWS offices are wise in not wading in the climate change waters too deeply. The NWS wants the public to trust them, instead of enguaging in wild speculation.

    From experience, I know that Eastern Montana climate has its roots in the equatorial pacific. ENSO, MJOs, and so forth. Even typhons that track north by Japan into the Aleutians changes the weather patterns over Montana. The latest IPCC report admits that the models are split on the ENSO trend. If it is towards La Nina, then Montana will see more drought. If it is towards El Nino, then Montana will see more wet periods. Hell, another climate paradigm could evolove over the Pacific that changes how El Nino and La Nina affects weather patterns over the west. The NWS office in my area doesn’t want to speculate on this topic. Isn’t okay to say “I don’t know?” The NWS can and should present to the public what has happened in the past in terms of drought and floods and encourage stakeholders to prepare in advance.

    Comment by VirgilM — 1 Jan 2008 @ 1:01 AM

  75. Re #73,
    I cannot comment on what definition you have of tidal or fluvial, as it is not given.

    The mention of tidal and fluvial in my text was a quote from the then Minister from the Hansard in 2004. More recently, January 2007, Ian Pearson – Minister for Climate Change and Environmental Agency – stated (Hansard ):

    “At present the Thames Barrier is closed on average three to four times a year. In extreme conditions more frequent closures have been necessary to protect London from flooding—such as during the winter of 2000-01, when the barrier was closed 24 times and January 2003, when it was closed 19 times. These unusual occurrences were generally the result of continued high freshwater flows which only required a smaller tidal surge to necessitate a closure of the barrier.”

    So, 19 it was in the space of one month, but note the reasons in the last sentence above. It is not widely realised that a river in full spate has a considerable gradient between weirs, and any obstruction or impediment to flow will cause levels up-stream to be higher. It is for this fluvial reason that the barrier is raised under such circumstances, even against moderate tides, enabling the run-off more room between Teddington and Gallions Reach in which to flow.

    Comment by Derek — 1 Jan 2008 @ 7:43 AM

  76. Henning,#72 says “I don’t believe the paleo record really explains whether the current pattern will or will not generate negative or positive feedbacks or none at all.”

    Actually, we know that there are significant positive feedbacks having to do with planetary albedo (melting of ice and snow, changes in vegetation) and release of more greenhouse gasses. The latter in particular are a serious concern in that they take away from us the only real handle we have on limiting the warming that does occur. Keep in mind that we are at CO2 levels that have not been seen in at least 800000 years, and quite possibly many millions of years (after all, that carbon has been sequestered in that coal and oil a long time). And we show no sign of seriously modifying our behavior.

    Comment by Ray Ladbury — 1 Jan 2008 @ 8:38 AM

  77. Re Thames Barrier

    Thames Barrier frequency of use no longer a useful indcation of climate change

    [Response: This is what I linked above and pointed out it was confused. – gavin]

    Comment by JAC — 1 Jan 2008 @ 9:40 AM

  78. Midwest flooding, if the Missouri is representative, doesn’t seem to be significantly worse or even as bad since 1970 as it was earlier before GW “showed up”. Only 1993 surpassed a near half-dozen floods since mid-1800s, and there’s a difference of opinion of whether 1993 was worse than 1952. It seems much statistics about nothing.

    Comment by Rod B — 1 Jan 2008 @ 3:25 PM

  79. Rod B. said “if the Missouri is representative, doesn’t seem to be significantly worse or even as bad since 1970 as it was earlier before GW “showed up””

    A mighty big “if” Rod. The West where the Missouri begins has been suffering from a severe drought during much of the past decade or so. Also keep in mind that many towns were rebuilt further from the river.

    Comment by Ray Ladbury — 1 Jan 2008 @ 5:52 PM

  80. > midwest flooding over time

    Did you account for the wetlands zoning keeping development out of some floodplains, and on the work of the Corps of Engineers?

    If that’s hard to do, it might be useful to look for data sets on streamflow in undeveloped watersheds, and precipitation information of any sort that’s not likely changed by big flood control projects.

    One quick example, reading only the abstract, from a brief search, just to point out how the researchers approach this question:

    —begin excerpt——-
    … the amplitudes were particularly strong after 1980.

    Peak flow due to snowmelt, typically the highest flow in each year, appears to be the only streamflow statistic that has not changed at a significant rate. Peak flows due to rainfall events in the summer are increasing, as well as the number of days with higher flows (high flow days). Increases in low flow (base flow) in summer and in winter have been significant. Wetter summers and more frequent snow melt events due to warmer winters are the likely cause.

    Stream flows in Minnesota reflect observed changes in precipitation with increases in mean annual precipitation, a larger number of intense rainfall events, more days with precipitation and earlier and more frequent snowmelt events. For water resources management the results suggest that the threat of snowmelt flooding has not increased, but floods due to rainfall events are more likely….
    —–end excerpt——

    Comment by Hank Roberts — 1 Jan 2008 @ 6:04 PM

  81. More water data — declining levels in some of the Great Lakes:

    Comment by David B. Benson — 1 Jan 2008 @ 7:24 PM

  82. VirgilM mislead readers in his comment in #78 regarding the elevation of Devils Lake in ND, which feel from an annual peak level in June of 2007 (1447. 9 ft) to the current 1446.8 (0.6-0.7 ft below crest levels shown in his table from 2001-2006. The lowering of Devils Lake is indeed happening as is the lowering of the Great Lakes since 2000.

    Comment by Pat Neuman — 1 Jan 2008 @ 8:05 PM

  83. In the 1950s they began building several dams along the Missouri in the Dakotas. Among other things, they were intended to help control flooding. Most, if not all of them, were built after the 1951 flood, which held my mother’s new piano hostage in Kansas City.

    Comment by JCH — 1 Jan 2008 @ 8:57 PM

  84. This may have be linked already, but seems the latest estimates of sea stand rise during the Eemian interglacial:

    For those who don’t have access to this paper, here is the abstract:


    Nature Geoscience 1, 38 – 42 (2008)
    Published online: 16 December 2007 | doi:10.1038/ngeo.2007.28

    Subject Categories: Palaeoclimate and palaeoceanography | Oceanography
    High rates of sea-level rise during the last interglacial period

    E. J. Rohling1, K. Grant1, Ch. Hemleben2, M. Siddall3, B. A. A. Hoogakker4, M. Bolshaw1 & M. Kucera2

    The last interglacial period, Marine Isotope Stage (MIS) 5e, was characterized by global mean surface temperatures that were at least 2 °C warmer than present1. Mean sea level stood 4–6 m higher than modern sea level2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, with an important contribution from a reduction of the Greenland ice sheet1, 14. Although some fossil reef data indicate sea-level fluctuations of up to 10 m around the mean3, 4, 5, 6, 7, 8, 9, 11, so far it has not been possible to constrain the duration and rates of change of these shorter-term variations. Here, we use a combination of a continuous high-resolution sea-level record, based on the stable oxygen isotopes of planktonic foraminifera from the central Red Sea15, 16, 17, 18, and age constraints from coral data to estimate rates of sea-level change during MIS-5e. We find average rates of sea-level rise of 1.6 m per century. As global mean temperatures during MIS-5e were comparable to projections for future climate change under the influence of anthropogenic greenhouse-gas emissions19, 20, these observed rates of sea-level change inform the ongoing debate about high versus low rates of sea-level rise in the coming century21, 22.

    I posted a table from the supplimental information of this paper as commetn #122 on the Hot off the projector #3: Atmospheric CO2 to 800 kyr ago thread.

    Comment by David B. Benson — 1 Jan 2008 @ 9:18 PM

  85. is a study that shows changing channel conditions is probably the largest factor in recent increases in flood stages, for the Wide Mo. at least. But it could prove either way over time, I guess. I would simply suggest keeping an eye on (and mentioning it is certainly O.K.) but holding the gilding off loosey-goosey statistics to come up with a smoking-gun proof of GW.

    Comment by Rod B — 1 Jan 2008 @ 10:25 PM

  86. Rre # 81 David B Benson: Water levels in Lake Great Lakes

    A declining water level was predicted for Lake Erie over a year ago, and this could have some ecological benefits:

    U.S. Water News Online
    August 2006

    CLEVELAND — The newest update to a Lake Erie management plan predicts global warming will lead to a steep drop in water levels over the next 64 years, a change that could cause the lake’s surface area to shrink by up to 15 percent.

    The drop could undo years of shoreline abuse by allowing water to resume the natural coastal circulation that has become blocked by structures, experts said.

    Updated annually, the plan is required by the Great Lakes Water Quality Agreement between the United States and Canada. It is developed by the U.S. Environmental Protection Agency, Environment Canada and state and local governments with help from the shipping industry, sports-fishing operators, farm interests, academics and environmental organizations.

    The newest update addresses for the first time, when, where and how the shoreline will be reshaped. It says the water temperature of Lake Erie has increased by one degree since 1988 and predicts the lake’s level could fall about 34 inches. It also says the other Great Lakes will lose water.

    If the projections are accurate, Lake Erie would be reduced by one-sixth by late this century, exposing nearly 2,200 square miles of land and creating marshes, prairies, beaches and forests, researchers said.

    Researchers said new islands are appearing in the western basin, where Lake Erie is at its lowest and some reefs are about 2 feet below surface.

    “There is now stronger evidence than ever of human-induced climate change,” states the report, dated this spring. “Our climate is expected to continue to become warmer. This will result in significant reductions in lake level, exposing new shorelines and creating tremendous opportunities for large-scale restoration of highly valued habitats.”

    A predicted drop in water levels also has been addressed by the International Joint Commission, an American-Canadian panel that controls water discharges out of Lake Superior and the St. Lawrence River. The commission told scientists at a workshop in February that research showed water levels should begin decreasing before 2050.

    “We can try to be positive about climate change, really positive,” said Jeff Tyson, a senior fisheries biologist at the Ohio Department of Natural Resources, who helped write a portion of the management plan. “If it continues to be hot, once you lose that meter of water over the top, we get an entirely natural, new shoreline along a lot of the lakefront. If we manage it right, things could look a lot like they did when the first white settlers arrived.”

    The report was written in an effort to spark thought about what the shoreline could become, said Jan Ciborowski, a professor at the University of Windsor who specializes in aquatic ecology and also helped write the plan.

    “There is a lot of opinion among scientists who study the Great Lakes that we need to get the public to start thinking: ‘What are things going to look like?”‘ Ciborowski said.

    The plan monitors issues ranging from pollution to invasive species, said Dan O’Riordan, an EPA manager at the Great Lakes National Program Office in Chicago. He said the agency recognizes the views of experts who predict the lake will shrink.

    “They’ve done the math; I would trust the math,” he said.

    Comment by Chuck Booth — 1 Jan 2008 @ 11:28 PM

  87. Changing channel conditions and land uses change were not factors in the devastating Aug 2007 flash flooding, which led to six deaths in southeast MN, from a 24 hour MN state record rainfall of 15.1 inches near Houston, MN – most occurring in less than 12 hours. The culprit was the high volume of precipitation and the high rainfall intensity which pounded the soil and all ran off.

    Comment by Pat Neuman — 1 Jan 2008 @ 11:47 PM

  88. Re:16 Gavin, Thats what frustrates me no end as well. For some unknown reason so many people like to hammer the life out of one very small irregularity hiding amongst a whole ocean of corroborative evidence supporting ACC and glacial melt. I have surfed a great many web sites re: Glacial melt and have only seen what you have researched yourself..that glaciers are retreating all over the world with the greatest and most obvious retreat amongst the tropical glaciers. With by far the greatest rate of retreat occurring in the last 20 years and accelerating. If that isn’t concurrent with a nett global increase in land/sea temp..I’ll eat my hat! What these idiots are effectively saying is that an elephant isn’t an elephant because it happens to have pimple behind it’s left ear..c’mon get real and stop wasting our time!!

    Comment by Lawrence Coleman — 2 Jan 2008 @ 2:27 AM

  89. There is an important social principle that is currently being violated by many manufacturing activities: the principle that, while engaged in a profit-making activity, one must not leave a mess behind for the rest of society to clean up.

    This principle is understood in a societal context as common decency, but is continually breached in our economy to such an extent that nobody even objects!

    The easiest example is that of mineral water and soft-drink manufacturers, who sell a product that results in a consumer who usually discards a non-biodegradable PET bottle into the environment in an unregulated manner.

    We should mobilize citizens to demand legislation that every manufacturer must repurchase/collect and recycle as many tonnes of raw material as he uses on a week-by-week basis. For example, if a mineral-water manufacturer uses ten tonnes of plastics per week to manufacture bottles, he MUST buy back ten tonnes of plastic scrap and safely recycle it. The same goes for automobile manufacturers, who must buy back that many tonnes of metals, plastics, glass etc. every week, and find ways to recycle them. The cost may be met by raising the market price of their product… but the responsibility to make the recycling activity happen MUST be fixed on the manufacturer of every product.

    The same goes for manufacturers of tyres, batteries, plastic goods, newspapers, clothes, chemicals, auto-lubricant oils, etc. The list is long.

    And if this makes some manufacturing and marketing processes unviable, it means that their economic activity was unviable in the first place, and was sustainable only by passing on hidden costs to the environment, to society, to consumers etc !

    Many industrial activities are environmentally and socially subsidized to keep them economically profitable. Let us lobby governments to knock off that subsidy and see how many activities remain sustainable!

    I propose peaceful demonstrations to remedy this

    Small groups of citizens shall collect the branded packaging material of various manufacturers from the environment, and delivering them in large bundles every week to their corporate offices. It belongs to them, right? So let them have it back!

    A peaceful demonstration like this, sustained over some weeks, would make a powerful statement. I think this will make a powerful media impact as well… and thereby, an impact on the consciousness of people.

    What say? I would appreciate detailed responses to this idea.

    Warm Regards

    Comment by Krish — 2 Jan 2008 @ 6:44 AM

  90. I’m not sure who said that the majority of glacial ice on Mt Kilimanjaro retreated in the first half of the 20th century because I’ve just looked up google earth and the furtwangler glacier specifically and half of it has disappeared since 1976 but if all this person can do is spout totally fictitious information he better look for a more appropriate career in fantasy writing. May I say that the kilimanjaro glaciers now look pretty sick and pathetic than the majesty and awe they once commanded. Find Kilimajaro on google earth at coordinates 3deg 03min 42.36sec S and 37deg 21min 07.93sec E. Very sad!.

    Comment by Lawrence Coleman — 2 Jan 2008 @ 8:41 AM

  91. Pat Neuman…

    [edit – differences of time periods considered should be simply pointed out]

    A quote on top of the page…

    “Devils Lake is in northeastern North Dakota. Throughout the 1990s, the lake level has risen drastically, inundating much of the surrounding area and having an impact on the region’s surface transportation facilities.”

    The facts remain that the highest crest recorded was recorded in May 2006. A have a neighbor who have relatives in Devils Lake, ND and she confirms that the rising lake levels is causing problems around the area.


    Comment by VirgilM — 2 Jan 2008 @ 11:31 AM

  92. Lawrence, the furthest back I’ve been able to trace it is a Livescience article that quotes Mote in this regard:

    The denialist blogs fail to mention the Mote then says that Kilimanjaro may be the ONLY example of retreating glaciers that isn’t related to climate change. Again, typical denialist tactic: focus on one isolated factoid and only tell half the story wrt that!

    Comment by Ray Ladbury — 2 Jan 2008 @ 12:09 PM

  93. Two more links to back my contention that Devils Lake has risen after year 2000, instead of lowered as Pat Neuman cliams. If it was falling, then why is North Dakota trying to build an outlet from the lake to the Red River?’s_Lake_(North_Dakota)

    Comment by VirgilM — 2 Jan 2008 @ 12:53 PM

  94. I have a simple question, a bit unrelated, but this thread is still being looked at (and is relevant to impacts, and is a barrier to my understanding).

    If the greenhouse effect contributes 33 K and 150 W/m^2 of atmospheric absorption, then why can’t you just divide 33/150 to get the K/W/m^2 so that you know the temperature response for a given RF? IT also seems like 1.6 W/m^2 compared to the 150 is small, but how do you get a 1.2 K rise + feedbacks, if 150 W/m^2 gives 33 K rise?

    [Response: If you do this, you a) are implicitly ignoring feedbacks, and b) assuming sensitivity is linear over the whole range. Neither is a good idea. Remember that a ‘radiative forcing’ is a very special W/m2 number and is not the same as the net absorption of LW. – gavin]

    Comment by Greg — 2 Jan 2008 @ 2:22 PM

  95. VirgilM,

    I travel back to the Dakotas about twice a year, at Christmas and in the summertime, and have done so since the 1970s. From my viewpoint the climate in the Dakotas is much different than it was when I grew up there in the 1950s and 1960s. The winters are less severe; they seem warmer and there appears to be less snowfall. The summers seemed to be about the same until all the water showed up in the 1990s. I don’t know how to sift through what is caused by natural variation and what, if any, is caused by AGW, but I think he new warmth is probably a factor.

    My lake is feeling ignored:

    It’s huge now.

    Comment by JCH — 2 Jan 2008 @ 2:24 PM

  96. #94 response

    Thanks gavin. Could you (or someone) just clarify how it is distributed over the range- and just how the “W/m^2” concept changes from the “background absorption” and “adding more GHG’s”. I get that Rf is the change in down minus up irradiance, but it still feels that I’m comparing apples to apples when I say “another 1.6 W/m^2 on top of the 150 W/m^2”

    [Response: W/m2 is just a unit, not a concept. If you want to know what will happen to the 150 W/m2 net LW absorbed once the climate adjusts to a (for instance) 2xCO2 forcing, then model results suggest that it increases to about 170 W/m2. The difference between the 4 W/m2 initial forcing and the 20 W/m2 change in the equilibrium value is related to the positive LW feedbacks (i.e. more water vapour, cloud changes, temperature profile changes etc.). The net feedback includes changes in SW components as well (negative in this particular model). – gavin]

    Comment by Greg — 2 Jan 2008 @ 6:28 PM

  97. Thanks again. Would you have anything I could read on that? I’ve never seen the 170 number before- I looked it up quickly and am just finding stuff on the absorbed shotwave at the surface. I guess I’m still confused on the temperature response to that, and how you get, say, 16 Wm^2 (20-4) from feedbacks but the temperature only goes up by a factor of around 2.5. IS there any literature on this that I could look at for further clarification, because I feel funny playing student here, dont want to take up people’s time.

    One last question though. From 6.2.1 in the TAR, the climate sensitivity paramter is 0.5 K/W/m^2; in your article on “CO2 problem in 6 easy steps” it is 0.75 K/W/m^2. Is this improved understanding from the TAR or more confusion by me?

    Comment by Greg — 2 Jan 2008 @ 8:46 PM

  98. You need to mention all the snow and ice that we are currently experiencing here in New England more often.

    Comment by Mike — 2 Jan 2008 @ 10:09 PM

  99. re: #98 Mike

    Do you think, for example, that a few storms will save (or bring back) Southern New Hampshire’s ski resorts.

    “When New Hampshire skiers hit the slopes this winter, they will have fewer choices than they did 30 years ago — the state has lost approximately 60 percent of its downhill ski areas since the 1970s.”

    Or will save skiing elsewhere in new England, or maple sugar, or the old-style fall foliage season?
    Global warming already affecting New England, June 5, 2007.

    If you do think so, why do you think people going out of business due to warming and less skiing days *don’t* think so?

    Comment by John Mashey — 3 Jan 2008 @ 1:41 AM

  100. You need to mention all the snow and ice that we are currently experiencing here in New England more often.

    Oh my God! How could we ignore the fact that AGW can’t be real because WE STILL HAVE WINTER!!!! Just look out your window, climate science is a fraud!!!!

    Get a grip, dude, and do some exploratory reading before posting something as silly as that.

    Good call, though, only using your first name …

    Comment by dhogaza — 3 Jan 2008 @ 3:41 AM

  101. To all the frustrated real climaters out there, you need to know that infiltrated, paid (by big oil, alas the Texas connection)”moles” try to confuse the issues for several years now. You will find one or two on every popular blog, not only climate related. Peak oil is a very popular target too. Of course, there are some real ignorants and incompetent out there as well. Just ignore them ;-)
    We show some proof of this on our website

    Cheers, the Mare team

    Comment by Mare Initiative — 3 Jan 2008 @ 8:22 AM

  102. Re #98 Mike

    Winter’s weather today in The Marches: cold easterly wind (20–30 kph), 100% cloud cover, temperature ~1°C @ 13:00 GMT (230 m asl); forecast of possibility of snow flurries (which will bring the UK to a grinding halt).

    There’s enough “noise” around hereabouts without being given periodic weather updates (from either side: the believers in real climate science and the delusional, denialist blogosphere inhabitants).

    Kindly desist/resist the urge. Individual weather events cannot be attributed (with any statistical confidence) to either side’s arguments (whether those arguments are from the reasoned or whether they are promulgated by the delusional).

    Many thanks for your anticipated cooperation. :-)

    Comment by P. Lewis — 3 Jan 2008 @ 8:33 AM

  103. P. Lewis, quite so: but you cannot distinguish between “reasoned” and “delusional” in this case; all such “arguments” are delusional.

    BTW the weather’s exactly the same in the Home Counties. ;-)

    Comment by Fair weather cyclist — 3 Jan 2008 @ 9:36 AM

  104. Re: #103 Fair weather cyclist

    P. Lewis, quite so: but you cannot distinguish between “reasoned” and “delusional” in this case; all such “arguments” are delusional.

    Quite so. I was trying to distinguish between a “you know what” and a “you know what”, if you know what I mean ;-) … and you do. :-)

    Perhaps a “mistaken enlightened” and a “plain delusional” would have been better when talking about talking about attributing weather events.

    And enough of the regional weather updates for the UK (or elsewhere) please :-)

    Comment by P. Lewis — 3 Jan 2008 @ 10:20 AM

  105. dhogaza (100), take it easy on Mike. No more worse than the proponents saying, ‘Oh my God! How could we ignore the fact that AGW real because LOOK AT THE EARLY CHERRY BLOSSOMS (fill in your own from thousands of examples)!!!! Just look out your window, climate science is … real …!!!!’

    Comment by Rod B — 3 Jan 2008 @ 2:13 PM

  106. From Russia with love:

    [Response: I’m embarrassed for the Russian Academy of Sciences. Even making allowances for a poor translation, this is rubbish. – gavin]

    [Response: I suspect that the Russian Academy of Sciences is equally embarassed by this, given that their official stated position on climate change stands in stark contrast to the views expressed in this piece. – mike]

    Comment by JCH — 3 Jan 2008 @ 2:42 PM

  107. Re #105 Rod B

    But no, Rod B. There is very good phenological evidence for early springs (early flowering, etc.) and later autumns (delayed senescence) that is/approaches the scale over which climatology data are assessed statistically.

    Stick to weather, fine. But don’t. Enough of weather.

    Comment by P. Lewis — 3 Jan 2008 @ 2:43 PM

  108. Rod B.

    Here are some studies citing long term trends in things like the “cherry blossoms are blooming” that seem to be pretty well researched and supported.

    Phenological changes reflect climate change in Wisconsin
    Proc Natl Acad Sci U S A. 1999 August 17; 96(17): 9701–9704.
    Nina L. Bradley et al

    Freeze and breakup dates of ice on lakes and rivers provide consistent evidence of later freezing and earlier breakup around the Northern Hemisphere from 1846 to 1995.

    Historical Trends in Lake and River Ice Cover in the Northern Hemisphere
    Magnuson et al.
    Science 8 September 2000: 1743

    These and other studies are summarized in this rather attractive little publication from the University of Wisconsin:

    Comment by Paul Middents — 3 Jan 2008 @ 3:22 PM

  109. Re: #97: Greg (on 6.2.1 in the TAR): Here is the quote from 6.2.1: “In the on-dimensional radiative-convective models, wherein the concept was first initiated, lambda is a nearly invariant parameter (typically, about 0.5 K/Wm2; Ramanathan et al., 1985)…”

    I think it is pretty clear that this number is _not_ the best estimate from the TAR: For that, you would look at F.3 in the Technical Summary, where it notes that climate sensitivity is likely to be between 1.5 to 4.5 degrees C, which would be equivalent to about 0.4 to 1.1 K/Wm2. Note that 0.75 is smack dab in the middle of the range. I think the AR4 updates this by actually giving a probability distribution rather than a range(and maybe by shaving off the bottom end of the range?).

    Going back to #94: You might consider the following back of the envelope calculation: According to the Water Vapor: Feedback or Forcing? post, somewhere between 15 and 34% of the total forcing is attributable to GHGs other than water vapor and clouds. If we assume that water vapor and clouds are “feedbacks”, then the 33K of warming we see could possibly be attributed to between 0.15*150 and 0.34*150 W/m2 primary forcings. This would give you a sensitivity of between 1.5 and 0.65 K/Wm2, which is actually higher than the IPCC best estimates.

    Of course, this back of the envelope calculation is also rather crude: one expects that the water vapor + cloud response to be non-linear, and of course this doesn’t include any albedo change feedbacks (positive: less snow, glacier + arctic ice retreat, etc, or negative: increased desertification, etc.).

    Comment by Marcus — 3 Jan 2008 @ 4:03 PM

  110. Statements (#93) made earlier by VirgilM’s on Devils Lake need to be corrected.

    Devils Lake was in a state of fluctuation from January 1 of 2000 to January 1 of 2006.

    However, reading on January 1 of 2006, 2007 and 2008 (below) show that the elevation of Devils Lake in ft. above mean sea level, has been in a state of recession.

    In 2008 Devils Lake will have a short term rise (approximate 1.0 ft, or less) in the elevation of Devils but the lake elevation on January 1 of 2009 will be lowered than the lake elevation was on January 1, 2008.

    I’m willing to accept bets on this if there are any takers.

    Jan. 1 2006 was 1447.89 ft abv mean sea level
    Jan. 1 2007 was 1446.96 ft abv mean sea level
    Jan. 1 2008 was 1446.79 ft abv mean sea level

    Forecast by Pat Neuman
    Jan. 1 2009 less than 1446.79 ft abv mean sea level

    Comment by pat neuman — 3 Jan 2008 @ 5:21 PM

  111. Re: #110: Pat Neuman: I have to say, having looked at the data myself, Virgil’s arguments are fairly convincing. Personally, I think arguing about one lake (or even one hydrological region) doesn’t make much sense when looking at climate, but it seemed like the two of you were having an argument that would be easy to resolve.

    If I go to the USGS website to get data, the first thing I note is that in 2005 they shifted their monitoring station because of excessively high lake levels. If I actually then _get_ the data which goes back to 1979 (though it is spotty for the first decade), it is clear that current lake levels are at historic highs: 1995 is the first year it exceeds 1430 feet, 1998 the first year it exceeds 1440 feet, and only in 2000 did it break 1446 feet – the level you list for your January “low” prediction.

    So I don’t understand why you are trying to defend a prediction that the level of Devils Lake is dropping, when it is at a level higher than any recorded from 1980 to 2000?

    Comment by Marcus — 3 Jan 2008 @ 7:08 PM

  112. No 68.
    Barton Paul Levenson: Check the data on your post. Go to:
    Scroll down and try inputting:
    Data Type: Mean Temperature
    Period: Annual
    First Year To Display: 1998
    Last Year To Display: 2006
    Base period begin year: 1998
    Base period end year: 2006
    Output Type: Line or Bar Chart, Your Choice but select “Plot Trend Line”
    Sort By: Year
    Press Submit!
    ANNUAL 1998 TO 2006 TREND = -0.35 DEG F/DECADE


    [Response: Calculate the error bars on the trend: 2 sigma is +/-1.48 deg F/dec making this completely insignificant. This isn’t difficult to check. – gavin]

    Comment by Bob Tisdale — 3 Jan 2008 @ 8:46 PM

  113. Sorry, I just couldn’t resist my cold weather comment. I just get tired of hearing the news media blabbing day-in and day-out about extreme heat waves and blaming it on global warming.

    Comment by Mike — 3 Jan 2008 @ 9:52 PM

  114. And just to add to Gavin’s comment to Bob Tisdale’s #112, Tamino has an excellent analysis of this very topic at Garbage is Forever and at Wiggles.

    Comment by P. Lewis — 4 Jan 2008 @ 4:26 AM

  115. Bob Tisdale posts:

    [[ANNUAL 1998 TO 2006 TREND = -0.35 DEG F/DECADE ]]

    Those are temperatures for the UNITED STATES. I was using temperatures for the WORLD. For which the 1998-2006 trend is UP. Look again:

    Comment by Barton Paul Levenson — 4 Jan 2008 @ 8:26 AM

  116. Mike #113, I hope you will forgive our lack of enthusiasm for your rediscovery of Winter.

    Comment by Ray Ladbury — 4 Jan 2008 @ 8:53 AM

  117. It’s true that the lake tendency in the 1980s and 1990s was upward. However, that’s history. Climate change has now swung the other way – toward downward lake levels. Devils Lake observations show that the level of Devils Lake has been on a falling trend (averages for last three years falling, also see comment #110).

    The dropping levels are now being driven by longer ice free winter periods, longer growing seasons, warmer temperatures and higher evaporation rates. Longer growing seasons in the basin means increasing amounts of water loss from land areas due to higher rates of transpiration and evaporation – anuual inflows since 2006 have decreased.

    Water temperatures have been warming more rapidly than average annual air temperatures (Lake Superior). Annual lake water evaporation from the Great Lakes is greatest in fall when the water temperatures are warmer than air temperatures and due to lake effect snowfall.

    Devils Lake hydrology has also been complicated by human influence – for many years – including: Channel A cut in 1979, overflows to Stump Lake since 2000 and many other channel modifications within the basin.
    None the less, the current tendency in Devils Lake water level is recession. There is no need to create a diversion from Devils Lake to the Sheyenne River, and Red River, which has been pushed by those with little or no hydrologic knowledge of the basin.

    On the Great Lakes, warmer water temperatures in fall and early winter have resulted in higher losses from lake evaporation.

    Comment by pat neuman — 4 Jan 2008 @ 1:12 PM

  118. Pat Neuman,

    I think my point stands: Devils Lake in North Dakota hit a record high in May of 2005, which caused significant problems around the area. Your proposed statement in 2000 made no mention of record lake levels that was broken a few times from 2001 to 2005. Your statement said that lake levels would fall becasue of human induced climate change.

    I suspect that your prediction is a personal opinion that you tried to get into a NWS product. If it is not, then reference me a peer-reviewed journal article that modeled the future climate in Eastern North Dakota and specifically said that lake levels will drop for Devil’s Lake.

    North Dakota has moved into a drought that last two years. That has happened many times in the last 1000 years. When that happens, lake levels drop because precipitation is a big part of the equation. A very small drop in lake levels in the last two years only proves that drought as moved into the area. Connecting it with human climate change takes much more work, because correlation does not mean causation. Where is that work in the journals?

    Comment by VirgilM — 4 Jan 2008 @ 6:54 PM

  119. My experience includes hydrologic model development, model calibration and accurate annual operational forecasting the elevation of Devils Lake, 30 years, gained from first hand experience at the NOAA NWS Kansas City River Forecast Center from 1976 to 1979 and at the NOAA NWS North Central River Forecast in Center im Minnesota, officially awarded retirement for 30 years of “Loyal Service” rendered to the government of the United States by the NWS Central Region director (Feb. of 2006).

    Comment by pat neuman — 4 Jan 2008 @ 8:17 PM

  120. VirgilM asked: … “Where is that work in the journals?”

    Answer: NOAA NWS was a road block for publishing material related to climate and hydrologic change, in jounals, for many years. While at NWS I was told to remove reference to myself as a NWS employee on the paper below even though I had been allowed to do some of the research on the timing of snowmelt runoff shown in the paper on government time.

    Comment by pat n — 5 Jan 2008 @ 3:36 PM

  121. Gavin:

    Long term trends from the forcing are expected to be around 0.2 – 0.3 deg/decade. Therefore you need to be able to get uncertainties down to well below those values in order to find a clear discrepancy. Judging from the last thirty years, that period is around a decade.

    Seems to me it’s more complicated than this. If you look at the historic forcings, before roughly 1975, if climate models are to be believed, there was a rough balance between the positive forcings from CO2 and the net negative forcings associated with aerosol particles. (I use this figure from the WIki article to illustrate the balancing of these two anthropogenic forcing terms).

    It should be noted that industrialized nations have been reducing their CO2 intensity (ratio of CO2 production to GDP), e.g. see this [As an aside, the total US CO2 production (US CO2 production dropped by 2% in 2006. I’ve read a press account, but don’t have a more trustworthy link, that ironically Europe’s CO2 production increased by 0.4% over the same period.] Put another way the CO2 contributions from developed nations are decreasing as a percentage of the global anthropogenic CO2 budget.

    It should also be noted that developing nations like China are adding coal-burning electric plants at a prodigious rate (I heard as high as 1 per day). Because these facilities produce copious quantities of aerosols, one might expect the relative balance of CO2 forcing to aerosol forcing to shifting back towards a balancing of the two contributions.

    I don’t have ready access to global aerosol production, so please accept this as just a plausible scenario meant to illustrate a point.

    It may very well be the case in the near future, that we reach another period in which global mean temperature either slows or reaches a plateau. I would emphasize that this would occur in a manner completely consistent with the climate models and our understanding of anthropogenic climate change. Under such a scenario, would expect as the developing countries were to continue to industrialize that, like us, as their industry addresses pollution issues, their aerosol production would diminish while their CO2 production would continue to increase—tipping us back into an upwards trend in global mean temperature. (We’d end up with a step in the warming trend like seen between roughly 1945-1975.)

    Obviously without the aerosol data this is pure speculation, but I’m just suggesting that it’s important to not take trends like 0.2°C per decade as gospel. People who are demanding a definite answer on this (on both sides), may simply be underestimating the complexity of the anthropogenic forcings terms.

    [Response: It’s a reasonable idea but you forget one crucial fact. CO2 accumulates, and aerosols don’t. That means you have a competition between a forcing which is proportional to the total emissions, compared to one that is proportional to current emissions. At the beginning you can balance them out, but in the long term the accumulator is always going to dominate. Thus for this to work out, you have to start making emissions dirtier and dirtier from here on in. That ‘faustian bargain’ is just not sustainable – not least for human health issues. Total aerosol in recent decades seems to be going down slightly (a big decrease in the US/Europe/FSR balanced by increases in India and China) and so is either near neutral at the moment or slightly positive (it depends on the make up of the aerosols – ratios of reflective vs absorbing from the different sources). The aerosol issue isn’t going to go away as an uncertainty, but I don’t think anyone expects it to be able to cancel the growth of forcings associated with CO2 at present or the near future. – gavin]

    Comment by Carrick — 17 Jan 2008 @ 10:20 AM

  122. Gavin:

    It’s a reasonable idea but you forget one crucial fact. CO2 accumulates, and aerosols don’t. That means you have a competition between a forcing which is proportional to the total emissions, compared to one that is proportional to current emissions.

    I’m really not trying to be argumentative, but I understand the relationship between the amount of CO2 emitted by anthropogenic processes and the change in CO2 concentration to be more complex than that. For example, there are carbon sinks that are affected by the availability of CO2 in the boundary layer: It’s a nonlinear system and it has memory. (I’m thinking of Inez Fung’s work on this.) You could have e.g. a step function change in the rate of CO2 emissions, and end up with nearly the same total concentration levels, due to the response of the other carbon sinks to the increased availability of CO2 in the boundary layer, depending on the magnitude of the step function that is.

    To make it clear, I wasn’t proposing that a long-term stable situation could be set up e.g. increasing our aerosol production to balance the increased CO2 concentrations. Rather I was suggesting these changing demographic patterns represents a potentially confounding effect over some short term interval (20-30 years) that could mask a very real long-term trend in global warming. How probably this confounding effect is to be seen, obviously you’re the expert on this not me.

    My only real point is that because of changing demographics, we might expect the net forcings from CO2 and aerosols to change over time, and potentially we could be going into a short-term lull (on climate scales, e.g., 20 years) in global warming. That is, it hasn’t stopped, just slowed by poor industrial practices in third world nations. However, this wouldn’t signify either a problem with climate models or signify a long-term end of the warming period.

    I absolutely agree with your other comments, I hope you weren’t trying to take my question as a “well it’s going to flatten out indefinitely, so there’s no worry.” Clearly I agree on the need to moderate both CO2 emissions and aerosol production.

    Faustian is a great choice of words by the way, for the other scenario (whereby global warming is stopped long-term because we produce enough pollutants to balance the increased CO2 emissions. I wasn’t proposing this idea, and obviously it would never work.

    [Response: Your point that regional relations between CO2 and aerosols are variable is completely correct, and incorporating this into the emission data and scenarios is tricky. As far as I can tell from talking to our aerosol people, the changes in recent years due to aerosols do not approach the magnitude the changes due to increasing CO2 – so globally and right now, the CO2 rise is dominant and is expected to remain so for a while. If aerosols emissions were actually increasing faster than we currently anticipate then that could slow the expected global warming trend, though I don’t think it would be fair to say it would be masking it. All the forcings should be taken on an equal footing. The standard scenarios generally assume a decrease in aerosols over the next few decades, but are very uncertain on increases in black carbon and other species. – gavin]

    Comment by Carrick — 17 Jan 2008 @ 3:36 PM

  123. Gavin — do they have an annual time series for industrial aerosols? I’ve been looking for such a thing for a while now without finding one.

    [Response: We have estimates, but the emissions data don’t have annual resolution for the most part, and so we do it in decadal chunks. More info here: – gavin]

    Comment by Barton Paul Levenson — 17 Jan 2008 @ 4:33 PM

  124. The link shows one chart with what seems to be annual resolution of “global sulfate emissions.” Wouldn’t that serve as an adequate proxy? Where can I find that time series?

    Comment by Barton Paul Levenson — 18 Jan 2008 @ 6:42 AM

  125. Never mind — found it. On Steve McIntyre’s web site, of all places, though his source is legitimate (Stern et al.’s work from a peer-reviewed journal article). Now I’ve got sulfate emissions to 2000 and volcanic DVI to 1995. I’d be happier if I could fill in the last few years, but hey, ya gotta go with what ya got.

    Comment by Barton Paul Levenson — 18 Jan 2008 @ 11:16 AM

  126. …”global measures of temperature rise (~0.2ºC/decade)…”

    You mean the rising trend in the global mean temperature anomaly that’s calculated from averages of sea surface measurements and air sampling, I take it. From this data is that correct?

    I can’t see that being very exciting either, no.

    Comment by Ralph Smythe — 18 Jan 2008 @ 12:36 PM

  127. This thread is a bit long to follow… but I think I need to propose a slightly different and geological viewpoint. It is also maybe the old anthropic principle peeking out from under the rocks.

    If we look at the fossil record we can see that there are dominant species/groups of species that crop up. Chalk – coccoliths. Various other limestone facies that show how some organism has had a huge impact on the sequestration of carbon. We do not have good data for the change in atmospheric composition that might have also happened – but we do see the carbon in the rocks.

    Now – human beings have an obvious effect on the earth’s surface. Maybe as much effect as bamboo does. More effect than (say) cats do, so it is very liekly that we will and do effect the climate.

    The nasty, pessimistic geologist point is – if we do not do it some other species or set of species will and the net outcome will be the same – a shift in climate. A tiny change on the planetary scale, but significant for things clinging to the surface. We are intrinsically bound up in a complex system with a very large humber of feedback loops, time constants and trip points. No one factor or function will let us predict outcome.

    So – calls to save the planet by riding a bike will come to nothing. Calls to spend less on electricity by using LEDs might have a result – but only in terms of daily per-cpaita power consumption. We simply cannot make the cause-effect link between personal action and change in climate.


    Comment by John Hennessy — 4 Feb 2008 @ 1:05 PM

  128. In letters to The Australian ( Rupert Murdoch bastion of rationality), some people have picked up this claim [*] that sea level rises are slowing down rather than accelerating. Note particularly the following snippets from the paper:

    ‘[IPCC, 2001] made an estimate of all variables and their possible contribution to sea level rise. They arrived at a mean value of 0.9 mm/year. This value is in harmony with the records of the present and near-past given in Table 2.

    Still—and this is remarkable —IPCC compared their own value with a model value of 1.8 mm/year (cf. above), which they termed “observed”, and discarded their own estimate as unrealistic. The mean value 0.9 mm/year is close to the truly observed value of 1.0–1.1 mm/year for 1850–1930 and, consequently, quite reasonable.’


    ‘When we (the INQUA Commision on Sea Level Changes and Coastal Evolution) consider past records, recorded variability, causational processes involved and the last centuries’ data (Fig. 1, Fig. 2 and Fig. 4), our best estimate of possible future sea level changes is +10±10 cm in a century or, maybe, even +5±15 cm.’

    Anyone care to comment on this? (You’ll need a subscription to read the whole article.)

    Who in any case is INQUA?

    [*] Nils-Axel Mörner. Estimating future sea level changes from past records, Global and Planetary Change vol. 40 issues 1-2, January 2004, pp 49-54

    Comment by Philip Machanick — 17 Feb 2008 @ 5:52 AM

  129. > INQUA
    Links here:

    Comment by Hank Roberts — 26 Apr 2008 @ 1:55 PM

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