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Mise à Jour sur les températures 2005

Classé dans: — gavin @ 11 novembre 2005 - (English)

En complément du message sur le record de température possible de l’année 2005, Jim Hansen a écrit une courte discussion (en anglais) sur l’article du Washington Post report et des discussions sur cet article. Et pour le record, avec les données disponibles d’octobre, 2005 est passé devant 1998 dans les deux types de données du GISS, l’index “GISS land” sur des stations météo terrestres (0.76 comparé a 0.73°C) ainsi que pour l’index “GISS land-ocean” (0.59 to 0.58°C). Les mises en garde précédentes sont toujours valables…


51 Responses to “Mise à Jour sur les températures 2005”

  1. 1
    Pat Neuman says:

    In RealClimate (22 Sep 2005),
    from comment #2 of subject: What is a first-order climate forcing?
    Excerpt:
    “I’m glad that people are beginning to move away from global mean temperature as the primary indicator of climate change. It’s good to look at, to be sure, but how is it relevant to society? Who actually lives in a globally-average place?”

    I think globally averaged mean temperature is an important indicator of global warming. I think numerical measures for global warming are important. They are an indicator of how the rate of global warming changes. Globally averaged temperatures are also important because they allow scientists to make numerical predictions, which allow others to make preparations and hopefully reduce greenhouse gas emissions.

    In addition to global temperatures, I think it’s important to consider the proportion of Earth’s water in it’s various states (ice, liquid, vapor), because that is also an important measure of global warmth. Questions remain about the strength of the water vapor feedback. I think scientists need to monitor global water vapor very closely. We all need to get it right the first time, there is only one Earth.

  2. 2
    Mark A. York says:

    Speaking of Dr. Hansen, science nemesis Steven Milloy derides him here.

    There has to be some way to crush these propagandists.

  3. 3
    Pekka Kostamo says:

    There is a lot of interest in the surface temperature data as a proof that the climate models describe the real world. As an engineer who has worked on weather instrumentation for the past 35 years, one might contribute a few related observations.

    Technically it must be noted that 0.1 deg accuracy in temperature measurement remains white coat lab stuff, definitely not available in field conditions. Relative accuracy over short periods of time is easier, of course, but it is not the need of the climate monitoring community.

    The role of urban heating has been adequately discussed, and hopefully this effect has been removed from the analyses. In contrast, there is little visibility of the several factors that lead to systematically lower readings over time from the thermometers. Related results of recent experimental work can be found i.e. on the World Meteorological Organization web site, as well as at several European weather service sites.

    Less warm bias result from technical changes in the observing systems. These transitions are mostly not critical for the prime purpose of the observing stations, which is the daily weather forecasting. Many of the biases can be ignored there as long as a degree of homogeneity is maintained in a local or regional network. Long term stability is of rather limited interest there, but a necessity for climate analysis. An improvement of accuracy, paradoxically, may reduce the value of a record for climate analysis (as the satellite community knows all too well) if the transition is not properly done.

    One key change is the ventilation of thermometers. Most of the world still uses naturally ventilated wooden Stevenson screens to protect an actual sensor from the daily weather, such as solar radiation, wind and rain. This design has large biases, but it is one way of maintaining an operational standard. However, in the U.S. and in some other areas, a forced ventilation screen has been adopted, which certainly provides a better accuracy. At some point of time there was a transition from naturally ventilated to forced ventilation, and this would need to be taken into account in the long term trend calculations. This shift probably caused a drop in indicated average temperatures, of the order of -0,2 to 0,5 degrees C. Accommodating this change is not easy, as the (removed) warm bias in an unventilated screen measurements is quite complex and varies from one station to another.

    A related change on many stations with naturally ventilated thermometer screens is the gradual improvement of screen maintenance over the years. A flaked and dirty screen of this kind easily causes a warm bias of a degree or much more in the worst cases. Regular cleaning, re-painting and replacement are necessary for accuracy. Improvements of maintenance programs, and the field practice, have certainly resulted in less warm bias, but mostly in an uncontrolled way. It must be borne in mind that stability of these procedures over many tens of years are considered in the climate context.

    Fluctuations in the ‘market share’ of the standard Stevenson screen are also a reality in the global station network. Some of the oldest temperature measurements have been taken in a ‘shade’of any kind, including bamboo huts of many designs, quite literally. A move to the standard screen leads to substantially better accuracy, and probably to cooler climate indications. There is, however, also a recent mixed trend due to the introduction of automatic weather station technologies. The thermometer screens used in these systems have several designs, some are more and some are less efficient than the Stevenson standard. Few automatic stations have forced ventilation due to the common power economy constraints.

    The naturally ventilated screens are sensitive to the general environmental factors. Increased wind speeds obviously result in lower temperature indication, increased cloudiness likewise. Any change in the ground (and its seasonal cycle) over which the sensor is installed is also a factor.

    In summary, my perception is that the indicated surface temperature change based on routine weather station records probably underestimates the actual warming to some extent. As a first order questimate I would venture about 0,5 deg C over the last century. It is perhaps very lucky that the climate models are not statistical extrapolations of measured temperatures. After all, the surface temperature measurements are not even usable as input to the daily weather models – although they are a most useful verification of the weather predictions. Anyway, the key impacts of climate change are found in the developments of extreme weather and the redistribution of precipitation.

  4. 4

    May I be the first to congratulate Dr Hansen et al., about their
    successful prediction on this year’s Global temperature. Whether
    it is # 1 warmest for the Globe or #2 they were very accurate.

  5. 5
    Paul says:

    Regarding post #2

    Here’s a record of all things Steven J. Milloy, the Junkman

    http://tinyurl.com/cuevz

  6. 6
    Harry Pollard says:

    Perhaps someone can enlighten me.

    I understand that there were many more temperature measuring stations in the past than there is now. I believe many (most?) of the Russian stations were closed down.

    This would make past and present measurements difficult to compare.

    What is the situation?

    [Response: The total number of stations has indeed decreased in recent years, but there are still plenty enough stations to get a good estimate of the global temperature anomaly. The number of degrees of freedom for this are only about 60, and so theoretically, you could get a good estimate with that number of carefully spaced independent stations. Obviously, stations aren't that carefully placed, so more are required, but we still have enough to be able to make a reasonable estimate. - gavin]

  7. 7
    Pat Neuman says:

    In order to accurately predict river levels with hydrologic models, temperature and precipitation data for hundreds of climate stations are evaluated using data consistency and double mass plotting techniques. Short distance moves at a station during it’s period of record happen occasionally. A station move usually shows up on a data plot as a change in slope (when the data for that station is plotted against the data for an average of stations that surround it). Before using the data in calibration and for probabilistic outlooks, hydrologists adjust the data for consistency (to eliminate the discontinuities between before and after station moves).

    For global temperature averages, has the station data been adjusted to eliminate discontinuities within records due to station moves? Have adjustments been made to account for changes in observation times at the stations?

    Some of my efforts with station data can be viewed at:

    Air Temperatures & Dew Points â?? Great Lakes States (Apr 2003)
    http://www.mnforsustain.org/mn_dewpoints_neuman_p_special_report.htm

    Earlier in the Year Snowmelt Runoff and Increasing Dewpoints for Rivers in Minnesota, Wisconsin and North Dakota (Sep 2003)
    http://www.mnforsustain.org/climate_snowmelt_dewpoints_minnesota_neuman.htm

    Plot of five year moving averages for annual temperatures at Minneapolis (1820-2004).
    http://groups.yahoo.com/group/ClimateArchiveTwo/

  8. 8
    Harry Pollard says:

    Thank you Gavin.

    However, that didn’t quite answer my point. In fact, it raises another.

    I am talking of comparison. How many stations were there in (say) 1950, 1970, 1990, and so on? Can we compare (say) 200 stations with 5,000

    Don’t worry, I’m not suggesting you hunt up difficult statistics! But, I seem to recall the number of stations diminished in the order of thousands. In particular, I recall the Russian contingent was cut to the bone.

    The other question is the matter of estimates which, as you must, you so describe the analysis of these measurements.

    Are you very confident of our ability to estimate such tiny changes in temperature?

    Further, if you limit stations to (say) 60 will this give a global or regional result?

    [Response: The GISS analysis used about 3000 stations in 1950, 6000 in 1970, and back down to around 4000 currently. The accuracy of the estimate given the current network is around 0.05 deg C in the annual mean, so differences of a hundredth of a degree are not terribly useful scientifically. The degrees of freedom issue is discussed quite fully in Estimating the degrees of freedom in a climate field (Wang and Chen, 1999), and implies that depending on hemisphere and season, 60 stations would give you a reasonable hemispheric mean. -gavin]

  9. 9
    Eli Rabett says:

    Pekka Kostamo’s comment was wonderful. I have a question, it appears that most of the variation is due to the screen, however, are there aging effects associated with the sensors?

  10. 10
    Eli Rabett says:

    Gavin will obviously do this better, but Harry Pollard can find at least some of the information he seeks at http://data.giss.nasa.gov/gistemp/station_data/
    and in the paper
    http://pubs.giss.nasa.gov/docs/1999/1999_HansenRuedyG.pdf

  11. 11

    There is a lot to say about success, and how, in this case it is assailled without acknowledgement.
    But there is a great science story here, from hard work and sound reasoning came a capable prediction,
    If the drilled out usual routine of suggested flaws are true, then why did Hansen’s prediction come through? Could it be that the mentionned fallacies are not as overwhelming as they seem?
    I made a similar prediction while using a totally different method than numeric models dedicated for Anthropogenic Greenhouse gases, and there is a great feeling in success, none more than when it is achieved with very little ressources, however I must salute the very long term dedicated guys in NYC. The ultimate skeptic will make it unlikely that anything happened at all, just the luck of a draw, but the science of weather and climate predictions is not as wretched as a random number generator, our understanding seems more potent, than Dr Lindzen’s alleged 4 days.

    What is missing in this thread is that a CO2 temperature model was capable of precisely predicting 2005. I know of no other model that has done likewise.
    Offering a glimpse that past measurements of that Global Temperature average was not so bad after all.
    There should be more interest in successful methods of prediction, how they work, and replicate them for a finer refinement for all other models.

    Temperature changes in present day Arctic are not a a mere 0.5 degrees. Lately monthly averages were +2 to 3 degrees C above the 1950-1990 mean. This is not attributable to instrument error. Nor is the last few days +7 C above normal weather explained by Ventilated Stephenson screen implementation dates. To assuage temperature errors one must look at about 1940 onwards to get a more reassuring view, the Washington Post temperature graph in the link above shows the end of the temperature “hockey stick” quite well.

  12. 12
    Ian says:

    My name is ian, and i’m doing a school project on how climate has an effect on the salinity of seawater. I was wondering if you could help me by giving me more specific examples and theories and facts that will help me in my project. Your help will be greatly appreciated.
    Thank you.

    yours sincerely,
    Ian

  13. 13
    Lynn Vincentnathan says:

    I just saw the TV movie, CATEGORY 7: END OF THE WORLD, on CBS. It was about the urban heat effect causing a lot of heat to go up to the cold mesosphere, causing chunks of mesospheric ice? to fall & contributing to really strong hurricanes/tornados over cities. I know there was very large hail falling on Brownsville during Hurricane Emily this summer (which a scientist on this blog said was unusual).

    So, how much is fact & how much is fiction re CAT 7? (Apparently they were into filming it way before Katrina.)

    The contrarians have been harping so strongly about the urban heat effect (as polluting temp data), that I had begun to think urban heat’s not a good thing, at least for the heat deaths it causes – so all the more reason to reduce the activities that produce GHGs AND generate heat. So, be sure to reduce to save lives, even if you think urban heat is polluting GW data. Any other contrarian arguments? I have answers.

    [Response: Timothy (#15) has already answered but, indeed, what you are describing sounds like junk. Sorry - William]

  14. 14
    Pat Neuman says:

    Re #12 … how climate has an effect on the salinity of seawater

    ian, studies suggest that the Atlantic’s Gulf Stream slowed or stopped due to a large freshwater input as the last ice was coming to an end. That phenomenon will likely not be part of our future, for various reasons. Perhaps the article below will help in your search.

    Geologic Evidence of the Permian-Triassic Extinction
    Geology Newsletter
    … “Salinity in the sea fell sharply during the Permian for the first time, changing oceanic physics to make deep water circulation more difficult”. …
    http://geology.about.com/od/extinction/a/aa_permotrias.htm?nl=1

  15. 15
    Timothy says:

    Re: #13 “…the urban heat effect causing a lot of heat to go up to the cold mesosphere…”

    Sounds like complete hogwash to me like most science-fictional telly dramas. For what it’s worth even strong tropical convection [part of the Hadley Circulation] rarely produces much transfer between the troposphere and the stratosphere. Given that the mesosphere is even higher up [is there an ionosphere in between as well?], then it would appear that transport between the troposhere and the mesosphere that could be attributable to particular processes in the troposhere would be nil.

    Salinity and GW: You’d expect the Ocean salinity to decrease slightly due to the melting of ice, but I’d doubt whether this would be measureable. There’s been some work done recently on looking at Great Salinity Anomalies [GSAs] in the North Atlantic and possible connections with the Atlantic-Multidecadal Oscillation [AMO] the North Atlantic Oscillation [NAO] and the gulf stream [or the Atlantic Meridional Overturning Circulation MOC] and comparing observed patterns with coupled model results.

    However I don’t recall anything particularly noteworthy being said about possible future changes due to GW.

  16. 16
    Lynn Vincentnathan says:

    RE #13 & 15, any-who, it’s good they’re having movies about GW on TV, even if they’re as off as green Martians & red Venusians. I had almost thought any mention of GW on TV had been banned or something (I nearly never hear about it).

    The movie did attribute more intense hurricanes to AGW, and that part is at least within science. It’s just that they needed a really scary hurricane (Cat 7) to ratchet up the suspense, and some do-able solution for a happy ending. Unfortunately they gave the impression that by simply turning off all our heat-generating things for an hour or so we can avoid mega-hurricanes. But real AGW may not have such a happy ending…

  17. 17
    Blair Dowden says:

    Re #16: You appear to approve of any support for global warming, no matter how false or nonsensical. Maybe honesty and accuracy are not an important part of your life, but even from an ends-justifies-the-means point of view you should consider the impact. Skeptics take material like this, easily demonstrate how false it is, then imply all global warming information is hype, and the people who provide that information are not honest. You are playing into their hands.

  18. 18
    Mark A. York says:

    OK I don’t expect you guys to respond to every crank naysayer from AEI but here’s another one someone just dished me.

    “Testimony of Dr. James J. O’Brien
    Director, Center for Ocean-Atmospheric Prediction Studies (COAPS)

    The original CO2-doubling model by NASS,GISS under the leadership of Dr. Jim Hansen, estimated around 10ºF surface temperature change by 2050. This was so dramatic because no ocean was included. I remember reading in the Tallahassee Democrat, a story that said, as a result of the GISS model, that sea-level would rise 3 meters or 7-10 feet by 2050. The current IPCC estimates a few degrees temperature rise by 2100 and a doubling of the current sea-level rise of around 8 – 10 inches to 20 inches as the worst case by 2100. Certainly, policymakers will react differently to plan for a two feet rise in 100 years vs. 10 feet rise in a generation.

    Let me provide one more remark on sealevel rise. In order to double sealevel, one would expect to observe an increased rate of rise by 2002. Everyone agrees that the current average rise is about 7 -10 inches a century, averaged over the globe.

    However, the experts who have tried to find any acceleration find none.”

    As a journalist I want to dispel these frauds, since truth as we know it is my only concern. As a scientist myself I find it essential for integrity. But there seems to be a problem with some meteorologist professors in red state universities. This is the second one I’ve been attacked with. What’s this guy’s deal?

    I find the accusation too general to be valid on its face. Dr. Hansen responded to the Milloy/Crichton farce.

    http://columbia.edu/~jeh1/hansen_re-crichton.pdf

  19. 19
    Tom Rees says:

    Re: #18. It sounds like he’s seen the results of an ‘instantaneous CO2 doubling’ experiment, and misunderstood what it means.

  20. 20
    Chris Reed says:

    Re #18

    I assume you’re dealing with some contrarist response? Correct me if I’m wrong.

    Firstly I calculate an increase of 10F as 5.55deg C. The IPCC Third Ass’t Report Summary for Policy Makers shows a range of temperature increase in fig d here: http://www.grida.no/climate/ipcc_tar/wg1/figspm-5.htm . So I’d have 2 points here, firstly quoting the “original CO2-doubling model” is disingenuous because things have moved on since then. Secondly stating a 10deg F increase and then implicitly reverting to deg C when looking at the IPCC results is misrepresentation. Actually 10deg F is at the very top end of the range of results, 5.55 degC or thereabouts. It was 50 years earlier than the IPCC results but again this was a ref to what I presume to be a superseded study, comparing apples and oranges.

    Furthermore with ref to The IPCC Third Ass’t Report Summary for Policy Makers here (bottom of page): http://www.grida.no/climate/ipcc_tar/wg1/005.htm . The writer you quoted states “current sea-level rise of around 8 – 10 inches to 20 inches” this is wrong. They haven’t even got to grips with inches vs metres. The IPCC state “Tide gauge data show that global average sea level rose between 0.1 and 0.2 metres during the 20th century.” i.e. 10 to 20 cm, 3.9 to 7.9 inches. Furthermore I doubt if any worthy policy maker would rely upon an unattributed story in the Tallahassee Democrat, whatever that may be.

    Finally the statement ” In order to double sealevel, one would expect to observe an increased rate of rise by 2002″ pre-supposes a linear response. I’m just an amateur but even I understande the fatuity of such a supposition. It is entriely reasonable to expect non-linear behaviour in climate and it’s facets. I’m not sure what doubling sea level actually means, but I wouldn’t have thought that a doubling of rate of increase for this century over the last is inherently improbable.

    Is this really a statement by “Dr. James J. O’Brien, Director, Center for Ocean-Atmospheric Prediction Studies (COAPS)”? Because on face view I wouldn’t let the man who made these statements near my plumbing let alone allow him to make climate predictions.

  21. 21
    Bob says:

    RE #17: Whoever this O’Brien is he is seriously WRONG.

    Sun, S., and J.E. Hansen 2003. Climate simulations for 1951-2050 with a coupled atmosphere-ocean model. J. Climate 16, 2807-2826.

    The authors simulate climate change for 1951-2050 using the GISS SI2000 atmospheric model coupled to HYCOM, a quasi-isopycnal ocean model (“ocean E”), and contrast the results with those obtained using the same atmosphere coupled to a passive Q-flux ocean model (“ocean B”) and the same atmosphere driven by observed SST (“ocean A”). All of the models give reasonable agreement with observed global temperature change during 1951-2000, but the quasi-isopycnal ocean E mixes heat more deeply and hence sequesters heat more effectively on the century timescale. Global surface warming in the next 50 yr is only 0.3°-0.4°C with this ocean in simulations driven by an “alternative scenario” climate forcing (1.1 W/m2 in the next 50 yr), only half as much as with ocean B. From the different models the authors estimate that the earth was out of radiation balance by about 0.18 W/m2 in 1951 and is now out of balance by about 0.75 W/m2. This energy imbalance, or residual climate forcing, a consequence of deep ocean mixing of heat anomalies and the history of climate forcings, is a crucial measure of the state of the climate system that should be precisely monitored with full-ocean temperature measurements.

  22. 22
    Richard Foy says:

    It is interesting that in this whole series of msgs, I see nothing concerning the statistical probablity of the weather extremes. There have been numerous extremes in the last few years of temerature. Major examples are the 2003 European Heat Way and the recent India heat wave. The Atlantic Tropical Storm data, and the various major flood data. All of these strongly suggest that global climate change is having strong effects on current weather.

    I have set up the goggle alert system to give me daily news reports on both “weather extremes” and “global warming.” The number of extremes is noteworthy, especially when the reports list the prior records as being some where in the last couple of decades.

    It can also be a bit scary.

    Richard

  23. 23
    Pat Neuman says:

    For globally averaged temperature to have great public value, it is necessary that a comparison be made to one or more global warming episodes in Earth’s past. Note, we already know globally averaged temperature has great scientific value, comment #1, above.

    Need an important analog to present-day

    Global warming episodes in Earth’s past include the species boundaries of the Permian/Triassic ~245 million years ago (mya) and the Paleocene/Eocene ~ 55 mya.

    The Paleocene/Eocene boundary
    —————————————–

    An article in Science, 11 Nov 2005, “Transient Floral Change and Rapid Global Warming at the Paleocene-Eocene Boundary, Scott L. Wing, et al., states:

    “At the beginning of the Eocene Epoch ~ 55.8 million years ago, global temperatures increased by 5° to 10 °C over a period of ~ 10 to 20 thousand years(ky) then returned to warm background climates over the succeeding ~ 100 ky (1-4)”. …

    “Biotic events at the PETM include mass extinction among benthic formaminifera (10), changes in the latitudinal range and species composition of marine plankton (11,12), and shifts in the taxonomic and trophic composition of terrestial vertebrate fauna, probably after dispersal over high-latitude and land bridges (13,14)”. …

    “Conclusion: The PETM provides an important analog to present-day anthropogenic global warming, because the two episodes are inferred to have similar rates and magnitudes of carbon release and climate change (6)”.

    Scott L. Wing: Department of Paleobiology, Smithsonian Museum of Natural History, Washington, DC

    (6): J.C. Zachos et al., Science 308, 1611 (2005)

    —————————————————-

    My comments
    ——————

    The PETM as an analog for the 21 century, carbon releases and global temperatures

    For a meaningful analog, the amount of carbon released into the atmosphere and the increases in global temperatures for the 21st century should be compared to the amount of carbon released and the rate of increase in global temperatures during just the second century of warming which preceded the PETM, not the ~ 10 to 20 thousand years(ky).

    It’s likely that both the amount of carbon released and the increases in global temperatures during the 21st century will greatly exceed the amount of carbon released and increase in global temperature during just the second century preceding the PETM.

  24. 24

    #23

    I specifically asked Ellen Thomas about that, and she was of the opinion that the general consensus on the event which precipitated the PETM was ‘geologically instantaneous’ i.e. – a few centuries at most. I’ve only scanned the literature since then to see where that idea is going.

  25. 25
    Pat Neuman says:

    #23, #24

    The Science article (11 Nov 2005 by Scott L. Wing, et al.,) also states (in it’s “Conclusion”) that:

    … “In this context, it is notable that terrestial floras underwent rapid (within ~10 ky), individual range change during the PETM, including both intra- and intercontinental migration”. …

    My comments, question
    ———————————-

    Although it may be true that “the event which precipitated the PETM was ‘geologically instantaneous’ i.e. – a few centuries at most (from #24), it would seem that the length of the period of warming needed for the vegetation to survive and migrate would need to have been several k years, otherwise the abrupt heat would have eliminated much of the vegetation before it had enough time to migrate.

    Is it reasonable to conclude that the Paleocene Eocene thermal maximum (PETM-peak), followed the maximum concentration of CO2 and methane by perhaps 10 ky?

  26. 26
    Pat Neuman says:

    #12 Re: “school project on how climate has an effect on the salinity of seawater”

    Reference to PETM salinity changes, abstract below

    Abstract: The microfossil content of the upper Paleocene parts of the Nahal Avdat section (Negev Desert, Israel) and the Abu Rudeis section (Sinai Desert, Egypt) was studied. …

    … “On the basis of these data, it is concluded that the hypothesis involving a temporal shift of bottom water formation from high to low latitude, inducing warm saline bottom water to spread through all oceanic basins, is tenable. However, oxygen deficiency of this postulated watermass originating at low latitudes, can not be the controlling factor in the worldwide extinction. A change in other properties, e.g. salinity and/or temperature, must at least have played a role as well”.

    Speijer, R.P. (1994): The late Paleocene benthic foraminiferal extinction event as observed in the Middle East. In: P. Laga (Editor), Paleocene РEocene Boundary Events. Bulletin de la Soci̩t̩ belge de G̩ologie 103, 267-280 (Published 1995).

    Also, refereced salinity at end of Permian in #14

  27. 27

    You would have to deconvolute and resolve the geological ‘peak’ from the biological ‘peak’ whatever that is. At 55.5 Mya that’s going to be fairly difficult, but one can presume that the biological effects would lag the geologically pointlike events that caused the abrupt climatic changes, and we see no massive dieoffs of land flora and fauna, just rapid and extensive evolution. One can presume that the plants and animals weren’t living well beyond their sustainable means at that time, like we are now. It’s the combustion of hydrocarbons that is sustaining our civilization, pure and simple, we have already greatly exceeded the conventional carrying capacity of the planet Earth.

    To answer your question, no, the evidence indicates that temperature follows GHG concentrations very closely – +- decades if not centuries.

  28. 28
    Ian Maclaine-cross says:

    Please use correct SI units in your articles. James Hansen’s temperature
    indices are temperature differences for which the SI unit is kelvin (K).
    Please write 0.73 K not 0.73°C. I know Hansen gets this wrong but the
    rest of us should try to communicate more precisely and clearly.

  29. 29
    Pat Neuman says:

    It may be true that … “the event which precipitated the PETM was ‘geologically instantaneous’ i.e. – a few centuries at most”,

    But, if polar regions were frozen before the event which precipitated the PETM, the global warming feedbacks would have been significant in delaying both peak accumulation of GHGs and peak global temperature. What was the nature of the “event”?

  30. 30
  31. 31
    Pat Neuman says:

    #29 *****What was the nature of the “event”?*****
    #30 Abrupt. Methane plumes, presumably.

    It may be more complicated. …

    A relative sea-level fall (~30 m) immediately preceded the late Paleocene thermal maximum, during which sea-level rose again by ~20 m. This rise may have been eustatically controlled, possibly through a combination of thermal expansion of the oceanic water column and melting of unknown sources of high-altitude or polar ice caps in response to global warming.
    http://www.palmod.uni-bremen.de/FB5/geochron/Robert/RPSabstr.html

    During the Early Cenozoic India began to Collide with Asia.
    http://www.scotese.com/newpage9.htm

  32. 32
    Mark A. York says:

    Yeah they’re contrarians personified squared. I’ll use your response.

  33. 33
    Magnus says:

    Hi!

    I’ve recently come across the theory that the models predict that there will be bigger differences in temperature change near the poles and that it there fore now should be possible to notice this, but that it isn’t…

    Is it any body here that would like to comment on this?

    [Response: More warming is predicted, and seen, near the north pole. Skeptics are fond of claiming that its both poles, but thats wrong. I have a bit about this here; see-also this from RC - William]

  34. 34
    lee says:

    This is a very helpful blog to spread the science of climate. But it takes me so much time to read every blog, including insignificant blog.
    Why did you not use Wiki to write a climate cyclopaedia. It is more systematic and also it takes less time to get the knowledge.

  35. 35
    Michael Jankowski says:

    ***RE #17: Whoever this O’Brien is he is seriously WRONG.***

    O’Brien’s statement was made in July 2002 in reference to “the original CO2-doubling model by NASS, GISS under the leadership of Dr. Jim Hansen.” The Hansen paper you refer to was published in 2003, long after O’Brien’s statement.

    ***Is this really a statement by “Dr. James J. O’Brien, Director, Center for Ocean-Atmospheric Prediction Studies (COAPS)”? Because on face view I wouldn’t let the man who made these statements near my plumbing let alone allow him to make climate predictions.***

    It really wasn’t that hard to find-out. I googled “James J. O’Brien,” and the first link was his bio http://www.coaps.fsu.edu/bios/obrien.html . He seems a tad peculiar at first glance, but it’s hard to attack his credentials.

    The 3rd link in my google search turned-up his quotations here http://energycommerce.house.gov/107/hearings/07252002Hearing676/OBrien1145.htm . I think the brunt of his commentary was the promotion of improved modeling coming from the US.

  36. 36
    Michael Jankowski says:

    Gavin: ***The accuracy of the estimate given the current network is around 0.05 deg C…***
    Exactly how are you assessing “the accuracy of the estimate” when you don’t have a known value of the actual average global temperature to compare to?

    Mark: ***Dr. Hansen responded to the Milloy/Crichton farce.

    http://columbia.edu/~jeh1/hansen_re-crichton.pdf***
    I found Dr. Hansens response interesting. It looks to me like Scenario C has been the best predictor of annual trends and overall magnitude of temperature change since it started in 1990, yet Scenario C was described by Hansen as “a more drastic curtailment of emissions than has generally been imagined,” including greenhouse gas emissions flatlining starting in 2000. In fact, starting with 2001, the supposedly almost unimaginable Scenario C is almost matching the observations year-for-year.

    Lynn: ***I had almost thought any mention of GW on TV had been banned or something (I nearly never hear about it).***
    I hear/see it mentioned pretty much weekly, and I don’t watch that much TV.

  37. 37
    Steve Bloom says:

    Re #33 response: It’s worth mentioning that very recently there has been warming of the Southern Ocean adjacent to Antarctica, although the exact mechanism for this is apparently murky (i.e., as I understand it this warming is not a model prediction). This warming is of great concern, perhaps much more so than an equivalent interior warming would be, since it seems to be affecting the stability of the ice (even in east Antarctica). I’d love to hear more about this, BTW.

    Re #34 (lee): A major purpose of this blog is to respond to breaking climate news, a task to which an encyclopedia format isn’t well-suited. FYI, one of the RC authors (William) is also an active Wikipedia contributor, which means that material from this site is being added there. Bear in mind that none of the RC authors are being paid for their work on this site (or on Wikpedia in William’s case).

    Re #18 (MY): FYI, O’Brien is the Florida State Climatologist and as such is a member of the American Association of State Climatologists, which if we go by the public statements of its members comes very close to being a skeptic/contrarian network. In addition to O’Brien, members include Pat Michaels (Virginia), Roger Pielke Sr. (Colorado) and George Taylor (Oregon). It’s hard to locate the qualifications for many of them, but some are very much not climatologists despite the their titles (e.g. George Taylor, who has a masters in meteorology and whose peer-reviewed publications appear to be limited to Oregon-centric weather issues; this does not prevent him from calling himself a climatologist and taking a prominent public role as a climate expert, something he most assuredly is not). That said, the majority of state climatologists don’t appear to participate in the public skeptic stuff, even though they must be constantly lobbied to do so by some of the other members.

  38. 38
    Lynn Vincentnathan says:

    RE #23 etc on the end-permian & end-paleocene GW extinction events. I don’t know much about the situtations then. It seems to me there may be several differences now (I have no idea). In addition to the positives that would work against such mass extinctions (life is more resilient & continental configuration):

    (1) Is the initial warming (the AGW of today & projected for the next 100 years) happening a lot faster than in the 2 earlier eras?

    (2) There were no animals or mechanisms then, it seems to me, to dig up and burn the buried fossil fuels, as we are doing now – or at least not at the current rate or extent.

    (3) Is there more potential for CO2 & CH4 release in this current era (from human activities AND natural releases due to the warming) than in those two past eras (excluding from vulcanism — which could also happen in this era, in addition to human GHGs)? I’m thinking that life has been very successful in the past 55 mill.yrs, and there may be more organic sources of CO2 & CH4 than in the past 2 eras that can be released into the atmosphere as we reach various warming milestones. I really don’t know.

    (4) Can someone shed more light on “super-anoxia” for me (CH4 & O2 reactions over 10, 20 year period, producing CO2 & depleting O2). See: http://news.nationalgeographic.com/news/2005/10/1018_051018_fossils.html
    Could that be a cause of land animal harm or die off, or is it only limited to sea animal die off? And when might that start happening — when we get to 4, 5, 6, or 7 degrees above todays average? And would it only happen in only a few local areas, or more extensively. It seems to me if we are warming the world a lot faster, then anoxia or super-anoxia might happen a lot faster. Hippocrates said something like it’s the dose that makes the medicine or the poison. Perhaps in the same way, the faster rate of warming (at least in this initial period) might in itself be harmful, compared with the same warming over a much longer time frame.

    I’m not a scientist, so please forgive my ignorance.

  39. 39
    Jim Dukelow says:

    re methane outbursts:

    Seabed methane hydrates form from methane produced at depth in the seabed under warm conditions by methanogenic bacteria, rising toward the sea floor until it reaches the region of temperature (near freezing) and pressure for the formation of methane hydrate. The corollary is that methane hydrates in the seabed will always be near their critical point. As an ice age deepens and sea levels drop, they will finally reach the point where sea floor pressures are low enough that methane hydrate can evolve methane. At that point sea bed slopes can destablize, unloading more hydrates and releasing more methane, producing a methane spike that turns the ice age around. At any rate, that’s my theory and I’m sticking to it. It seems consistent with some of the Antarctic ice core data I have seen, which has a methane spike leading the warming.

    Localized methane spikes can be caused by seismic destablizations of sea bed slopes or bolide strikes.

    re “dose makes the poison”:

    Paracelsus was the one who said it, not Hippocrates.

    Jim Dukelow

  40. 40
    Pat Neuman says:

    Re #39

    I’m thinking that the sea level drop which preceded the PETM…
    http://www.palmod.uni-bremen.de/FB5/geochron/Robert/RPSabstr.html

    … and the methane plumes(#30) acted together to trigger a methane spike that powered a large part of the PETM. Mountain building, volcanoes (with a basalt flow in the North Atlantic) may have been additional factors in both the cooling (sea level drop) and warming (sea level rise) during the Paleocene and early Eocene epochs.

    Continents were in similar positions as today (except India).
    http://www.scotese.com/newpage9.htm

  41. 41
    Andrew Dodds says:

    Re: 38

    Lynn, remember that the National Geographic is a pop-sci magazine at best, and as such has to provide headlines to get people to buy it. And try to remember that a new reason for mass extinctions seems to come along every month or so; always treat such as hyppothtical unless they stay around for a decade or so.

    The anoxia they talk about is ocean-botton anoxia caused by heating induced circulation chages. Such changes are interesting – a switch from thermal to salinity based circulation can cause a rapid sea level change (geologically speaking) just from thermal expansion.

    But that isn’t going to happen, not with the continents where they are. The establishment of the current ocean circulation regieme dates to the eocene-oligicene boundary, at which point glaciation started in Antartica – and global temperatures were a lot higher then; so the idea of whole ocean anoxia is very unlikely indeed.

    The total maximum estimates of methane hydrates (which are a bit overblown IMO) are in the region of 200 Pcf, or 4×10^15 kilos. The total mass of oxygen in the atmosphere is in the region of 1×10^18 kilos; hence even in the unrealistic situation that all the methane hydrates on the planet went into the atmosphere, oxygen concentrations would not be significantly affected.

    As regards the End-permian event, this is still very much open. We have ongoing flood-basalt vulcanism, a large scale sea level drop and the physical restriction of ecosystems due to the formation of Pangea. Plus possible metorite impacts.

    http://www.ace.mmu.ac.uk/Resources/gcc/5-2-2-3.html

    http://geology.uprm.edu/Morelock/GEOLOCN_/paleoceanog.htm#6

  42. 42
    Andrew Dodds says:

    Re: 40

    As a nitpick, continental configurations at 50ma were slightly different in a couple of significant ways – there is (just) a seaway around the equator and not quite a deep passage around antartica.

  43. 43
    Chris Reed says:

    Re #35

    Hi Michael, you say “He seems a tad peculiar at first glance, but it’s hard to attack his credentials”.

    Sorry but I have less concern for credentials and more interest in arguments and their strength. I recognise that what was posted was a snip from what may well be a large body of one person’s work. But I stand by my criticisms (I may be somewhat harsh, but I can take it as well as dish it out). Perhaps he was having a very bad day.

  44. 44
    Tom Rees says:

    Re #35. O’Brian’s statement “The original CO2-doubling model by NASS,GISS under the leadership of Dr. Jim Hansen, estimated around 10ºF surface temperature change by 2050. This was so dramatic because no ocean was included.” probably referred to Hansen et al, 1984, and fundamentally misunderstands the nature of the model experiment.

    It was not an attempt to predict (or even project) climate change in 2050. It was an attempt to estimate climate response to a doubling of CO2 (i.e. the model’s equilibrium climate sensitivity). To do this, they doubled CO2 instantly and let the model come to equilibrium. The model used was GISS Model II. This is an atmosphere-land model, with prescribed sea surface temperatures. It is not suitable for predicting the time course of climate change (because the main buffer that slows climate response is ocean heat uptake). i.e. it is only suitable for conducting equilibrium (not transient) experiments. The climate sensitivity of GISS model II under these conditions is around 4.2 K – not 10F. Even 4.2 is probably a little high, but this has nothing to do with the absence of an ocean.

    It is ideal for such experiments because it comes to equilibrium very quickly (because there is no ocean). It takes about 100 years for the model to come to equilibrium. If you use as a baseline the 1958 conditions (as is conventional), then equilibrium will be reached around 100 years later. This is, obviously, not an attempt to describe conditions in 2050, but probably explains how O’Brian got confused.

    A later version of GISS model II included a slab ocean with parameterised deep-ocean heat flux, which does permit transient experiments. Hansen used this version of the model in his famous (and broadly accurate) 1988 projection.

  45. 45
    Pat Neuman says:

    Re #41

    For more on flood-basalt vulcanism, check this out:
    http://www.geolsoc.org.uk/template.cfm?name=fbasalts

    For more on tempereature effects on sea life see:
    Microbes In Marine Sediments React To Temperature Changes
    Athens GA (SPX) Nov 16, 2005
    http://www.terradaily.com/news/life-05zzzzzzzze.html

  46. 46
    Michael Jankowski says:

    Re#43: “Sorry but I have less concern for credentials and more interest in arguments and their strength.”
    No need to apologize – I am in full agreement with you. There is way too much emphasis on credentials when it comes to climate change topics.

    I was simply pointing-out that this individual is for real and has had a relatively deep career in the field.

  47. 47
    Harry Pollard says:

    Gavin,

    The information given by Eli Rabett includes graphs on the number of stations and seems to indicate that the number is down to 1,000. Also my fugitive memory of the severe Russian decline in stations seems confirmed by a table on the same site. There are now few stations where there used to be many.

    However, your point is well taken that as few as 60 will provide good information.

    I won’t trespass on your good offices any more, but I do have another question to anyone.

    After some 35 years of cooling, around 1976 (this date seems to be somewhat indefinite) temperatures shot up.

    Why the almost abrupt change? Surely, not because of anthropogenic increase in CO2 unless some kind of threshold was reached. Yet, how can this be when preceding the ‘threshold’ is a downward movement?

    In fact, in 1972 a Conference of climatologists met at Brown University to discuss evidence of an “imminent” Ice Age.

    [Response: I'm glad you put imminent in quotes. See here for more - William]

    Four years later, the ‘hockey stick’ began.

    [Response: No. Look at http://en.wikipedia.org/wiki/Image:2000_Year_Temperature_Comparison.png The "hockey stick" begins much earlier. The minor cooling mid centiry bares shows up on a longer scale - William]

    It seems to me that something other than increasing CO2 – a condition that continued during the cooling period – must have been responsible for the sudden change of direction of temperature.

    [Response: Mostly sulphate aerosols and some natural variation. See also http://www.grida.no/climate/ipcc_tar/wg1/figspm-4.htm and refs therein - William]

    I am not criticizing the ‘hockey stick’ – I wonder why it happened?

  48. 48
    Harry Pollard says:

    William,

    At the International Conference at Brown in 1972, climatologists were worried about increasing pack ice around Iceland that was becoming a hazard to shipping.

    They reported that Baffin Island – seasonally snow-free for a century – was banked high with snow. Warm climate animals were heading south.

    They noted that the amount of sunshine reaching the ground had dropped 1.3% over 8 years and a large increase in snow cover was evident in the Northern
    Hemisphere in the winter of 1971-72.

    Etc.

    In other words, they had real concerns about the possibility of a coming Ice Age.

    When exactly the ‘hockey stick’ began is of far less interest than why it began.

    Why, after a temperature decline over some 35 years was there an abrupt movement upward?

    Such a sudden reversal seems to have little to do with CO2 forcing. But, maybe it does. Can anyone provide a plausible explanation?

    [Response: Ummmm... I'm wondering if you bothered to read the link I provided. Here it is again: http://www.wmconnolley.org.uk/sci/iceage/. The (very mild) cooling in mid century is usually put down to aerosols and... hold on, I've said that already. Why are we going round in circles? - William]

  49. 49
    Pat Neuman says:

    #48 states: Why, after a temperature decline over some 35 years was there an abrupt movement upward?

    I think El Niño Impacts can explain that (above).

    The NOAA CDC website shows a graph of ENSO and states:
    “The time-series graph shows the monthly evolution of the amplitude and phase of EOF1 from January 1950 to present. Large positive departures, shown in red, denote warm events, whereas large negative departures, shown in blue, denote cold events.”
    http://www.cdc.noaa.gov/ENSO/impacts/currentclimo.html

    The graph shows:
    cold events 1950-mid 1970s,
    warm events late 1970s-late 1990s.

    I’ve seen a graph going back to the early 1900s, which showed:
    warm events 1920-late 1940s.

    If the 1880-current plot of global temperatures was adjusted slightly downward for to remove the warm ENSO bias for 1920-late 1940s, and if the global temperatures 1950-early 1970s were adjusted slightly upward to remove the cold ENSO bias, then the global temperature plot for the 20th century would show a gradual rise from 1920-mid 1970s, followed by the sharp upward late 1970s to late 1990s (which was a period when CO2 was rising more rapidly combined with more warm ENSO events than cold ENSO events).

  50. 50
    Pat Neuman says:

    Global warming is not a hoax.

    Global Temperatures:

    NOAA NCDC: … “During the past century, global surface temperatures have increased at a rate near 0.6°C/century (1.1°F/century) but this trend has increased to a rate of 1.7°C/century (3.1°F/century) during the past 25 to 30 years”. …
    http://www.ncdc.noaa.gov/oa/climate/research/2004/ann/global.html#Gtemp

    NASA: … “Is 2005 going to be the warmest year as we predicted? The 2005 temperature for the first ten months of the year exceeded that of 1998 –so far the warmest year on record”.
    http://data.giss.nasa.gov/gistemp/graphs/

    Measurements of CO2 in Earth’s atmosphere:
    http://www.cmdl.noaa.gov/gallery/ccgg_figures?page=2
    http://www.cmdl.noaa.gov/infodata/faq_cat-3.html

    Water Vapor
    http://www.realclimate.org/index.php?p=212#comments

    Influence of ENSO on global temperatures:
    warm ENSO(1920-late1940s)
    cold ENSO(1950-mid1970s)
    warm ENSO(late1970s-1990s)
    neutral ENSO(2000-2005)

    Table*: Change in Global Temperatures by 10 year averages

    Interval: Deg C
    1906-1915 -.037
    1916-1925 0.054
    1926-1935 0.142
    1936-1945 0.122
    1946-1955 -.092
    1956-1965 0.001
    1966-1975 -.067
    1976-1985 0.206
    1986-1995 0.256
    1996-2005 0.319
    —————–

    1896-2005 0.904

    *Table shows 10 year changes in global temperature land data by 10 year averages.
    Data downloaded from NOAA NCDC website.
    Annual global land temperature used for 2005 was the same value occurred in 1998.
    10 year averaged increase in global temperatures (land data) = .319 C (1996-2005).

    Summary:
    Although near neutral ENSO occurred 1999-2005, the rate of increase in global temperatures continues to increase (accelerate)… to the latest 10 year averaged rate of .310 Deg C (1996-2005). The reason that global warming is accelerating is due to an increasing accumulation of greenhouse gases in Earth’s atmosphere.


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