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2008 temperature summaries and spin

Filed under: — gavin @ 16 December 2008 - (Italian)

The great thing about complex data is that one can basically come up with any number of headlines describing it – all of which can be literally true – but that give very different impressions. Thus we are sure that you will soon read that 2008 was warmer than any year in the 20th Century (with the exception of 1998), that is was the coolest year this century (starting from 2001), and that 7 or 8 of the 9 warmest years have occurred since 2000. There will undoubtedly also be a number of claims made that aren’t true; 2008 is not the coolest year this decade (that was 2000), global warming hasn’t ‘stopped’, CO2 continues to be a greenhouse gas, and such variability is indeed predicted by climate models. Today’s post is therefore dedicated to cutting through the hype and looking at the bigger picture.

As is usual, today marks the release of the ‘meteorological year’ averages for the surface temperature records (GISTEMP, HadCRU, NCDC). This time period runs from December last year through to the end of November this year and is so-called because of the fact that it is easier to dice into seasons than the calendar year. That is, the met year consists of the average of the DJF (winter), MAM (spring), JJA (summer) and SON (autumn) periods (using the standard shorthand for the month names). This makes a little more sense than including the JF from one winter and the D from another as you do in the calendar year calculation. But since the correlation between the D-N and J-D averages is very high (r=0.997), it makes little practical difference. Annual numbers are a little more useful than monthly anomalies for determining long term trends, but are still quite noisy.

The bottom line: In the GISTEMP, HadCRU and NCDC analyses D-N 2008 were at 0.43, 0.42 and 0.47ºC above the 1951-1980 baseline (respectively). In GISTEMP both October and November came in quite warm (0.58ºC), the former edging up slightly on last month’s estimate as more data came in. This puts 2008 at #9 (or #8) in the yearly rankings, but given the uncertainty in the estimates, the real ranking could be anywhere between #6 or #15. More robustly, the most recent 5-year averages are all significantly higher than any in the last century. The last decade is by far the warmest decade globally in the record. These big picture conclusions are the same if you look at any of the data sets, though the actual numbers are slightly different (relating principally to the data extrapolation – particularly in the Arctic).

So what to make of the latest year’s data? First off, we expect that there will be oscillations in the global mean temperature. No climate model has ever shown a year-on-year increase in temperatures because of the currently expected amount of global warming. A big factor in those oscillations is ENSO – whether there is a a warm El Niño event, or a cool La Niña event makes an appreciable difference in the global mean anomalies – about 0.1 to 0.2ºC for significant events. There was a significant La Niña at the beginning of this year (and that is fully included in the D-N annual mean), and that undoubtedly played a role in this year’s relative coolness. It’s worth pointing out that 2000 also had a similarly sized La Niña but was notably cooler than this last year.

While ENSO is one factor in the annual variability, it is not the only one. There are both other sources of internal variability and external forcings. The other internal variations can be a little difficult to characterise (it isn’t as simple as just a super-position of all the climate acronyms you ever heard of NAO+SAM+PDO+AMO+MJO etc.), but the external (natural) forcings are a little easier. The two main ones are volcanic variability and solar forcing. There have been no climatically significant volcanoes since 1991, and so that is not a factor. However, we are at a solar minimum. The impacts of the solar cycle on the surface temperature record are somewhat disputed, but it might be as large as 0.1ºC from solar min to solar max, with a lag of a year or two. Thus for 2008, one might expect a deviation below trend (the difference between mean solar and solar min, and expecting the impact to not yet be fully felt) of up to 0.05ºC. Not a very big signal, and not one that would shift the rankings significantly.

There were a number of rather overheated claims earlier this year that ‘all the global warming had been erased’ by the La Niña-related anomaly. This was always ridiculous, and now that most of that anomaly has passed, we aren’t holding our breath waiting for the ‘global warming is now back’ headlines from the same sources.

Taking a longer perspective, the 30 year mean trends aren’t greatly affected by a single year (GISTEMP: 1978-2007 0.17+/-0.04ºC/dec; 1979-2008 0.16+/-0.04 – OLS trends, annual data, 95% CI, no correction for auto-correlation; identical for HadCRU); they are still solidly upwards. The match of the Hansen et al 1988 scenario B projections are similarly little affected (GISTEMP 1984-2008 0.19+/-0.05 (LO-index) 0.22+/-0.07 (Met-station index); HansenB 1984-2008 0.25+/-0.05 ºC/dec) – the projections run slightly warmer as one would expect given the slightly greater (~10%) forcing in the projection then occurred in reality. This year’s data then don’t really change our expectations much.

Finally, as we’ve discussed before, what climate models did or did not predict is available for all to see. Despite many cautions about using short-term changes to imply something about the long-term trend, these comparisons will still be made. So just for fun, here is a comparison of the observations with the model projections from 1999 to 2008 using 1999 as a baseline. The answer might be surprising for some:

1999-2008 model and data trends

You can get slightly different pictures if you pick the start year differently, and so this isn’t something profound. Picking any single year as a starting point is somewhat subjective and causes the visual aspect to vary – looking at the trends is more robust. However, this figure does show that in models, as in data, some years will be above trend, and some will be below trend. Anyone who expresses shock at this is either naive or … well, you know.

As for the next few years, our expectations are not much changed. This coming winter is predicted to be ENSO neutral, so on that basis one would expect a warmer year next year than this year (though probably not quite record breaking). Barring any large volcanic eruption, I don’t see any reason for the decadal trends to depart much from the anticipated ~0.2ºC/decade.

Update: Just FYI, the same figure as above baselined to 1990, and 1979.


393 Responses to “2008 temperature summaries and spin”

  1. 301
    Andrew says:

    #300 Jim Cross

    I can appreciate that future solar cycles may have significantly less sunspots than recently. However, from top to bottom, a solar cycles only push solar irradiance from about 1365.5 to 1366.5 Watts/m^2.

    When I put those values into a stephan boltzmann equation, with standard values for albedo and emissitivity, I come up with about 0.05C of surface temperature change.

    When I review CO2 levels and how much they change, I calculate that the impact amounts to between 0.01 to 0.03 C/yr of warming. In other words, increases in CO2 are more significant after just a few years.

    Also, I know that ENSO events can push global temperatures up or down 0.2C.

    So, it is good to keep things in perspective.

  2. 302
    wmanny says:

    #291 The “lone persecuted genius” picture of scientific progress is a gross caricature.

    Agreed. I was merely referring to Darwin’s having to take on the established physics of his day, in this case Thomson-Kelvin’s.

    Darwin to Wallace: “Thomson’s views on the recent age of the world have been for some time one of my sorest troubles.”

    That’s all.

  3. 303
    wmanny says:

    #293c

    “But if you think adding to ignorance and increasing disinformation is a positive benefit to society.” No, I don’t think so, Gavin, obviously. Nor do I think engaging those with whom you disagree adds to ignorance, and it seems self-evident to me that lambasting rather than querying one’s opponents is the more ignorant approach. – Walter

    [Response: 'lambasting'? I critiqued his quoted argument. That is a long way from 'lambasting' - However, given his long history (see links passim), I'm not going to hold my breath waiting for a dialogue. - gavin]

  4. 304
    Nick Gotts, OM says:

    wmanny@302,
    OK. But Darwin’s theory of evolution, like modern climate science, made sense of a vast body of observations that had no alternative explanation: there was therefore a clash between disciplines. There is no such clash between modern physics and climate science; rather, AGW sceptics (even those few who may still deserve that title rather than “denialist”) are in the position of Darwin’s opponents in biology and geology – desperately hopping from one will-o’-the-wisp objection to another, without any sign of an overarching theory.

  5. 305
    Jim Cross says:

    #301

    On what basis do you assume that irradiance in solar cycle 25 will only go as low as a 20th century solar cycle minimum? Is there a reference for that?

    In addition, there are other things to consider that are not completely understood at this time. What are the climatic effects of a diminished solar wind and interplanetary magnetic field?

    I’ve admitted that I am spectulating somewhat but arguing from the experience of recent solar cycles and the last 50-60 years is spectulating somewhat too.

  6. 306
    Phil. Felton says:

    Re #280
    wayne davidson Says:
    25 December 2008 at 10:45 AM
    “276 Phil, Princeton is mostly awesome, where freedom of thought (even faulty) is allowed, take a look at Interesting IR downwelling surge in 2005″

    You’re right about Princeton, the most notable case being a distinguished professor and Dean of the Engineering School who set up a lab researching into psychic phenomena (much to the chagrin of many faculty members)!
    The IR data is interesting, in particular the consistent 300+ W/m^2 when the SW has hit 0 as also seen in the recent buoy.

  7. 307
    Andrew says:

    #305 Jim Cross

    Generally, the most recent observation and trends are the best prediction of the immediate future. This is true for most physical phenonimum.

  8. 308
    Hank Roberts says:

    http://www.grida.no/climate/ipcc_tar/wg1/images/fig12-7s.gif

    Modeled using only natural forcings compared to observations
    Modeled using anthropogenic forcing compared to observations
    Modeled using the combined forcings compared to observations

    One picture, sums it up. Understand it or go on pretending it can’t be understood. It’s easier to understand than not understand by now.

    Below, hat tip to
    http://www.climateshifts.org/?p=899
    Convincing the climate-change skeptics
    By John Bruno • Dec 23rd, 2008

    a brief excerpt from an op-ed published in the Boston Globe
    John Holdren, August 4, 2008

    “Their arguments, such as they are, suffer from two huge deficiencies.

    First, they have not come up with any plausible alternative culprit for the disruption of global climate that is being observed, for example, a culprit other than the greenhouse-gas buildups in the atmosphere that have been measured and tied beyond doubt to human activities. (The argument that variations in the sun’s output might be responsible fails a number of elementary scientific tests.)

    Second, having not succeeded in finding an alternative, they haven’t even tried to do what would be logically necessary if they had one, which is to explain how it can be that everything modern science tells us about the interactions of greenhouse gases with energy flow in the atmosphere is wrong.”

  9. 309
    RichardC says:

    305 Jim asked, “On what basis do you assume that irradiance in solar cycle 25 will only go as low as a 20th century solar cycle minimum?”

    Totally irrelevant. Andrew’s analysis was based on a potential grand minimum – as in ZERO sunspots for cycle 25. Even in that extreme and absolute case, the sun will only dim enough to counter a few years worth of CO2 increase.

  10. 310
    Hank Roberts says:

    > what are the climatic effects …..?

    Try plugging your question into Google Scholar, and reading the results (at least limit it to recent papers and read a few dozen).
    I found a variety of useful papers. You’ll find some of the ones from the PR blogs, BUT, you’ll also find others they don’t tell you about. So, just as a typical example, this:

    http://www.springerlink.com/content/g74070035274784x/

    Then look below the Scholar hit and click “Cited by” to read the list of papers that cited the paper you find, for example

    http://scholar.google.com/scholar?num=150&hl=en&lr=&newwindow=1&safe=off&cites=7969411931024483665

    If your purpose is to learn how to learn, you can do that here.

    To the “gaps” notion, so beloved of people who insist there must be some hidden actor or force not yet discovered, isn’t working out very well so far in any area — this will help you see how the “gaps” get smaller and smaller with more scientific work. Shine some light into your areas of dark.

    No hidden actor yet found.

  11. 311
    curious says:

    Re #299: Paragraphs might help!

  12. 312
    David B. Benson says:

    wmanny (283) — I’ve been reading and posting on RealClimate for a few years now. I commend the tolerance of the moderators and the patience with which various responses are made. I also commend the patience of the many amateurs here who have to repeated point out to newcomers that they really should go learn the subject of climatology. I suggest starting with W.F. Ruddiman’s books, “Earth’s Climate: Past and Furture” and his popular “Plows, Plagues and Petroleum”. I then suggest David Archer’s “The Long Thaw” before his other book and harder stuff such as Ray Pierrehumbert’s

    http://geosci.uchicago.edu/~rtp1/ClimateBook/ClimateBook.html

    Once you have read several books and a dozen or so papers you’ll be in a position to begin to understand why the fringe community, several members of which you have named, are simply wrong.

  13. 313
    Jim Cross says:

    #307, 309

    Obviously you guys have never read The Black Swan:

    http://www.fooledbyrandomness.com/

    Solanki and Figge tried to reconstruct the historical solar irradiance. The effort is difficult and inexact. As they point out:

    “Precise measurements of the irradiance have only
    been made since 1978, whereas longer time series are required
    in order to establish a possible relationship with climate.”

    Their reconstruction for the Dalton minimum has the value possibly as low as 1359 Watts/m^2.

    http://www.acrim.com/Reference%20Files/Solanki%20&%20Fligge_A%20reconstruction%20of%20total%20solar%20irradiance%20since%201700_1999GL900370.pdf

    But who is to say that the Dalton minimum is typical of a grand solar minimum? Perhaps the Maunder was even lower? Or perhaps solar cycle 25 may be the start of one lower yet?

    My point isn’t that CO2 isn’t the cause of most of our recent warming. My point is that you can’t extrapolate from a couple of recent decades of solar cycles and assume future solar cycles will be the same.

    This other article describes just how unusual the recent solar cycles have been and how unlikely future ones will be like the recent ones:

    http://cc.oulu.fi/~usoskin/personal/nature02995.pdf

  14. 314
    Hank Roberts says:

    Jim, have you read the previous threads where that paper has been discussed at length? Search box will help. One of the authors has participated.
    http://www.realclimate.org/?comments_popup=180#comment-3961

    You’ll find much talking about the same work at the adit and greenwash PR sites, but without the scientists.

    There are a lot of people claiming that the interesting science being done about solar activity must somehow prove there’s some connection to the last few decades of climate change. But nobody has shown one.

    Don’t confuse interesting work on solar activity with the wish to believe it has to explain what CO2 explains.
    Try reading the threads at RC, just to save retyping the same stuff.

  15. 315
    Hank Roberts says:

    PS, Jim — one useful way to distinguish blather from science is to watch for the phrase you coined above:

    “who is to say”

    is pretty consistently not part of a scientific discussion.

    Say it to any reference librarian — they’ll clear that up for you.

  16. 316
    Jim Cross says:

    Hank,

    Did you read my post? I didn’t say solar activity explained recent global warming. I said the opposite.

    The problem or issue is I see it is that future solar cycle might actually mitigate temporarily global warming.

    In one way, this would be good. It would give us some breathing room to fix the problem or maybe let peak oil or new technology to reduce human CO2 input into the climate system.

    But there would be a downside.

    The deniers could come out saying “I told you so.” The climate scientists would have to explain things that most people aren’t going to grasp about the problem not having gone away. And most reasonable people are going to be confused.

    The IPCC predictions are serious enough without some of the alarmist tendencies to overstate things about runaway greenhouse effect or oceans rising multiple feet. Let me be clear that scientists aren’t making those predictions but some of this site do.

    If the predictions are too alarmist, it will be so much the worse if something – anything, even a big volcano – comes along makes the predictions look ridiculous.

  17. 317
    Hank Roberts says:

    There are people who will try to make anything the climate scientists say look wrong. Remind them that scenarios include the various possibilities, that’s one way that scenarios differ from “predictions” — you can show them scenarios including volcanic events.

    I don’t off hand know of any climate scenario that includes a change in the sun great enough to alter Earth’s weather for a few years like a big volcanic event can do. It’d have to be comparable to what’s being suggested by the geoengineers.

    Nor do I know of anything like that described in the observations of other stars like our sun, and I know they’re being watched — it’s the only way to get a better idea of the range of variation that may be possible locally in a hurry.

    Come up with a scenario using what’s known. YOu will never be able to argue with the people who say “but something else might happen.”

    Yep, something else might happen. Don’t bet the farm on it.
    ________________________
    Can someone arrange to send a dozen roses to ReCaptcha for me?
    I think I’m in love. Today’s words: “Seitz missioners”

  18. 318

    #306 Phil, I still need some perspective, with respect to say at a more Southern location was the down welling. this paper:

    http://ams.confex.com/ams/Madison2006/techprogram/paper_113329.htm

    refers to a calibration and quality control effort, in Switzerland?? Where Downwelling was measured from 190-320 W/m2…. THat is virtually the same as over the North Pole to Fram quadrant, fascinating if so .

  19. 319
    Phil. Felton says:

    Wayne, I think they make IR downwelling measurements at Barrow, ARM or SIRS perhaps.

  20. 320
    Andrew says:

    Jim Cross

    I appreciate Solanki and Fligge’s work.
    They stress, however, that determining
    the quantitative long-term variations of the quiet Sun is highly speculative and subject to large uncertainties. Converting sparse sunspot observations from the 1700’s into watts/m^2 is a feat.
    Notice, they observe greatest uncertainty in the area of your concern (1750 to 1825).

    Anyhow, we are currently at an overdue solar minimum and TSI is about 1365.4 watts/m^2. This is just about the same as the minimum in 1996; so no trend. However, in the 1986 minimum, TSI was about 1365.5 watts/m^2.

    0.1 watt over 22 years works out to about 0.005 watt/yr.
    Plug this into Stephan Boltzmann and it works out to 0.001 C/yr.

    Recent global warming from the rise in GHG is about 0.0166 C/yr.
    0.0166 – 0.001 = 0.0156 C/yr.

    Concentrating on Solar Max and again, no trend between 1990 to 2002; but similar size from 1981 to 2002.

    So, while there may be a long term gradual decline in solar irradiance, it is barely significant compared to current rate of warming.

  21. 321
    Scott says:

    The IPCC predictions are serious enough without some of the alarmist tendencies to overstate things about runaway greenhouse effect or oceans rising multiple feet. Let me be clear that scientists aren’t making those predictions but some of this site do.

    If I read the some of the conclusions in the latest report on Abrupt Climate Change from the US Climate Change Science Program http://www.climatescience.gov/Library/sap/sap3-4/final-report/default.htm, in particular Chapter 2, it would seem possible to come up with multiple feet of sea level rise due to the understanding of ice dynamics.

  22. 322
    Andrew says:

    It almost funny.

    Claim 4 feet of sea level rise and you’re an alarmist.
    Claim 1.3 mm/yr and many people relax since they don’t know the differance.

    Or better yet, how about -480 Gt a^-1?

  23. 323
    Alan Millar says:

    “It almost funny.

    Claim 4 feet of sea level rise and you’re an alarmist.
    Claim 1.3 mm/yr and many people relax since they don’t know the differance. Andrew”

    Well it is funny isn’t it!

    It would take nearly 1000 years to get a four foot sea level rise at 1.3 mm per year.

    Why are you not relaxed?

    Alan

  24. 324
    Hank Roberts says:

    Lose the trailing comma to make that link work:
    http://www.climatescience.gov/Library/sap/sap3-4/final-report/default.htm

    There are two differences between “feet” and “millimeters per year” — change vs. rate of change is the important one.

    Nobody’s promising a millenium of tranquility followed by a rapid event.

  25. 325
    Paul D says:

    With regard to “alarmism”, have any climate scientists made a worst-case maximum credible prediction? Have they done any kind of probabilistic analysis – like seismologists and meteorologists do when developing design parameters for buildings and dams? In general, when loss of human life is involved the public demands that structures handle uncertainty by being designed for events with a rather remote probability of occurrence.

    For example, building codes have provisions for design to resist earthquake shaking that have a remote (usually one in 2000 years or so) probability of occurring. Critical facilities like nuclear power plants must be designed for a site-specific “maximum credible earthquake” as their safe-shutdown event. Dams that could result in loss of life must be designed to safely pass a “probable maximum precipitation” – a theoretically derived storm event with a very remote possibility of occurrence.

    Please correct me if I’m wrong, but the IPCC seems to be focusing on a “best prediction” – an event with a 50% probability of exceedence. But I could never consider design anything based on these predictions – it would have a 50% chance of failure.

    So we design for loadings and events with a remote chance of occurring – but we civil engineers never get accused of being alarmist. So shouldn’t planners have access to a “worst-case prediction without this talk of being “alarmist”.

    Thanks in advance for any responses.

    Paul D.

  26. 326
    Hank Roberts says:

    Paul, what kind of civil engineering are you doing? I’m surprised any sort is _not_ addressing these concerns by now. Well, except areas like utility power transformer replacement
    http://ag.ca.gov/globalwarming/pdf/ee_petition.pdf#xml=http://search.doj.ca.gov:8004/AGSearch/isysquery/3b7944bf-2b14-4344-9efb-f8365e3f5683/1/hilite/
    where DOE still says there’s no reason to consider climate change.

    E.g.
    http://www.google.com/search?q=%22civil+engineer%22%3A+%2BCalifornia+%2BBay+%2BDelta+%2B%22climate+change%22+%2B%22sea+level%22

    ReCaptcha:
    ________________
    “Stark revision”

  27. 327
    dhogaza says:

    Thanks in advance for any responses.

    Oh, very good points, indeed.

    To be honest, though, I’m more surprised that more conservatives don’t argue that we shouldn’t plan for exceptional low-probability events like large earthquakes.

    Perhaps it’s because that even though such events might be relatively rare, we see the effect of even moderate earthquakes, flooding, etc in parts of the world where stringent standards and planning have not been in effect?

    Scientists, engineers and political leaders can always point to the horror of (say) the last SE asian tsunami event when they upgrade a regional “tsunami danger zone” (such as was just done in Oregon), and people will relate.

    We can’t point to another planet and say, “hey, look, that’s what happened when *that* civilization ignored the consequences of climate change driven by their behavior”. We’ve only got our own planet.

    Also, the damage caused by climate change will never be as dramatic as, say, a huge earthquake, which can cause a great amount of destruction in a few minutes.

    And we don’t see a dishonest, intentional effort to hoodwink the populace about the danger of earthquakes, etc, as we do with climate science. That’s got to play a role :)

  28. 328
    Nick Gotts says:

    My point isn’t that CO2 isn’t the cause of most of our recent warming. My point is that you can’t extrapolate from a couple of recent decades of solar cycles and assume future solar cycles will be the same. Jim Cross

    But you can look at past climate records, and see no sign, over many thousands of years, that solar variations have had effects of anything like the size needed to cancel out the expected effects of increased greenhouse gas levels in the atmosphere over the next few decades.

  29. 329
    Andrew says:

    There are some nuclear power plants that had to be re-analyzed. The plants were of course designed with assumptions made for weather extremes (max/min temps, winds, water level and floods) However, some have experienced higher temperatures than originally assumed.

    Both cooling water temperature and ambie_nt have been found to exceed assumptions made during the 1970′s when most were originally sited. The engineering cost of these re-analysis has not been particurly expensive. Of course, the guys doing the work appreciated the pay.

    In the SE US, the prolonged drought has lowered water levels at some sites. I can’t say if they were able to just re-analyze or if they had to do mods or take de-rates. Similar problems have occured at times in the Midwest, but not lately.

  30. 330
    Hank Roberts says:

    Jim, do you have a library where you can read Science?
    http://www.sciencemag.org/cgi/content/summary/306/5693/68

    If not, see if you can find that online, or the papers referring to and discussing it. Often authors or teachers will have made copies accessible; the citing papers and related papers should help. Searching by the author’s names will also find more.

    http://www.ncbi.nlm.nih.gov/pubmed/15774756?ordinalpos=12&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

    http://www.ncbi.nlm.nih.gov/pubmed/16971941?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

  31. 331
    Richard Palm says:

    Just curious: has the following article been commented on here?

    http://www.telegraph.co.uk/comment/columnists/christopherbooker/3982101/2008-was-the-year-man-made-global-warming-was-disproved.html

    [Response: No. But his previous articles have attracted a fair bit of attention. - gavin]

  32. 332

    324 Phil, Stephen Schneider puts it at 324 watts/m2 per standard atmosphere. I am puzzled or rather feel quite the neophyte with this subject, astounding that we do not have more data readily available.

  33. 333
    Andrew says:

    Re 331: Global warming is expected to lead to greater precipitation during the NH winters. In particular November and December snowfalls have trended higher while rest of year shows decline.

    In other words, expect more snow fall and faster melting!

  34. 334
    jyyh says:

    Paul D… As a part-time alarmist I would answer that with a little bit of extrapolation added to some warnings of climate scientists I guess the worst case scenario at least includes the total collapse of the WAIS, creating tsunamis at least all over the Pacific rim, the subsequent sea level rise of c.7m will destroy most of the remaining harbours, communication centers near coasts, next up would be the melting of the collapsed ice in the southern ocean altering the climate of the entire southern hemisphere, making it near-impossible to guess what areas are good for similar agriculture as before, leading to massive movements of people. The tsunamis might enter also the Arctic ocean, destabilising the northern part of the Greenland ice sheet, giving a further rise of 3m. I think the runaway methane release suggested by some is not likely as long as there is plenty of ice on Greenland/EAIS as their melting will keep the ocean surfaces cool enough. I’m not saying this is going to happen, it’s just a possibility which might start f.e. with a large volcanic eruption or a large earthquake near or under WAIS, I don’t know how probable those are.
    To RC, if this post is too alarmist, please moderate it away.

    ReCaptcha: Hance Blackwood , I don’t know what that means.

  35. 335
    jyyh says:

    Heh, Hance Blackwood, the writer of high school physics book.

  36. 336
    Ray Ladbury says:

    Paul D., The IPCC is not doing engineering, but rather using “scenarios” to highlight trends. Their emphasis is science, so best estimates are what is expected. James Hansen, Lovelock and others are coming closer to specifying WC scenarios, although whether they are really worst-case remains to be seen.

  37. 337
    BeetleB says:

    The problem with the IPCC “scenarios” is that IPCC is using models or data in the models that are not predicting future events with any degree of certainty. Thus the “scenarios” as published are worthless.

    The marketing(a term I do not use lightly) of the models, before validation, seriously undermines the public’s confidence in the IPCC and if they are wrong will so undermine the public’s confidence in science that it may take generations to recover.

    [Response: Perhaps you could point us to a source of information about the future that is without uncertainty? I'm sure the IPCC would be happy to use it. - gavin]

  38. 338
    dhogaza says:

    The problem with the IPCC “scenarios” is that IPCC is using models or data in the models that are not predicting future events with any degree of certainty

    Maybe you can help us out by telling us how many tons, with a high degree of precision, of CO2 will be spewed into the atmosphere in 2050?

    Please show your work …

    If you can credibly provide such a number, climate scientists will be able to tighten their predictions by a huge degree of precision.

    If you can’t, then don’t complain.

  39. 339
    krisb says:

    ‘Response: Perhaps you could point us to a source of information about the future that is without uncertainty? I’m sure the IPCC would be happy to use it. – gavin]’

    Gavin; Newtonian physics can predict the future with a fair amount of certainty.

    [Response: Chaos occurs in purely Newtonian systems (like the weather). That doesn't actually help much (and of course is the basis of climate modelling in any case!). - gavin]

  40. 340
    Ray Ladbury says:

    BeetleB, Your post is not even logically correct: there are no degrees of certainty. You are either certain or you are not. You are also factually incorrect, as the models have been validated. To paraphrase Pauli, your post doesn’t even rise to the level of being wrong. You are a perfect example of how someone can be certain and yet flat wrong.

  41. 341
    Ray Ladbury says:

    Krisb, Great, so when can we expect your solution of the 3-body problem?

  42. 342
    krisb says:

    ‘[Response: Chaos occurs in purely Newtonian systems (like the weather). That doesn’t actually help much (and of course is the basis of climate modelling in any case!). - gavin'

    Gavin, my point is simply that laws of physics can predict the future - hence providing an example for a source of information that provides certainty about the future. I am not specifically talking about climate/weather, just science.

    The basis of climate modelling? what, the laws of physics? i have read that the earth cools primarily through convective currents - and that turbulence equations (the chaotic part) are somewhat unsolvable. correct me if i'm wrong though :).

    [Response: ??? Of course I agree that physics gives us some predictability (otherwise I wouldn't be a climate modeller), but that only goes so far, and the human factor in determining emissions in the future (the 'scenarios') are precisely the bits that aren't reducible to physical equations. - gavin]

  43. 343
    krisb says:

    ‘Krisb, Great, so when can we expect your solution of the 3-body problem’

    Ray, i dont think your post really says much, can you elaborate?

  44. 344
    Hank Roberts says:

    krisb, you replied to Gavin saying:

    “Newtonian physics can predict the future ….”

    That’s true within severe limits.
    Two items, Newton will take care of you forever.
    Three or more, Newton won’t help you quite so long.

    How many items involved in the climate of the planet?

    here, this may help.
    http://www.google.com/search?q=%2BNewton+%2B“three+body+problem”

    ______________________
    ReCaptcha? The words offered me for this posting are “Salonica said” which led me quickly to find

    “… the 13th conference in the Recent Developments in Gravity series. It will be held at Salonica (Thessaloniki, Greece) …”

  45. 345
    cw00p says:

    I’ve been following the blog for a while and have just now decided to post. For the record, I guess you can consider me a “denialist” although I don’t think the term as has been defined in here applies. I just don’t think we have reached the level that our anthropomorphic activities are significant enough to make the type of graphics climate changes attributed to humans. For the record, I sure think we can over time, but I haven’t seen anything that suggests we are there yet.

    My comment, statement, question is:

    The Permian die off, which is attributed to global warming, started when the earth’s climate was very similar to what it is now. I watched a Nation Geo special on the topic (http://science.nationalgeographic.com/science/prehistoric-world/permian-extinction.html ) in which it was determined that the level of CO2 in the atmosphere increased, principally due to the amount of gas released by the Siberian traps until the temperature had increased by 4 degrees c and then all of the methane hydrates began to thaw which put the warming into over drive.

    This warming, of course, lead to the biggest die off in Earth’s history.

    The problems with the global warming community of today relates to timeline. Whereas the CO2 levels increased during the Permian, and the earth did warm by 5 degree c total, it took 70,000 years with Co2 at much high ppm than today (7000 ppm by the time of the die off – http://www.geocraft.com/WVFossils/Carboniferous_climate.html ) to raise it the 3 to 4 degrees c needed to melt the hydrates. The final process took another 10,000 years to occur.

    We are seeing nothing approaching this scale.

    I realize MMGW does not suggest a die off like during the Permian; however, it is important to note that co2 levels were much higher during that period, increased at higher rates that today, and it still took 70k years to increase by 2 to 4 degree c.

    Further, the chart provided in the link above also show how co2 and temperature rarely seem to be in step enough to ever complement one another and bring about the predicted climate changes.

    Again, I don’t deny that humans can’t do grievous damage to our environment, as technology advances; we may have the capability to literally crack the planet in two and to induce Novae in stars (even our own). As it stands now, we don’t quite have the capability to change the climate in such massive ways as suggested by MMGW. But I do have faith we can poison it and, at least, kill ourselves off.

  46. 346
    Ray Ladbury says:

    Kris B., Just because classical physics is deterministic does not mean that every problem can be solved exactly or that every classical system is predictable. Even fairly simple solutions can exhibit chaotic behavior, where different realizations will end up in very different final states. Weather is an example of a chaotic system.
    My allusion to the three-body problem is because it is one of the most famous insoluble problems in physics.

  47. 347
    Tom Guilderson says:

    In a series of earlier posts (eg. #177,#100) were queries requesting what do “the models” look like with respect to MSU (mid-troposphere satellite derived) temperature estimates?

    For those interested in such a comparison they could look at Santer et al., Consistency of modelled and observed temperature trends in the tropical troposphere International Journal of Climatology, V 28, n13, Date: 15 November 2008, Pages: 1703-1722. This is mainly a statistical treatment of how to test the reliability of trends in short data-sets but Ben also has graphs of mid-troposphere from an ensemble of results from one of the AR models. Ben also composites the average trends for much of the AR4 suite, even models that only have a single realization.

  48. 348
    Hank Roberts says:

    cw00p, try this:
    http://scholar.google.com/scholar?q=rate+of+CO2+increase+in+Permian

    (click “recent” to limit it)

    You’ll find the information you’re missing, which is how fast the change is happening. Hits like this one.

    (Elsevier has copies behind a paywall, so you’d need to get this from a library or by searching further)

    Paleophysiology and end-Permian mass extinction – ►stanford.edu [PDF]
    AH Knoll, RK Bambach, JL Payne, S Pruss, WW … – Earth and Planetary Science Letters, 2007 – Elsevier
    … the key variable is rate of change … the rapid, unbuffered increase in P CO2 and not …
    Cited by 15 – Related articles

    Click the “cited by” and “Related articles” links (focus on articles cited by more other articles)
    And look for other papers by the same authors, many of whom likely have copies available online that you can read.

  49. 349
    tamino says:

    Re: #345 (cw00p)

    Let’s start with the fact that the source you link to in order to support your “7000 ppm by the time of the die off” claim, flatly contradicts you. It shows the CO2 level at the end of the Permian to be about 2000 ppm, not 7000.

  50. 350
    dhogaza says:

    Gavin, my point is simply that laws of physics can predict the future – hence providing an example for a source of information that provides certainty about the future…

    So the future is predictable

    The basis of climate modelling? what, the laws of physics? i have read that the earth cools primarily through convective currents – and that turbulence equations (the chaotic part) are somewhat unsolvable. correct me if i’m wrong though :).

    Yet the future is NOT predictable, because not everything is solvable (I’ll ignore the “somewhat”, which is meaningless, which ought to give you a clue that you don’t know what you’re talking about).

    Is it true that you don’t recognize the contradiction in your own post?

    You’re pretty much missing everything that chaos theory has told us about determinism at the scale at which Newtonian mechanics works well.


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