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Mind the Gap!

Filed under: — rasmus @ 18 November 2008 - (Italian)

Mean temperature difference between the periods  2004-2008 and 1999-2003
Confusion has continued regarding trends in global temperatures. The misconception ‘the global warming has stopped’ still lives on in some minds. We have already discussed why this argument is flawed. So why have we failed to convince ;-) ?

The confused argument hinges on one data set – the HadCRUT 3V – which is only one of several estimates, and it is the global temperature record that exhibits the least change over the last decade. Other temperature analyses suggest greater change (warming). Thus, one could argue that the HadCRUT 3V represents the lower estimate, if a warming could be defined for such a short interval.

Global mean temperature estimates: CRU, NASA-GISS data and the NCEP and ERA40 re-analyses
A comparison with other temperature analyses, such as the NASA/GISS (pink in the figure on the left), reveals differences. We can also compare with model-generated data (re-analyses), keeping in mind that one must be very careful with these data since they are not appropriate for studying long-term climate change (they give a misrepresentation of trends – at least on a local scale). Nevertheless, information from independent data suggest an increase in global mean temperatures even over the last decade.

All scientific questions involve some degree of uncertainties (error bars), and these can only be reduced if one can prove that they are influenced by an external factor (‘contamination’) or if some of the data are not representative for the study. Hence, if some of the data are incorrect, then it’s fair to exclude these to reduce the error bars. But this requires solid and convincing evidence of misrepresentation, and one cannot just pick the low values and claim that these describe the upper limit without proving that all the data with higher values are wrong. In other words, arguing that a lower limit is the upper bound is utter nonsense (even some who claim they are ‘statisticians’ have made this mistake!).

Another issue is that some of the data – i.e. the data from the Climate Research Unit (CRU) – have incomplete coverage, with large gaps in the Arctic where other data suggest the greatest increases in temperature. The figure below reveals the holes in the data knowledge. The figure compares the HadCRUT 3V data with the NCEP re-analysis.

Temperature measurements over the Arctic: CRU data and the NCEP re-analysis
Figure caption: The difference between Oct. 2007 – Sep. 2008 temperature average and the 1961-1990 mean temperature for HadCRUT 3V (upper left) and NCEP re-analysis (upper right). Below is a comparison between the 12-month 60N-90N mean temperature evolution (red=NCEP, black = HadCRUT 3v)). (click on figures for PDF-version)

Re-analysis data are results from atmospheric models where observed data have been fed into the models and used to correct the simulation in order to try to get a best possible description of the real atmosphere. But it’s important to note that the NCEP re-analysis and other re-analyses (e.g. ERA40) are not regarded as being appropriate for trend studies due to changes in observational systems (new satellites coming in etc). Nevertheless, a comparison between the re-analyses and observations can highlight differences, which may suggest where to look for problems.

Mean temperature difference between the periods  2004-2008 and 1999-2003
The animated figure shows the temperature difference between the two 5-year periods 1999-2003 and 2004-2008. Such results do not show the long-term trends, but it’s a fact that there have been high temperatures in the Arctic during the recent years.

The recent Arctic warming is visible in the animated plot on the right showing the NCEP re-analysis mean temperature difference between the periods 2004-2008 and 1999-2003.

The NOAA report card on the Arctic was based on the CRUTEM 3v data set (see figure below) which excludes temperatures over the ocean – thus showing an even less complete picture of the Arctic temperatures. The numbers I get suggest that more than 80% of the grid-boxes north of 60N contain missing values over the most recent decade.

Temperature measurements over the Arctic: CRU data and the NCEP re-analysis
Figure caption: The difference between Nov. 2007 – Oct. 2008 temperature average and the 1961-1990 mean temperature for CRUTEM 3v (upper left) and NCEP re-analysis (upper right). Below is a comparison between the 12-month 60N-90N mean temperature evolution. (click on figures for PDF-version)

The funny thing, however, is that the last decade of the Arctic CRUTEM 3v temperatures are closer to the corresponding estimates from NCEP re-analysis than the more complete HadCRUT 3v data. This may be a coincidence. The re-analyses use additional data to fill in the voids – e.g. satellite measurements and predictions based on the laws of physics. Thus, the temperature in areas with no observations is in principle physically consistent with surrounding temperatures and the state of the atmosphere (circulation).

Below is a figure showing a similar comparison between HadCRUT 3v and GISTEMP (from NASA/GISS). The latter provides a more complete representation of the Arctic by taking spatial correlation into account through an extrapolating/interpolating in space. But GISTEMP does not really have a better empirical basis in the Arctic, but the effect from the extrapolation (the filling in of values where there is missing data) gives the recent high Arctic temperatures more weight.

GISS-CRU warming difference over 1996-2004
Figure caption: The 2007 mean temperature anomaly wrt to 1961-90: (upper left) HadCRUT 3V, (upper right) GISTEMP, and (lower) temperature evolution for the Arctic (red=GISTEMP, black = HadCRUT 3v).

A comparison between temperatures over the most recent available 30-year period (1978-2007) shows high temperatures over parts of Russia (Figure below – upper left panel), and the difference between the GISTEMP and HadCRUT 3v shows a good agreement apart from around the Arctic rim and in some maritime sectors (upper right panel). The time evolution of the Northern Hemisphere mean for the two data sets is shown in the lower panel, showing a good agreement over most of the record, but with slightly higher GISTEMP estimates over the last 10 years (the global mean was not shown because my computer didn’t have sufficient memory for the complete analysis, but the two data sets also show similar evolution in e.g. the IPCC AR4).

GISS-CRU mean difference over 1976-2005
Figure caption: (upper left) HadCRUT 3V mean T(2m) anomaly over 1976-2005 (wrt to 1950-1980) ; (upper right) The GISS – HadCRUT 3V difference in mean T(2m) over 1976-2005; and (lower) the Northern Hemisphere mean temperature variations (red=GISTEMP, black=HadCRUT 3v).

Note, the low Arctic sea-ice extent over the last summers are independent evidence of high Arctic temperatures.

The insufficient observational coverage has also been noted by the IPCC AR4 and by Gillett et al. (Nature Geoscience, 2008), who argue that the observed warming in the Arctic and Antarctic are not consistent with internal climate variability and natural forcings alone, but are directly attributable to increased GHG levels.

They also suggested that the polar warming is likely to have discernable impacts on ecology and society (e.g.).

In their study, there are at least 15 grid boxes with valid data (usually representing one measurement) over 1900-2008 period. Furthermore, the only valid observations they used from the Northern Hemisphere were from the Arctic rim, as opposed to in the high Arctic itself. The situation is slightly better for the Antarctic (with one observation near the South Pole). Nevertheless, the title ‘Attribution of polar warming to human influence’ [my emphasis] is a bit misleading. Parts of the high-latitudes yes, polar no.

The attribution study was based on series of 5-yr-mean temperatures and spatial averages of 90 degree sectors (i.e. to four different sectors), where sectors and periods with no valid data were excluded.

There are some caveats with their study: The global climate models (GCMs) do not reproduce the 1930-1940 Arctic warm event very well, and the geographical differences in a limited number of grid-boxes in the observations and the GCMs may have been erased through taking the average value over the 90-degree sectors.

The 1930-1940 Arctic warming was probably not externally forced, but one could also argue that the models do not capture all of the internal variations because few reproduce similar features. Furthermore, the present GCMs have problems reproducing the Arctic sea-ice characteristics (which tends to be too extensive), ocean heat content, and fail to capture the ongoing decrease in Arctic sea-ice area. Most of these problems are seen in the gap with no CRUTEM 3v data, but there are also some uncertainties associated with the lack of data in the Polar regions.

The optimal fingerprint analysis hinges on the assumption that control simulations with the GCMs realistically reproduce the climate noise. I think that the GCMs do a good job for most of the planet, but independent work suggest local problems in the Arctic associated with a misrepresentation of the sea-ice extent. This may not have affected the analysis much, if the problem is limited to the high Arctic. Furthermore, the results suggested a one-to-one correspondence in trends between simulations and observations, but the analysis also gave a regression coefficient of 2-4 for natural forcings. The latter suggests to me that there may be some problems with the analysis or the GCMs.

Thus, this is probably not the final word on the matter. At least, I’m not convinced about the attribution yet. The whole boils down to insufficient amounts of empirical data (i.e. observations), GCM limitations at the high-latitudes, and too large data gaps. But the pronounced changes in the Arctic are consistent with AGW. The irony seems to be that the real world shows signs of more dramatic changes than the GCMs project, especially if you look at the sea-ice extent.

The lack of data in the polar region is a problem, and the ongoing International Polar Year (IPY) campaign is a huge concerted international effort to improve the data. Data is irreplaceable, regardless of the modelling capability, as science requires the theory to be tested against independent empirical data. The re-analyses provide a physically consistent description of the atmosphere – suggesting high temperatures in the Arctic – but we can only be sure about this when we actually have been there and made the real measurements (some can be done by satellites too)

A glimpse into the technical details
More technically, the complicated analysis involved a technique called ‘optimal fingerprinting‘ or ‘optimal detection’, looking for best signal in the noisy data and puts emphasis on regions where the GCMs give most realistic description of the climate variations. Basically, the optimal fingerprint techniques involved linear least-squares regression, which is familiar to many analysts.

The analysis of Gillett et al. involved ‘time-space’ orthogonal empirical functions (EOF) with truncation of 28 (and up to 78 modes for the Arctic, where the maximum truncation was the number of sectors multiplied with the number of 5-yr means – see supplementary material Fig. S3). These come into the equation through the estimation of the noise (covariance matrix), i.e. the internal variations and their magnitude. The clever thing is that they let each EOFs describe a set of 20 maps of 5-year-mean temperatures, thus representing both the spatial features as well as their chronology.

For the mathematically inclined, EOFs are similar to eigenvectors, and are mainly used to prepare data before further analysis. The purpose of using EOFs is often either to (i) compress the information or (ii) to make the data more ‘well-behaved’ (in mathematical terms: orthogonal). While one typically only use a few of the first EOFs, Gillett et al. experimented with just one up to the whole set because they took advantage of their orthogonal properties to allow the calculation of the inverse of the noise co-variance matrix. This is a neat mathematical trick. But this doesn’t help if the GCMs do not provide a good description of the internal variations.


419 Responses to “Mind the Gap!”

  1. 301
    Tim McDermott says:

    Just a nit, but why is the rotating globe going backwards?

  2. 302

    To Gavin and the rest, a big Thank You. Finding RC was like entering a haven of sanity. It cannot be easy to keep it up. It is clear that this is mostly Gavin’s baby, and it must take a lot of time. And the way research funding is structured, I don’t think he will be getting much material reward for this, either personally or in terms of research opportunities or achievement. Yet, this is a societal necessity. Know that it is appreciated.

    As to what RC has given and is giving me, the semi-anonymous commenter calling himself Lazar — apparently a true science amateur — expressed it best on Tamino’s blog:

    Climate is the most breathtakingly beautiful thing that I have seen and studied. I can’t believe people choose politics over science. What poor taste.

    http://tamino.wordpress.com/2008/10/14/bjorn-lomborg-how-did-you-get-those-numbers/#comment-23199

  3. 303
    Jim Eaton says:

    I heartily agree with Rich and Tamino regarding the importance and dedication of the Real Climate team. It is truly appreciated.

    I’ve been following this issue for more than two decades. I used to drive my wife crazy with each issue of Science News Digest, pointing out yet another news clip on a whole host of subjects indicating that global warming was real and worse than many of us anticipated.

    But in terms of understanding the science behind climate change, I have learned more in the past two years of reading Real Climate than in the two previous decades. Thanks so much.

    And yes, the information provided by Hank, Ray, Tamino, and other contributors also is greatly valued. And the humor often included makes this a fun site to visit.

    But what does Captcha mean this evening with “careless Chrystie?”

  4. 304
    Barton Paul Levenson says:

    Rod — so many functional biochemicals are possible that the chance aliens could eat us is next to zero. Their biochemistry will almost certainly be nothing like ours. The alien who eats a human deserves everything he gets, which will probably be, at least, analphylactic shock and a long hospital stay.

    All — I have put up the beginnings of a small database on gas properties on my web site (remove the hyphen):

    http://www.geocities.com/bpl1960/GasDatabase.html

    So far there are only 19 gases, the ones most often found in planetary atmospheres, and molecular weight and specific heat capacity are listed. I was tired of having to page through Google for half an hour just to locate one figure.

  5. 305
    Lawrence Coleman says:

    Re: Geoff Beacon. Wish I had heard Jim Hansen speak, he doesn’t come to Australia that often unfortunately. Geoff any forcing is positive feedback and there are many of those loops at work now working against climate homeostasis and the more from equilibrium climate becomes more additional +ve loops just join the fray. It’s like one guy wire on a suspension bridge that breaks and that causes additional instability which stresses the remaining ropes futher until very quicky (exponentially) there is a chain reaction and the bridge is destroyed. Climate homeostasis has a quite wide stress margin built into it’s design but once we go over those tipping points(it’s like a few more of those ropes breaking)..the fragile climate may teeter there for a while ocillating wildly until there is a natural forcing event eg. a solar maximum, volcanic activity etc to push it over the edge (the point of no return)- result…end of life. The methane issue could well push homeostasis well beyond the point of no return as I see it. When the oceans begin to slow the rate of CO2 uptake at saturation point that will futher push atmospheric CO2 even higher, simultaneously the massive amounts of additional CO2 and methane and nitrous oxide etc released from the decay and oxidisation of oceanic living creatures who cannot survive in a low ph environment will future ram the nail in the coffin.
    So if Jim Hansen sounds a bit worried..he has a right to be..we all have!

  6. 306
    Rod B says:

    BPL (304), well, that’s a relief. ;-) BTW, units on your gas table would be a little helpful.

    As a member of the loyal opposition (kinda) I, too, second the appreciation for, from my limited exposure, what looks like the best climate blog. While not perfect (what is??), it maintains an excellent focus on the science and greatly minimizes the screeding (is that a word? It should be!) and hyperbole. Mostly because of the herculean efforts of the moderators and the extensive postings of the first string contributors.

  7. 307
    PaulM says:

    ‘Why have we failed to convince?’
    I hardly know where to start. The rotating globes are very impressive, (although as pointed out above, they might be more impressive if they rotated the right way) but the same cannot be said of the content.
    The argument is not based on one data set as you claim. If you look at the four commonly used data sets (GISS HADCRU UAH RSS) since 1998 then three of the trends are negative. If you look from 1999 or 2000 then they are positive but if you start from 2001 or 2002 they are all negative.
    Most of those who say ‘global warming stopped in 1998′ do so tongue-in-cheek, perhaps to wind up you guys, but most reasonably objective people looking at for example http://data.giss.nasa.gov/gistemp/graphs/Fig.C.lrg.gif would think that there does appear to be a leveling off.
    And you won’t convince any skeptics by picking on one data set that doesn’t give the result you want, trying to find fault with it, feeding it into to one of your computer models for ‘re-analysis’ and magically creating a hot spot, and then plotting the results in a way to highlight the Arctic and hide most of the S Hemisphere.

  8. 308
    Hank Roberts says:

    Thanks, to all the real scientists. You all are the candles in the dark.

    Thanks especially to those scientists and mathematicians who blog on your own sites in ways that help understand climate. I started listing names and found I couldn’t find an end to naming you all. I’ll try to thank you at your own sites, more often.

    Thank you, teachers. Thank you, librarians. Thank you, all the people who keep citations current, pointers correct, and search tools honest about what they show us. Thank you reference librarians, for the tools for self-education freely offered and well supported.

    Thank you Gavin and Mike and each of the other Contributors here, and the scientists you’ve invited who have participated. You have made something new in science education with this site.

    Thanks to everyone who has asked good questions.

    Thanks to those trying to go beyond the science without losing the facts, who are coming up with ideas about what to do next.

    And thank you to the dark and the silent stars, in every direction, as far as we know, for the contrast with what we have.

    Thank you, home planet.

  9. 309
    tamino says:

    Re: #307 (PaulM)

    Most of those who say “global warming stopped in 1998″ do so tongue-in-cheek…

    No, they don’t. Either they actually believe it, or they’re trying to prey on the statistical ignorance of the general population.

    but most reasonably objective people looking at for example http://data.giss.nasa.gov/gistemp/graphs/Fig.C.lrg.gif would think that there does appear to be a leveling off…

    Most reasonably objective people looking at their surroundings would think the earth is flat. And that it’s not rotating, rather it’s the sky that spins around us. We have a way to overcome such falsehoods; it’s called science.

  10. 310
    PHE says:

    Re 308 Hank Roberts and 309 tamino.
    Yes Hank, “thanks to all REAL scientists”. As a working scientist, I can say, this is what counts.
    tamino: “it’s called science”. While I don’t agree with your arguments, I agree 100% with your sentiment: science rather than emotion or faith must rule.

  11. 311
    Mark says:

    PHE, #310. Science must RULE when it comes to ascertaining what the world is doing. That’s its job.

    It doesn’t rule when it comes to deciding what people should do about it. But what it does mean is that if you ignore the science and decide to act against it, you are definitely 100% at fault for the results of those actions. And when the result could be the end of civilisation (note I said “civilisation” not “mankind”, we now depend on technology for our supremacy and that technology now depends on our cities, factories and power structures to happen. Things that a climate catastrophe “business as usual” scenario would destroy).

  12. 312
    Mark says:

    PaulM, 307. When it was before 2000, the data showed a positive trend over 50 years, 30 of those pretty obviously and consistently.

    Yet, at the time, people like you demanded that this wasn’t any proof of global warming because the statistical errors were higher than the increases and we MUST therefore wait for more data before deciding. When the statistical errors were smaller, you said “but 0 is still [just] within the range of answers. We MUST STILL wait”. Now, when the graph is going up less and there’s a short segment where it goes down (8 years, remember 2005 is warmest year, so it isn’t 11 years) but the statistical errors are bigger than the drop you posit, this is no longer a problem and you already know the answer. It’s cooling.

    Additionally, despite continuing to demand more proofs, more complex models and more explanations about what has been left out or assumed invalid in the AGW models, you do not have any model yourself that explains why it is going down. You don’t even know when it will stop going down, how much it will fall, whether the “it’s a cycle” means you will find it going up again, etc. Nothing. No model, no explanation of where this cooling comes from, nothing. But that’s OK because you KNOW it’s cooling.

    Please, give us why it is cooling, give us the errors (not just the test, because over 1900-2008 it is still warmer overall, so you can’t just give “the slope is negative” because we can point out the slope is positive). Give us the model you run to show this. Give us all the information you demanded in 1990 for the proof of AGW that proves that the world is cooling.

    Do as you demanded of others.

    [edit]

  13. 313
    Mark says:

    Further to 304. Humans cannot eat grass. It is absolutely delicious to bacteria, though. Cows use them to digest grass.

    Now imagine an alien intelligent cow. It can eat grass but on their planet, grass walks about and has two arms, legs, a head etc. So they try to eat us.

    They are still a cow.

    Will it work?

    No.

    Only a genetic defect allows westerners to digest milk after about 18 months. Normal humans could breastfeed but stop being able to drink it after a certain age.

    Being able to chew and swallow doesn’t mean you will be able to digest, just that the organism being chewed isn’t going to survive the process.

  14. 314
    suicidal_syd says:

    When discussing ways of reducing C02 emissions frequent reference is given to the use of “renewable energy resources”

    What exactly do people mean by this? If this means planting more trees and increasing forestation I’m all for it. If they are talking about giant windmills in all the planet’s beauty spots to line rich business people’s pockets and politicians tax coffers I am not. The manufacture of these giant steel edifices releases large quantities of C02, their transport generates still more.

    Natural renewable energy sources I’m all for. Those which simply make the problem worse I am not.

  15. 315
    suicidal_syd says:

    and why do we need the proof or otherwise of global warming.

    it seems pretty clear there is an upward trend. it seems equally clear that the vast majority of temperature change is not influenced by man. That is not to say that we should be unconcerned about the relatively small proportion which is.

    put simply we are extracting carbon from the atmosphere and redistributing it to the atmosphere. irrespective of climate this is not a good situation for future generations. the carbon deposits (coal, gas and oil) are finite and the deforestation of the earth has prevented large amounts of this carbon being recycled back into future carbon deposits. Trees and vegetation are the best recyclers and the lack of interest I see from politicians and governments in reforestation suggests to me that they themselves don’t believe their own propoganda.

  16. 316
    suicidal_syd says:

    sorry to correct my previous post:-

    and why do we need the proof or otherwise of global warming.

    it seems pretty clear there is an upward trend. it seems equally clear that the vast majority of temperature change is not influenced by man. That is not to say that we should be unconcerned about the relatively small proportion which is.

    put simply we are extracting carbon from the earth and redistributing it to the atmosphere. irrespective of climate this is not a good situation for future generations. the carbon deposits (coal, gas and oil) are finite and the deforestation of the earth has prevented large amounts of this carbon being recycled back into future carbon deposits. Trees and vegetation are the best recyclers and the lack of interest I see from politicians and governments in reforestation suggests to me that they themselves don’t believe their own propoganda.

  17. 317

    I think that a lot of “Why have we failed to convince?” is the constant mantra of “Oh, we’ll have such hardships getting to an 80% reduction in CO2!” There are people out there working on solving the problems with the lifestyle issues (I’m working with a group of co-workers on solving power grid issues) and guess what — dramatic reductions in CO2 emissions can be had while maintaining, or even improving, quality-of-life. Once we get people over the “Oh, we’ll have such hardships!” lie, I think we’ll start to see real movement in CO2 reductions.

    There can still be questions about AGW, and I think that big ball of fire in the sky has a greater impact than many here believe, but reducing fossil fuel usage has a real potential for IMPROVING lifestyle. Distributed power generation can bring reliable power to developing nations, where today they have unreliable centralized power generation. Distributed power generation can even help in developed nations where grid imbalances create power sags, brownouts and rolling blackouts.

    I was chatting with a friend on Facebook and we’re both “green power” fanatics. When I think about how much power consumption I’ve reduced — about 80% now from 2 years ago — and the benefits from some of my CO2 reducing behaviors (not fighting with a gasoline lawnmower for the past 2 years) I count my lifestyle as “improving”. And I’ve done that with a very large reduction in CO2 emissions.

    We’re standing at the threshold of major improvements in technology that can achieve real reductions in CO2 emissions and if AGW proponents would just cut it out with the gloom and doom, acceptance of the same goals — reduction in CO2 emissions — would be more acceptable to the skeptical masses.

    (ReCaptcha says “Marie You”. No, I’m Julie. You must have the wrong person …)

  18. 318
    Hank Roberts says:

    Mark, do you have a cite for “genetic defect” anywhere? I suspect you’re misunderstanding how coevolution works. Groups of people who keep cows or goats show prolonged lactose tolerance, it’s natural selection in action.

  19. 319
    Jim Eager says:

    Re suicidal_syd @314: “If they are talking about giant windmills in all the planet’s beauty spots to line rich business people’s pockets and politicians tax coffers I am not. The manufacture of these giant steel edifices releases large quantities of C02, their transport generates still more.”

    For now and until manufacturing and transport are no longer dependent on fossil fuels. But that’s the catch: right now and in the immediate future manufacture, transport and installation of non-fossil energy sources, from windmill farms to solar thermal plants to solar voltaic panels, will require the emission of fossil fuel generated CO2. No way around it, like it or not. Yet to not manufacture, transport and install a non-fossil fuel energy infrastructure would truly be suicidal.

  20. 320
    Mark says:

    Hank, try googling with a few different options.

    genetic drink milk:

    http://news.bbc.co.uk/1/hi/health/6397001.stm

    Africa milk drinking:

    http://news.bbc.co.uk/1/hi/health/6397001.stm

    shouldn’t drink milk

    http://news.bbc.co.uk/1/hi/health/6397001.stm

    The back story is a problem nestle has with giving “charitable aid” in the form of baby powder which

    a) requires water which is very unsafe to drink in most of Africa
    b) isn’t right for kids (too old to digest milk)
    c) ensures that nestle write off profits against tax whilst giving “aid” as positive spin PR and also locking a market in

    Why is it you’re so lazy Hank?

  21. 321
    Mark says:

    PS Hank think about it. Milk is ALL a child that will only have two sets of teeth so cannot have them at birth (better fitting teeth means you can eat better but you can’t replace them so you can’t grow more teeth because they have nowhere to grow, so you need one set of teeth when you’re old to fit you for early life and throw them out and grow a second set that have more teeth to fit your adult jaw).

    But older children after weaning can have something other than mild because, like, they have teeth, man.

    So if you can share milk between older kids and the new young your later children will more likely die, reducing the possibility of replacement births. Not a good thing genetically speaking. The only other way is to have WAAAAY longer between births so that one set of children are gone before you have more. OK for short lived animals that don’t take long to breed but disasterous for the extended time needed to create an independant human. Add the extra probems of getting a brain pan big enough to hold a brain out of the woman’s birth canal (making childbirth exceptionally painful as well as dangerous for humans compared to other animals) and the greater likelihood of death in childbirth of an older woman and you have a species that won’t survive.

  22. 322
    Mark says:

    FCH: “There can still be questions about AGW, and I think that big ball of fire in the sky has a greater impact than many here believe”

    Nope. Without that hot burny thing the earth would be at about 3K.

    Are you saying that thinking the sun responsible for over 250K of heating is belittling it?

    However you seem to be belittling the effect of GHG. Without them the earth would be at about 250K and the entire earth merely a ball of ice. Something like 30K of heating is by the natural nature of GHG. And we’ve added 50% of one of the biggest ones. Do you think that change could not result in even a measly 10% change in the heating the earth would experience at this time without our intervention? That’s 3K. And that’s about the difference between a glacial and warm interglacial. Problem is we’re in a warm period. We shouldn’t be getting ***warmer***.

    So why do you belittle the effect of GHG on the earth’s temperature? The scientists definitely don’t belittle the effect of the sun’s warming: if they did the calculations being even 10% wrong would have the earth a sweltering hotpot or ball of ice if they were, yet you seem to be unable to accept the same level of change in GHG effects…

  23. 323
    Hank Roberts says:

    Mark, I’m no defender of modern marketing in general nor of Nestle’s tactics.

    I’m saying what you dismiss so easily merits a cite if you have one, and if not, some study.

    We are barely changed from the environment that shaped human evolution for tens, maybe hundreds of thousands of years. What you call a “defect” just exists.

    Study how it has changed in populations and you can learn something.

    Study it to understand why it exists and you can remedy some of its side effects in this new environment.

    Call it a “defect” and you label the person carrying it, and that’s ill considered.

    http://scholar.google.com/scholar?q=lactose+coevolution

    Evolution isn’t directed. “Defect” is your opinion — and a pigeonhole. Few genetic traits are simple, once examined.

    A trait that has increased in a population merely says people with that — among many other traits — had more grandchildren. It says nothing else. Coevolution isn’t some fuzzy Gaia-loves-ya idea.

    Cows and people — coevolved.
    People and the species involved in malarian transmission — coevolved.

    Evolution doesn’t optimize — or make mistakes.

    People who could digest lactose longer had more grandchildren than those around them in their area at the time the trait became widespread.

    People with sickle cell disease living in the malaria belt had more grandchildren than those around them in their area at the time the trait became widespread.

    http://scholar.google.com/scholar?q=sickle+cell+malaria

    Pick anything called a “defect” and look into the population distribution and trend over time, and you’ll have a PhD subject.

  24. 324
    Mark says:

    re 323, I gave links, Hank. The background was where I found out about the unnatural tolerance of milk westerners have.

  25. 325
    Jim Eaton says:

    Mark,

    I’m not sure what this has to do with climate, but why is the ability of a segment of humanity to drink milk a “genetic defect” and an “unnatural tolerance of milk.”

    Even the link you did post says, “this is probably the single most advantageous gene trait in humans in the last 30,000 years.”

    This is evolution in action. And your point is?

  26. 326
    Hank Roberts says:

    Oooookayyyy, Mark. I agree with the criticism of marketing milk to people who can’t digest it, certainly.

    The words you’re using — “defect” and “unnatural” — are heavily loaded from politics.

    Look at the population distribution of variations in the enzyme that confers alcohol tolerance. Selection pressure again.

  27. 327
    jcbmack says:

    “More complex interactions occur if the fitness of a heterozygote is outside the range specified by two homozygotes. Where one allele is fitter than another in the population, and the fitness of the heterozygote falls between the fitnesses of the homozygotes, selection is directional and will lead to fixation of the fittest allele. If the heterozygote is fitter than either homozygote (overdominance), the heterozygote will be selected and both alleles will be maintained in a balanced polymorphism. An example is overdominant selection for the normal (Hba) and sickle-cell (Hbs) alleles of B-globin. These are polymorphic in some African countries because, while Hbs is deleterious in the homozygous state,it confers malarial resistance in Hba/Hbs heterozygotes, a genotype which is thus fitter than Hba homozygotes.” (Advaced Molecular Biology bpp. 212-212, quote verbatim)

    Mark and Hank you are both right, the sickle cell trait may be beneficial in lieu of selective pressures, but is is driven by mutations and the homozygous state is not beneficial and here in the US where many African Americans and some people from other races (well, in biology we do not consider race to be different, just genetic adaptations to the terrain and environment; e.g. weather, climate, sun exposure etc…) who are not likely to be exposed to malaria (though it was last time I checked it was in a positive incline of incidence and very minor prevalence on a slight concave up trend) it can be a great burden and it does not look as if punctuated equilibrium will solve this problem either.

    Codon 6 of the B-globin chain from GAG to GTG (replacing glutamic acid with valine) generates hemoglobin S with increased intermolecular adhesion in its deoxygenated state. HBS thus crystallizes at low oxygen tension, causing the formation of inflexible, sickle shaped erythrocytes that block capillary beds and damage internal organs.

  28. 328
    jcbmack says:

    Lactose intolerance is solvable with minor genetic engineering, but that is for a different post.

  29. 329
    jcbmack says:

    meant to say pp. 212-213. Most genetic mutations fall on short tandem repeats known as introns, which are “junk DNA,” some are within an exon coding region and can be harmful, sometimes beneficial or both depending upon the external selective pressures, and the rate of change and degree of such pressures.

    Global climate change is not identical, but perhaps to some degree is analogous. If we have some time to prepare, the combination of lowering all the discussed emissions, utilizing current technology to implement alternative energy sources, and engineering new twists on said technology to both continue lowering emissions and adapting to global climate changes as well, we may be able to guide our response sets to outside, artificial selective pressures in conjunction with natural ones; natural, internal variability and external forcings/feedbacks. Humans have developed such efficient frontal lobes due to selective pressures and they serve us well if we continue to work as a team and not a group think or as completely independent of the whole.

    Evolution is random like weather, sensitive to minor perturbations, but adaptive through adaptive emergent properties, and difficult to understand in totality, but well understood in pieces and in short periods of time, sequentially linked, sometimes haphazardly to form a somewhat cohesive story.

  30. 330
    jcbmack says:

    Molecular medicine and molecular biochemistry provide the what and how these changes, especially deleterious ones may be treated, cured, suppressed, or understood in context with other gene regulatory mechanisms and transcription and translation coupled systems within the actual cellular environment. Cancer is not a good thing, most would agree, but some genes that code protective proteins against Alzheimer’s Disease increase likelihood of developing cancer, potentially rapidly metastisizing life threatening cell types; reducing gene regulating proteins may reduce cancer risk, but increase AD risk, stem cells are a promising therapeutic modality in a wide variety of disorders. yet misapplication of stem cell treatment will cause cancer, whereas proper application can ablate cancerous cells.

    Alzforum

  31. 331
    jcbmack says:

    Uncertainties do not mean that something is false. Keep in mind the Pauli exclusion principle and the like:)

  32. 332
    Barton Paul Levenson says:

    syd writes:

    If they are talking about giant windmills in all the planet’s beauty spots to line rich business people’s pockets and politicians tax coffers I am not.

    Neither is anybody else.

    The manufacture of these giant steel edifices releases large quantities of C02, their transport generates still more.

    They produce orders of magnitude less CO2 than the equivalent fossil-fuel burning power plants.

    I’ve been fascinated by how, as the global warming debate went on, the deniers all suddenly began to attack windmills. If there were ever clearer evidence that they are devoted to using fossil fuels and nothing else, I can’t imagine what it would be. It’s also a good indication of how closely the corporate world controls right-wing propaganda in this country.

  33. 333
    Mark says:

    Hank 326. I call it a defect because being able to digest milk beyond weaninis not helpful to the survivability of the species. We have domesticated animals to enable us to use these animals’ milk production rather than their meat (which is a one-time resource except for bleeding the animal, which used to be done in times of trouble). However by us using up the milk that would go to the children of these animals we were risking the next generation of animal to replace them by drinking what they need to grow.

    This makes milk a useful resource in good times but in bad times we’re better off eating the animals that are youngest and oldest and thinning out the herd.

    And most of the world has people who do not and cannot drink milk. E.g. to the Indic people who do not drink milk (~1.5 Bn) we westerners smell of sour milk because we drink hard to digest cow milk and the waste products are expressed in our sweat. Note too that cow milk is one of the less digestible forms of milk for humans, we use them instead of goat (one of the best) because it’s easier to get a lot of milk from one cow than from several goats.

    PS why the hissy fit over “defect”? I have astigmatism but should this not be referred to as a visual defect because it’s demeaning or some other PC BS???

  34. 334
    Mark says:

    Jim 325 the point is that even humans can’t eat the products of other animals on our very own planet. The chances of an alien biology making a meal of the human protein system is very remote indeed.

    That would be my point.

  35. 335
    dhogaza says:

    But older children after weaning can have something other than milk because, like, they have teeth, man.

    Like, hard cheese, man, aged hard cheese, which contains very little lactose. Of course, it’s made from milk …

  36. 336

    Mark,

    That’s twice now you’ve attacked my posts for no good reason and managed to get it wrong both times.

    My position on AGW is I don’t care which side is right, because whichever side is right, if we don’t get off the fossil fuel addiction we’re in big trouble.

    Let’s say AGW is a hoax. A big, fat hoax. Well, that doesn’t change the validity of ending our dependence on fossil fuels. And let’s say it isn’t a hoax — we still need to end our dependence on fossil fuels.

    I do have an opinion about AGW, and it includes why people aren’t accepting it as a theory. Part of my opinion is that very few proponents of AGW paint a rosy picture of a CO2 emissions free future. I think that a world in which we aren’t dependent on fossil fuels is one in which power is abundant, cheap, and readily available wherever we want it — and the facts are on my side on this one.

    Another part is that I do remember when “The Coming Ice Age” was a big problem, and instead of acknowledging that, a large number of AGW proponents try to brush that under the rug.

    And finally, if anyone tries to imply that the Big Ball of Fire in the sky is going to influence the near term climate, the response is “Oh, we’ve already done Galactic Cosmic Rays”. So, I just sit around and count spotless days (11 in a row most recently) and wait for the climate to do what it always does whenever the sunspot count is this low. Then, when SC25 rolls around, and the sun does (or doesn’t) return to normal, and the skeptics have used the current cycle to bolster their claims, I’ll be able to say “I told you so”. Then, perhaps, the “Oh, we’ve already done Galactic Cosmic Rays” crowd will understand that things aren’t so simple as steadily increasing CO2 levels.

  37. 337
    Hank Roberts says:

    Mark, why do you think evolutionary traits are conserved?
    Where does “not helpful to the survivability of the species” fit in your understanding of genetics?
    What do you think drives evolution?

  38. 338

    “Another part is that I do remember when “The Coming Ice Age” was a big problem, and instead of acknowledging that, a large number of AGW proponents try to brush that under the rug.”

    That has been discussed on this site, and it is quite clear that there was no scientific consensus whatever on “The Coming Ice Age.” Rather, the furor was largely a media creation. Here is an excerpt from a paper on the topic:

    “An enduring popular myth suggests that in the
    1970s the climate science community was
    predicting “global cooling” and an “imminent” ice
    age, an observation frequently used by those who
    would undermine what climate scientists say today
    about the prospect of global warming.
    A review of the literature suggests that, to the
    contrary, greenhouse warming even then
    dominated scientists’ thinking about the most
    important forces shaping Earth’s climate on
    human time scales.”

    The link: http://ams.confex.com/ams/pdfpapers/131047.pdf

    So, if that is one of your main concerns about the reality of AGW, perhaps you will reconsider. AGW proponents can’t acknowledge something that is not actually true.

    [Response: See also the relevant page on the wiki. – gavin]

  39. 339
    simon abingdon says:

    Tamino #295 “thanks to Ray, for not suffering fools”

    This fool would still like an answer to the following: [edit]

    Ray #234 “clouds remain a big uncertainty for climate models. However, they can provide both positive and negative forcing” and
    Ray #252 “we understand extremely well the way greenhouse gasses [sic] like CO2 warm the planet”
    So here we go –
    Assumptions from considerations of physics:
    Unless CO2 could enlist water vapour to amplify its forcing it would simply be an unremarkable trace gas in the atmosphere, but –
    CO2 + water (vapour) = +ve feedback implying warming
    CO2 + water (liquid) = -ve feedback implying cooling
    Facts:
    Clouds cover half the surface of the planet. (Recent citations this thread).
    The volume of clouds in the atmosphere is therefore vast, so its properties contribute to the resultant climate very considerably.
    Clouds comprise water droplets and water vapour at the phase transition interface in chaotic combination, involving imponderable exchanges of heat energy.
    Question:
    Do such considerations affect the current orthodoxy regarding the role of CO2 in establishing climate characteristics?

  40. 340
    jcbmack says:

    Evolutionary traits that are favorable in light of environmental pressures which are selective. We are definitely discussing one of my specific areas of expertise so I hate to see people get evolution wrong or oversimplify it. Of course we also know that there are many milk products with little to no lactose and milk alternatives like soy milk and so forth. If I am big strong and can run 20 miles per hour after a bison and that is the environment I am in, well, it is favorable, but if the bison dies out, and smaller more clever people move into my niche and have the ability to fool and manipulate me and my skills for their purpose, I either need to adapt based upon abilities I already have or if my biology limits my intelligence too much, then either my progeny must evolve in the face of new environmental pressures or my line may die out or be simply enslaved.

    Bacteria and other microorganisms adapt to various medications over time which favors their survival, but not ours, however, our own further actions in science, technology and medicine assists us in overcoming many (but not all) resistance mechanisms. We may have evolved from viruses and our mitochondria comes from bacteria (as do plant chloroplasts) and in this case symbiosis in addition to natural selection is involved in evolutionary processes. Now, back to the poor bacteria we destroy with antibiotics, well, antibiotic abuse is the number one form of drug abuse in the world, and yet antibiotics, a mistake,, serendipitous, are considered by most the greatest advancement of human kind; before penicillin people were dying in droves from streptococcus pyogenes and other infections. Evolution is not linear, sometimes certain brain regions become smaller, while others become larger, but in homosapiens, it comes down to the relative brain size to the body size, the frontal lobe and hippocampus connections and overall mass in these two regions especially.

    Evolution is usually a slow gradual process, but Gould was onto something when he proposed punctuated equilibrium, (since his death there have been more discovered transition fossils) and I suggest you guys read all of his “doorstop,” books. I also recommend to you physicist bloggers who have not done so or who are rusty, take biophysics for physicists and other scientist, non biologists.

    Also get a good book on drifts and shifts and niches and population genetics. And to understand the energetics and the statistical aspects for real take physical chemistry.

  41. 341
    jcbmack says:

    Simon #339, the past trends, the averages, the weighting of the data, better delineation of noise versus signal and using the laws of physics as a foundation while at least modeling clouds is a big step in the right direction.

    Also clouds and their affects on insulation and insolation etc, vary so, the percent of clouds or number,or vastness of clouds in and of themselves do not answer any questions, however, they do raise questions in the current “orthodoxy,” in your vernacular, but that at least we know what some of the questions are, we can design methods to ascertain answers, or at least partial answers which raise still more questions. The models do not consider the full range of feedbacks from water, (in a nutshell) and cloud formation and their exact properties…this is an ongoing area of improvement, and unfortunately the chief area of contention from denialists and contrarians alike.

    Now, clouds do not make heat exchange imponderable, especially in long term trends of climate analysis, the averages due to what we already know about dynamic equilibrium outcomes and what we observe in the feedbacks going back even greater then 30 years.

    Clouds do provide cover to approximately 50% of the Earth, this is true, and this fact raised several questions and then various lines of questioning. Bottom line questions to think about are: what affects do these clouds have on the heat budget as a whole, how do these cloud types and altitudes change in response to weather, climate, GHG’s short term and long term, what do we not know about cloud micro physics and what do we need to know, and how can we better delineate and model cloud dynamics in real time to ascertain better predictive quality.

  42. 342
    Chris Colose says:

    #339

    There’s an old political technique of making an accusation in a question. “Have you quit cheating on your income tax” is an example. “Do such considerations affect the current orthodoxy regarding the role of CO2 in establishing climate characteristics?” is another. Such is rather unlikely to generate productive response.

    The temperature response to a given change in CO2 is the product of the radiative forcing and the sensitivity of the climate system. The “forcing” of CO2 is well known but the sensitivity less so. There is no question that cloud feedbacks are uncertain and that modeling them is hard — I don’t think that anyone has ever seriously claimed otherwise.

    However, the best evidence we have suggests that cloud feedbacks are positive rather than negative, and if it’s negative it can’t be really big. Paleoclimatic and modeling constraints put a 2x CO2 response at 2 to 4.5 C which is still a large range (clouds have a lot to do with that) but it is very unlikely that clouds can produce such a change to force the response outside of that range. If anything, there is more of a chance of a large positive feedback than a large negative feedback.

  43. 343
    jcbmack says:

    not to sound broken up and ‘incoherent,’ but Simon the dynamics between CO2 and H2O are extremely critical to global climate trends.

  44. 344
    simon abingdon says:

    #339 My penultimate sentence should have read “Clouds comprise (water) ice-crystals, droplets and vapour at the relevant phase transition interfaces in chaotic combination, involving imponderable exchanges of heat energy.”

  45. 345
    simon abingdon says:

    #342 Chris Colose “there is more of a chance of a large positive feedback than a large negative feedback” We don´t need a “large negative feedback” to avoid global warming, so there being more chance (like 1 in a million perhaps) of a “large positive feedback” is neither here nor there.

  46. 346
    Rich Creager says:

    Evolution takes us to Lynn Margulis, who takes us to Gaia, which takes us to James Lovelock, who, voila, brings us back to climate change.

  47. 347

    #339: Simon, you wrote:

    “Assumptions from considerations of physics:
    Unless CO2 could enlist water vapour to amplify its forcing it would simply be an unremarkable trace gas in the atmosphere, but -”

    From AR4 SPM:

    “The combined radiative forcing due to increases in carbon dioxide, methane, and nitrous oxide is +2.30 [+2.07 to +2.53] W m–2.” [Mostly due to the CO2.]

    Would you consider that “remarkable?” I certainly wouldn’t call it insignificant.

    (Captcha: “bit FORGOT”)

  48. 348
    Phil. Felton says:

    Re #339
    simon abingdon Says:
    30 November 2008 at 1:31 PM
    Tamino #295 “thanks to Ray, for not suffering fools”

    This fool would still like an answer to the following: [edit]

    Assumptions from considerations of physics:
    Unless CO2 could enlist water vapour to amplify its forcing it would simply be an unremarkable trace gas in the atmosphere, but -

    But for the CO2 in the atmosphere there would be substantially no water vapor in the atmosphere and it would be a damn sight colder! You need a permanent gas not a condensible vapor.

  49. 349
    Ray Ladbury says:

    Simon, the idea that the contribution of CO2 is insignificant in the absence of feedbacks is just flat wrong. CO2 is the second largest contributor to the greenhouse effect–without which Earth is a lifeless snowball. Moreover, the same feedbacks apply, regardless of the forcing. That is, Earth doesn’t care where the extra watts come from.
    As to clouds, yes, they are uncertain. However, paleoclimate, the response of climate to transient forcings, etc. place constraints, and a significant negative forcing is unlikely. What you are doing is playing the “God of the Gaps” game–trying to hold on to your rationalizations by overemphasizing the uncertainties. Fact: The climate is warming quite rapidly. Fact: The overwhelming body of evidence indicates that it is due to CO2 and that the increase in CO2 is due to human activity. Fact: There is absolutely zero evidence that contraindicates the above.

    If you look at constraints on CO2 sensitivity–3 degrees is by far the most likely level, but the chances of it being higher than 4.5 degrees are more than those of it being below 2 degrees. If you want to talk uncertainties, fine. They aren’t on your side, though.

  50. 350
    Phil. Felton says:

    Re #333

    I call it a defect because being able to digest milk beyond weaninis not helpful to the survivability of the species. We have domesticated animals to enable us to use these animals’ milk production rather than their meat (which is a one-time resource except for bleeding the animal, which used to be done in times of trouble).

    That would normally be termed an ‘adaptation’! Also you appear to not understand some of the practices of dairy farming. African pastoralists as well as drinking milk drink blood e.g. Maasai.

    “The Maasai are also famous for drinking a mixture of cattle blood and milk during ceremonial rites. An arrow is shot at close range to punture the jugular vein of the cow. The blood is drawn into a skin gourd and later mixed with milk to be drunk by the gathering. The animal is not left to bleed but is carefully tended to, till it fully heals.”


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