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Making sense of Greenland’s ice

Filed under: — gavin @ 9 July 2007

A widely publicised paper in Science last week discussed the recovery ancient DNA from the base of the Dye-3 ice core (in southern Greenland). This was an impressive technical feat and the DNA recovered may well be the oldest pure DNA ever, dating back maybe half a million years. However much of the press coverage of this paper dwelt not on the positive aspects of the study but on its supposed implications for the stability of the Greenland ice sheet and future sea level rise, something that was not greatly discussed in the paper at all. So why was this?

As we have seen before, the frame for most media reports are set by the press release, and in this case, the press release from the Wellcome Trust (jointly issued by NERC) entitled “Greenland’s ancient forests shed light on stability of ice sheet”. This contained the quote “… this means that the southern Greenland ice cap is more stable than previously thought.” from the lead author Professor Willerslev which ended up being the peg for many of the stories. This quote did not appear in simultaneous releases from AAAS, University of York or the University of Alberta, which were much closer to the text of the paper.

The context for these statements is the uncertainty associated with the history of the Greenland ice sheet – particularly what happened during the last interglacial period (also sometimes called the Eemian) around 125,000 years ago – a time when the orbital configuration lead to Northern Hemisphere summer temperatures being perhaps 1 or 2 deg C warmer than today (and 3 to 5 degrees warmer around Greenland). It is uncontroversial that sea level was then about 4 to 6m higher than present but exactly which ice sheets (Greenland vs. Antarctica) provided this extra water and in what proportion is unclear. The last word on the subject was probably from two papers in Science last year, which suggested that it was roughly half/half with 2m or so from Greenland, and the rest presumably from Antarctica.

Those studies had used as a data point the fact that the Dye 3 core did not appear to have any Eemian ice (unlike ice cores further north), and the minimum Greenland contribution came from a calculation of the minimum amount of ice Greenland would have to lose in order to deglaciate Dye 3. The new data in this weeks paper implies that at least some ice there appears to predate the Eemian (although the dating is uncertain enough so that it can’t be absolutely ruled out), thus the maximum Greenland contribution is likely slightly less than the numbers reported earlier. (Note that all of these estimates are based on ice sheet models, that as we have noted previously, do not fully incorporate all the physics thought to be important).

The University of Copenhagen also issued a release which expanded on the ‘stability’ issue. One of the sections is entitled “Climate theories overturned” and apparently refers to the theory that the whole Greenland ice sheet will melt as a result of global warming. This is a very odd statement indeed and doesn’t accord with any serious discussion of the issue. The authors of the press release must have received some feedback along those lines themselves, because there is an addenda added at the end that gives a bit more context:

The scientists do not want to put into question the rise in sea level during a global warming. During the last interglacial period 125.000 years ago, temperatures in Greenland were 5 degrees higher and global sea level was 4-5 meters higher than it is today. However, since the new scientific results show that the ice sheet also covered southern Greenland, the melting of the Greenlandic ice cap can only have caused a sea level rise of about 2 meters. Therefore some of the ice contributing to the sea level rise must have come from other sources, for instance the Antarctic. Furthermore, thermal warming of the oceans will cause expansion of the sea water and result in a sea level rise of half a meter, and the melting of small glaciers around the globe will result in an additional half meter rise.

This is very similar to the discussion of Eemian sea levels seen in the IPCC report, and so it is very unclear to what extent these new results ‘overturn climate theories’. And of course, the central finding – that southern Greenland was indeed deglaciated at some point in the last half million years – implies that Greenland is indeed unstable – though with a sensitivity that is still uncertain.

So we have, yet again, good science giving rise to bad press coverage, and yet again, it is unfortunately the scientists themselves that appear to have engendered the confusion.


235 Responses to “Making sense of Greenland’s ice”

  1. 51
    Justin says:

    This article:

    http://www.suntimes.com/news/otherviews/450392,CST-EDT-REF30b.article

    “Alarmist global warming claims melt under scientific scrutiny”

    cited a paper that discussed the dynamics and trends in glacier retreat and advance in the western Himalayas. The article, I fear, made up the quote it purportedly drew from the paper. The issue of Himalayan ice is not very related to the Greenland issue, but the distortion (or media modification) is closer. Was this an instance of deliberate and direct misrepresentation? And what can we do about it if it was?

  2. 52
    Lawrence Brown says:

    There’s an item in today’s “NY Times”, that doesn’t mention the stability of instability of the Greenland ice sheet, but it quotes Dr. Willerslev as saying “…I think it’s very likely that what we are seeing is vegetation from and insects from the last time it was ice free.”
    http://www.nytimes.com/2007/07/10/science/10observ.html?_r=1&ref=science&oref=slogin

    One thing for certain is that one half million years ago, or 120,000 years ago or even about 1000 years ago when Eric The (infra?)Red went ashore on Greenland,there weren’t nearly 7 billion bipeds around, using energy at a prolific rate.We’re consuming about 2000 watts each, with developed countries using 5 times that number, and highly populated areas like India and China are becoming developed. This is unprecented and is certainly much different from anything that’s happened in the past, and should prevent us from becoming too complacent about even remote possibilities respecting the Greenland and West Antarctic ice sheetsl.

  3. 53
    Timothy Chase says:

    Re Justin (#51)

    The link to the article was broken.

    I have fixed it below:

    Alarmist global warming claims melt under scientific scrutiny
    June 30, 2007
    BY James M. Taylor
    http://www.suntimes.com/news/otherviews/450392,CST-EDT-REF30b.article

    Taylor quotes the essay as saying:

    “Glaciers are growing in the Himalayan Mountains, confounding global warming alarmists who recently claimed the glaciers were shrinking and that global warming was to blame.”

    The second paragraph from the abstract (entire paper at link):

    The impact of observed seasonal temperature trend on runoff is explored using derived regression relationships. Decreases of 20% in summer runoff in the rivers Hunza and Shyok are estimated to have resulted from the observed 1°C fall in mean summer temperature since 1961, with even greater reductions in spring months. The observed downward trend in summer temperature and runoff is consistent with the observed thickening and expansion of Karakoram glaciers, in contrast to widespread decay and retreat in the eastern Himalayas. This suggests that the western Himalayas are showing a different response to global warming than other parts of the globe.

    Conflicting Signals of Climatic Change in the Upper Indus Basin
    H. J. Fowler, D. R. Archer
    Journal of Climate, 19(17), 4276â??4293 (2006)
    http://www.staff.ncl.ac.uk/h.j.fowler/fowler&archer_JC2006.pdf

    Taylor’s “quote” appears no where in the essay. However, Taylor’s “quote” is showing up a whole lot:

    Google search: “Glaciers are growing in the Himalayan Mountains”

    997 hits and counting…

  4. 54
    Ray Ladbury says:

    Oh, the Heartland Institute. Those kooks! Those guys couldn’t even get through the abstract of a scientific paper. I think some letters to the editor of the Sun-Times are in order–maybe a couple thousand of them.

  5. 55
    Timothy Chase says:

    Re Ray Ladbury (#54)

    The paper:

    Conflicting Signals of Climatic Change in the Upper Indus Basin
    H. J. Fowler, D. R. Archer
    Journal of Climate, 19(17), 4276â??4293 (2006)
    http://www.staff.ncl.ac.uk/h.j.fowler/fowler&archer_JC2006.pdf

    … actually looks fairly interesting. Apparently changes in the large scale atmospheric circulation patterns involving the monsoon – heavier rains in Nepal, although some have implicated the aerosol effects of the Asian Brown Cloud. Cooler temperatures during the summer, warmer temperatures during the winter. The Tibetan Plateau might be throwing us a bit of a curve-ball.

    Too bad the evil zombies are twisting it to their ends – but I suppose they would do that with anything they could. At this point I would say they are nearly to the shores of the Phlegethon.

  6. 56
    Hank Roberts says:

    Ray, you’ll never compete until you can match what they pay for ad space.
    Full page in the NYT today.

  7. 57
    Nigel Williams says:

    That the Karakoram glaciers are rebuilding a little is not that surprising. Here in NZ we are experiencing a marked increase in the frequency and severity of westerly weather patterns that are no doubt slowing the AGW decline of the galciers on our western-facing alps. But overall snow mass will be continuing downward as warmer temperatures (probably partly created by the fohn effect of the stronger westerlies) hit the east.

    Are the reductions in outflow from Karakoram glaciers due to changes in temperature, or are they driven (at least in part) by the fact that there is less ice left to melt?

  8. 58
    Timothy Chase says:

    Hank Roberts (#56) wrote:

    Ray, you’ll never compete until you can match what they pay for ad space.

    Full page in the NYT today.

    Funded by Exxon.

    Exxon will next review the groups it funds in November this year. Cohen would not confirm if there were plans in place to remove some of the more contentious names from its funding lists. The grants it gives are not huge. Two controversial groups, the Heartland Institute and the George C Marshall Institute, for example, received about $200,000 between them in the current financial year.

    Exxon Mobil: A proud oil giant comes to the climate change policy table
    3 July 2007
    http://www.climatechangecorp.com/content.asp?contentid=4859

    Above the table $200,000 between Heartland and Marshall. Hard to believe that is what is financing Taylor’s campaign. (Deltoid has dug up a bit where he also points out that these are glaciers “feeding just one out of seven of the major rivers coming out the Himalayas…”) Heartland seems to be taking tips from the Discovery Institute in how they get out the message though, calling their opponents “fascists,” and their propaganda oftentimes appeals to the groups. Bigger bang for the buck – when Daddy Big Bucks wants to do things on the cheap.

  9. 59
    John Monro says:

    I don’t think there is any shame on the scientists here (making comments that might be misinterpreted). It is true that the lead scientist in the study, Eske Willerslev, is reported as saying “Part of the ice cap is more stable than previously thought”. But according to this article in Bloomberg.com, he also went on to say, as part of an amplification of the meaning of this study,: “It doesn’t mean that we should just continue to put out CO2 into the atmosphere. The sea-level rise that you experienced during that last warm period must’ve come from somewhere. People in the Netherlands won’t care if it’s the Greenland ice cap or the Antarctic ice cap when they’re sitting in their rubber boats.”

    It is not the scientist’s fault if a tiny fraction of what they say is taken out of context, grossly exaggerated and cynically misused by people who are pursuing their own, mischievous agenda.

  10. 60
    Anders Lundqvist says:

    Re: The glaciers of Karakoram:

    http://news.nationalgeographic.com/news/2006/09/060911-growing-glaciers_2.html

    Excerpt from the article:

    Lonnie Thompson, a paleoclimatologist and glacier expert at Ohio State University in Columbus, thinks the latest findings might be a short-term trend only.

    “My guess is that the glaciers in [Haley and Fowler's] area of study might find short-term benefit where increased winter snowfall outweighs summer melt,” Thompson said.

    “[But] it’s likely these glaciers will follow the same pattern of those in Sweden and Norway, which were growing until 1999 due to increasing winter snowfall even as temperatures rose.

    “However, since 1999 these same glaciers are now retreating.

    “The balance of glaciers globally shows retreat and even acceleration in the rate of retreat,” Thompson stressed. (Related news: “Greenland Glaciers Losing Ice Much Faster, Study Says” [February 2006].)

    It may take many years to understand climate change’s lasting effects on Pakistan’s glaciers.

    — End excerpt —

  11. 61
    pete best says:

    OFF TOPIC – SUN NOT TO BLAME FOR AGW

    Mike Lockwood a physicist at the Appleton Rutherford labratory in the UK apparantly dismayed by the TGGWS carried out this research and has consluded that the Suns activity is no to blame for the 0.3 of warming of the earths surface since the 1980′s.

    http://uk.reuters.com/article/domesticNews/idUKL101501320070711?pageNumber=2

    http://environment.guardian.co.uk/climatechange/story/0,,2119695,00.html

    Thats that then, probably not but lets hope that this story is well reported globally.

  12. 62
    nicolas L. says:

    re 51, 53: melting glaciers

    Same kind of story happened a few weeks ago when France and Switzerland scientists published a paper on the study of the highest European glacier:

    Very high elevation Mont Blanc glaciated areas not affected by the 20th
    Century climate change
    C. Vincent1, E. Le Meur1, D. Six1, M. Funk2, M. Hoelzle3 and S. Preunkert1
    http://www-lgge.obs.ujf-grenoble.fr/axes/glaciers/Publications/Vincent2006MontBlancJGR.pdf

    When reading the article entirely, you see that the writers are stating the very high altitude Mont Blanc glacier has shown no particular melting trend during the 20th century, and explain why. The article states:
    “The 20th Century climate warming affected the atmospheric temperature in the Alps by +1°C (Böhm et al., 2001). However this change did not significantly affect the ice deformation rate in the high-altitude ice fields since the ice temperature remains far below the melting point and therefore keeping the glacier frozen to its bed.”
    Translation, the glacier is still too high to be affected by temperature changes. Note it is actually stated that there was a 1°C warming trend during 20th century.

    The article concludes:
    “Over the next 100 years, according to climate warming scenarii, a significant part of precipitation could become rain above 4300 m a.s.l. which could warm up the deep firn and ice. Some studies show that substantial warming of the firn temperature at shallow depths has taken place over the last few decades (Lüthi and Funk, 2001., Suter et al., 2001). Should this warming reach the bottom ice, the ice dynamics would be greatly modified.”
    Basically, if warming goes on, the glacier could become much more unstable than it has been by the past.

    It is also to be noted the same scientists published a lot of articles on the subject, showing the tremendous impacts of global warming on lower altitude Alp glaciers:
    http://www-lgge.obs.ujf-grenoble.fr/axes/glaciers/Publications/
    See specially:
    Ice ablation as evidence of climate change in the Alps over the 20th Century
    C. Vincent, G. Kappenberger, F. Valla, A. Bauder, M. Funk and E. Le Meur.
    J. of Geophysical Research, Vol 109, No D10104, pp 1-9.

    But of course, some people apparently stopped reading at half the title of the paper, saw the words they wanted to see in a scientific paper (“not affected” seems to be the key here), and went cherry picking here and there to state the lines of the article they’d like.
    And these are a few examples of what you can find on the net now, based on this article:
    http://www.iceagenow.com/Glaciers_Growing_in_France_and_Switzerland.htm
    http://www.worldclimatereport.com/index.php/2007/06/26/mont-blanc-glaciers-refuse-to-shrink/
    http://www.libertypost.org/cgi-bin/readart.cgi?ArtNum=193090

    I feel very sorry for those 6 guys who probably made a hell of a job to publish this article, and finally see their work misinterpreted and twisted this way.

  13. 63
    Ryan Stephenson says:

    Only 6m higher water levels despite a 2celsius increase in global temperature? (Although on the BBC it was quoted as 5Celsius).

    I guess us Brits can go back to sleep then. London is sinking into the mud it is built on far faster than global warming is likely to cause sea levels to rise.

  14. 64

    [[Only 6m higher water levels despite a 2celsius increase in global temperature? (Although on the BBC it was quoted as 5Celsius).

    I guess us Brits can go back to sleep then. London is sinking into the mud it is built on far faster than global warming is likely to cause sea levels to rise.]]

    I don’t think you understand the seriousness of the situation. Rising seawater doesn’t have to drown a city to make it uninhabitable. All it has to do is seep into the aquifers and back up the sewers. With no fresh water supply and sewers backed up all over the city, Miami and New York and London will be uninhabitable long before they are under water.

  15. 65
    Ray Ladbury says:

    Timothy, I haven’t read the paper, but you are right, based on a quick skim, it does look interesting. The thing is that the paper may be quite reasonable, but no matter what it says, Heartland will spin it to its agenda. I can’t figure these guys out. Do they really believe their spin or are they so cynical that they figure as long as they can buy up all the high ground, they’ll be fine? Or maybe they’re like former Interior Secretary James Watt who saw no point in conservation since “the Lord” would be back soon. What really amazes me, though, is that such ham-handed efforts actually seem to be effective. They ought to be simply laughed off the planet.

  16. 66
    Vernon says:

    RE: 47 Well, I do not expect this to be posted, but I figure why not give it a try.

    I generally accept the standard definition of a theory as a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena.

    Keeping that in mind, here is what I understand and what I have issues with the Theory of CO2 based warming and would like to see addressed:

    The physics of CO2 as a green house gas I don�t question, however, I cannot find any examples of CO2 causing global warming. I can see where CO2 is lagging indicator in the historical record but not where it is a driver.

    The proxies used to show global temperatures for the last interglacial do not show a medieval warming or a little ice age, but they do not show late twentieth century warming either. If the proxies are not accurate with compared with current instrumented readings, then why were they accurate in the past?

    If the MWP and the LIA were regional only, then why are two sites good enough to get the global CO2 measurement? Ice cores from Vostok and Mouna Loa Observatory good enough to represent the globe, why don�t they just represent a region?

    One indicator of global warming is sea level rise but the actually satellite measurements show no rising trend for the last 10 years. The rising trends are based on tide gages.

    Finally, solar activity correlates better with global climate than CO2, which correlates poorly (lagging indicator and all). While correlation does not mean causation for solar activity, neither does it for CO2. So, why does solar activity correlate with the global climate? I do not see an answer to that in the CO2 Theory.

    Normally, I would not bother to watch scientist argue over the flavor of the month theory. But unlike the change from classical to relativity, to quantum physics or the move from string theory to 11 dimension theory, climate theory has gone political. Based on a model it is being proposed that all society be changed. With that level of impact, empirical evidence is needed to support the CO2 model, and Gavin has not provided it. He says that UCI is wrong because Hanson is right, not able to point to any empirical studies.

    So, while I don�t expect this to ever get posted here, before I am going to accept this Theory, I want to see it proven empirically.

  17. 67
    ghost says:

    RE: Timothy’s #58
    The administration apparently has ad hommed AGW and all of us who care about it away:

    “[Former Surgeon General Carmona] described attending a meeting of top officials in which the subject of global warming was discussed. The officials concluded that global warming was a liberal cause and dismissed it, he said.

    â??And I said to myself, â??I realize why Iâ??ve been invited. They want me to discuss the science because they obviously donâ??t understand the science,â?? â?? he said. â??I was never invited back.â??”

    http://www.nytimes.com/2007/07/11/washington/11surgeon.html?_r=2&hp=&adxnnl=1&oref=slogin&adxnnlx=1184155421-sCHadWKv3yoCNLEcjcKDXg

  18. 68
    Ryan Stephenson says:

    “I don’t think you understand the seriousness of the situation. Rising seawater doesn’t have to drown a city to make it uninhabitable. All it has to do is seep into the aquifers and back up the sewers. With no fresh water supply and sewers backed up all over the city, Miami and New York and London will be uninhabitable long before they are under water.”

    They will indeed – regardless of whether the rising sea levels are caused by land ice melting or because of land subsidence. In the case of London the land subsidence is happening anyway, so it will become expensive to keep it inhabitable due to the subsidence. Not only that, it will probably require a lot of horsepower to turn London into the Venice of Northern Europe. The point remains that global warming need not concern Brits any more than land subsidence currently does, although no doubt Wimbledon will be wet again next year, which could be irksome.

  19. 69
    L. David Cooke says:

    Dear Gavin;

    My apologies, I just read your response at the top of this series of comments and noticed that in review of black carbon that though it may be a contributor that it is not significant enough to account for the apparent ice field reductions. You suggest that the only significant explanation is likely CO2 or what appears to be a Greenhouse Gas radiant barrier.

    I had read much of Dr. Hansen’s and your work in relation to working models and the apparent radiative increase reaching the earths surface due to the increase in Greenhouse gases and the approximate value of added radiant value appears to be about 2.6 Watts/Meter^2. In regards to this estimate has there been actual measurements in the ice fields that supports this modeled value? Secondly, have studies exclusively done on the site excluded any other possible ice field melting contributors?

    (My apologies for sounding like a Doubting Thomas; however, like most, I suspect, empirical evidence support for modeled theories helps greatly with the comfort level with the modeled evidence. Plus I like seeing non-manipulated forecasts that track close to empirical evidence before assigning much confidence to the model.)

    Dave Cooke

  20. 70
    Hank Roberts says:

    >65, James Watt
    Ray, remember there are liars and whackos on all spokes of the political wheel.
    That particular piece of bogosity you attribute to Watt was made up, I gather by someone writing for Grist, and published by someone who failed to check their authors’ cites. Bill Moyers is among those who fell for the misattribution, and apologized.

  21. 71
    Alan K says:

    #64, #67 – England under water.
    will I be late in asking why England should have more problems than I don’t know, say, Holland, which manages to cope lying largely beneath sea-level? As the man says – I have no fear, ’cause London is drowning and I live by the river..

  22. 72
    Timothy Chase says:

    Ryan Stephenson (#63) wrote:

    I guess us Brits can go back to sleep then. London is sinking into the mud it is built on far faster than global warming is likely to cause sea levels to rise.

    I think five meters in this century unlikely although several are a distinct possibility. But things like the heat wave of which hit the continentals will probably become more commonplace.

    I’ve heard that the London fog has gone the way of the dodos, but you blokes weren’t especially fond of it anyway. I understand its been getting drier out there so far, that they are already suggesting that you cut back on watering your lawns and plant different flora for your gardens, but all-in-all, from what I see you will have it easier than those us who live on this side of the pond or those of us in Asia or Australia.

    It looks like the states are going to be hit especially hard in the latter part of this century. Falling agricultural output due to droughts affecting the states and Asia will in all likelihood raise prices across the globe – as will falling fish harvests, but yes, you should have an easier time of it I believe.

  23. 73
    James says:

    Re #67: [The point remains that global warming need not concern Brits any more than land subsidence currently does...]

    That would be true if rising sea levels were the only effect of climate change. (Indeed, since I live at a higher elevation than the highest point in the British Isles, I should have even less to worry about.) Unfortunately, it seems as though rising sea levels are going to be only a minor part of the problem.

  24. 74
    Sam says:

    RE: 71, more wisdom from the Clash, actually kind of eerie and prescient:

    The ice age is coming, the sun’s zooming in
    Meltdown expected, the wheat is growing thin
    Engines stop running, but I have no fear
    ‘Cause London is drowning, and I live by the river

  25. 75
    SomeBeans says:

    #72 Timothy Chase

    I understand its been getting drier out there so far

    It’s been raining heavily most of the last month in the UK, and there have been pretty bad floods in several areas! April was ~5C above the average and 1-2C above the average for the remaining months this year. Qualitatively I remember it being frosty in the winter more often than now, so I’d argue the temperature increase is perceivable.

  26. 76
    Walt Bennett says:

    #66 Theory not proved empirically…

    Vernon,
    As a complete “civilian” in this subject, it matters to me when something doesn’t make sense to somebody else.

    One thing you should understand: RealClimate does not stifle debate nor does it discourage dissent. It should not surprise you to see a meritorious post published. You raise issues which no doubt appeal to many.

    Of course, those from the science community will perhaps look at your post as naive or agenda-driven, or perhaps they will simply lament that the politicization of this issue has led to a great deal of public confusion.

    The truth of course is that much of this is fuzzy. Scientists do not understand all of the relationships which lead to shifts in climate; the global mean temperature is not nearly as important as the ways in which regional climates change, especially when they become drier; the models, as Gavin readily admits, do not incorporate all of the physics thought to be important. Anybody who wants to call climate science a guessing game will find plenty of evidence.

    However, your rational mind must know that the current state of climate science is built upon very thin layers of knowledge which have been gained over more than a century, with a great acceleration of that knowledge in the last 60 years or so. You must recognize that long before politics entered into the equation, real world observations were leading scientists in a direction: that CO2 is accumulating in the atmosphere, and that over time this will affect global temperatures. How much? How soon? and just, How? Are mostly unknown.

    One thing that can be generally stated: a warmer planet holds less frozen water. It holds less snow in the mountains and it holds less ice at the poles. This is a historical fact: when temperatures rise, so do sea levels.

    With regard to the Greenland ice sheet, the important point being made by Gavin was that a scientifically benign report was twisted by the P.R. people of science organizations, to imply that the report in some way undermined climate theory.

    In order for you, me or anybody to make real sense of climate science (to the extent that our limited experience allows us), we need to recognize spin and separate it from science.

    As to the specific issues you raised, you can research them yourself, and many of them are addressed right here at RC.

  27. 77
    shargash says:

    Re: Vernon at #66:

    You ask for proof, but you’re not going to find proof. You’re going to find “preponderance of evidence”. Gavin has several times pointed you to further information, as have others.

    Many of your questions are answered in articles here at Real Climate. Your concern about CO2 concentrations lagging temperatures in the historical record, for example, is really basic stuff and has been covered many times. The short answer is that you won’t find CO2 leading temperatures in the historical record, because you won’t find any industrial civilizations before ours priming the feedback-forcings cycle by pumping huge amounts of CO2 into the atmosphere. Your other issues are similarly addressed in other articles.

    I think you’re getting something of a rough reception, because you come here demanding proof and seem unwilling to go read with an open mind the stuff that’s already been written.

  28. 78
    Tom Adams says:

    #66

    “If the MWP and the LIA were regional only, then why are two sites good enough to get the global CO2 measurement? Ice cores from Vostok and Mouna Loa Observatory good enough to represent the globe, why don’t they just represent a region?”

    They do both have regional characteristics, that’s a good insight. But nobody relies on only those two to represent the globe. There a a number of ice core sites from both polar areas and from glaciers. And many locations where CO2 is measured. The two you mentioned are just a couple of more famous ones.

    Keep on learning.

    [Response: CO2 is actually very well mixed in the free atmosphere and so you do only need a few measuring stations. You need many more for temperature anomalies... - gavin]

  29. 79
    L. David Cooke says:

    RE: #76

    Hey Walt;

    What you shared with Vernon, likely applies to my questions as well in #69. I have to say that I have done research on as many .gov or .edu sites as I can, if the site does not require a professional affiliation or dues. From all the research I have attempted I have found that the main character of the data closely follows your synopsis. This raises the question as to how can such a strong case be built based on the data as you characterize it?

    This is not to belittle the work done, only that I am uncertain that the trend of the arrow appears so strongly to point in a certain direction. Though the balance of scientific work is clearly suggesting a warming event, it appears that there would not be a strong enough signature or “handprint”, if you will, to specify the hard values in the press and some of the articles.

    Granted the models are fantastic in comparison to the trending models of the 1970′s. What bothers me is when I attempt to build a model and populate it with representative data, the variance between the median and the mean would be enough to account for the current noted deviation in the Global Average Temperature. Hence, this is why I try so hard to see if the raw data, with notes, over the past 30 years collected by the various science expeditions could be placed in a publicly available share point. (The CDIAC data set has been a boon; however, as noted before by others, the move to a gridded model worries me a bit.) It is not that there is a denial of trust in the work of those who are professionals, it is an attempt for me to prove to myself that the data as they have portrayed it vindicates their hard work. (I find it helps me in my understanding when I get the chance to work it out for myself.)

    What makes it even more frustrating is when data is placed in public it has been massaged so that the delineation of local variance is lost. When combined with the error bars, in my analysis, the global warming signature disappears. (I guess I would rather have the data with the value flagged that it is likely an estimate taken from a nearby station. (With the estimate modified based on the comparative historic run of the instrument sets for that day of the year and time.)) What makes it exceedingly more difficult is I do not have the higher math skills to attempt a Fourier Analysis to attempt to retrieve the signal from what appears to be noise.

    As to specific help, I continue to fail to see that the GHG radiant energy is affecting local temperatures. These changes appear to be driven not by additional radiant heating; but, by changes in large scale atmospheric patterns. Has anyone seen anything describing how GHG radiative heating is changing the character of the Jet Stream or Zonal Barometric Pressure Waves?

    As to your comment about the popular press and media slant; I found 7 years ago the best bet is only to get your announcement that a new Study has been generated there. I usually try to go to the source or to a trusted site for the details. My thanks for your time in writing back to Vernon, I am sure he and I are not alone…

    Personally, I am impressed with the work that has been accomplished so far. When we the public, start complaining about the state of the science, we need to look first to ourselves. Proper funding over the last 40 years, in many areas, may have made a big difference in the state of the science today… My thanks to the professionals who persevered.

    Dave Cooke

  30. 80
    biffvernon says:

    Re#64 London is not built on the sort of mud one sinks into and the aquifers are not the sort that sea water can seep into. Sewage is already pumped. In due course the Thames Barrier at Woolwich will need to be improved but we have the technology to cope. But in Bangla Desh…that’s another story.

    (no relation to ‘Vernon’)

  31. 81
    Timothy Chase says:

    I (#58) had written:

    I understand its been getting drier out there so far…

    SomeBeans (#75) responded:

    It’s been raining heavily most of the last month in the UK, and there have been pretty bad floods in several areas! April was ~5C above the average and 1-2C above the average for the remaining months this year. Qualitatively I remember it being frosty in the winter more often than now, so I’d argue the temperature increase is perceivable.

    You are quite right. In fact I see that the amount of rain has been tending to increase over the years:

    Dave Watkins on Rainfall Trends in Cornwall
    http://www.people.ex.ac.uk/dcwatkin/rainfall_in_cornwall/index.htm

    … which I find a little odd since we had a fellow through here just recently who was complaining about too many sunfilled days. (I prefer the rain myself – which is part of the reason why I picked Seattle.)

    I would guess that this has something to do with the gulf stream shifting to the NE. It probably rains less often, but harder when it does rain.

    What I was going off of were my memories of 2005:

    High and dry
    The UK has its first hosepipe ban in nine years after a dry winter…
    Wednesday, 8 June, 2005
    http://news.bbc.co.uk/1/hi/magazine/4613851.stm

    Climate change threat to gardens
    Fields of sunflowers could replace the traditional English landscape
    The English country garden is unlikely to survive in the South East beyond the next 100 years, scientists say.
    Monday, 13 June, 2005
    http://news.bbc.co.uk/1/hi/england/4089044.stm

    River levels ‘as low as in 1976′
    Reservoirs and rivers are as parched as they were during the hot summer of 1976
    Monday, 4 April, 2005
    http://news.bbc.co.uk/1/hi/england/4410707.stm

    2005 was an especially dry year.

    But the temperatures are clearly on the rise:

    State of the Cornish Environment – 2002 Baseline Edition
    2.1 Climate Change
    http://www.cornwall.gov.uk/index.cfm?articleid=11616

    … and interestingly enough, 2005 didn’t even merit a mention for top ten temperature records, although 2006 did:

    2006 sets British heat records
    Feeling the heat: Plants’ behaviour is affected by the climate
    Several records for temperatures in Britain have been broken during 2006.
    Thursday, 14 December 2006
    http://news.bbc.co.uk/1/hi/sci/tech/6177663.stm

    However, when Ryan Stephenson (#63) states:

    Only 6m higher water levels despite a 2 Celsius increase in global temperature? (Although on the BBC it was quoted as 5 Celsius).

    … I believe what is going on is that the 2 Celsius is the increase in the global average temperature, whereas the 5 Celsius is the increase in the UK average temperature. The southern hemisphere won’t warm as much as the northern hemisphere, the tropics won’t warm as much as the higher latitudes, and the ocean won’t warm as much as the land. Being on the Atlantic might work to your advantage there, particularly with the direction of the jet stream and the Gulf Stream.

    Anyway, my apologies for my presumption.

  32. 82
    Neil B. says:

    This is not directly on-topic, but is breaking news about global warming studies:

    http://www.theage.com.au/news/national/solar-activity-cleared-of-global-warming-blame/2007/07/11/1183833599508.html

    Solar activity cleared of global warming blame

    James Randerson, London
    July 12, 2007

  33. 83
  34. 84
    Timothy Chase says:

    Neil B (#82) wrote:

    This is not directly on-topic, but is breaking news about global warming studies:

    http://www.theage.com.au/news/national/solar-activity-cleared-of-global-warming-blame/2007/07/11/1183833599508.html

    Solar activity cleared of global warming blame.

    Good to see – otherwise we might have had a heck of a time bringing him in for questioning.

    Of course they are already arguing that if the solar years are cooling, this explains the cooling of the stratosphere – and as the upper and lower atmosphere go in opposite directions as the result of global warming, this explains the rising temperatures in the lower atmosphere. However, this asymmetry between the lower and upper atmosphere to changes in carbon dioxide levels, not solar output.

    An increase in solar output would warm both, and a decrease would cool both.

  35. 85
    Omar says:

    Completely off topic…

    Many seem to have the impression that the weather system, or at least a special case of it, has been proven to be caotic. However, they seem to get the impression that the climate system is assumed (by climate modellers) to be largely independent of initial data, or in other words is assumed to be a boundary value problem. Are they mistaken? And if not, is this a provable fact? I would appreciate answers with references.

    Best regards,

  36. 86

    Hey Greenies!

    I’m assuming most of the followers of environmental issues have an opinion about Live Earth, which happened last weekend…

    I think it’s important to listen to the skeptics in order to make informed decisions about climate change. This man makes some interesting points, even if they’re just points to bounce opposite ideas off of:

    Celebrity Earth?
    http://www.orato.com/node/2974

    Celebrity Earth?

    what do you guys think?
    http://www.orato.com

  37. 87
    James says:

    Re #79: [This raises the question as to how can such a strong case be built based on the data as you characterize it?]

    What you seem to miss is that the case for AGW is not built on that temperature data, it’s built on a) an observed increase in CO2 (known to be human-caused); and b) known radiation physics. The data is confirmation: the models predict such-and-such patterns of temperature increases, and since we find that actual temperatures match those predictions pretty well, it gives confidence in the models.

    On the other hand, if the observed temperatures didn’t match the model predictions, people would go looking for reasons – either flaws in the models, or bad measurements. The weather site validation people want to do this in reverse. They want to cast doubt on the models’ predictions, so they attack the measurements in hopes that they can show that the match was spurious, and that therefore the models are wrong.

  38. 88
    tamino says:

    Re: #83 (Gary)

    Unlike Professor Lockwood I do not see much of a drop in cosmic rays reaching Earth.

    I do, even in the graph you link to. And you will too, if you subtract away the solar-cycle variations. That’s what Professor Lockwood did, very adeptly.

  39. 89
    David B. Benson says:

    Re #85: Omar — This has been treated, in considerable detail, here on RealClimate. I encourage you to read previous threads, include comments. Consider the important links on the sidebar(s).

    You’ll find that indeed, climate models are not chaotic. As experimentally verified.

  40. 90
    SomeBeans says:

    #81 Timothy Chase

    It’s true that the general impression of rainfall in the UK is of reduction, however it just so happens that v. recently it’s been very wet (so I’m feeling a bit bedraggled). I think, compared to other countries, the UK has relatively large variations in climate across a relatively small area. You’ll also tend to hear more media reports from London and environs which is generally drier than the more westerly areas of the country.

    I think 2C is a better estimate of our current warming over average for this year (April was pretty exceptional).

    Should you wish to relocate to the UK, I suggest Wales may provide just the sort of rainfall you’re looking for!

    #86 Heather
    Not really sure how many of us would describe ourselves as ‘greenies’. Personally I’m pro-GM, pro-nuclear (power) and pro-”dumping old oil platforms in deep ocean” (as the best of a set of non-ideal choices) – none of which are particularly green positions. I am pro-science, and I don’t see politics (or pop stars) as a way of answering scientific questions.

  41. 91
    Ryan Stephenson says:

    @SomeBeans:

    It is indeed very wet here this year. Apparently this is due to warmer temperatures ove rthe oceans. This causes higher evaporation of course, and thus greater cloud cover. Clouds are white on top so they reflect a lot of radiant heat. Under the clouds, the temperature tends to be lower, and over land the clouds lose their ability to retain water vapour and thus we get rain. It is also colder than a June without cloud cover (by about 10Celsius), since the clouds block the radiant heat energy. During the day that is. During the night the temperature is warmer, as the clouds help to keep the heat in whilst there is an absence of radiant heat from the sun. Due to this heat retention affect, the MEt office reports June temperatures as being higher than usual for June. This is partly because MET office temperatures are alwas measured in the shade, so direct radiant heat energy has less impact, and daily temperatures are averaged over a full 24 hours. Thus it feels cold during the day but actually it measures out warmer than an average June.

    And the upshot of all this? Well my garden is loving this weather. The grass is growing like crazy. But I shall fly off to the Canary Island with the family in October, to get some sun.

  42. 92
    Luke Silburn says:

    SomeBeans @90 “It’s true that the general impression of rainfall in the UK is of reduction, however it just so happens that v. recently it’s been very wet”

    The recent weather is a monsoon system apparently. It seems that there is a monsoon for NW Europe (it’s a result of the landmass heating up as we hit the long days of summer, heating air over the land, which convects and sucks in weather systems from the Atlantic) but it’s usually pretty weak and so not that noticeable to laymen (other than the regular laments about why Wimbledon gets rained off all the time).

    Every now and then you get a year (like this year) when it’s stronger and more long lived than usual which is when people sit up and take notice. There’s been some speculation that AGW will tend to reinforce the European monsoon and thus make the ‘noticeable’ years more frequent, but I don’t think this is a solid prediction yet.

    Regards
    Luke

  43. 93

    [[Or maybe they're like former Interior Secretary James Watt who saw no point in conservation since "the Lord" would be back soon. ]]

    This “quote” of James Watt has become famous, but if you read the original transcripts, that’s not actually what he said. What he said is that since he didn’t know when the Lord would return, it makes sense to take care of the land in the meantime — exactly the opposite of what is usually attributed to him.

    I didn’t vote for Reagan and I don’t think Watt was a great choice for Interior, but this particular quote is an urban legend.

  44. 94

    [[Finally, solar activity correlates better with global climate than CO2, which correlates poorly (lagging indicator and all).]]

    Solar activity has been approximately flat for the last 50 years, so it can’t account for the sharp warming of the last 30 years. We’ve been measuring the solar constant from satellites like Nimbus-7 and the Solar Maximum Mission. The rise in temperature of the last 30 years can only be accounted for by taking greenhouse gases into account.

  45. 95

    [[The point remains that global warming need not concern Brits any more than land subsidence currently does, although no doubt Wimbledon will be wet again next year, which could be irksome. ]]

    It will concern them if it messes up their agriculture, which global warming is likely to do.

  46. 96
    Ryan Stephenson says:

    “It will concern them if it messes up their agriculture, which global warming is likely to do. ”

    “Likely”? Well the last 60 years of “global warming” certainly hasn’t. I would be more worried about mad cow disease – to keep things in some sort of perspective. Global cooling in the shape of the next ice-age is a different matter. That will be bad news for the whole world, and not much chance of escape.

    However, there is little chance of glabal warming being a problem for food supplies in the UK. UK food production meets the needs of 60% of the population – the rest is imported. However, food production accounts for only 1% of GDP. Even if food production was to decline dramatically its effect on GDP would be small. Consequently the possibility to import food from elsewhere would remain high. With new areas of global land mass opened up to fertile use by retreating permafrost and ice sheets, there is little reason to suspect that global food production will diminish.

  47. 97
    guthrie says:

    Umm, Ryan, whilst the UK may well be able to afford to import food at will, many other countries cannot. As a related illustration, in Mexico they had riots due to the rising price of corn, which in turn was related to the increased use of corn in biofuels making a scarcity of it, which meant rising prices.

    Or in other words, in a world with reduced agricultural output, poor people will starve whilst the rich carry on eating. (And wasting)

  48. 98
    J.C.H says:

    Why do people presume these vast areas can produce food in the quantities that will be needed?

    The sun is not going to alter its ways to save our bacon.

  49. 99
    L. David Cooke says:

    RE: #87

    Hey James;

    I guess that I was trying to address the mechanisms of the GHG theory rather then address the AGW Carbon Dioxide concentrations. I am not denying that CO2 is higher or that the models are portraying relationships correctly. What I am trying to understand is the natural science mechanisms involved.

    I also have difficulty in understanding how approximately 2.6 watts/meter^2 (Hansen et al 2005 suggested @1.85, I have seen estimated values between 1.46 and 6.4, the most recent was 2.64) in the 1.8 � 3.2 um range is increasing the average localized surface temperatures 0.5Deg C. Especially in light of the balance of solar insolation in the roughly 250 nm to 25um centered around the 550um frequency, at about 850 to 1200 watts/meter^2 for 9-16 hours per day. If I calculate the amount of daily energy, I have approximately 0.9% of the daily radiant energy coming from the CO2, if I understand this correctly. Based on 850 watts / 8 hours /day, I am seeing that it takes about 23.2 watts/meter^2/deg to raise the earths surface temperature to about 293 Deg. K (excluding any geothermic heat sources). Based on this rough calculation, I am seeing that the increased CO2 sourced radiant energy should be responsible for about a 0.1 Deg increase, at this energy level.

    In essence, I do not understand how the presence of CO2 is increasing my localized temperature average around 0.5 deg C. If the issue were that this extra energy was resident in the atmosphere longer and it takes 8-12 hours to release 6800 watts of energy /meter^2 in a clear night sky then the 62 watts associated with the radiant CO2 induced long wave temperature should only require about 4 min. I have done a lot of research on .gov and .edu sites, it appears that eventually most of the added energy does escape the atmosphere eventually.

    This only goes to suggest to me that the issue of AGW is not direct radiant warming; but, changes in large scale weather patterns. The localized temperature average does not appear to be increasing because of added radiant energy; but, because of changes in Jet Stream flows, stagnant weather fronts and possible changes in cloud characteristics. I guess my big question is, does anyone have any publicly available references as to how the increased atmospheric temperatures are affecting these large weather patterns?

    I do not argue that the models of today have amazing capabilities; however, a mathematical construct is not helping me understand the natural mechanisms involved. It helps me with my understanding when I can couple the source and the effect. At least it helps me understand why my garden does not get enough rain or whether I should go to the effort�

    (A little off topic, I recently saw a NASA article on the Earth�s Observatory site: http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17698 about the warming of the upper troposphere and the cooling of the stratosphere demonstrated by satellite tracking. Has anyone seen any C14 measurements in this region? I am curious if this is actually due to the increase in CO2, which Dr. Georg Hoffman may have suggested in Ukweatherworld, is concentrated in the lower troposphere based on direct measurements, or an increase in UV due to stratospheric Ozone reduction. (I figure if the Dobson Units correlate and there is an increase of C14 in the region this might help with the validation.) As to anomalies, the CloudSat and CALIPSO LIDAR experimental packages have demonstrated increased water vapor intrusion in the Polar stratospheric regions and a correlation here may help as well.)

    Again thanks James, my apologies if there is a miscommunication, my primary concern is to try to understand the specific mechanism of regional or localized warming not necessarily global warming. Direct insolation radiative measurements either here at my house or in the ARM.gov SKYRAD/GNDRAD databases are not helping. An understanding of the mechanisms of the reduction in the range of daily temperatures and changes in weather patterns and their causes will.

    Dave Cooke

  50. 100
    Lawrence Brown says:

    “Empirical evidence” seems to be the last refuge of the naysayers.There are many papers that have been written that show empirically that global warming is indeed attributable to human greenhouse activities. One by Stott, Stone and Allen titled Human Contribution to the European Heatwave of 2003.” Nature 432(Dec 2,2004). This study gives a statistical analysis that the European heat wave of 2003 has a small probablilty to have been a cause of natural variability alone, and most likely human activity bears responsibility for a component of this anomaly. Borehole evidence, of which there are plenty, show that surface warming caused by increased greenhouse gases is reaching to deeper levels. Models are able to best match the existing record when both natural and anthropogenic factors are included.
    There will always be uncertainties. Science has never been 100 percent sure. This is what science is about.Karl Popper made references to it being characterized by its disprovability. Waiting for bullet proof evidence of human induced warming before taking any action would be like waiting for your house to burn down before buying fire insurance.
    As far the word theory is concerned. When applied to science it is not speculation or a hunch. A scientific theory is an explanation of world phenomena that are supported by data, analysis, and coherent conclusions and can be rejected when evidence contradicts this explanation. The theory doesn’t have to describe all aspects of the phenomenon. Just because climatologists don’t know every aspect of Earth’s very complex climate system doesn’t disprove the greenhouse theory.


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