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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. 101
    John Mashey says:

    #96

    I visit the UK regularly, as my wife is from Yorkshire, and I would indeed be surprised if the UK’s own agriculture would be much negatively affected soon, and you may even get to have vineyards in Scotland, a fine thing, I’m sure, to replace the losses of vineyards in Spain & Italy. You may have to deal with insects that aren’t currently bothersome.

    A) Agricultural production depends not only on temperature but on water and soil quality.

    For North America:
    a) Do you think you know enough about soil quality in Canada AND
    b) Enough about likely future rain patterns

    to be *sure* that food production will not diminish as crops like wheat shift from US to Canada?

    Take a look at the chart at end of:

    http://news.bbc.co.uk/2/hi/science/nature/6200114.stm

    Unlike UK agriculture, some places in the world really have to worry about water; California (which grows half the fruit & vegetables in US) has state planners seriously worried about global warming’s effects on agriculture here. The US West, in particular, is strongly dependent on snowmelt patterns, as is much of South & East Asia.

    Likewise:
    The “Green Revolution” saved India & China from starvation. I’m sure they’ll be quite happy to get wheat from Mongolia and Siberia.

    Do you know enough about the soil & rain conditions in Russia to be sure all is well?

    B) The world currently supports a global market in food, at least for developed countries. This depends on cheap energy. Oops. The further food has to travel, the more expensive it’s going to get. Of course, a lot of very productive agriculture depends on serious energy inputs.

    C) And finally, how are UK fisheries doing?

    None of this says: “the world is doomed”, but blithely writing this off as a problem is *not* what people are doing who actually are involved in food production.

  2. 102
    L. David Cooke says:

    RE: #99

    Hey All;

    My apologies to the purists in the prior post, I had not converted to Joules or watts/meter/sec/sec in my calculations. Basically this involved a ratio and since both values were in the same form a direct ratio without the conversion should be fine. Granted my values might be more in question; however, it certainly helped me in understanding what I was trying to share. (Though it might be an impediment to others…)

    Thanks Dave

  3. 103
    Hank Roberts says:

    Dave, greenhouse gases intercept the infrared photons. Greenhouse gases emit infrared in any random direction once they’ve absorbed infrared; in addition they bump and grind, and transfer the energy to other molecules.

    The only energy outbound is the infrared photons that don’t interact again, that go directly out into space.

    Do you understand the “mean free path” number, and how that controls the rate at which energy moves off the planet from the atmosphere? You seem to be stuck on the old, frequently asserted, frequently explained notion that all the radiant energy could just zoom out into space somehow. If it could, the infrared astronomy people wouldn’t be building all those satellites —- the sky is _bright_ in the infrared, our atmosphere _glows_ in the infrared and half that heat is pointed downward on average.

  4. 104
    Hank Roberts says:

    Oh, and, dang, this is entirely off topic. As Ray and others remind us, RC is not a climate chat room. Pointer, hosts, please, to where the recycling of the fundamental questions frequently repeated should happen. Maybe at Stoat? Dano’s “How To …” page?

  5. 105
    Vernon says:

    I think Dave Cooke just summed up my problem, the models have amazing capabilities but they do not help me understand. I listed the main points that I have problems I have accepting the CO2 Theory yet I have not seen anyone point me to a study that uses empirical data to explain these issues. If the proxy record is not correct, then how do we know current warming is unusual? Since there has never in the past been a time when CO2 has driven warming or cooling, how do we know the climate sensitivity is that high? If the sensitivity is low, then adding CO2 will have little impact. Can any one here provide something other than a model to show what is really happening?

    I realize my support for a Theory in the scientific community means nothing, but since this is being used to drive economic and political change I think it does. So, please show how this Theory address the question I have asked, with empirical studies, and I will support it, if not, accept that the theory is not correct yet and find out why the climate is getting warmer.

    [Response: Your conclusions are based upon fundamentally flawed premises. i) we do not think GW is caused by greenhouse gas increases simply because current changes are unusual, ii) there are plenty of times in the past when CO2 has driven warming - the PETM, the Quaternary ice ages as a whole, the Cretaceous, etc. iii) there are multiple ways to determine climate sensitivity: http://www.realclimate.org/index.php/archives/2006/03/climate-sensitivity-plus-a-change/ - and they all give pretty much the same answer. - gavin]

  6. 106
    Ryan Stephenson 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”

    Supreme irony don’t you think? Riots caused by proponents of AGW telling us to use less fossil fuel so we burn Mexcian food sources to allow us to use our cars. Maybe it would have been better if we had let them eat and not made a big thing about AGW… (you could also have a word with the Mexicans about fecundity).

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

  7. 107
    Lynn Vincentnathan says:

    RE #106 and biofueld v. food. As a person concerned about AGW, I have never been an advocate of biofuels from food crops (though they are fine from cow dung and other agri waste). In fact when you extract gas from cow & human dung, I read that the left over product is even a better fertilizer than if gas had not been extracted from it.

    There are 100s of ways to reduce our energy consumption without lowering our living standards or fun in life. It just takes a little thoughtfulness and a big heart. And when the plug-in hybrids come out, I plan to get one so I can do 95%+ of my driving on my wind-powered Green Mountain electricity.

    We don’t have to take food out of starving people’s mouths to run our SUVs coast to coast in pursuit of some illusory happiness.

  8. 108
    David donovan says:

    Vernon.

    Completely independently of the past climate records, one expects GHGs to warm the Earth based on what we know about radiative transfer and spectroscopy. In fact speculation that increased CO2 levels would warn the Earth was first made about a century ago….long before the current warming or any of the paleoclimate data.

    See

    http://www.aip.org/history/climate/index.html

    http://www.realclimate.org/index.php/archives/2007/04/learning-from-a-simple-model/

    http://www.realclimate.org/index.php/archives/2007/05/start-here/

    and…

    http://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument/

  9. 109
    Timothy Chase says:

    I will be focusing on Greenland and perhaps more widely the cryosphere in later posts, but as some of our participants are focused on the effects of climate change upon England, the following might be of value to them…

    A quick note regarding the UK:

    I would strongly recommend checking out the Met Office Hadley Centre – a world class climate modeling center in the UK. They have some projections specific to the UK.

    Here is their website:

    Met Office: Climate Change (Hadley Centre)
    http://www.metoffice.gov.uk/research/hadleycentre/index.html

    Here is one of their non-tech documents:

    New scenarios of UK Climate Change (UKCIPnext)
    IRCCCG, 17 October 2005
    http://www.ukcip.org.uk/scenarios/ukcip08/documents/UKCIPnext_powerpoint.pdf

    A few of the projections they make:

    1. The likelihood of 2003-type European summers has already doubled and may be the norm by 2040
    2. Precipitation will increase roughly by 30% during the winter by the 2080s
    3. Summers will be drier by roughly 30% by the 2080s
    4. Storm surge will increase by roughly a meter by the 2080s
    5. Current emissions will have little effect upon what happens on land until 2040 after which there will be increasing divergence

  10. 110
    Hugh says:

    Ryan

    I love the way you seem to refer to AGW in the past tense.

  11. 111
    Lynn Vincentnathan says:

    RE #86, Heather, I’m a greenie & proud of it, but don’t have time to follow your links or the live earth concert (tho I vaguely heard about it & some criticism that the travel involved GHG emissions).

    My opinion would be that anything to inspire people to do the right thing would be good, even if there’s some upfront GHG emissions, as long as there’s net reductions. Like sometimes it takes GHG emissions to reduce GHG emissions overall.

    And I’m thinking that if all the “brownies” out there (not to be confused with Girl Scouts) would have started doing the EC (ecologically correct) things like the greenies did 17 or more years ago when everyone really should have started reducing their GHGs, then I guess they wouldn’t need to have live earth concerts to inspire people to do so now. So, perhaps the brownies are to blame, not the greenies.

    For instance, when I became aware of AGW in the late 80s, early 90s I reduced my GHG emissions by about 1/3 or more, and thought all I had to do was tell other people about AGW & how much I was saving by reducing GHGs, and then get back to my regularly scheduled life. Instead it’s been a VEEERRRRY long haul. I just hope the concert has some effect, and changes some hearts and minds, but my experience tells me the brownies are just getting worse, not better.

  12. 112
    Jim Eager says:

    Re 96 Ryan Stephenson: “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….
    However, there is little chance of glabal warming being a problem for food supplies in the UK.”

    Perhaps not in the UK, but much of Southeast Asia is already nearing the heat stress upper limit for rice, regardless of how much water is and will be available as the Himalayan glaciers recede. Australia’s western grain district has been devastated by the current ongoing drought. The southwestern US is also in long-term drought, and the Colorado River reservoirs–source of much of the agricultural irrigation water for the region–are down alarmingly. World fisheries are all in decline, many having already collapsed.

    GW does not bode well for the UK’s 40% imports.

  13. 113
    L. David Cooke says:

    RE: #103

    Hey Hank;

    Actually, I feel very comfortable with a radiation path value or as you call it a “mean free path number”, it should describe emission rate from the earths surface into space. I also am familiar with the inherent infra-red signature of the earth and its atmosphere in the 15-20um band (excluding the additional radiation load from increased atmospheric CO2).

    I was responding to James’s statement that temperature was not the significant factor from increasing CO2 instead it was long wave radiation. I have not seen an earth surface radiation increase signature in the arm.gov SKYRAD databases, nor a regional long term daily temperature mean increase.

    In essence, locally, over the past 27 years, at most I have seen more indicators of wide scale drier air masses and less precipitation. Based on the news, it appears that it is not necessarily that there is less precipitation globally, only that the precipitation appears to be more regionally concentrated.

    I was simply suggesting that the additional radiant energy must be retained in the atmosphere and must be affecting the large scale weather patterns, as the increase of 0.009% in the CO2 sources radiant energy does not appear to explain a global daily temperature range compression or an approximate daily mean increase of 0.5 to 0.8 Deg. However, stagnant air masses and a lack of the influence of the sub-tropical Jet Stream moving northward during the Summer Season here in the NH, does help explain the increase in temperatures and the reduction in precipitation.

    In essence, it appears that the Summer Seasonal sub-tropical Jet Stream appears to be less active apparently resulting in more stagnant barometric pressure waves between 25 and 35 Degrees. Hence, I was asking if James or anyone else might be aware of any studies demonstrating this mechanism or an interpretation of this mechanism. I seem to remember a study about 2 years ago wrt changes in the Walker Circulation. I remain curious if there had been any follow up or any new work in regards to either the ENSO or NAO and the energy input from CO2.

    My apologies if the search for this data appears to have ruffled your feathers; however, based on the specifics I was looking for and my failure to find them, along with the lack of recent periodicals misquoting science professionals, it is now apparent that this remains an opportunity for further research. By the same token, apparently the NASA reference I had included in my post, looking for more data, apparently remains out side of the current state of the knowledge of climate science…

    Believe me Hank, I respect the resource, if I want to blog, I play elsewhere… Your reaction told me much!

    Dave Cooke

  14. 114
    Jim Eager says:

    Re 101 John Mashey: “For North America:
    a) Do you think you know enough about soil quality in Canada AND
    b) Enough about likely future rain patterns
    to be *sure* that food production will not diminish as crops like wheat shift from US to Canada?
    Take a look at the chart at end of:”
    http://news.bbc.co.uk/2/hi/science/nature/6200114.stm

    I’ve deflated this one before.
    1) The blue shaded are is less than half the size of the yellow shaded area.
    2) Much of the eastern third of the blue area is Canadian Shield, some of the oldest exposed bedrock on Earth.
    3) The western sixth is the Canadian Rockies, the next sixth is watered by them, and the glaciers that feed the rivers are shrinking.
    4) The upper half has plenty of water, but it is presently boreal forest and muskeg.

    Lots of luck feeding North America from what remains, let alone exporting food.

  15. 115
    Hank Roberts says:

    Dave, I’m just another reader, so don’t mistake _my_ ignorance for the current state of the knowledge of climatologists! More like the measure of ignorance of well meaning, too busy, and mathematically limited readers (grin). I recall mentions that we should expect more precipitation, not less, but “local variability” rules, and likely more intense precipitation when it happens. The soil erosion folks are looking at the erosion at the end of the last ice age for examples, and some are scary looking.

  16. 116
    John Mashey says:

    re: #114 Jim Eager:
    I’m not sure I understand your post: I thought I was pretty clear that I did not support Ryan’s “don’t worry.” I picked the map because it was from the UK & obvious that the change would substantially lessen the area for an important crop, even if water and soil conditions were equal (which is unclear or unlikely).

    If anyone else thought I was saying “don’t worry”, I’m sorry for any ambiguity. I’m an old farmboy, I’ve visited Canada dozens of times, I’m up there 2-3 times/year, and there’s no way I can think of that higher temperatures & likely rainfall patterns improve North American food production overall. I know how much CA worries about effects on agriculture, and better grapes in the Okanagan will not compensate for the loss in Napa+Sonoma.

  17. 117
    John Mashey says:

    re: #114 Jim Eager:
    I’m not sure I understand your post: I thought I was pretty clear that I did not think that the blue piece was likely to replace the yellow piece, even if water and soil were fine.

    Did anybody else read #101 and think I was supporting Ryan’s “don’t worry?”

    If so, I’m sorry for any ambiguity. I’m an old farmboy, I visit Canada ~3 times/year, and there’s no way I can think of that higher temperatures & likely rainfall patterns improve North American food production overall.

  18. 118
    L. David Cooke says:

    RE: 115

    Hey Hank;

    Thanks! I appreciate your basis…, grining back!

    I had been trying to run down the soil erosion and precipitation as part and parcel of the carbon sink question, John Mason at UKweatherworld has been helpful there. I was hoping to put together a quick post there to address Vernon’s questions.

    I am afraid Vernon and I are not necessarily alone. We have the background; but, cannot convert the “knowledge of what” to the “mechanics of how”, the radiative model (sensitivity), recommended is not helping much. Contrary to Lawrence’s suggestions, the empirical is not a bastion; but, a conveyance, for those of us that may be more limited… David’s additions have been welcome; but, not necessarily in line with the need. The problems may resolve themselves as the regional empirical evidence may change in the next few years, as the model grid resolutions improve (RC’s 27 May Talking Point.)

    Dave

  19. 119
    Lawrence Brown says:

    Re 109:
    Timothy Chase says in part:
    “I would strongly recommend checking out the Met Office Hadley Centre – a world class climate modeling center in the UK. They have some projections specific to the UK.

    Here is their website:”

    Met Office: Climate Change (Hadley Centre)
    http://www.metoffice.gov.uk/research/hadleycentre/index.html

    Amen to that.
    This is an excellent source. Though what they say about the Greenland Ice Sheet seems optimistic. Here’s what they said in June 2006 about the Greenland Ice Sheet: ” In the case of the Greenland Ice Sheet,if summer regional temperatures were to rise by about 3C,the ice sheet would begin to reduce in size.It would be slow to disappear, perhaps half of it taking about 1000 years to melt.This critical temperature is predicted to be reached by the end of the centuryby most combinations of climate models and future emissions scenarios.”
    Here’s the URL http://www.metoffice.gov.uk/research/hadleycentre/pubs/brochures/2005/clim_green/slide56.pdf

  20. 120
    Jim Eager says:

    Re: #116/117 John Mashey: “I’m not sure I understand your post: I thought I was pretty clear that I did not think that the blue piece was likely to replace the yellow piece, even if water and soil were fine.”

    You were perfectly clear, John, I was just trying to emphasize the point to Ryan that the impact of a warmer climate on food production will not likely be a positive one in much of the world.
    Sorry for my own ambiguity.

  21. 121
    catman306 says:

    As Ray and others remind us, RC is not a climate chat room.
    -Hank Roberts

    Is there a site, of the caliber of RC, where people discuss meteorological trends, phenomenon and theories that can be recommended?

  22. 122
    James says:

    Re 113: [I was responding to James's statement that temperature was not the significant factor from increasing CO2 instead it was long wave radiation.]

    If you’re referring to my comment #87, I think you misunderstood what I was trying to say. It’s not that temperature increases aren’t a significant result of increasing CO2. I was trying to make a point about how AGW theory developed. It’s not the case that people observed increasing temperatures and looked around to find some reason for the increase. Instead, the increase was predicted on theoretical grounds. Knowing how CO2 interacts with radiation, it’s possible to predict the temperature changes that will result from a particular change in CO2 levels. (This is complicated by feedbacks and so on, which is why you need computer models to compute it.)

    So we have this theory, and measurements show increases in CO2 level. Run everything through the computer model, and you get a predicted temperature increase. Now you look at actual measured temperatures and see if they agree with what was predicted to date. If they do, that increases your confidence in the models’ predictions going forward.

  23. 123
    Hank Roberts says:

    Pointer off-topic for Dave Cooke, this is very cautionary:
    Abrupt increase in seasonal extreme precipitation at the Paleocene …
    http://ic.ucsc.edu/~jzachos/eart120/readings/Schmitz_Puljate_07.pdf

  24. 124
    Phil. Felton says:

    From post #99
    “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.”

    The problem with this ‘rough calculation’ is that it is based on totally false data!
    The average insolation is 342 W/m^2 of which 77 W/m^2 is reflected from clouds and 30 W/m^2 is reflected from the surface plus 67 W/m^2 leaving 168 W/m^2 reaching the surface.
    See J. T. Kiehl and Kevin E. Trenberth, Bulletin of the American Meteorological Society, Vol. 78, No. 2, February 1997. I suggest you recalculate with more reasonable numbers

  25. 125
    John Wegner says:

    Gavin raised the issue of climate sensitivity to CO2 during the paleoclimate in the response to post #105.

    My math shows about 1.0C of warming per 2XCO2 (or at least very close to the low end of the range of 1.5C of warming per doubling.)

    For example, the following shows the estimates of CO2 concentrations in the atmosphere during the Phanerozoic (the last 540 million years.) [I use Berner's estimates here, the yellow line, since he seems to have the most credibility on this issue.]

    CO2 levels were as high as 2,000 ppm, 150 million years ago; 4,000 ppm, 400 million years ago and 7,000 ppm, 500 million years ago.

    http://www.globalwarmingart.com/wiki/Image:Phanerozoic_Carbon_Dioxide_png

    The temperature estimates in the palaeoclimate, however, are only about 2.0C warmer for 150 million years ago (3 doublings of CO2 from the natural level of 280 ppm), 5.5C warmer for 400 million years ago (4 doublings) and 6.0C warmer for 500 million years ago (nearly 5 doublings).

    http://upload.wikimedia.org/wikipedia/commons/thumb/f/f5/All_palaeotemps.png/800px-All_palaeotemps.png

    The Eocene Optimum is clearly a special case with temperature estimates of 6.0C warmer with a range of estimates for CO2 of 500 ppm to 3,000 ppm

  26. 126
    Hank Roberts says:

    Rate of change, John.

  27. 127
    L. David Cooke says:

    RE: #122

    Hey James;

    Thanks, actually that does help in my understanding of what you were trying to express.

    What I was trying to share is that in my goal to understand the mechanics of the GW theory, I do not see the earth surface measurement of CO2 radiant spectrum energy during a clear night sky in the SKYRAD database. Hence, I was trying to consider if it might be possible that the energy was “trapped” in the atmosphere and causing weather changes resulting in increased mean temperatures rather the actually heating the earths surface.

    Dave Cooke

  28. 128
    L. David Cooke says:

    RE: #123

    Hey Hank;

    If it is okay, I would like to share this with Andre and John on UKww, I am curious if this might have something to do with an uplift we have been discussing… I also want to look at it more indepth as well to see if how they have characterized the sedimentation in this region.

    Thanks
    Dave

  29. 129
    ghost says:

    RE: #101 Mr. Mashey, #114 Mr. Eager:

    Your timely comments about growing conditions resonate with my annoyance over the recent ‘rising CO2 will be a good thing’ jaunt by Bertrand, Prevost, et al., where they go from this statement: “The authors grew well watered and fertilized alfalfa” to this conclusion: “as the environmental transformation that is currently underway automatically insures that there will be a “greening of the earth” throughout natural and agro-ecosystems alike.”

    Assuming ample water, fertilizer, and non-stressful temperature conditions seems to me to leap over the probability of chaotic growing conditions associated with an AGW world. Not to mention that their report doesn’t state whether they subjected the specimens to the multiple cuttings typical of alfalfa production, address heat stress issues or the conditions’ concurrent effect on 4C weeds, or discuss the usual planting/seedling growth issues from unsettled weather conditions. Considering their experiment’s scope, that last quoted phrase strikes me as somewhere between a political statement and quite a leap in logic.

  30. 130
    L. David Cooke says:

    RE:#124

    Hey Phil;

    Actually, I am looking at specific numbers in watts per meter squared on the arm.gov data base for April the 13th 2007 on Nauru Island at the TWP SKYRAD daily insolation long wave detector. The Peak during the Spring Equinox there averages 1200 watts for nearly two hours with an average of 850 watts or above for a min. 8 hours with a rapid slope from 50 to 500 watts both preceding and succeeding the peak levels. (Except in the case of excessive cloud cover in which the value will be no less then an average of 500 Watts/meter^2 for most days for a minimum of 4 hours.)

    I am sorry if I have used a value you question. However, the value I have used is a direct observation with a known accuracy of around +/- 5 watts, based on the last quality check I noted.

    Based on my best understanding the insolative value at most ARM.gov sites supports a minimum of 850 watts/meter^2 of peak long wave incoming energy from sites ranging from about 53 Degrees N to around 23 Degrees S. during
    most days from mid spring to mid fall here in the NH. (This happens to be the peak solar insolative period and most likely to “charge” the atmospheric resident CO2.) I will have to go back and find the minimum long wave value; however, as my memory serves me it was not less that about 500 Watts/meter^2 in the Western Plains site. I am not sure; but, I believe the Alaska site may get down to a 300 watt region peak during the winter here in the NH.

    Maybe I am misunderstanding you, are you saying that the 324 watts/meter^2 is considered the 360 degree average global input? Such that you are comparing a globally averaged solar input against a modeled 24 hour CO2 radiant down welling input. Meaning, that you are saying that 0.8% of the 24 hour average radiant down welling energy is equal to the CO2 source. And this would be different from me saying that 850 watts for 8 of 24 hours means a total of say the solar 6800 watt hours/meter^2 as opposed to CO2 62.4 watt hours/meter^2 per day, resulting in about 0.9% of the long wave down welling energy being due to CO2.

    Could you please assist me in understanding your point. I apologize if I was not absolutely correct in how I approached the rough approximation; however, the values are fairly close. The only real difference is that I am allowing for my calculations to more closely follow the actual inputs and outputs rather then theoretical.

    If we wanted to be more accurate yes, you are correct we would have to express the specific surface detectable daily solar gains and distribute them then compare that to the distributed CO2 radiant gains. I am afraid all I have done was to demonstrate my apparent ignorance, my apologies.

    Dave Cooke

  31. 131
    Hank Roberts says:

    Dave, if you are asking about porting the digression somewhere, or permission for quoting or linking, I guess you’d want to ask the Contributors (contact info is behind the “About” link, top of page). I’m just another reader; I’ll follow pointers if you leave’em.

  32. 132
    Chuck Booth says:

    Re 129 “Assuming ample water, fertilizer, and non-stressful temperature conditions seems to me to leap over the probability of chaotic growing conditions associated with an AGW world..”

    Not to mention also the possible effects that CO2-stimulated growth could have on plant protein levels, carbon/nitrogen ratios, and differential responses by plants carrying out C3 vs. C4 photosynthesis, all of which could alter the productivity of crops and grasslands, the invasiveness of weeds, and food quality for grazers.
    Ref: Ehrlinger, J.R. et al. (2002) Atmospheric CO2 as a global change driver influencing plant-animal interactions.
    Integrative and Comparative Biology 42:424-430.

  33. 133
    J.C.H says:

    Fear not, giant veggies will feed the world:

    http://seattlepi.nwsource.com/getaways/091996/vege19_top.html

  34. 134
    Bruce Tabor says:

    I’m not sure where to put this.
    Last night our national broadcaster (the Australian Broadcasting Corporation, ABC) showed the Great Global Warming Swindle (GGWS):
    http://www.abc.net.au/tv/swindle/
    It was followed by an interview of director Martin Durkin and a panel debate that included 3 vehement sceptics out of a total of 8 panelists.
    http://www.abc.net.au/tv/swindle/panel.htm
    The main sceptic with “relevant” expertise was Bob Carter (an environmental geologist), who was ably countered by David Karoly. Journalist Michael Duffy and Lavoisier Group secretary Ray Evans were also on the panel.

    It has generated huge debate:
    http://www2b.abc.net.au/tmb/Client/MessageList.aspx?b=89&t=1&a=0&te=False&ps=20
    http://www.abc.net.au/news/stories/2007/07/12/1976998.htm

    There were several in the audience who made bizarre statements during question time (eg. the eugenics roots of environmentalism) and online pre-show polling may well have been influenced by them (49.5% did not think human activity was a significant contributor to global warming).

    There was a mention of Lyndon LaRouche’s name and the group may have been the Citizens Electoral Council who venerate LaRouche:
    http://cecaust.com.au/
    http://cecaust.com.au/main.asp?sub=info&id=aboutlhl.htm
    They were clearly trying to motivate members prior to the show:
    http://www.cecaust.com.au/main.asp?sub=global_warming&id=ABC.html

  35. 135
    nicolas L. says:

    re 407 John

    Thanks for the link… quite astonishing. Seems the new game is to cut climate scientists from their data sources:
    _ Ground measurment gets trashed by a few pics circulating on the net;
    _ Satellite data is gonna lack because NASA’s directive board decided it was more important to go back to the moon.

    Hope Nasa’s move is not conscious (looking at last Micheal Griffin’s words about GW, I wonder…).
    We’ve got a nice expression in my country to call this: the ostrich policy (when facing a problem, hide your head in the sand and wait for it to go away…)

    Maybe off the scientific topic, but I’ve got a question for our excellent contributors here. Is climate science communauty gonna protest about this? Make some sort of official statment to the NASA directive board, through the IPCC for exemple?

  36. 136
    MikeB says:

    Sorry for being a little late for replying to Ryans comments #96 (of which much has already been said!).

    Since I also live in the UK, I’m seeing farmers waterlogged fields, with the high chnace of a ruined crop, as well as the continuing problem of large part of East Anglia becoming increasingly arid. Soil erosion continues to be a problem, and the mixture of wet mild winters and increasingly hot summers will increase pest damage, etc. Agricultural land in the UK will decrease under pressure from development, such as housebuilding. Lets not even talk about fishing.

    Importing food from the US? The latest IPCC report makes it clear that North American food production (as has already been mentioned) will fall as tempertures rise (after a small initial lift), and I suspect that European farmers as a whole will have much the same problems as the UK, with tempertures perhaps even higher in the South.

    Water stress will lower rice yields in SE Asia, and increased chances of flooding in certain areas of the Indian sub-continent will reduce the amount of land available for crops, and shortages will increase prices.

    China will also suffer problems with food scurity and water stress, and Africa will probably have even more problems feeding itself (and those cute little trays of veg in Tesco’s flown in from Kenya, etc will possibly disappear as oil prices rise anyway).

    As for London, the Thames barrier was build to protect the captial against storm surges, etc such as the one in 1953, which caused so much damage in both eastern England and in Holland. Climate change and the continuing sinking of southern Britain will increase the chances of another disaster, even with the Thames barrier. Dungeness power station is already under threat from the sea, with a constant effort to replemish the gravel banks that protect it.

    Of course we may get the fabled grapes as far as York, which at least means we will have some wine on hand – because I suspect that given the projections of climate change, we are all going to need a good stiff drink…

  37. 137
    pete best says:

    re #105 Regarding the eemian interglacial. It has been suggested that this period was around 2 C warmer than today due to the higher sun in the northern hemisphere and not CO2 levels which I believe were similar than todays ?

    it is true though that climate simulations of that era cannnot produce the same temperatures as found in the paleoclimatic data without large simulated CO2 increases and that something appears to be missing from the simulations.

    This is mentioned in the book 6 degress by Mark Lynas. He claims that the reductionist nature of the models is to blame and that climate feedbacks of a systemic nature are more than likely the cause of the discrepency.

    Any truth in this ?

  38. 138
    Ryan Stephenson says:

    London rate of sinking into its own mud maybe as much as 100% faster than the rise of sea level:-

    http://news.bbc.co.uk/1/hi/sci/tech/6231334.stm

  39. 139
    L. David Cooke says:

    RE:#124

    Hey Phil;

    Oops, I forgot to include the reason I choose 850 as my median value. I used a simple RMS to Peak to Peak conversion 850 by 1.414 equated to around 1200 watts. The difference was around 350 watts. The min then would be approximately 500 watts which seemed to fit the application fairly well. That my value would equate to an average of 283 watt hours/ hour per day as opposed to calculated 324 watts you referenced may have been a little low. I leave it to you to suggest which may be a better approach. At least with mine I understand how it fits into direct measurements. I hope this helps…

    Dave Cooke

  40. 140
    nicolas L. says:

    Oups, sorry guys… it appears the last message i posted found its way to the wrong thread: 135 here, though I was replying to a message in “No man is an (Urban Heat) Island”. Must have don’t some wrong somewhere when I was posting it.

    Can you fix it, or do I have to post it again in the right place?

    Sorry again

  41. 141
    Craig Allen says:

    Re: 134 and the Screening of the Global warming swindle show on Australia’s ABC.

    The audience for the panel discussion after the Swindle screening was hilarious. Besides the Larocheans there was at least one creationist. They threw it open to questions from the audience at the end only to discover that the place was stacked with incoherent loonies.

    As an antidote to the general silliness, there was a great interview on the ABCs Lateline show the next day with Carl Wunsch on what he thought of his involvement. He puts his points-of-view very well. You can see it here. Aaah, sanity and rationality. Well done Dr Wunsch.

  42. 142

    [[Based on my best understanding the insolative value at most ARM.gov sites supports a minimum of 850 watts/meter^2 of peak long wave incoming energy from sites ranging from about 53 Degrees N to around 23 Degrees S. during
    most days from mid spring to mid fall here in the NH. (This happens to be the peak solar insolative period and most likely to "charge" the atmospheric resident CO2.) I will have to go back and find the minimum long wave value; however, as my memory serves me it was not less that about 500 Watts/meter^2 in the Western Plains site. I am not sure; but, I believe the Alaska site may get down to a 300 watt region peak during the winter here in the NH.
    ]]

    You are confusing peak radiation received with average radiation received.

    The Solar constant at Earth’s orbit averages 1,367.6 Watts per square meter. But because the Earth is a sphere, half in darkness, and much tilted away from the source of illumination, the average insolation at the top of the atmosphere is only S / 4 or 341.9 W m-2. Another way to put it is: the Earth receives solar radiation on its cross-sectional area (π R2) but has an actual surface area four times this (4 π R2); thus the factor of 1/4.

    The amount that actually goes into the climate system is less still, since about 30% of Solar radiation is reflected back into space by clouds, atmosphere and ground (mostly clouds).

  43. 143
    Nick Gotts says:

    Re #138 As the article Ryan references actually makes clear, London isn’t “sinking into its own mud”, at least as a whole (parts of it are sinking due to the abstraction of water, and settlement of Holocene deposits along the Thames); rather, Britain itself is tilting, with the north rising and the south sinking, in a rebound effect following the melting of glaciers at the end of the last ice age. The article gives values of 1-2mm/year for this process, and about 1mm for sea level rise (as measured by tide gauges). Sea-level rise may of course speed up over the next century, while the rebound will not. As someone else noted, the current rate of relative sea-level rise can be handled technologically using barriers and pumping (and if necessary we can call on Dutch expertise, as we did to drain the East Anglian fens some centuries ago!), but the technology is of course expensive.

  44. 144
    Paul says:

    Timothy

    RE 109 Perhaps you should tell the 30,000 people in the UK made homeless by flooding in the last few weeks that the Met Office are predicting 30% drier summers. I am sure it will make them very happy.

  45. 145
    Bruce Tabor says:

    Re #141, #138 The ABC GGWS debate
    Hi Craig and others,
    The unusual audience comments/questions can perhaps be explained by this article on the LaRouche Youth Movement’s (LYM) US site. Interesting reading for us “warmers”. See:

    http://larouchepac.com/news/2007/07/12/australian-lym-raises-nazi-eugenics-roots-environmentalism.html

    ‘Australian LYM Raises the Nazi Eugenics Roots of Environmentalism
    July 12, 2007 (LPAC) At a live Australian Broadcasting Corporation debate on Global warming, with 15 Larouche activists present in the audience out of 80 attendees, the ALYM and Australian chapter members present got to ask 4 questions to the panelists, exposing the genocidal roots of environmental philosophy.

    The show was aired at 8:30pm, the two and a half hour broadcast on Australian TV started with a showing of the Global Warming Swindle documentary, then showed 2 interviews. The first was with the director of the documentary, Martin Durkin, in which he fended off attacks on his work. The other was with Karl Wunsch, the MIT oceanographer who has said that his contributions to the documentary were misquoted and misconstrued. After this, a live broadcast roundtable discussion was held with 5 “warmers” and 3 “skeptics.” Some notable panelists were Professor Bob Carter, (James Cook University), Australia’s most famous global warming skeptic, and Greg Bourne, CEO of the Australian branch of the World Wildlife Fund. The broadcast’s aim was to completely discredit the Global Warming Swindle documentary.

    It was at this live debate in the studio of ABC Sydney and broadcast on Australian national television that we intervened. Three organizers were kicked out on sight for “suspicion of being potentially disruptive,” while 15 activists, LYM and chapter members, made it in safely. Two of questions centered on the relationship between Nazi race science, eugenics, and environmentalism. One ALYM member, wearing a t-shirt that said “Anthropogenic Global Warming is a bigger fraud than your girlfriend’s orgasm!”, asked about statistical vs. dynamic analysis concerning the method in which the “warmers” gather their data. For the last question of the broadcast an organizer sharply asked if the panelists were for or against human populations. A more detailed report, including the reactions of the panelists to the questions, is forthcoming.

    The ALYM will stay in Sydney for a week in effort to force the Australian Government to investigate the BAE scandal. A full report on this campaign is also forthcoming.’

  46. 146
    Nick Gotts says:

    RE #106 “Supreme irony don’t you think? Riots caused by proponents of AGW telling us to use less fossil fuel so we burn Mexcian food sources to allow us to use our cars. Maybe it would have been better if we had let them eat and not made a big thing about AGW… (you could also have a word with the Mexicans about fecundity).” – Ryan Stephenson

    This is something of a distortion. Campaigners on climate change issues have been warning for some time that biofuels are not a viable alternative to fossil fuels, because of the amounts of land required, and that in some cases there is little or no reduction in net GHG production (when coal is used in the extraction process), or even (when tropical forests cut down for oil palm plantations) a large increase. The increase in biofuel production in the US that has caused rising tortilla prices in Mexico is down to subsidies (about $6.5bn annually and growing, according to http://www.iisd.org/subsidies/gsi_nov_2006.htm). The Bushites have been promoting biofuels to subsidise US farmers and to reduce dependence on oil imports, not out of concern over GHG emissions – although they have recently started presenting the latter as an additional advantage. Incidentally, the annual growth rate of Mexico’s population has come down from 3.5% in 1965 to 1% in 2005, so it appears they may not need Ryan’s condescending “word about fecundity”.

  47. 147
    Nick Gotts says:

    Re #144 [RE 109 Perhaps you should tell the 30,000 people in the UK made homeless by flooding in the last few weeks that the Met Office are predicting 30% drier summers. I am sure it will make them very happy.]

    Why should it? Drier summers on average are quite compatible with more frequent flooding if rain, when it comes, does so in more concentrated bursts.

  48. 148
    Nick Gotts says:

    Re #86 Heather, I don’t agree “this man” (one Ken Liston) makes any interesting points. He makes the very obvious and oft-repeated point that globe-trotting celebrities appear hypocritical if they campaign for a reduction in greenhouse gas emissions while continuing their wasteful lifestyles. Because this is such an easy point for denialists to make, I doubt whether the overall effect of the “Live Earth” concerts was positive in terms of making action to reduce emissions more likely. However, the point has no relevance whatever to the causes of climate change – so there is no reason why it should have changed Liston’s opinion on anthropogenic climate change from “sceptical” to “very sceptical” as he claims it did. When someone says something as stupid as that, you know they are either a fool, or are making a false claim for rhetorical effect.

  49. 149
    L. David Cooke says:

    RE: #142

    Hey Barton;

    Thanks, I think I accounted for this, only I was looking at the data from an earth side detector. In essence, the amount of energy constant I calculated from ran at about 283 watts/meter^2 rather then either the 324 from Phil’s reference and the roughly 342 from your reference.

    My actual fallacy in my estimates, and my apologies to James, should be related to my error in suggesting that the radiative value would have been about 0.1 Deg in #99. I reviewed what I had done and found that if the references I have found subsequently are correct, the atmospheric heat content due to CO2 should be about 12% and the atmospheric heat content should be about 30-38 Deg. If this is correct then the atmospheric CO2 heat content should be about 4 Deg. with an increase of about 0.6 Deg down welling since about 1850 due to the additional 100ppm.

    The issue of the mechanism question appears to remain, for me… If this input is direct radiative energy, I have more research to do. If the warmth is actually driving large weather patterns then it makes more sense to me; but, again I have more research to do. However, my thanks for your input. (Note: I am trying to establish data at the point of perception, so that I can relate to it better.)

    Dave Cooke

  50. 150
    Lynn Vincentnathan says:

    Reading Kim Stanley Robinson’s FIFTY DEGREES BELOW, a novel. This second one in his trilogy about global warming is about the N. Atlantic ocean conveyor & downwelling stopping bec of fresh water from Arctic and Greenland ice melt. It talks about the eastern portion of N. America and much of Europe going into a deep freeze, tho Robinson’s rendition is more realistic than DAY AFTER TOMORROW.

    I believe this topic has been covered on this site, and I think the upshot was the experts said that even if the ocean conveyor slows greatly or stops (and I believe there ARE signs of it slowing), that the resulting cold would be offset somewhat by global warming (since we are at a high, interglacial plateau, not in an ice age valley at present), so it wouldn’t be so cold as to ruin agriculture. That the earlier shutdowns had occurred when the world was just coming out of deep ice ages, so the N. lat temps got a lot colder than they would today, and the resultant ice/snow albedo reinforced the reversions to ice ages.

    (Of course, none of this addresses just how hot it will get at my place in the Gulf of Mexico, bec the warm current has stalled in the south, and we won’t be getting as much cool water coming in — bec the muckity mucks live up north and not down here, I guess.)

    Anyway, let me know just how wrong I got this, and whether Robinson’s novel has any validity.


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