Ross Ice Shelf melt and other cool fables

Ross Ice Shelf

Rob Fenwick, in Accelerating melt reason to worry (The Press, 21 May 2012), launches into a worry-fest about all the fabulous calamities said to be on the way with “continued” man-made global warming.

The astute reader will know that the word “fabulous” is derived from “fable”. It means unreal or imagined more than it means magnificent. I chose that word because all the disasters Mr Fenwick briefly catalogues are fantastic (cf. “fantasy”). But I should begin at the beginning of his niggle-gala. He says:

When the world’s polar scientists gathered in Montreal last month – all 3000 of them – it seemed like a case of preaching to the choir.

After 20 years of intense study of the effects of changing climate conditions at the poles, there is certainly no longer any debate over what is going on.

The ice sheets in Greenland and West Antarctica are melting, oceans are rising and acidifying, ecosystems are struggling to adapt. No-one can argue with the facts.

First, I am astounded that he claims that no debate took place at a conference. Those events are exactly where debate is most likely. They are arranged in the expectation of debate, designed to encourage debate, people go along anticipating debate and the organisers try to provide the very best means of managing debate (it’s the same with Caribbean fishing competitions — they try to manage de bait).

But he says there was no debate — the conference must have been a dismal failure, no better than a long lecture, and that’s hard to accept. Does he expect us to believe that, among 3000 scientists, none disagreed with any other? It implies that, astonishingly, not one of them even had an ego.

Second, it’s disappointing to hear this, because I have studied climate change for over eight years and I know that scientists differ on some vital features of climate change, yet he ignores them all.

Rob Fenwick is a leader in polar science and scientific management, and as a director of CarbonZero he makes money from the faddish measuring of carbon footprints, inspired by the story that humans are responsible for global warming. So it’s fair to assume that he is acquainted with some of the details of polar science and global warming. The reasonable conclusion therefore is that he has wilfully ignored them. Let me explain.

There are uncertainties, unknowns and there are strong disagreements on many aspects of global warming. Yet he says:

there is certainly no longer any debate over what is going on. The ice sheets in Greenland and West Antarctica are melting, oceans are rising and acidifying, ecosystems are struggling to adapt. No-one can argue with the facts.

But the ice sheets are not melting. 21st-Century Evolution of Greenland Outlet Glacier Velocities (Moon et al., 2012) reports Greenland glacier acceleration this century that indicates that “sea level rise from Greenland may fall well below proposed upper bounds.” The great Antarctic and Greenland ice sheets are not melting and even if they were, they would take hundreds of years to vanish.

Mr Fenwick mentions the Ross Ice Shelf, citing the depth of it as 750 metres. It actually measures about 330 metres at the ice front (out in the ocean), which is an astounding thousand feet down into the water. Closer to the land, where it rests mostly on the sea bed, it deepens to more than 800 metres — 2600 feet of solid ice. It’s enormous.

I calculated it contains something like 240 trillion tonnes of super-dense ice. I’m happy to share the calculations of that, but that slab of ice isn’t going anywhere in a hurry, whether as ice, water or vapour. Human emissions of CO2 are about 4% of the natural flux — 30 gigatons added to a natural 750 gigatons.

So we expect 30,000,000,000 tons of gas to melt 240,000,000,000,000 tons of ice at an average temperature well below freezing — yeah right. Anyone who fears that gargantuan glob of ice could be melted by our dainty emissions of carbon dioxide is pushed for entertainment.

Sea ice in the Antarctic (as Mr Fenwick must know) has been growing for the 30 years of satellite observation and in the Arctic has been recovering since the one-off record decline five years ago.

Yes, oceans are rising, but at the same steady and unremarkable rate as for the last 6000 years. Sea levels increased during the 20th Century by about 185mm and recent papers report no acceleration. For all the excitable chatter about Pacific islanders becoming homeless and evacuating to New Zealand, none of that has happened and the South Pacific Sea Level and Climate Monitoring Project run by the Australians continues to report it has nothing to report.

Ocean acidification is not a matter for concern. He should know that the oceans are still robustly alkaline. Acidification is minor, limited in extent, the effects on biota are hotly disputed, though many are beneficial, and the magnitude of predicted acidification is almost entirely a matter of guess-work.

The widely-available ocean maps showing regions of declining pH reveal that, as in the eastern equatorial Pacific, lowered pH is probably caused mainly by upwelling bottom water, not absorption from the atmosphere. There are also numerous sites where carbon dioxide bubbles naturally from the ocean floor and the ecosystems adapt.

Oceanic bottom water has slightly elevated pH due to higher levels of dissolved carbon dioxide. When it’s only just above freezing, water dissolves an enormous amount of CO2, which is available in abundance from the dead bodies constantly raining down. When that water surfaces and warms, it releases CO2 which feeds plankton and other plant life.

Chemists among the polar scientists will confirm that as oceans heat up from any cause, the dissolved carbon dioxide will outgas, instantly reversing any recent acidification caused by absorbing more CO2 from the slight anthropogenic increase.

Ecosystems may struggle in future to adapt if the wilder fancies of computer models are realised. But they’re certainly not struggling now, for the simple reason that there’s been no uncharacteristic warming.

Of the Ross Ice Shelf, Mr Fenwick says it is “not yet showing signs of significant, unseasonal melt.” As he cannot point to observations of dangerous change, he simply speculates. See how cleverly he leaves the impression that he’s making predictions.

What will cause the Ross Ice Shelf to melt?

When will it start and how fast will it be?

How will it affect the Pacific Ocean, New Zealand and its Pacific neighbours?

What should we be doing now to try to slow it down and prepare for it?

But he gives us no evidence for his outlandish suggestion that the ice shelf will melt.

So then he says, almost as though he heard me getting worried: “However, researchers are puzzled by unusual pulses of warm southern ocean currents that are circulating around Antarctica and which, in other parts of the continent, are starting to melt ice from below.”

The simple fact is that those “unusual pulses” are nothing more than natural current fluctuations. For what else, in heaven’s name, might they be? What is he trying to alarm us with? The ice has been floating in the Southern Ocean for thousands, nay, millions of years. It comes and it goes, waxes and wanes. Don’t panic, Rob!

Now he imagines what might happen IF it melted. Because to replace reality we must construct a dream.

If the Ross Ice Shelf starts to melt, its affect [sic] on the Pacific Ocean both physically and chemically, and its impact on the economies of our Pacific Island neighbours, will be catastrophic.

He doesn’t say what would cause that but I guess the effect would be even worse when it finished melting. Hundreds and hundreds of years later.

And even if all of these things were true, there’s still no evidence that we caused them. There’s still no reason to change what we’re doing, unless it is causing real environmental harm.

One of his statements is almost true: no-one can argue with the facts — except Rob Fenwick.


Rob Fenwick is chairman of Antarctica New Zealand and a former chairman of the Antarctic Heritage Trust. In 2005 the New Zealand Geographic Society named the Fenwick Ice Piedmont in the Ross Sea for his work in Antarctica.

Visits: 106

62 Thoughts on “Ross Ice Shelf melt and other cool fables

  1. Andy on 24/05/2012 at 7:58 am said:

    3000 people get together. They all agree about everything.

    How does this differ from a religious revivalist meeting?

  2. Bob D on 24/05/2012 at 7:58 am said:

    How will it affect the Pacific Ocean, New Zealand and its Pacific neighbours?

    Easy – it won’t. If it “melts” it will have zero effect on sea levels. Ice shelves, by definition, float.
    Archimedes.
    QED.

    • You’re right, but, to be fair, there could be some effect. If the melt is swift, there might be dilution by fresh water (though doing what, exactly?), and a fair proportion of the shelf is grounded, so there could be a contribution to sea level rise. But it will be far in the future so there’s surely time to adapt.

  3. Bob D on 24/05/2012 at 7:59 am said:

    (it’s the same with Caribbean fishing competitions — they try to manage de bait)

    That hurt.

  4. Andy on 24/05/2012 at 8:12 am said:

    In 2005 the New Zealand Geographic Society named the Fenwick Ice Piedmont in the Ross Sea for his work in Antarctica.

    It seems quite appropriate that he gets a feature named after him that by his own predictions will disappear in due course.

  5. Alexander K on 24/05/2012 at 9:59 am said:

    To reiterate my opinion from an earlier post, the gentleman in question (and I use the term very loosely) is a self-aggrandising opportunist of the first water who has more in common with revivalist preachers that star on and own bad-taste religious TV channels in the USA, selling religion’s version of snake-oil. While the gullible abound, so will such creatures who prey on them.
    As someone once said, ‘A lie gets halfway around the world before Truth gets it’s boots on.’

    • That’s a damn strong opinion, Alexander. Bad-taste preachers? Whatever happened?

    • Alexander K on 24/05/2012 at 4:54 pm said:

      Richard, you are damned right it’s a strong opinion! I have been in the position of trying to unpick some of the damage such people do even here in NZ.
      I have no problems with religion per se, and know that millions of people have some sort of religious belief which they find helpful in their attempts to live morally and ethically ‘good’ lives, but when Man’s religious urge is misused by opportunists and con-men, they do make me more than a little angry.

  6. PeterM on 24/05/2012 at 2:19 pm said:

    The Václav Klaus talk at Heartland is worth reading. He understands the socialist mindset.

    Also of interest is

    ‘Media liaison staffers have been sent to an international polar conference in Montreal to shadow Canadian government scientists during interviews, in what critics are calling the latest example of extreme information control by the Harper Conservatives’.

    http://www.cbc.ca/news/canada/montreal/story/2012/04/24/scientists-muzzling-canada.html

  7. Richard C (NZ) on 24/05/2012 at 5:54 pm said:

    “The ice sheets in Greenland and West Antarctica are melting”

    Do they still only melt at and above O C or has the change of state changed? Even if it has I don’t see steams of melt water coming off the surface.

    I suspect too that those figures are not attired for Caribbean fishing.

    “….oceans are rising”

    A team of researchers reports in Nature Geoscience that land-based water storage could account for 0.77 millimetres per year, or 42%, of the observed sea-level rise between 1961 and 2003. Of that amount, the extraction of groundwater for irrigation and home and industrial use, with subsequent run-off to rivers and eventually to the oceans, represents the bulk of the contribution.

    http://www.nature.com/news/source-found-for-missing-water-in-sea-level-rise-1.10676

    Kinda leaves anthro SLR out in the cold (Ha!).

    At least Rob Fenwick has a hobby.

  8. Mike Jowsey on 24/05/2012 at 7:32 pm said:

    The astute reader will already know that manmade global warming is so last year.

  9. Gary on 24/05/2012 at 8:49 pm said:

    Having had Rob Fenwick as a neighbour I can tell you that his carbon foot print is far greater than the average man. If there is money to be made Rob will be into it.
    Rest assured he is a spin doctor, just another Al Gore seeing what he can rent seek.

  10. Nick on 25/05/2012 at 3:58 pm said:

    Hi Richard T,
    Moon et al. 2012 shows that glacier melt in Greenland is accelerating. The rate is slower than the theoretical upper limit upper limit from ice shelf dynamics but how you get from accelerating but less than the worst case scenario to “ice sheets are not melting” seems like a bit of a leap. Can you clarify your reasoning here please?

    • Bob D on 25/05/2012 at 6:05 pm said:

      Nick,
      AR4 says (emphasis added):

      The present SMB of Greenland is a net accumulation estimated as 0.6 mm yr–1 of sea level equivalent from a compilation of studies (Church et al., 2001) and 0.47 mm yr–1 for 1988 to 2004 (Box et al., 2006).
      …Sufficient warming will reduce the SMB to zero.

      (SMB is surface mass balance.)

      This is reinforced by the following papers:
      H.J. Zwally et al, Growth of the Southern Greenland Ice Sheet, Science 281, 1251 (1998). They found an ice sheet thickening rate of about 5 cm/year.

      C. H. Davis, C. A. Kluever, and B. J. Haines, Elevation Change of the Southern Greenland Ice Sheet. Science 279, 2086-2088 (1998). They found a small increase (1.5 cm/year) over the period 1978-1988.

      R. Thomas et al, Mass Balance of the Greenland Ice Sheet at High Elevations. Science 289, 426-428 (2000). They find that “On average, the region has been in balance”.

      O. M. Johannessen, K. Khvorostovsky, M. W. Miles, and L. P. Bobylev, Recent Ice-Sheet Growth in the Interior of Greenland. Science 310, 1013-1016 (2005) – They used satellite altimetry over the period 1992-2003, and found the “spatially averaged increase is 5.4 cm per year over the study area”.

      H.J. Zwally et al, Mass changes of the Greenland and Antarctic ice sheets and shelves and contributions to sea-level rise: 1992-2002. J. Glaciol. 51, 509-527 (2005) – Found an overall mass gain of 11 GT/yr.

      How much warming will it take to melt the Greenland ice sheets? Well according to AR4 if CO2 levels quadrupled today, then we’re talking about 3 millennia.

      All AGW modelling assumes an acceleration in glacial flows. Moon et al. found that a few areas in Greenland had experienced acceleration, but it wasn’t by any means widespread and it was affected by complex interactions. In fact, Moon et al. specifically throws cold water on the alarmist assumptions. They say:

      Earlier research (33) used a kinematic approach to estimate upper bounds of 0.8 to 2.0 m for 21st-century sea level rise. In Greenland, this work assumed ice-sheet–wide doubling of glacier speeds (low-end scenario) or an order of magnitude increase in speeds (high-end scenario) from 2000 to 2010. Our wide sampling of actual 2000 to 2010 changes shows that glacier acceleration across the ice sheet remains far below these estimates, suggesting that sea level rise associated with Greenland glacier dynamics remains well below the low-end scenario (9.3 cm by 2100) at present.

      So even where it is accelerating, it’s way below expected levels.

      Just one more failed prediction.

    • I was perhaps incautious in picking Moon et al. from a bunch of references. My intention was to show a recent retreat from the strident claims of alarm over ice cap melting. Sorry, I chose entirely the wrong reference.

      But even Moon et al. don’t claim that the Greenland glaciers are actually melting. Ice caps are too cold to melt and the mass balance is determined more by precipitation, ablation and velocity of outlet glaciers. Such velocity is not increased or reduced by melting except perhaps at the base, at temperatures well below freezing and nothing to do with atmospheric temperatures or even insolation. I’m still searching, but I’m pretty sure the ice caps are not generally considered to have a greatly negative mass balance.

      Anyway, that was my thinking.

  11. Nick on 25/05/2012 at 8:04 pm said:

    Hi Bob D,
    Just to be clear,
    1 – Do you agree that Moon et. al 2012 shows glacier speeds are accelerating?
    2 – How do you reconcile this with Richard T’s claim that Moon et. al 2012 shows “ice sheets are not melting”?

    Thanks

    • Bob D on 25/05/2012 at 9:03 pm said:

      Nick,

      1 – Do you agree that Moon et. al 2012 shows glacier speeds are accelerating?

      Moon et al. show that some are, some aren’t. It’s highly variable, driven by complex processes (“…numerous observations indicate that the trigger for the majority of dynamic thinning in Greenland during the last decade was episodic in nature…”).

      Certainly it is incorrect for anyone to suggest they are all accelerating due to global warming.

      2 – How do you reconcile this with Richard T’s claim that Moon et. al 2012 shows “ice sheets are not melting”?

      They aren’t melting anyway, as Richard rightly points out. Please show me in the text of Moon et al. where they state the Greenland glaciers are “melting”.

      Glaciers flow like rivers – you can think of them as giant rivers of ice. Precipitation in the interior flows slowly outward, just like a slow-motion river, driven by the great mass of ice in the centre.
      They don’t “melt”, except at the very edges where they meet the sea, or fall to low altitudes where it’s warmer. Ablation occurs too, of course. Often the sheet extends out over the ocean as a shelf, and this breaks off after a while due to wave and swell action etc. Which is how ice bergs are formed.

      Mass balance is what it’s all about, because water is water. If it’s all building up in the interior of Greenland as ice, it’s not in the ocean, is it?

      At the last count (AR4) the surface mass balance of Greenland was increasing (see references above).

      The mass balance is all about precipitation in the interior versus flow of ice to the edges.
      So the reconciliation is simple: Glacial speeds are not accelerating in bulk, some are, some aren’t, and the glaciers definitely aren’t “melting”. The flow speeds may increase, perhaps because the interior mass has increased. It’s the ice mass that drives the flow after all.

  12. Nick on 25/05/2012 at 9:50 pm said:

    Hi Richard T,
    Thanks for explaining your error, I appreciate your candor. I think we (and Bob D) have some common ground here saying mass balance is the only real measure total of ice loss.

    So maybe we should start with what appears to be the latest research. Jacob et al, 2012 use the GRACE satellites mass measurements to determine that “Glaciers and Ice Caps (GICs), excluding the Greenland and Antarctic peripheral GICs, lost mass at a rate of 148 ± 30 Gt yr−1 from January 2003 to December 2010”. This certainly this seems to show that the ice sheets are melting.

    • Does that represent a trickle or a flood? I’m trying to give it some context but I completely stuffed up the arithmetic so I’ll try again in the morning. The other day I worked out that Antarctica’s ice cap is about 24.0 × 1013 tonnes. Greenland’s is given in Wikipedia as 2.85 million km3, or 2.85 × 1015 m3. The glacial ice density I used for Antarctica is 850 kg/m3. What is the combined mass of the two ice caps?

      Perhaps some kind soul will have the answer ready for me tomorrow.

  13. Nick on 25/05/2012 at 10:11 pm said:

    By the way Bob how much of your response is cribbed from here?

    https://sites.google.com/site/globalwarmingquestions/ar4green

    Have you actually read any of the abstracts for these papers? You might want to be a bit more careful because the paper you cite.

    H.J. Zwally et al, Mass changes of the Greenland and Antarctic ice sheets and shelves and contributions to sea-level rise: 1992-2002

    Shows a net loss of mass in the ice sheets. Some might even go so far as to say it shows that ice sheets are melting.

    Please try to continue this discussion in good faith, dumping loads of papers copied from someone else’s analysis of a different topic is just wasting all our time.

    • Bob D on 25/05/2012 at 10:48 pm said:

      By the way Bob how much of your response is cribbed from here?

      The references I gave were nicely laid out on that site, which is why I used the summary instead of typing the same stuff over again. Usually, all we get from warmists are links to Skeptical Science, I try to include text instead.

      …Have you actually read any of the abstracts for these papers? You might want to be a bit more careful because the paper you cite [Zwally (2005)] shows a net loss of mass in the ice sheets.

      Drivel, it doesn’t. How can you get it so wrong? Have you read the paper yourself (I have a copy if you’d like one)? It says quite plainly:

      The Greenland ice sheet is thinning at the margins (–42±2Gt a–1 below the equilibrium-line altitude (ELA)) and growing inland (+53±2Gt a–1 above the ELA) with a small overall mass gain (+11±3Gt a–1; -0.03mma–1 SLE (sea-level equivalent)).

      Which is exactly the number given: 11 Gigatons every year. That’s a lot of tons.
      And again in the conclusions:

      The small mass gain in Greenland is contrary to the widely held view that Greenland is losing significant mass during approximately the same period

      You say:

      Some might even go so far as to say it shows that ice sheets are melting.

      Some might, but they’d be idiots.

      Please try to continue this discussion in good faith

      I trust an apology will be forthcoming, in the interests of good faith?
      You say:

      …dumping loads of papers copied from someone else’s analysis of a different topic is just wasting all our time

      What? The papers are all valid, they all say what the summary of each says, what is your problem with them, apart from your made-up stuff?
      In what way have those references “wasted all our time”?

      The fact is you don’t like being confronted with the truth, which is that all the peer-reviewed literature, AND the IPCC, says that Greenland is GAINING ice mass, not losing it. The sea level contribution from Greenland is NEGATIVE. Get it?

    • Whew. I don’t know how you keep your cool, my friend.

    • Nick on 25/05/2012 at 11:36 pm said:

      We seem to have our wires crossed. I understood Richard was referring to all the ice sheets when he said “The great Antarctic and Greenland ice sheets are not melting and even if they were…” The paper you referenced shows Antarctic ice loss of 47Gt/yr so the net loss is 36Gt/yr. If you have taken offense I certainly apologise but perhaps we can stick to the subject of net ice loss as Richard originally defined it?

    • Bob D on 26/05/2012 at 11:31 am said:

      My apologies, Richard and Nick. I’ve just been dealing with Rob Taylor, who wouldn’t know a fact if he walked into it on a clear day, so I’m losing patience with some of the warmists who just insult, nit-pick and refuse to see the truth of things, constantly moving the goalposts.

      If you’re genuinely interested in the science, Nick, then by all means press on, and I’m sure we’ll find some common ground. But if all you want is to score cheap points, then talk to the others, I’m out.

  14. Nick on 26/05/2012 at 12:00 am said:

    Richard T,
    I’m not sure what percentage 150Gt is of the total ice sheet mass but is suspect not a lot. But 150Gt/yr of ice sheet loss is approximately 0.04mm/yr of sea level rise, which looks pretty trivial.

    Unfortunately this neglects accelerating ice sheet loss as measured by:

    Velicogna, I. (2009), Increasing rates of ice mass loss from the Greenland and Antarctic ice sheets revealed by GRACE, Geophys. Res. Lett., 36, L19503, doi:10.1029/2009GL040222

    To be about 56Gt/yr with net ice loss in 2009 of 532Gt/yr.

    My quick calculations extrapolating Veliconga’s trend would equate to about a 78cm sea level rise by 2100 from ice sheet melt alone, at which point the sea level would be rising at about 15mm or 5,628Gt per year. I’m slightly surprised at how large this is so if anyone else wants to have a go at the calculation please do so.

    • Bob D on 26/05/2012 at 11:35 am said:

      Nick, be careful of GRACE. It’s brand-new technology, and is at odds with all the current literature on this subject. Recently they found significant errors in their method and had to revise their numbers – we covered it here on CCG, you’ll have to search for it I’m afraid, I don’t have time. Basically GRACE uses a baseline geoid for their “calibration”, and it was in error.

      I believe the same geoid is used for the satellite sea level measurements, and may explain (purely my speculation) the discrepancy between the satellite and tide gauge measurements around the world.

  15. Nick on 26/05/2012 at 2:14 pm said:

    Hi Richard and Bob, to recap, do you have any evidence for your claim that ice sheets (Greenland AND Antarctic) are not melting? I think we agree that the preferred metric is mass balance.

    Perhaps we could concentrate on what is currently happening rather than dragging papers from 10 years ago into it. If anything showing that there was no melting a decade ago supports contention that current ice sheet loss is accelerating.

    I’m not trying to score cheap points here, I’m just trying to understand the evidence behind your position so that I can clarify my own understanding. If you have problems with GRACE then I’m happy to look at another data set but I do think we have to concentrate on ice sheet loss of both Antarctica and Greenland.

    • Richard C (NZ) on 26/05/2012 at 7:30 pm said:

      Nick what is the anthropogenic component of ice sheet melt assuming they are?

      And what is the evidence (i.e. a verified mechanism – hopefully there’s a solid physical basis for it unlike the IPCC’s vagueness/guessing on a radiative SLR effect)?

      Isn’t the current situation just a drop in the bucket?

      I ask this because it’s not as if ice sheets have not melted before – after spectacular growth:-

      18,000 years ago ice sheets covered large areas of land

      [See plot and Click for Animation]

      The growth of the ice sheets began about 120,000 years ago as ice built up on the continents in the Northern Hemisphere, especially in Canada and Europe. The largest extent of these ice sheets occurred 18,000 years ago. At that time the largest ice sheets were between 3.5 and 4 km thick. In North America the largest ice sheet was the Laurentide Ice Sheet centered on Hudson Bay with other sheets centered on Greenland and in the Canadian Rocky Mountains. As these ice sheets expanded they grew together, covering Baffin Bay and eventually the Great Lakes and New England. In northwestern Europe the Fennoscandian Ice Sheet began to grow and expand south to cover what is now Norway and Sweden and north to cover the exposed continental shelf. Over time the ice sheet grew to cover Finland and the United Kingdom. This ice sheet extended east to the Ural Mountains where it met the Siberian Ice Sheet. Before the last ice age ice sheets already existed on Antarctica and on Greenland.

      http://earth.rice.edu/mtpe/cryo/cryosphere/topics/ice_age.html

      Plenty of glaciated valleys in the NZ SI sans ice too.

      I would have thought that ice sheet growth is a rather more alarming prospect given the inundation of the above countries not so long age.

    • Bob D on 26/05/2012 at 11:17 pm said:

      Nick:
      Greenland’s mass balance is increasing, as is the bulk of Antarctica (ie: the East). In the western area (mainly the peninsula), there is a decreasing mass balance. The reasons seem mainly to relate to changes to the regional ocean currents rather than warmer air. I don’t think the processes are fully understood yet in this region, I’d be interested in any papers you have that clearly explain what’s happening, and why the same isn’t happening everywhere else. This decreasing mass balance is greater than the increasing Greenland and East Antarctica mass balances.

      AGW theory has long held that the polar regions would display the greatest increase in warming. The loss of Arctic sea ice is well-known, but it has of course no effect on sea levels. The main sea level rise scare has always been two-fold: thermal expansion and ice sheet/glacier loss.

      Regarding just the ice sheet loss, the increasing mass balance of Greenland puts paid to the Arctic ice component (there are no other significant ice sheets in the Arctic) and the bulk of Antarctica is also increasing in mass balance, so there’s no danger there, so once again the main AGW predictions have been found to be deficient.

      All that remains is the changes to the ocean currents around the peninsula, causing large losses there. It’s clear that AGW isn’t “melting” the ice, otherwise we would see “melting” at both the other sheet locations. In fact, Antarctica in general is cooling very slowly.

      The overall sea level equivalent from the net loss of ice from the sheets is only about 0.04mm/yr, pretty much negligible when we look at the 1.8mm/yr we measure from all the tide gauges.

      Once again, calculations extrapolated out 90 years from one year’s GRACE measurements are fraught with problems.

      A last point: it is natural that during the LIA the glaciers and ice sheets would have grown somewhat, and it’s equally natural that the recovery from the LIA would undo some of this growth. So the loss of ice sheet mass and glaciers does not prove anything about AGW.

  16. Nick on 27/05/2012 at 1:51 pm said:

    Hi Richard and Bob, sorry if this all seems a bit labored, I just want to see what areas of common ground and understanding we have before we get into more difficult discussions. We largely agree, I think, that the net mass balance of the ice sheets is decreasing which shows a loss of ice, either through melting or ablation. The effect on sea levels is the same either way.

    I also think we agree that East Antarctica and Greenland had small mass gains in the period between 1992 and 2002. This was offset by the larger mass loss in West Antarctic as shown by

    H.J. Zwally et al 2005, Mass changes of the Greenland and Antarctic ice sheets and shelves and contributions to sea-level rise: 1992-2002

    Which Bob cited earlier. What interests me and I think is more relevant to your claims that the ice sheets are not melting is what has happened since then. Bob has indicated that he believes that the GRACE data is questionable so lets look at what H.J Zwally has published since his paper in 2005:

    H.J. Zwally et al 2011 Greenland ice sheet mass balance: distribution of increased mass loss with climate warming; 2003–07 versus 1992–2002

    Shows that the Greenland ice sheet is losing ice at a rate of 171Gt/yr. This uses ICESat laser altimetry rather than GRACE so I presume you are happy with this data set? Do you have any data that refutes the current rate of ice loss in Greenland as measured by Zwally in 2011?

    • Bob D on 27/05/2012 at 4:51 pm said:

      Nick,
      On the Zwally (2011) paper, there are some things to consider immediately:
      1) Two different techniques (ERS radar and ICESat laser altimetry) are used to compare two different periods (10 and 4 years). While it is of interest, it simply isn’t valid to draw conclusions from this sort of analysis, and as I mentioned before, extrapolating a short period of 4 years forward over a century is never valid.
      2) The interior of Greenland continues to thicken. Over the 4-year period 2003-7, however, the edges thinned faster than the centre thickened, leading to an overall decrease in mass balance. This is entirely consistent with the general known reduction in Arctic sea ice loss during this period. However, the Arctic sea ice has since recovered, and it is equally possible that the Greenland low altitude thinning has reduced to previous levels, possibly restoring the positive mass balance, or reducing it to zero. Again, the short period of 2003-7 tells us little about this.
      3) The edge thinning was by no means uniform. The SE and N regions showed no thinning (in fact the SE region increased), while other thinned greatly. Once again, this doesn’t lend itself to the conclusion that general increases in air temperatures caused this.
      4) It is generally accepted that glacial response lags behind temperatures, by about 5-10 years or so. It is noteworthy that 5-10 years before 2003-7 was the warm period at the end of the 20th century. This was an anomalously hot period that included the super El Nino of 1998, and it is hardly surprising that the Greenland response would be seen some years later. What matters going forward, though, is what happens next, now the warming has plateaued. My guess is that the edge thinning will have reduced somewhat since 2007.

      A general comment: It would be helpful if all the warmists got together to work out exactly what their story is. We have recently been harangued at great length by Ken because apparently 15 years is way too short a period to derive any climate signals. Now you’re telling us that a 1-year and a 4-year period is long enough to extrapolate out until 2100, and we should, by inference, be getting very alarmed about it.

  17. Nick on 27/05/2012 at 2:09 pm said:

    You may also want to consider:

    Rignot, E., J. E. Box, E. Burgess, and E. Hanna (2008), Mass balance of the Greenland ice sheet from 1958 to 2007, Geophys. Res. Lett., 35, L20502, doi:10.1029/2008GL035417.

    Which shows accelerating ice loss of 267 Gt/yr on the Greenland ice sheet in 2007.

    • Bob D on 27/05/2012 at 4:52 pm said:

      Which shows accelerating ice loss of 267 Gt/yr on the Greenland ice sheet in 2007.

      See comments above regarding 2007 and short time periods.

    • Nick on 30/05/2012 at 8:45 pm said:

      Bob, Rignot et. al 2008 refered to above covers 50 years (the clue is in the title). They say

      “We find that the ice sheet was losing 110 ± 70 Gt/yr in the 1960s, 30 ± 50 Gt/yr or near balance in the 1970s–1980s, and 97 ± 47 Gt/yr in 1996 increasing rapidly to 267 ± 38 Gt/yr in 2007.”

      I’m not sure what you consider to be a “short time period” but Rignot et al. basically show 50 years where the Greenland mass balance was not increasing and shows accelerating ice loss since 1977.

    • Richard C (NZ) on 31/05/2012 at 6:47 am said:

      Completely contradicts ARC (annual update) and Wake, see this comment https://www.climateconversation.org.nz/2012/05/ross-ice-shelf-melt-and-other-cool-fables/#comment-96716 and this comment https://www.climateconversation.org.nz/2012/05/ross-ice-shelf-melt-and-other-cool-fables/#comment-96710

      Does Rignot chronicle the years that gained too? If not, loss only is only half the story.

    • Richard C (NZ) on 31/05/2012 at 7:05 am said:

      Paper finds Greenland unlikely to melt from climate change

      http://hockeyschtick.blogspot.co.nz/2012/05/paper-finds-greenland-unlikely-to-melt.html

      Knud Rasmussen pictures: Greenland is melting less quickly than 80 years ago

      http://motls.blogspot.co.nz/2012/05/knud-rasmussen-pictures-greenland-is.html

    • Nick on 31/05/2012 at 9:58 pm said:

      Hi Richard, can you be more specific about how Rignot contradicts ARC?

      ARC says:

      “Rignot et al. (2011) find an acceleration of Greenland ice sheet mass budget deficit during 1979-2010, in close agreement with an independent mass balance model.”

      So I would be surprised if they completely contradict each other as you claim.

      Rather than asking me what Rignot (2008) says perhaps you could read it yourself. Here’s a link for your convenience

      ess.uci.edu/researchgrp/erignot/files/RignotetalGRL2008GL035417.pdf

      While Greenland may not melt completely if the temperature rises 5C to the level 125,000 years ago I do note that the sea levels were 5m higher at that time. That is quite a lot.

      If the entire Greenland ice sheet melted sea levels would rise by 7.2 meters from this alone not including contributions from the Antartic ice sheet or thermal expansion. I’m not saying that this is likely to happen, I’m just trying to put into perspective the effects of even partial melting.

      You seem to have misrepresented the Knud Rasmussen pictures. The article state

      “…the average rate of retreat (in meters per year) is higher today than it used to be…”

      So if anything the evidence shows a higher rate of melting than 80 years ago.

    • Richard C (NZ) on 01/06/2012 at 7:58 am said:

      I’ll start with the Knud Rasmussen pictures to clear up your own misrepresentation Nick. The full quote from Motl’s article is:-

      The pre-satellite pictures of ice shelves are rare. One may evaluate them in various ways.

      For example, 55% of the retreating glaciers were retreating at a faster rate 80 years than in recent years. On the other hand, the average rate of retreat (in meters per year) is higher today than it used to be because there are some isolated very quickly retreating glaciers today.

      So whether the retreat of Greenland’s glaciers was faster 80 years ago than today may depend on the detailed specification of the “contest”. However, one thing is clear.

      And the clear fact is following one: the evidence convincingly shows that the dynamics of the Greenland’s ice is qualitatively similar to what it was 80 years ago when the carbon dioxide emissions per year were 4 times lower than today.

      That is, carbon dioxide has NOT been a factor in the recent retreat.

      Now for ARC vs Rignot. Not sure where you got your ARC quote from because neither ARC 2010 nor 2011 cite Rignot. Are you confusing ARC with Wake?

      Here’s the contradiction: Rignot says:-

      We find that the ice sheet was losing 110 ± 70 Gt/yr in the 1960s, 30 ± 50 Gt/yr or near balance in the 1970s–1980s, and 97 ± 47 Gt/yr in 1996 increasing rapidly to 267 ± 38 Gt/yr in 2007

      As plotted in Figure 3 page 4 Rignot, ARC certainly does NOT reproduce “or near balance”. Of the 52 year span of their SMB series, 30 yrs (1967 – 1997, 75%) are significantly ABOVE the 0 anomaly line.

      Both ARC and Rignot show SMB INCREASING from about 1967 – 1977, the ARC gain starting in 1958.

      In short, there is no Greenland SMB correlation with CO2 whatsoever from ARC or Rignot.

      You say:-

      While Greenland may not melt completely if the temperature rises 5C to the level 125,000 years ago I do note that the sea levels were 5m higher at that time. That is quite a lot.

      Big “if” (we’re heading into a solar grand minimum) and so what?

      Hannah, Bell and Paulik states:-

      Best evidence suggests that post-glacial eustatic sea level rise culminated on the New Zealand coastline close to the present sea-level approximately 6,500 years ago. Since then, eustatic sea level oscillations of up to 1 m above present sea levels are thought to have occurred from 5,500 to 3,000 years ago at sites in or close to the Auckland region (Gibb, 1986; Woodroffe et al. 1983; Hicks and Nichol, 2007). This period of higher sea levels has also been observed on other coastlines in the Tasman Sea (Woodroffe et al. 1995), Queensland (Lambeck et al., 2010) and southeast Australia (Sloss et al. 2007). It is commonly argued that the sea level oscillation was instigated by the mid-Holocene climatic optimum, a period when global temperatures are thought to have been at least 1 to 2ºC (and perhaps as much as 6ºC in some regions) higher than at present (Chappell, 1987).

      Are you attributing anthropogenic cause (or even just natural CO2 levels) to the Pleistocene Epoch and mid-Holocene climatic optimum too?

      BTW, do you prefer the convenience of denying the cyclicity apparent in Greenland SMB?

    • Richard C (NZ) on 01/06/2012 at 8:08 am said:

      The relevant ARC SMB plot is here:-

      http://www.arctic.noaa.gov/report10/figures/GL5.png

      [Some things get mistakenly omitted after 10hr night shifts]

      I note this from the Rignot conclusion:-

      “Most likely, the ice sheet mass deficit in the 1925–1935 warm period was larger than in 1958”

      That pesky 30s warm period again. Still around despite Hansen’s best efforts to adjust it away.

    • Richard C (NZ) on 01/06/2012 at 8:26 am said:

      A conundrum especially for you Nick:-

      Ice Age At 2000+ PPM CO2

      Climate during the Carboniferous Period [linked]

      Earth experienced an ice age 450 million years ago, with CO2 somewhere between 2000 and 8000 ppm. According to Hansen’s theories – all life on Earth should have been extinct before it even evolved.

      http://stevengoddard.wordpress.com/2012/05/31/ice-age-at-2000-ppm-co2/

      How does that CO2 “forcing” work again?

    • Nick on 02/06/2012 at 4:57 pm said:

      1 – Knud Rasmussen’s pictures. You originally claimed that the article showed Greenland was melting more quickly 80 years ago than it is today. From the quote above it is clear that the author makes no such claim, at best he shows that the rate may have been about the same.

      I don’t know why you are dragging CO2 into it I have never made any claim regarding correlation between CO2 and melting. I’m just pointing out that contrary to what many here seem to believe the ice sheets are melting and at an accelerating rate as shown by many independent lines of inquiry. Since we both appear to agree that melting is occurring perhaps we can look at how this compares with past events rather than rushing into attribution to CO2 or otherwise, I suspect we will find little common ground there and I would prefer to discuss things where there is some hope of agreement (however faint 🙂 ).

      It is also worth noting that the actual pattern of glacier retreat is much different today than it was 80 years ago. In the 30’s it was land terminating glaciers retreating. Today it is ocean terminating glaciers. So the suggestion that what is happening now is the same as what happened in the 30’s is false.

      2 – Rignot quote in ARC. Go to the link you provided earlier
      http://www.arctic.noaa.gov/reportcard/greenland_ice_sheet.html
      press ctrl-f, type Rignot and there it is.

      3 – ARC does not contradict Rignot. If you look at the paper that the figure from ARC you refer to is originally from

      Fettweis, X., G. Mabille, M. Erpicum, S. Nicolay, and M. Van den Broeke, 2010: The 1958-2009 Greenland ice sheet surface melt and the mid-tropospheric atmospheric circulation. Climate Dyn., doi:10.1007/ s00382-010-0772-8, in press.

      You will find that they explicitly say that they are in agreement with Rignot 2008. I suspect that although the results are slightly different the margins of error overlap.

      3 – I think it is generally accepted that the Holocene climatic optimum was due to Milankovitch cycles. Certainly I am not attributing anthropomorphic causes to something that happened 9000 years ago.

      4 – Greenland SMB cyclicity. Perhaps you could tell me the period and amplitude of the cycle you are claiming exists before I decide if it is apparent or not.

      5 – Ice Age At 2000+ PPM CO2. It is well under stood that the solar output was less back then. Have a look at

      D. L. Royer. 2005. CO2-forced climate thresholds during the Phanerozoic

      For a full analysis

    • Richard C (NZ) on 03/06/2012 at 11:49 am said:

      “I don’t know why you are dragging CO2 into it”

      That is why we are here Nick. If CO2 is not the controlling factor (no correlation) then man-made climate change wrt Greenland ice loss is not an issue.

      “ARC does not contradict Rignot”

      What I am getting at Nick is that you have portrayed Greenland ice SMB as a loss-only situation (citing Rignot) when clearly that is NOT the case (75% of ARC values are ABOVE the 0 anomaly line last 30 yrs 1967 – 1997). This at a time when anthrro CO2 is said to be influential (the undisputed predominant climate driver and planetary control knob),The influence is apparently SMB greater than normal for 3/4 of the standard climate period.

      “I think it is generally accepted that the Holocene climatic optimum was due to Milankovitch cycles”

      Thank you finally for acknowledging cyclicity,

      “Perhaps you could tell me the period and amplitude of the cycle you are claiming exists before I decide if it is apparent or not”

      If you can tell me the period and amplitude of the interdecadal oscillations in GAT and SST (I would be interested too, to know if you’ve decided they’re apparent or not) then I’ll tell you the period and amplitude of Greenland SMB.

      “It is well under stood that the solar output was less back then”

      Thank you finally for acknowledging the solar climate driver too (predominant then it seems). Perhaps now you will lend credence to the astrophysicists predictions of a coming (not long now) solar grand minimum and the repercussions of it.

      “Certainly I am not attributing anthropomorphic causes to something that happened 9000 years ago”

      Great, then you will no problem attributing natural causes to the current situation that is of a far minor degree by comparison (not worth worrying about) in the current period.

      The next 30 – 70 years are of concern on the other hand. William Hershel was first to discusses an anticorrelation between the price of wheat and the number of sunspots visible on the Sun.

      http://www.hao.ucar.edu/education/bios/herschel.html

      Growing winter wheat in the limited window is already an almost prohibitive problem in the US (worlds biggest wheat exporter) and Canada. A solar grand minimum will mean the latitudinal growth limit for crops will move south in the Northern hemisphere and the window will shorten even for non-winter wheat, barley, oats etc (good for AU wheat growers though).

      Crop and fruit losses (40 – 100% not unusual) from recent cold are being reported from both Northern and Southern hemispheres. Just start reading what has been recorded right here at this blog under the region headings in Open Threads:-

      Australia
      UK
      USA
      Europe
      Asia
      Pacific
      South America
      Africa

      Use the Open Threads Index at top of page or this Index:-

      https://www.climateconversation.org.nz/open-threads/climate/disproving-agw/#comment-26342

    • Richard C (NZ) on 03/06/2012 at 2:13 pm said:

      Re your conundrum Nick.

      The climate models use a forcing parameter based on the equation ÄF = 5.35 ln C/Co

      Further documentation in the IPCC reports states that the forcing of each watt/m2 raises the global temperature by 0.75°C.

      Therefore, for the situation 450 million years ago when CO2 levels rose 500 ppm here:-

      http://stevengoddard.files.wordpress.com/2012/05/image277.gif?w=640&h=404

      We can use the values Co = 4000 and C = 4500.

      ÄF = 5.35 ln 4500/4000

      ÄF = 5.35 ln 1.125

      ÄF = 0.63 W/m2

      Global temperature rise (supposedly) = 0.63 x 0.75 = 0.47°C

      But in reality (something we’re particularly focussed on here Nick), Global temperatures plunged 15°C.

      And just as it was 450m yrs ago, the CO2 rise this century has not resulted in global temperature rise. It would seem then, that the IPCC’s RF methodology is one of the more bone-headed constructs in respect to AGW because it neglects the overwhelming influence of natural variations. Wouldn’t you agree Nick?

      [Someone check the calcs (Bob?). I have a brain full of kiwifruit dust, sleep deprivation and ears ringing from the incessant clatter of packing operations (labellers 80db). Not always conducive to clear reasoning I’ve found]

    • Mike Jowsey on 03/06/2012 at 3:19 pm said:

      It’s not an overdose of Keystrepto is it Richard?

    • Nick on 05/06/2012 at 8:24 pm said:

      Hi Richard,
      There may well have been a small net gain of ice between 1970 and the 1990s. Certainly the Rignot paper does not preclude it. You do need to keep in mind that increasing temperatures increase precipitation (ie it snows more) as well as increasing run off. It is quite possible that ice mass increases in the short term until increasing ocean temperatures and run off become the dominant factor.

      It is also worth noting that the current rate of ice loss is about 6 times greater than the rate of ice gain in 1970-2000 and while the mass gain of approx 50Gt/yr was fairly constant the current mass loss of greater than 300Gt/yr is accelerating.

      Regarding the Grand solar minimum

      Feulner and Rahmstorf. 2010. On the effect of a new grand minimum of solar activity on the future climate on Earth

      http://www.pik-potsdam.de/~stefan/Publications/Journals/feulner_rahmstorf_2010.pdf

      Find that

      “a moderate temperature offset of no more than −0.3°C in the year 2100 relative to a scenario with solar activity similar to recent decades. This temperature decrease is much smaller than the warming expected from anthropogenic greenhouse gas emissions by the end of the century”

      The existence of natural cycles in no way precludes the possibility of anthropomorphic influences as well. The fact that the natural cycles are by their nature cyclic while the anthropomorphic influence is steadily increasing is why there is cause for concern. As I’m sure you understand. I don’t really know why I have to explain this to you.

      Finally apart from your confusion between the Carboniferous and the Ordovician (which we can perhaps attribute to the sleep deprivation) and the questionable providence of the graph you linked (perhaps you could find a peer reviewed version such as D. L. Royer. 2005 which I mentioned above) it seems like a waste of time discussing a change in CO2 of 500ppm when the uncertainty measurement is several thousand ppm.

    • Richard C (NZ) on 06/06/2012 at 10:21 am said:

      Still searching for that CO2 correlation Nick? Greenland ice loss (or gain) is of no consequence to man-made climate change alarm if you can’t.

      Re F&R2010

      “a moderate temperature offset of no more than −0.3°C in the year 2100 relative to a scenario with solar activity similar to recent decades”

      Forget the “scenario with solar activity similar to recent decades”. The actual scenario has yet to play out and possibilities range from continued stasis (no warming or cooling but with sporadic cool episodes to conditions similar to LIA.

      “This temperature decrease is much smaller than the warming expected from anthropogenic greenhouse gas emissions by the end of the century”

      Is the warming expected from anthropogenic greenhouse gas emissions by the end of the century similar to what we’ve experienced at the start?

      You say:-

      “….the anthropomorphic influence is steadily increasing”

      In the disconnected world of climate change alarmism it is but in the real world it has been conspicuous by it’s absence.for some time now.

    • Richard C (NZ) on 06/06/2012 at 10:32 am said:

      Re Rignot:-

      “The new Bjørk et al. (2012) study (as well as a slew of other recent studies which we have discussed: see here, here, here, here, here , and here for example) strongly suggests that “present trends” will not continue—and thus the Rignot et al. extrapolation is grossly inaccurate (i.e., far too large).

      http://www.worldclimatereport.com/index.php/2012/06/04/historical-imagery-of-greenland-glaciers-lessens-sea-level-rise-alarm/

    • Richard C (NZ) on 06/06/2012 at 11:28 am said:

      Fraunfeld et al., 2011 concluded (from WCR):

      The forces acting in concert with ice melt across Greenland to produce higher global sea levels currently, should also have been acting during the extended high‐melt conditions from the mid‐1920s to the early 1960s. There is some qualitative indication of an observable influence of the variations in input from Greenland in the decadal rates of sea level change over the course of the past century… However, there is no indication that the increased contribution from the Greenland melt in the early to mid 20th century, a roughly 40 year interval when average annual melt was more or less equivalent to the average of the most recent 10 years (2000–2009), resulted in a rate of total global sea level rise that exceeded ∼3 mm/yr. This suggests that Greenland’s contribution to global sea level rise, even during multidecadal conditions as warm as during the past several years, is relatively modest.

      http://www.worldclimatereport.com/index.php/2012/06/04/historical-imagery-of-greenland-glaciers-lessens-sea-level-rise-alarm/

      All very underwhelming.

      WRC goes on:-

      Currently, ice loss from Greenland contributes about one-to-two hundredths of an inch per year to the global average sea level—that’s a total of 1-2 inches by the year 2100. So, even if the rate of ice loss doubles or triples, the resulting sea level rise falls far short of being catastrophic. And the more evidence that comes in, the more confidence we have that as temperatures rise, Greenland will shed ice only gradually and through somewhat self-limiting processes—rather than catastrophically through rapid acceleration and “slipping into the sea” as Al Gore so indelicately described his (incorrect) vision of the future.

      Thus ends another “cool fable”.

  18. Nick on 27/05/2012 at 9:09 pm said:

    Bob,
    I’m happy to leave predictions of future ice loss or sea level rise and attributions of the cause out of this. Richard asked a question about trying to get the numbers into context and I tried to help.

    While we clearly disagree on the causes and future predictions for ice loss, from your comments above can I take it that you agree that the current science shows that ice sheets, both Greenland and Antarctic, are losing ice rather than “not melting” as you and Richard originally claimed?

    Btw I’m not particularly worried about getting my story straight with any particular group. I’m just interested in figuring out what is going on by reviewing the known science and I certainly appreciate you assistance with this.

    • Richard C (NZ) on 28/05/2012 at 7:55 am said:

      ‘….from your comments above can I take it that you agree that the current science shows that ice sheets, both Greenland and Antarctic, are losing ice rather than “not melting” ”

      Nick, why do you make no attempt to read, absorb, assimilate, comprehend, understand, analyze and generally extract the key specifics of what has been put before you? Is it your position that Bob’s rundown of the issues is of no consequence to you because you want to dumb down the argument in typical warmist fashion into a nice simple story line so that any contrary argument to your foregone conclusion is wasted effort.

      You respond with a simplistic, abstracted, generalization of those uncertainties and differentiations of the observed counteracting phenomena at various locations that immediately alerts that you have no intention of actually entertaining anything other than what you have decided is what everyone should “agree” to i.e. your opinion stands no matter what. You wont get much agreement from that approach here.

      Suggest a quick scan of ‘Climate Science and the Uncertainty Monster’ by J. A. Curry and P. J. Webster for some perspective http://journals.ametsoc.org/doi/pdf/10.1175/2011BAMS3139.1

      Uncertainty Lexicon

      The nature of uncertainty is often expressed by the distinction between epistemic uncertainty and ontic uncertainty.

      Epistemic uncertainty is associated with imperfections of knowledge, which may be reduced by further research and empirical investigation. Examples include limitations of measurement devices and insufficient data. Epistemic uncertainties in models include missing or inadequately treated processes and errors in the specification of boundary conditions.

      Ontic (often referred to as aleatory) uncertainty is associated with inherent variability or randomness.

      Natural internal variability of the climate system contributes to ontic uncertainty in the climate system. Ontic uncertainties are by definition irreducible.

      Walker et al. (2003) provides a complete logical structure of the level of uncertainty, characterized as a progression between deterministic understanding and total ignorance: statistical uncertainty, scenario uncertainty, and recognized ignorance.

      Statistical uncertainty is the aspect of uncertainty that is described in statistical terms. An example of statistical uncertainty is measurement uncertainty, which can be due to sampling error or inaccuracy or imprecision in measurements.

      Scenario uncertainty implies that it is not possible to formulate the probability of occurrence of one particular outcome. A scenario is a plausible but unverifiable description of how the system and/or its driving forces may develop over time. Scenarios may be regarded as a range of discrete possibilities with no a priori allocation of likelihood.

      Recognized ignorance refers to fundamental uncertainty in the mechanisms being studied and a weak scientific basis for developing scenarios. Reducible ignorance may be resolved by conducting further research, whereas irreducible ignorance implies that research cannot improve knowledge.

      An alternative taxonomy for levels of uncertainty is illustrated by this quote from U.S. Secretary of Defense Donald Rumsfeld (U.S. DOD 2011): “[A]s we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we do not know we do not know. And if one looks throughout the history of our country and other free countries, it is the latter category that tend to be the difficult ones.”

      Climate science is not an exercise in absolutes and precision Nick.

    • Richard C (NZ) on 28/05/2012 at 10:14 am said:

      Also, it is entirely possible for the Greenland ice sheet to be losing ice but “not melting”. Glaciers flowing to the sea are by definition: ice forming where accumulation of snow exceeds melting. Howat et al 08 found that nearly 75 percent of the loss of Greenland ice can be traced back to small coastal glaciers.

      Melting occurs at the melt zone EVERY summer. From NASA Earth Observatory:-

      [See melt zone image http://eoimages.gsfc.nasa.gov/images/imagerecords/5000/5597/greenland_tmo_2005165.jpg%5D

      In this image, the melt zone appears along the western edge of the ice. In this zone, water has saturated the ice, darkening its color from white to blue-gray. The colored lines indicate the approximate melt zone extents for June 2001 through June 2005. Between June 2001 and June 2003, the melt zone increased substantially, then shrank somewhat in June 2004. The melt zone for June 2005 appears roughly equivalent to that of June 2002, the same year that later set a record in Greenland Ice Sheet melting. These images show the Greenland Ice Sheet midway through the seasonal melt. Summer melting generally extends from the spring through the early fall.

      http://earthobservatory.nasa.gov/IOTD/view.php?id=5597

      That is, the melt zone RECOVERS each year . 2003 was an aberration (reasonable as Bob points out) but 2005 was back between 2001 and 2002.

      Temperatures at the Capital Nuuk in West Greenland average below freezing for 7 months of the year. The coldest month is March, at −8 °C (17.6 °F), while the warmest is July, at 6.5 °C (43.7 °F), while the year averages out at −1.42 °C (29.4 °F). Extremes have ranged from −29.5 °C (−21 °F) to 24.2 °C (76 °F) http://en.wikipedia.org/wiki/Nuuk

      Not much melting at sub-zero winter temperatures. Change of state is liquid to solid (in the physics I’ve studied that is).

    • Richard C (NZ) on 28/05/2012 at 12:54 pm said:

      Here’s summer melting for the entire Greenland ice sheet from the 2011 Arctic Report Card (ARC): Year 2011 is 6th for melting, after 2010, 2007, 1998, 2002, 2005 http://www.arctic.noaa.gov/reportcard/greenland_ice_sheet.html [The 2011 update at this link will be superseded by the 2012 update and 2011 goes to ‘Previous Arctic Report Cards’ see below].

      I note:-

      “A dominant source of energy for melting is absorbed solar irradiance, which depends on the surface solar reflectivity from ~0.3 µm to ~4 µm in wavelength, known as the albedo” […] “Negative albedo anomalies are widespread over the ice sheet during the 2011 melt period”

      The Inconvenient Skeptic has compiled Mass Accumulation and SMB graphs from 2010 ARC and Wake (going back 150 yrs) here http://theinconvenientskeptic.com/2010/12/mass-accumulation-of-greenlands-ice-sheets/ (not vouching for their veracity). Quoting:-

      “If only the last 8 years are looked at (like SkS) it appears that the recent behavior is abnormal. If a longer period is looked at it is clear that such behavior appears to happen in cycles.”

      Previous Arctic Report Cards http://www.arctic.noaa.gov/reportcard_previous.html

    • Bob D on 28/05/2012 at 10:07 am said:

      Nick,
      I must say I agree with Richard C here. Either step up with some science or retire gracefully. I’ve seen no actual scientific discourse from you, you haven’t actually responded in any way to any of the points I or Richard C have made, you just keep re-stating your position and claiming we agree or disagree with it, despite the paragraphs of text I’ve written above discussing the science itself.
      You say:

      …from your comments above can I take it that you agree that the current science shows that ice sheets, both Greenland and Antarctic, are losing ice rather than “not melting” as you and Richard originally claimed?

      No you cannot. As I have explained at some length above, a short 4-year trend bang in the middle of a known downward spike in the Arctic sea ice does not prove that Greenland is losing ice to any great degree, certainly not enough to undo the decades of ice build-up previously. Remember too that all experts agree that Greenland has significantly more ice now than it did in the 1930s and 40s. And also during the MWP.

      As for Antarctica, the bulk of Antarctica is gaining ice, not losing it. A small portion (the peninsula and some area around it) is losing a lot of ice, yes, but this appears to be due to changes in ocean currents rather than anything else – in other words the causes are currently uncertain, and it is pretty certain that AGW isn’t causing it, otherwise we would see a general loss of ice across the whole of Antarctica.

      So it is clearly incorrect to state that “both Greenland and Antarctica are losing ice”. The correct statement is “on relevant climatic timescales, Greenland and Antarctica are gaining ice, apart from the Antarctic peninsula which is losing it.”

      And regardless of anything else, Greenland and Antarctica are not melting. I know the warmists like pithy little terms like “melting” because it’s something that the masses can relate to, but it just isn’t true, sorry.

    • apart from the Antarctic peninsula which is losing it.

      So readers understand, the last thousand kilometres of the much-discussed Peninsula isn’t even part of the Antarctic, as it protrudes out of the Antarctic Circle into the normal world that sees the sun every day of the year. It’s hardly surprising there’s evidence there of some warming.

    • Nick on 29/05/2012 at 9:05 pm said:

      Bob and Richard T, recent research shows that ice loss in West Antarctica extends far beyond the Antarctic peninsular and well into the Antarctic circle.

      Rignot et al 2008. Recent Antarctic ice mass loss from radar interferometry and regional climate modelling. Nature Geoscience

      “In East Antarctica, small glacier losses in Wilkes Land and glacier gains at the mouths of the Filchner and Ross ice shelves combine to a near-zero loss of 4±61 Gt /yr. In West Antarctica, widespread losses along the Bellingshausen and Amundsen seas increased the ice sheet loss by 59% in 10 years to reach 132±60 Gt /yr in 2006. In the Peninsula, losses increased by 140% to reach 60±46 Gt /yr in 2006.”

    • Bob D on 28/05/2012 at 10:17 am said:

      See Howat (Science 2007):

      Greenland was about as warm or warmer in the 1930’s and 40’s, and many of the glaciers were smaller than they are now. This was a period of rapid glacier shrinkage world-wide, followed by at least partial re-expansion during a colder period from the 1950’s to the 1980’s. Temperatures indeed were warmer in the 1930s and 1940s in Greenland. They cooled back to the levels of the 1880s by the 1980s and 1990s before resuming a rise in the middle 1990s. The recent warming is not yet at the same level as that of the 1930s and 1940s.

  19. Nick on 28/05/2012 at 12:10 pm said:

    Thanks to everyone for the carefully considered responses.

    Bob D what do you consider to be the “relevant climatic timescales”? I was expecting about 15 years but feel free to correct me if you had something different in mind.

    • Bob D on 28/05/2012 at 1:24 pm said:

      Nick,

      Bob D what do you consider to be the “relevant climatic timescales”? I was expecting about 15 years

      I’m not sure to be quite honest. Most of the statements I’ve read seem to consider 15 years to be a minimum, but I suppose it depends on what you’re measuring. For example, it may be valid to use 10 years of data if the trend is statistically significant, but then the question arises: have we used a long enough period to exclude natural periodicity?

      What I mean by that is: take for example the PDO. We know that every 60 or so years there is a naturally-occurring cycle in world temperatures. Any 15-year period within that is quite likely to produce a significant trend, but if we ignore the larger cycle, we make fools of ourselves, as we saw happening in the 1970s (cooling scare) and in the 1990s (warming scare). It’s like taking a trend within a sine wave, and trying to draw conclusions from it. One moment it’s up, the next it’s down!

      And on top of those cycles there are even longer cycles, for example every 1,000 to 1,500-odd years. There is little doubt that the MWP was warmer than now, and the Roman WP warmer than the MWP, and the Minoan WP warmer than the RWP.

      So how long is long enough? Until we know exactly and predictively what is causing each cycle and sub-cycle, we cannot possibly declare with any certainty that what is happening in any period is in any way unnatural.

      For example, the case of Greenland. It was warmer than now in the MWP, then colder during the LIA, then it warmed until the 1930/40 peak, then cooled, now it’s warming again apparently. So what? Unless we understand exactly why the MWP and LIA happened, we simply cannot declare that the 1990s warming was unprecedented or unusual. Since 2000 there has been little warming to speak of, in fact now we’re all arguing over whether there was a significant trend or not.

      Does mainstream climate science understand exactly why the MWP or LIA happened? No, their only answer so far has been to try to make them disappear. Are there other theories? Yes, quite a few, but they’re still all theories, they need time to prove themselves. Few of them involve CO2, by the way, since CO2 remained pretty constant over these periods.

      Oftentimes in science we have to acknowledge that we just don’t know the answer. This is one of those times – it’s just a pity that certain people went rushing off to scare the world when they thought they understood what was driving the climate. They should have waited a bit longer, to see whether their predictions held water. Now it’s become politicised, and they have nowhere left to go. The public, however, has seen through it, simply because the activist scientists cried ‘wolf’ once too often, and became foolish in their predictions.

    • Richard C (NZ) on 28/05/2012 at 1:45 pm said:

      If you use ARC (Greenland), 15 yrs gives small gain then loss http://theinconvenientskeptic.com/wp-content/uploads/2010/12/ARC-Accum-550×370.png

      Wake shows similar but pronounced loss for the same 15 yr period http://theinconvenientskeptic.com/wp-content/uploads/2010/12/Wake-Accum-550×370.png\

      ARC 1958 – 2010 gives loss – gain – loss but not yet back to 1970 level at 2010. Wake 1866 – 2005 gives gain – loss.

      In terms of CO2, the last 15 yrs is hardly the relevant climatic timescale. The CO2 uptick started around 1950, that’s 60 yrs. of supposed influence.

      See this comment https://www.climateconversation.org.nz/2012/05/ross-ice-shelf-melt-and-other-cool-fables/#comment-96710 re ARC and Wake.

  20. Nick on 29/05/2012 at 12:15 pm said:

    Hi Bob,
    You say “on relevant climatic timescales, Greenland and Antarctica are gaining ice, apart from the Antarctic peninsula which is losing it.” but if you are not sure what the relevant timescale is how do you know that Greenland and Antarctica are gaining ice?

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