Uncertainty be damned, let’s make ice and sea level projections anyway

‘A better path’ toward projecting, planning for rising seas on a warmer Earth

From Princeton University, by Morgan Kelly, Office of Communications

More useful projections of sea level are possible despite substantial uncertainty about the future behavior of massive ice sheets, according to Princeton University researchers.

In two recent papers in the journals Nature Climate Change and the Proceedings of the National Academy of Sciences (PNAS), the researchers present a probabilistic assessment of the Antarctic contribution to 21st-century sea-level change. Their methodology folds observed changes and models of different complexity into unified projections that can be updated with new information. This approach provides a consistent means to integrate the potential contribution of both continental ice sheets — Greenland and Antarctica — into sea-level rise projections.

“No single ice sheet model or methodology for projections provides sufficient information for good policy and planning decisions,” explained lead author Christopher Little, a postdoctoral research associate in the Program in Science, Technology and Environmental Policy in Princeton’s Woodrow Wilson School of Public and International Affairs.

“Furthermore, there are fundamental limitations in the observational data available on and near ice sheets,” Little said. “Projections of their response to 21st century climate changes are thus very poorly constrained. There’s unlikely to be a single answer in the near future: a better objective is a comprehensive, transparent baseline that can be improved over time.”

The Princeton approach provides a more informative projection of future sea levels that politicians and coastal planners can use to prepare for higher seas, said Little, who works in the group of co-author Michael Oppenheimer, Princeton’s Albert G. Milbank Professor of Geosciences and International Affairs. Little and Oppenheimer worked on both papers with Nathan Urban, a former postdoctoral researcher with Oppenheimer now at the Los Alamos National Laboratory.

Oppenheimer

In two recent papers, Princeton University researchers present a probabilistic assessment of the Antarctic contribution to 21st-century sea-level change. Their methodology provides a consistent means to integrate the potential contribution of continental ice sheets such as Greenland and Antarctica into sea-level rise projections. In existing projections, the contribution of Antarctica to future sea-level rise is almost entirely derived from locations where present-day mass loss is concentrated (area 15, above). This is despite evidence that future discharge in other drainage basins — which comprise more than 96 percent of the ice sheet’s area — remains uncertain. (Image courtesy of Christopher Little)

Little explains the findings of both papers as follows:

“Gauging the future rate of sea-level rise is critical for climate-change policy and coastal-planning efforts. One crucial component is the melting of polar ice sheets.

“During the past 20 years, the Greenland and Antarctic ice sheets have lost an increasing amount of ice and now contribute roughly one-third of the rate of global mean sea-level rise. However, the standard tools used to project these ice sheets’ contribution to future sea levels are limited by inadequate process understanding and sparse data. Ice sheets interact with the ocean on small spatial scales, and their motion is strongly governed by poorly understood properties of the ice as well as the sediment hidden several miles beneath it. Sea-level rise projections should reflect these uncertainties.

“Recently, several groups have used alternative techniques to forecast maximum possible sea levels — known as upper bounds — that do not explicitly model ice dynamics. Upper bound estimates by the year 2100 projected using these techniques are up to 6 feet (three times higher than future sea level estimates from the Intergovernmental Panel on Climate Change (IPCC)). However, the physical basis underlying these projections and their likelihood of occurrence remain unclear.

“In our group, we think we can more consistently assess disparate sources of information. In two recent papers, we introduce a novel framework for projecting the mass balance of the Antarctic ice sheet that allows for the conversion of current and future uncertainties of ice-sheet dynamics into probability distributions that may be supplemented by expert judgments. The power of this framework arises from its ability to improve and compare projections in a transparent manner.

“Like watersheds on land, ice sheets discharge precipitation that falls over a wide drainage basin through relatively narrow outlets. Although ice flow is linked across basins, each basin may remain relatively independent over time periods less than a century. The framework described in these two papers projects mass balance separately for each drainage basin, while allowing for correlated trends driven by underlying physical processes occurring at larger spatial scales.

The first paper, published in PNAS, introduces this ‘basin-by-basin’ framework and reveals that, even with limited information, a comprehensive probabilistic approach can provide insight that is missing from previous projections. We performed sensitivity analyses by changing the set of assumptions applied to each basin. For each set of assumptions, Monte Carlo simulations [computer algorithms based on random sampling] were used to generate 30,000 to 50,000 scenarios of mass changes originating from each basin and the continent as a whole.

“In previous scenario-based projections, the contribution of Antarctica to future sea-level rise is almost entirely derived from locations where present-day mass loss is concentrated. This is despite evidence that future discharge in other drainage basins — which comprise more than 96 percent of the ice sheet’s area — remains uncertain.

“By incorporating the entire ice sheet, the PNAS study demonstrated that uncertainty in ice discharge outside regions where scientists ‘expect’ ice loss might result in additional sea-level rise that must be considered in projections. In addition, we quantitatively show that the likelihood of upper bounds must be taken into account when assessing their magnitude and appropriate uncertainty reduction efforts.

The second paper, published in Nature Climate Change, extended the framework to include Bayesian updating, which allows prior assumptions to be updated as new data are collected. We combined model-based basin-level projections with data-based extrapolations and previously reported continental-scale observations to forecast the Antarctic contribution to sea-level change.

“The paper projected a 95th percentile ice-mass loss equal to a 13-centimeter (5.1-inch) increase in sea level by 2100; other estimates provide upper bounds reaching up to 60 centimeters (roughly 23.5 inches), but with no quantification of probability. This paper suggests that most earlier projections either overestimated Antarctica’s possible contribution to sea-level rise; implied physical changes inconsistent with underlying methodological assumptions; or, assume an extremely low risk tolerance.

“Future work on this framework includes further addressing inconsistencies in different methodologies, which will continue to refine the range of upper-bound sea-level projections. Our group also intends to include the solid earth and gravitational response that modulates sea-level changes at the local level, allowing the generation of a global map of the local probability distribution of sea-level rise.”

The paper, “Probabilistic framework for assessing the ice sheet contribution to sea level change,” was published February 26 in the Proceedings of the National Academy of Sciences. The article, “Upper bounds on twenty-first-century Antarctic ice loss assessed using a probabilistic framework,” was published online March 17 in Nature Climate Change. Both papers were funded by the Princeton Environmental Institute‘s Carbon Mitigation Initiative, and Princeton University’s Program in Science, Technology and Environmental Policy.

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87 thoughts on “Uncertainty be damned, let’s make ice and sea level projections anyway

  1. My prediction for this Arctic summer melt season is season. I predict tha Arctic Ice will melt again but not as severe as last year and should bottom just above 2007 low. Lets see how good I do.
    I do have two concerns, the BC (black carbon) deposits on the sea ice and snow from the past 6 months+ and the arctic storms were strong with lost of cracking of the sea ice since Feb.
    Air travel has been up big the past 6 months and mankind in the N hem was burning lots of dirty fuels to stay warm so BC emmisions were heavy.

  2. ‘More useful ‘ to whom ?
    ‘novel framework’ is that another way of saying ‘we guess ‘
    ‘The Princeton approach provides a more informative projection of future sea levels that politicians’
    By ‘Lucky chance ‘ would this produced results which are ‘useful’ to those with particular agenda to push and would this work by further ‘lucky chance ‘ call for more research in the area ?
    ‘changing the set of assumptions applied to each basin’
    Of course how they select the ‘assumptions’ and why is the key but has above you can’t help but fell that ‘lucky chance ‘ will mean the assumption process gives them the results they wanted to get at the start.

  3. Second paper:
    ‘Probabilistic framework……’ Says ‘no quantification of probability’. WUWT?

  4. Looking on the bright side, at least they have given up telling us that sea levels will rise if the Arctic ice melts!

  5. A picture speaks a thousand words. From MasterResource.

    http://www.masterresource.org/2011/09/rapid-sea-level-rise-nature-no/

    Is Antarctica losing or gaining ice?

    Melt may explain Antarctica’s sea ice expansion
    Climate scientists have been intrigued by observations that Antarctic sea ice shows a small but statistically significant expansion of about 1.9% per decade since 1985,….

    http://www.bbc.co.uk/news/science-environment-21991487

    They need to let go of Antarctica for the time being. It’s just a stubborn climate change denier.

  6. Was this actually released on 1 April? More consistent WRONG projections aren’t any better than inconsistent WRONG projections. Until they really delve into the actual physics occurring on the ground and get out of their “models as reality” paradigm it won’t get better!

  7. After reading the above, I was forced to spend a half hour checking the ‘WUWT’ Sea Ice Page in order to get back on a solid factual basis. You would have thought that Princeton Environmental Institute‘s Carbon Mitigation Initiative could have been funding something useful instead of funding this sort of stuff.

  8. During the past 20 years, the Greenland and Antarctic ice sheets have lost an increasing amount of ice and now contribute roughly one-third of the rate of global mean sea-level rise.”

    Have they actually checked the ‘amount of ice’ in Antarctica recently? It has been at record levels for a considerable time. Greenland the ice melt that everyone was panicking about turns out to be less and cyclical.
    So how can the lack of ice melt from these areas contribute “one third of the rate of global sea level rise“?

  9. Let me see how this works. We have biased researchers using biased models and biased measurements of other biased researchers. Yeah, what could go wrong.

    Has anyone in climate science every heard of double blind studies and why they were created?

  10. They already “know” what is happening in Antarctica. Now they just have to build models to make their position plausible, and produce wonderful graphs and maps to help the gullible understand and support them. How frustrating they have to constantly beg for funding. %P

  11. “…for good policy and planning decisions,”

    So, right off the bat they are explicitly stating that the whole purpose of their research is for political purposes.

  12. I just had a flashback to one of my old teachers ‘ comment on assumptions.
    “If you assumed elephants had wings, could you make money selling steel umbrellas?”

  13. “The paper projected a 95th percentile ice-mass loss equal to a 13-centimeter (5.1-inch) increase in sea level by 2100; other estimates provide upper bounds reaching up to 60 centimeters (roughly 23.5 inches)
    Let’s see, 1.5mm/decade to 69mm/decade when we have been ~3mm/decade for decades. So we can look forward to a 50% to 2300% increase in the rate of sea level rise. The main thrust, 95% CL, is sea level increase will be half of what it was for the last century. WTF

  14. These papers and the people who write them are like cockroaches. As soon as a paper is squashed and debunked, there is a lot of scurrying around in the dark by “researchers” and a new one appears.

  15. These clowns could save money by simply using the script from “The Day After Tomorrow” and borrow some visuals as well.

    The end game of AGW hype is endlessly entertaining.

  16. The key point, as others here have touched upon, is not that the projections be accurate, but that they be “useful.” Useful in supporting the alarmist agenda, that is.

  17. “Has anyone in climate science every heard of double blind studies and why they were created?”

    Of course they have! And since the desired result is always FAR more important than the method used to reach it, they sure aren’t going to let themselves get caught by that trap!!!

    As far as their “predictions”, I got a dartboard that’ll match or beat their results any day of the week.

  18. “Probabilistic” or problamatic? more along the lines that Hoser points out. This is what politicians point to as “peer reviewed science” when explaining what their decisions are based on. Former Congressman Bart Gordon was the hand-picked successor to Al Gore’s seat in The House. Using his leadership position on the Science and Technology Committe he funneled billions to dodgy studies like this. His response on the release of the Climategate emails “we need more research” With the gig up he then reversed his decision to run for re-election and is now a lobbist working on science and energy issues. This study should have appeared in a political science mag.

  19. ICE MELT ALERT..!
    Its spring (although you wouldn’t know it here in the UK) and the Arctic sea ice is (at last) beginning to melt..!
    Man the lifeboats..!

  20. Maybe I read it too fast, but are they actually predicting a sea level rise from 13-60 centimeters, attributable to Antarctic ice melt, at a time when the Antarctic is increasing ice mass and sea ice area to record levels? Do the models account for the observational increases in actual ice? So what good are models that don’t begin with real world observations?

  21. They get an immediate “F” for inaccuracy!

    ““During the past 20 years, the Greenland and Antarctic ice sheets have lost an increasing amount of ice and now contribute roughly one-third of the rate of global mean sea-level rise.”. All data I’ve seen says Antarctica ice sheets have shown a net increase over the past 20 years and the ice mass is still increasing!

    Two simple ways to predict sea level rise:

    1) Linear projection over then next 20 years based on the average annual increase over the past 100-120 years.

    2) K*(^GL + ^AA) = ^SL. (tough to do equations on basic iPad)
    K = conversion constant (if you don’t know, guess!)
    ^GL = change in Green Land ice content
    ^AA = change in Antarctica ice content

    Can I get the copious funding now for my brilliant work?

    Bill

  22. So they declared Uncertainty to be non-existent with the power of SCIENCE !

    Just go to show that if you get enough PhD in one room they can declare the sun to be blue and the politicians would run on it.

  23. The planet is cooling and Antarctica leads the way!

    My fellow Dutchmen have completely gone off their trolley. The ice is expanding because it’s melting?

    But you wouldn’t want to feed the many that lap up such crap like manna from heaven.

  24. “Their methodology folds observed changes and models of different complexity into unified projections that can be updated with new information. This approach provides a consistent means to integrate the potential contribution of both continental ice sheets — Greenland and Antarctica — into sea-level rise projections.”

    This sounds like the IPCC’s ensemble of models. You know, this may seem like a good idea on casual inspection, but from my perspective, making a big honkin framework that mixes the less bad with the worse isn’t the answer; it just makes it harder to figure out exactly where the problem is when the predictions projections are found to be totally off base. They can say

    … novel framework for projecting the mass balance of the Antarctic ice sheet that allows for the conversion of current and future uncertainties of ice-sheet dynamics into probability distributions that may be supplemented by expert judgments. The power of this framework arises from its ability to improve and compare projections in a transparent manner.

    all they want, if there’s any support for the idea that this framework will allow projections to be compared and improved in a transparent manner, they’ve failed to explain it here.
    Not buying it.

  25. I’m not so upset with this. They admit it is very uncertain, introduce a second paper that will allow corrections to be made based on changes in data and are only predicting 5 inch increase in 100 years. Not the 9 feet that some fools are.

    If and when sea levels are measured to not be increasing by much at all, then this 5 inches can be adjusted downwards (or upwards) as the data indicate. If there is any cooling at all, this will cause contraction of oceans and an even smaller sea level rise. Don’t be so gloomy. They’re not all incompetent or liars.

  26. The majority of non-scientists sadly do not understand science at all. The majority of “scientists” are button pushers, paper shufflers, and/or downright toadies. That leaves a VANISHINGLY SMALL percentage of the population that understands, and is performing, actual scientific work. These papers are unfortunately the product of “scientists” that fall into the button-pusher, paper-shuffler, toady categories, as is the case with over 95% of all climate-related studies at this time.

  27. Nice headline, Anthony :)

    “There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact. ”
    Mark Twain
    ——-
    Just for the fun of it….

    “The difference between the right word and the almost right word is the difference between lightning and a lightning bug.”
    Mark Twain

    “The man who doesn’t read good books has no advantage over the man who can’t read them.”
    Mark Twain

  28. Richard M says:
    April 5, 2013 at 4:19 am
    ……….
    Has anyone in climate science every heard of double blind studies and why they were created?

    This is what is at the core of the problem with climate science. They go into a study with assumptions already built in. Result = models diverge from observations = fail. Then they try again using another model run.

    Recently scientists have been reported to be baffled by the 16 year temperature standstill. Why? Assumptions.

  29. Ay least the 30 meters by 2100 Sea-Level rise projections placed into play by the dimmer bulbs seem to have drowned (into the rising seas???)!!!

  30. Ian W says:
    April 5, 2013 at 4:16 am
    “So how can the lack of ice melt from these areas contribute “one third of the rate of global sea level rise“?

    Unfortunately, Ian, in climate science today you have to consider every possible way you might be being deceived. The scientific bond of trust has largely been broken as far as I am concerned.

    Consider the sentence from the article;

    “During the past 20 years, the Greenland and Antarctic ice sheets have lost an increasing amount of ice and now contribute roughly one-third of the rate of global mean sea-level rise. “

    Now, imagine: If more snow/condensation formed during some months, then more might possibly melt during other months, right? Or one location increase while another location decreased. Hence an “increasing amount of ice loss” could easily occur when total amounts were increasing. (Also note they don’t even use the word melt. It could be glacial flow rate).

    Also imagine: If the rate of global sea level rise decreased, and Antarctic ice loss remained the same, then the fraction it contributed would increase. But it would be an increasing fraction of a decreasing amount.

    I’m not saying either is the case, but these are the pathetic little tricks which get sprung on readers both in science and general-media. The two hypothetical examples above would not be lies, but would be unethical deceptions I am no longer be surprised to find in this area of politicized science.

    A political-environmentalist camel has been invited into the climate-science tent, but there are still other camels defecating on the exterior. What is the purpose of the tent now?

  31. “During the past 20 years, the Greenland and Antarctic ice sheets have lost an increasing amount of ice” is offered with no proof; it is part of the (failed) hypothesis.

  32. I managed to download the Tide Gauge database from the Permanent Mean Sea Level Service. Anybody who has tried to do this before knows that it comes down in over 2000 individual files and one would need two grad students, fortran programming and much help from the PMSL database managers over several months in order to track how the Tide Gauges are changing over time.

    http://www.psmsl.org/data/obtaining/complete.php

    I took one of the archive files and kept sorting and consolidating it down until all that was left was the Tide Gauge measurements by Year. There are 30,966 individual annual measurements going back to 1807 and as many as 400 individual Tide Gauge measurements in some years.

    So this isn’t really tracking each Gauge over time, but more the average of all measurements in each year. It will not be 100% accurate since Gauges moving into and then out of the database which will change the baseline a small amount over time, but it is what it is.

    So, here are all 30,966 Tide Gauge measurements by year going back to 1807. (note there are some groups that are rising or declining at a high rate due to glacial isostatic adjustment which is still continuing today).

    On average, the Tide Gauge sea level is increasing at 0.28 mms/year since 1807. (Note that GPS indicates the Land is rising by an weighted average of 0.3 mms/year so the actual volume/sea level might be rising at 0.6 mms/year on average over the period.

    To test the trends over time, I’ve Zoomed into the 1930 to 2009 period. Generally, from 1930 to 1980, the trend was similar to the previous rise and, from 1980 to 2009, the Tide Gauge sea level increase went up to 1.41 mms/year.

    I don’t really see a 60 year AMO cycle in there or any further acceleration, but there is certainly an El Nino and a volcano impact which should be taken into account. So, the Satellites, from 1993, start right at the low stand provided by the Pinatubo eruption.

    Here is the PMSL Tide Gauge database going back to 1960 (1.13 mms/year) against the other sea level reconstructions which have been done by Church2011 (1.9 mms/year), Jarajeva2006 (1.6 mms/year), Domingues2008 (1.5 mms/year) and the Satellite Altimetry (now up to 3.2 mms/year).

    At 1.41 mms/year in reality since 1980, sea level is rising very slowly and there is no reason to consider it to be dangerous at these rates.

  33. Regardless of your stance on the overall issue here, I think a lot of commenters fail to understand some basic issues. First, there is a difference between sea ice area and land ice mass. The article refers to the latter, but many commenters point to the former as evidence that ice mass is increasing. I’m not trying to support the authors’ conclusions here, but discussing sea ice area is completely irrelevant the points they are making.

    Also, a model is inherently almost always “wrong”. As the article states, their model is a “probabilistic assessment” that considers the likelihood of various potential outcomes. The probability that a specific one of these outcomes will occur is very small. These kinds of models are used for all kinds of things, including local weather forecasts. Forecasts more than 24 hours out are very rarely 100% precise, but they are still helpful for planning purposes. This doesn’t mean that I think the model in the paper is correct, but to attack the concept of a model is just poor reasoning.

    I’m not even close to an AGW supporter, but nor am I a blind critic. It seems to me that many here are guilty of the same logical fallacies that you accuse the warmist crowd of. I was hoping to find a reasonable community for logical discussion here, but so far I sense a serious lack of credibility. Even the title of this article, with the phrase “uncertainty be damned”, applies an unnecessarily negative bias toward an integral part of any projection.

  34. AR 5 is essentially focused on the dangerous sea level change. That is what Jouzel in France is pushing hard, that is what is promoted, models, ad hoc satellite “corrections” especially since Envisat was suicided.
    This is their last chance at fearmongering…

  35. Typical climate change denier gobbledygook, but it begs the question: “Has anyone tried to accurately measure the rate of change – if there is one – in the volume (rate of change!) of the total Antarctic ice cap?”

  36. Brian says:
    April 5, 2013 at 8:02 am
    I was hoping to find a reasonable community for logical discussion here, but so far I sense a serious lack of credibility.

    I made no reference to sea ice, Brian, or (don’t get me started) models. Not everyone addresses all the points that could be addressed. If you want to find a site where everybody is always correct and deferential then you are going to be searching for a long time.

    What I sense most from contributions here is a serious lack of gullibility, not credibility.

  37. Brian says:
    April 5, 2013 at 8:02 am

    Also, a model is inherently almost always “wrong”. As the article states, their model is a “probabilistic assessment” that considers the likelihood of various potential outcomes. The probability that a specific one of these outcomes will occur is very small. These kinds of models are used for all kinds of things, including local weather forecasts. Forecasts more than 24 hours out are very rarely 100% precise, but they are still helpful for planning purposes. This doesn’t mean that I think the model in the paper is correct, but to attack the concept of a model is just poor reasoning.

    —–
    You’ve got to put the distaste around here for models in context. Models have been used as justification for extremely painful and disruptive policy changes, and have overstated warming spectacularly. It’s not unreasonable for people to view the subsequent application of further models to climate problems with a certain amount of prejudice in my view. Particularly when we read lead author Christopher Little, a postdoctoral research associate in the Program in Science, Technology and Environmental Policy; this seems to imply a continued drive to associate policy with model results. Models can be great, just take the necessary decades to properly test and validate your results before using them as a basis for policy, that’s all I ask.

  38. Michael Hart,
    I understand that many people here know what they’re talking about. I was referring to the slew of comments about Antarctic sea ice growth on nearly every article that has anything to do with ice. And those who attack various accepted scientific procedures because they don’t agree with the results.

    I’m not looking for a site where “everybody is always correct”, but one with two-sided dialogue involving educated people who are simply trying to understand climate. Sadly, I don’t believe that such a site exists. The fact that there are very few dissenting opinions (from the poster’s intended point) on this site indicates either widespread gullibility or a severe case of confirmation bias. I think there are at least as many commenters who want to be spoon-fed material to demonize AGW proponents as there are commenters who want to learn and discuss. And the posters cater to those people, which makes sense, but credibility is still lost because of it. I am fully aware that all pro-AGW sites suffer from the same symptoms as well.

    I think it would help if posters, like yourself, who know their stuff would call out incorrect comments, even if they support your conclusions. I think it would make us all a bit smarter and less susceptible to preconceived biases.

  39. Additionally, who cares about the actual sea level? What matters is the relationship of the land level to the sea level and whether we can adapt IF the water level is going up with relation to the land level.

    What part of the increase in these graphs is melt water?
    And if you were going to PREDICT how these so called curves might continue?
    In addition, what part of these increase are C02?
    Yeah, kinda hard to tell.

  40. Chuck L says:
    April 5, 2013 at 5:02 am
    “These papers and the people who write them are like cockroaches. As soon as a paper is squashed and debunked, there is a lot of scurrying around in the dark by “researchers” and a new one appears.”

    Note that the faculty mentor and co-author is “Michael Oppenheimer, “Princeton’s Albert G. Milbank Professor of Geosciences and International Affairs.” He is all propaganda, all the time. He published the scare article claiming that global warming would cause a flood of people across the Mexican border into the US.

  41. Mark Bofill,
    I agree. I think the politics involved is really the problem. Most politicians likely do not understand the implications of models and predictions. So I get the disdain for models. But let’s try and not let that disdain permeate discussions of research and prematurely form opinions for us. In general, I think the paper presented in this article is very reasonable in acknowledging its own shortcomings.

  42. Brian says:
    April 5, 2013 at 8:02 am

    “Also, a model is inherently almost always “wrong”. As the article states, their model is a “probabilistic assessment” that considers the likelihood of various potential outcomes. The probability that a specific one of these outcomes will occur is very small. These kinds of models are used for all kinds of things, including local weather forecasts. Forecasts more than 24 hours out are very rarely 100% precise, but they are still helpful for planning purposes. This doesn’t mean that I think the model in the paper is correct, but to attack the concept of a model is just poor reasoning.”

    Brian, you seem to be unaware of the long history of WUWT discussion of computer models. The chief complaint is that modelers obsessively claim or insinuate that their computer models can substitute for well confirmed physical theories. Sometimes, modelers are so blinded by computer model lust that they claim that the results of a model run should be counted as scientific evidence. The truth of the matter is that if climate scientists had any well confirmed physical hypotheses, in important areas such as cloud formation and behavior, then they would need their computer models only as calculational devices.

    Computer models cannot substitute for well confirmed physical theories or serve as scientific evidence.

  43. Bill Illis says:
    April 5, 2013 at 7:35 am

    What an erroneous calculation! The title of this article regards Uncertainty. It just upsets me to no end, you deniers. How can you possible estimate sea level without known guage conflicting aliases and human induced changes over time.

    You neglected to correct your data for sea foam, encrusted rust, salt and barnacles, floating cigarette butts, total volume of reduced endangered whales minus increased oil barge traffic, increased pressure from atsmospheric CO2, swimming polar bears, New York garbage barge dumping, discharge from transocean jet traffic, plate tectonics, deforestration, Russian vodka, pygmy goats, sasquatch, my hairloss, skinny dippers, and the death of the Loch Ness monster.

    Taking these data into consideration, I calculate the actual rise at 1.4009 mms/year.

    /s

  44. The extreme AGW paradigm pushers have logically painted themselves into a corner. They have set up the biggest scientific and political scandal of the 21st century.

    How does one back track from statements that the science is settled and those who point out the observations and analysis unequivocally does not support the extreme AGW paradigm are deniers?

    The AGW theory predicted there would be a tropical troposphere hot spot (At about 10 km above the planet’s surface, as the CO2 warming mechanism is saturated in the lower atmosphere. The warm troposphere would then warm the surface of the planet by radiative heating.) The AWG theory predicted that the majority of the warming would be in the tropics, amplified by water vapor, not high in the Arctic. There was no significant warming in the tropics, there is no tropic troposphere hot spot.

    The explanation for the lack of any significant tropical warming and the fact that there is no warming of the tropical troposphere is that clouds in the tropics increase or decrease, reflecting more or less solar radiation off into space thereby resisting any forcing change. The extreme AGW paradigm requires amplification, positive feedback, if the planet resists rather than amplifies the CO2 warming, a doubling of atmospheric CO2 will result in less than 1C warming with most of the warming occurring at high latitudes which will result in an increase the biosphere.

    http://www.johnstonanalytics.com/yahoo_site_admin/assets/docs/LindzenChoi2011.235213033.pdf

    On the Observational Determination of Climate Sensitivity and Its Implications
    Richard S. Lindzen1 and Yong-Sang Choi2
    We estimate climate sensitivity from observations, using the deseasonalized fluctuations in sea surface temperatures (SSTs) and the concurrent fluctuations in the top-of-atmosphere (TOA) outgoing radiation from the ERBE (1985-1999) and CERES (2000- 2008) satellite instruments. Distinct periods of warming and cooling in the SSTs were used to evaluate feedbacks. An earlier study (Lindzen and Choi, 2009) … ….We argue that feedbacks are largely concentrated in the tropics, and the tropical feedbacks can be adjusted to account for their impact on the globe as a whole. Indeed, we show that including all CERES data (not just from the tropics) leads to results similar to what are obtained for the tropics alone – though with more noise. We again find that the outgoing radiation resulting from SST fluctuations exceeds the zerofeedback response thus implying negative feedback. In contrast to this, the calculated TOA outgoing radiation fluxes from 11 atmospheric models forced by the observed SST are less than the zerofeedback response, consistent with the positive feedbacks that characterize these models. ….

    The observations and analysis support the assertion that the majority of 20th century warming has caused by a different mechanism, by something related to the solar magnetic cycle change. The public interest in climate change will return if there is even slight global cooling, say a return to 1970’s temperature. Each time there is another cooling event, coldest month, coldest year and so on, the media that have been pushing the extreme AGW paradigm will need to provide an explanation. There are cycles of warming and cooling in the paleoclimatic record that correlate with solar magnetic cycle changes.

  45. “…a novel framework for projecting the mass balance of the Antarctic ice sheet that allows for the conversion of current and future uncertainties of ice-sheet dynamics into probability distributions that may be supplemented by expert judgments…”

    And what direction might those supplemental expert judgements take?

    “Both papers were funded by the Princeton Environmental Institute‘s CARBON MITIGATION INITIATIVE,”

    I’m sure Steve McIntyre will have something to say about the novel probablistic “methodologies”. However, for my two cents worth, if you are wedded to the assumption that global warming and sea level will continue to rise, then you are leaving out half the picture. The probable variation isn’t just between +30cm and several metres sea -level RISE. They admit to high uncertainties of the upper bound of the RISE, but judge 100% probability to some lower bound level of RISE (what? +10cm? +20cm?). Where does the confidence for the lower bound of positive increase in sea level come from? What would have been the 100% probable lower bound of the rise in the heydays of the mid 1990s? With 1/6 of a century of no global warming, what should this 100% probable level of rise have fallen to? If they believe that there is fair probability of, say, a +15cm rise and a low but possible chance of +300cm rise, they shouldn’t rule out a low but possible drop in sea level, say, of 50cm (some long period of “flat” oscillations followed by gradual decrease – who knows what the lags, and accelerations would be?). I also note that they plan to dovetail in the probability of isostatic sea level changes as well to confound the whole issue. Transparent indeed.

  46. Theo, I’m not a long-time reader, but I completely agree with you that models should not be considered evidence. But does this paper do that? I think they do a great job of describing all of the inputs, processes, and outputs of the model without exaggerating its implications. And this is where the bias comes in. Since many models have been inappropriately used in the past, this one has been prematurely dismissed and the researchers compared to “cockroaches…scurrying around in the dark”. WUWT?

  47. Brian says:
    April 5, 2013 at 10:04 am
    ———-
    Maybe. Maybe I’m becoming overly accustomed to trying to decode doubletalk and I’m false rejecting on phrases like ‘may be supplemented by expert judgments’. Might be I’m just becoming cynical. I will say this for myself however, if the approach proves to model reality to a degree that it does in fact produce meaningful projections, I’ll gladly take my hat off to these guys and pay attention to their results.
    BTW – I agree with Theo’s point as well although I neglected to mention it. I’d qualify it slightly to say this: models are only good substitutes for observations after it’s been solidly established that the models demonstrate predictive skill; this isn’t a straw man argument, people have seriously argued this point with me.

  48. I found it interesting that at the end of the day they predicted about what we see today. The language is alarmist, but the results say that there will be little change in sea level rise.

    Encouraging …

    w.

  49. Brian says:
    April 5, 2013 at 9:25 am

    … I’m not looking for a site where “everybody is always correct”, but one with two-sided dialogue involving educated people who are simply trying to understand climate. Sadly, I don’t believe that such a site exists. The fact that there are very few dissenting opinions (from the poster’s intended point) on this site indicates either widespread gullibility or a severe case of confirmation bias.

    Or it could just mean that people mostly agree about a topic. Or that they totally misunderstand the topic. Or they don’t much care about the topic. Or it could mean that people are simply wrong, but neither gullible nor subject to “confirmation bias”. Or it could just mean that the poster is correct, and people find little to disagree about. There’s lots and lots of possible explanations … but you only think of two of them, both of them insulting to your readers.

    The fact that you impute a lack of discussion on a particular question to either “gullibility” or “confirmation bias” shows me that you’re not really looking for a two-sided dialog. People actually looking for dialog don’t start by calling folks gullible and the victims of confirmation bias just because they may not disagree with a certain post.

    So I’m sorry, Brian, but I’m not buying it. You’ll find more two-sided dialog going on here than most anywhere else on the web … but you’re not a part of it with your “gullible” and your “confirmation bias”. You claim you came here for dialog, and then you start the dialog, not by discussing the issues but by insulting people? Yeah, that’s the best plan for dialog …

    In fact, by accusing people of not holding valid opinions (your two choices are that we’re all suckers or we’re just agreeing with each other to agree, so our opinions can obviously be ignored), you’ve proven that you don’t care much about dialog, you’re more about insulting folks … no wonder nobody wants to have a “two-sided dialog” with you after you start by calling them “gullible”.

    Now, I’m sure that your “I’m just looking for an honest website so I can have an honest discussion” line of bull fools your friends, and perhaps it impresses the girls in your philosophy class.

    Here it just makes you look like a shallow poseur … get with the picture, join the discussion, and stop bitching about the quality of people around you, you’ll get much farther in life that way.

    w.

  50. John Parsons AKA atarsinc
    Jimbo says:
    April 5, 2013 at 4:01 am
    “…Antarctica losing or gaining ice?”
    Your link is about sea ice. Antarctic Ice Mass is declining. JP

  51. Brian, while I do find myself in agreement with you at times, that there are many posts that are simply argumentative without being helpful, I disagree with you completely on your conclusion that models are useful for planning, and your tacit presumption that models are scientific in nature. A model prediction/projection in the context of ice melt that would take thousands to millions of years, even if the worst heating proposed by CAGW proponents occurred, is worse than worthless, as it cannot be tested. Furthermore, in the climate modeling field, they have broken the most fundamental of “laws” in presuming predictive accuracy of their output does not degrade over time. Every weather model builder can tell you that this is nucking futs. The further out in time a model projects, the closer to zero it’s ability to accurately predict. If climate science would actually worry about stuff like this, and test their models and allow them to be falsified in normal scientific ways, the term cockroach might be a bit less prevalent among the more vociferous of the opposing political camp.

    Models that fail (or are merely pointless, as in this case) still have propaganda value, a fact not lost on people who want the color of science as they advance their collectivist, radical green agendas (which pretty much describes the entire pro-alarmist faction of climate science, in my opinion) under the rubric of saving us from our own freedoms.

    In the future, when you hear terms like “cockroaches scurrying” I hope you think of the poor ability of models to predict real world climate, Hanson’s historic flip-flop from cooling to warming, the downright idiotic “science” of Lewandowsky, the intentional muddying of linguistic precision in political terminology (ie. from Global Warming to Climate Change to Climate Disruption) in order to conceal model failures, the movement’s us-vs-them mindset, the “ends justify the means” ethics of Peter Gleick and his cheerleaders, the near-fascist levels of political correctness at major western public universities, the information bubble machines that are John Cook, Bill McKibbon, HuffPo, Think Progress and “Real” Climate, the subtle yet fully exposed money grubbing hypocrisy of Al Gore, not to mention the sheer number of Greenpeace activists who participate in the IPCC with little or no scientific credentials at all. Maybe then the term “scurrying cockroaches” won’t sound quite so severe to your ear.

  52. This article is about what I have termed “Trenberth Events”, or TEs, named, as you will see, after Kevin Trenberth, he of the Consensus Climate Team.

    There are two types. One, called Negative, is an observation (event) that has not been observed but is predicted to exist by a model. The other, called, Positive, is an observation (event) that has been observed but is predicted not to exist by a model. The Event leads to more than a simple contradiction to the the established (consensus) opinion. The Event leads to strident remarks that observations, not the model or opinion, are in error. Furthermore, when we are dealing with a TE, serious effort is made to find work-arounds to explain away the disconnect or even to discredit the source of the problem observations.

    The sea-level non-acceleration of this article is a Negative Trenberth Event. The sea-level is supposed to be accelerating in its rise. The non-warming of the mid-tropospheric is another. Both are supposed to exist, but do not. In both these cases, observation has been deemed faulty: tidal guages are inadequate in the first, and millions of balloon radiosondes in the other. A third is the non-projected rise in oceanic heat content (Trenberth’s missing heat): the answer is that the thousands of Argo floats are not sampling deep enough.

    An example of a Positive Trenberth Event is the increase in mass and ice area of Antarctica. It has observed, but shouldn’t have happened. An increase in cloud-seeing nuclei (even if small) with gamma ray radiation should not have happened at CERN, but did. That is an established Positive TE, and was met with the reply that the nuclei were too small and NO, we aren’t doing follow-up tests to determine if the small will grow to the large. The original researchers, after all, are denialist idiots.

    A possible Positive TE is occurring right now, in that temperatures are dropping and cloud cover is increasing (at least in the European part of the NH) as sunspot activity has slowed down; we need more data to know if this is global or regional. We already have Al Gore saying that the idea the sun is responsible is BS, and that it doesn’t matter that Europe is cold because the open “warm” Arctic water (from whence the “cold” comes) caused it. Besides, it’s been a mild winter in the mid-continental US of A. So there.

    Trenberth Events are a prime feature of the current CAGW argument. When a TE is upon the scene, alarm bells ring and the Climate Team leap about like the teenage “fire drills” in which everyone leaps out of a car stopped in traffic at a red light, runs madly around the car while bystanders gawk, only to leap back in when the light changes and drive away laughing hysterically.

  53. atarsinc,

    Antarctica is steadily gaining ice, both sea ice and continental ice. There is no problem. In fact, both Arctic and Antarctic ice is growing.

    Total global ice cover [red graph] is back above its long-term average. How does that affect your world view? Are you willing to change your mind when facts change? Or is your mind made up and closed tight?

  54. Sorry to give you that impression Willis. I certainly haven’t added any original points of my own, so I can understand your position. I suppose the most interesting thing I took from the article is that nearly all of Antarctica’s ice mass loss comes from a very small area in the west part of the continent. I’m curious as to why that is.

    The line about gullibility was a response to Michael Hart saying “What I sense most from contributions here is a serious lack of gullibility, not credibility.” There is certainly a lack of dissenting opinions here across all articles. The possible reasons you mentioned can apply to specific articles, but for a large collection of articles, I believe confirmation bias is the most likely. (Confirmation bias is highlighting evidence that supports your opinion and ignoring/attacking evidence that opposes it, not “agreeing with each other to agree” as you put it) I’m sure you would say the same about, say, skepticalscience’s comment section.

    I come here, as well as other sites on both sides of the issue, to read and learn of new research. I am frustrated by the many close-minded and uninformed comments I see. I don’t normally comment myself, but I felt compelled to on this article for some reason. Perhaps I am misguided and I should keep to myself. I find your accusation of “bitching about the quality of people around you” line ironic, since this site is full of insulting AGW scientists while praising those who oppose them and ignoring their failings. I’m not picking a fight here, and certainly not personally insulting anyone. You can do without the references to philosophy class (I assume that was derogatory) and calling me a “shallow poseur” with a “line of bull”.

  55. “No single ice sheet model or methodology for projections provides sufficient information for good policy and planning decisions,” explained lead author Christopher Little.

    Does the above mean, “If we make it complex enough, using lots of models and methods, those pesky realists (use the D-word, if you want to), will never have their mitts on enough information to throw our theories out. We can refute them by saying, ‘Ah, but you’re missing the…[fill in the blank].’

    What about: “Furthermore, there are fundamental limitations in the observational data available on and near ice sheets,” Little said. “Projections of their response to 21st century climate changes are thus very poorly constrained. There’s unlikely to be a single answer in the near future: a better objective is a comprehensive, transparent baseline that can be improved over time.”

    Does that mean, “Shifting our goal posts is always an option – We like to move around a lot”?

    To me the “transparent baseline” is a promise of the exact opposite. Call me skeptical.

  56. Mickey, your post illustrates my point perfectly. I said that weather forecast models are useful in planning, and that the model in this article did not claim to be hard evidence. At no point did I say that all models should be used in planning/politics and should be viewed as scientific evidence. Similar to how you have lumped my comments in with what many warmists believe, many commenters here are lumping this article in with all of their preconceived negative bias toward models.

    I agree with your list of corruption of the science, but I could also list many instances of overt propaganda against it. They’re not hard to find on warmist blogs. I think the truth lies somewhere in the middle.

  57. Brian:

    I read your reply, at April 5, 2013 at 12:31 pm, to the clear and just comments of Willis.

    And I was reminded of this
    Queen Gertrude, “The lady doth protest too much, methinks “
    Hamlet, Act III, scene II (written by Shakespeare W).

    Richard

  58. @ Brian.

    How about you start over and post what you want to say about this topic, leaving out complaints and criticism about others who comment here. If you are not familiar with WUWT, then look around a little, there’s HEAPS here to explore. I get as much out of the comments as I do from the articles and have found people wonderfully diverse.

    It looks to me as though you started off on the wrong foot and now you’re having a hard time defending your position. Don’t worry about it. Ditch the lot, start over. Add what you want to about the TOPIC, and let the dialogue continue from there. The people here are very smart and very quick, but they are also very forgiving if your intention is as honest as you say it is.

    We’ve all been roughed up in here a little. I’ve put my foot in my mouth more than once, or used faulty reasoning, and been rightfully jumped all over – but it’s wonderful. I’ve learned to think before I type (mostly). :) Just trying to help. Cheers.

  59. Brian says:

    April 5, 2013 at 1:09 pm
    Mickey, your post illustrates my point perfectly.
    ======================
    And the point is well taken.
    Unless you feel the need to drive it even harder.
    It’s a free internet.
    (time to make a belated donation to Anthony and crew, thanks for the reminder).

  60. Phase 1 of Climate Science: Models become so popular we stop experimentation on actual physical systems resembling the atmosphere, oceans and the biosphere.

    Phase 2 of Climate Science: With model predictions so entrenched we stop comparing model results to the actual weather we have and its recorded historical patterns. After all, weather is not climate and we know today’s weather must be warmer and worse that it was before.

    Phase 3 of Climate Science: We stop using observational data to feed into the models and instead focus on “probabilistic frameworks” and other mathematical methods (including advanced data manipulation and opaque averaging techniques.)

  61. Mark Bofill says:
    April 5, 2013 at 2:18 pm

    A.D. Everard says:
    April 5, 2013 at 1:02 pm
    ———
    Exactly – you cracked it! :)

    *

    Thanks! I didn’t think I’d be the only one to see it. :)

  62. One of the problems with most Antarctic glacial ice mass balance estimates is that they used an inaccurate glacial isostatic adjustment model.

    The newest models based on GPS receivers and/or the IceSat satellite is showing that Antarctic ice loss is actually between 75% lower or might actually be +25% on the gaining side instead.

    We can’t expect climate scientists to keep up with the latest science since they are stuck believing their 1980 theories.

    http://www.the-cryosphere-discuss.net/6/3703/2012/tcd-6-3703-2012.pdf

    http://www.climate-cryosphere.org/en/events/2012/ISMASS/AntarcticIceSheet.html

    (I note the original paper from Jay Zwally seems to have blocked for some US Export Control Laws reason. Now that is really out there which has a climate science mafia-type smell on it).

    http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120013495_2012013235.pdf

  63. @Bill Illis
    “1.41 mms/year in reality since 1980″
    Thanks for that.
    I have an irregular collection of records for three relatively local tide gauges (out of about 40 available in the region), collected for mandatory design requirements, eg mean sea level and highest astronomical tide. Rough average is 1.4mm/yr. Maybe trending down.
    No wonder the olds who have been fishing off the beach for 60+ years can’t see any cause for alarm :-)

  64. John parsons AKA atatsinc

    dbstealey says:
    April 5, 2013 at 12:29 pm
    atarsinc,
    You say:
    “Antarctica is steadily gaining ice, both sea ice and continental ice. There is no problem. In fact, both Arctic and Antarctic ice is growing.” But your links only show sea ice. What about that is supposed to change my mind? JP

  65. Mark Bofill wrote something like “mixing the less bad with the worse”. This reminds me of something that I read recently that mixing a bottle of sewage with a shot of fine wine produces sewage, while mixing a bottle of fine wine with a shot of sewage produces sewage

  66. atarsinc,

    Post a link that shows Antarctic land ice declining. But there is no such data. Antarctic ice is steadily growing, which negates any and all your claims of global warming. And as posted above, Arctic ice is also increasing.

    The global warming/AGW scam is baseless pseudoscience. What would it take to change your mind? Or is your mind made up and closed tight?

  67. Richard M says:
    April 5, 2013 at 4:19 am

    Let me see how this works. We have biased researchers using biased models and biased measurements of other biased researchers. Yeah, what could go wrong.

    Has anyone in climate science every heard of double blind studies and why they were created?

    How exactly would one do a double blind study on ice sheets? Not tell the ice sheets if they’re using a placebo?

  68. Brian –

    Models — I don’t think you understand what is going on.

    Models are not Science — they are Art.
    Modelers are creating a representation of the world — the world as they see it. That is what an Artist does.

    So when we use models to look at the world we are actually looking through the eyes of the modeler — seeing what he sees — just as we look through the eyes of the Artist when we look at a painting that the artist has produced.

    I will now give definitions for two well-known areas of Art. They are basically the opposites of each other.

    Realism — “It may generally be defined as the attempt to represent subject matter truthfully without artificiality and avoiding artistic conventions, implausible, exotic and supernatural elements.”

    Romanticism — “A movement that validates strong emotion as an authentic source of aesthetic experience placing new emphasis on such emotions as apprehension, horror and terror and awe.”

    To understand climate models you have to understand what type of “artist” the modeler is. After all, you are seeing the world through his eyes, right? The “body of his work” — as it has been produced — will tell you what school of Art he practices.

    Now obvious point — climate models have all been about creating as much fear and hysteria as they can.

    So Brain, from which school of Art do you want your climate modelers to be from? — Realism or Romanticism?

    Well, there doesn’t seem to be any from the school of Realism around. So now do you understand why there is so much scorn for climate models on this site?

    Eugene WR Gallun

  69. Doug Proctor says:
    April 5, 2013 at 12:27 pm

    Very impressive. I think your “Trenberth Events” just might give legs to a meme. Anyway, the idea is funny and the name is catchy.

  70. I just love playing Internet tennis.

    Hi Brian. I don’t mean to be disrespectful, nor do I wish to put words in your mouth. You came here with essentially two claims; a vague one that somehow this Antarctic model is useful, and a much more concrete one that WUWT has many partisans. I’ll stipulate the latter point, and I confess to being one of them. I openly state my biases.

    Now it’s your turn. Here’s another chance to address my disagreement with your far more interesting claim about this model being useful (ie. that one which juked me into presuming your agenda isn’t as neutral or non-partisan as you state).

    Please explain why you think a computer model, which claims to represent the real world physics of ice melt in the Antarctic, is useful for planning? What is it exactly that “we” (society) can plan? What compelling data can this model produce of which you think the body politic could make use to decide … uh what, exactly?

  71. Doug Proctor April 5, 12:27pm

    Trenberth Events!!!!!!!!

    It has been said that truth is stranger than fiction. You have demonstrated that truth is also funnier that fiction! You just can’t make stuff like this up!

    Yes, I think the phase “Trenberth Events” will fall into common usage among scientists. The man is making his name famous by his actions. To quote from Mr. T — “I pity the fool!”.

    Eugene WR Gallun

    .

  72. Another Positive Trenberth Event: the recovery of offshore Australian reefs from a ’98 bleaching. Supposed to take decades. Took 12 years even though isolated.

    Bet the bleaching was not just the ’98 El Niño, either. Coral reefs has thrived from the Ordovician to the present despite mass extinction events. If corals were that sensitive, they would be extinct. I’ll bet the specific reef mass was genetically near identical due to its isolation (and is so now) and some sensitivity to virus + temperature did it in.

    The TEs are piling up. It’s not just the “missing heat”, Kevin: it’s all of them.

  73. Those making projections should be liable for the financial consequences of any actions based on them if they make outrageous claims like the science is beyond question. Perhaps we would see a shred of honesty in the known defects in the work instead of concealment of information and police harassment of those who try to publicise the deceptions the so called scientists are fully aware of.

  74. Many of the replies to my comments make the assumption that I believe the model in this paper is useful for planning. I do not believe that whatsoever, and I never said it. My original post was simply making the point that models are always “wrong”. The only reason the model is useful is that it will hopefully help scientists to eventually understand all of the factors that go into ice mass change and sea level change. We are nowhere near that point yet, but models are a step in the learning curve. The authors of this paper acknowledge that the model is a work in progress, and I am taking the unpopular position of defending that point. I do not think that this model should be used to make any political decisions.

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