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chris at 05:05 AM on 8 August 2010Confidence in climate forecasts
Argus at 02:58 AM on 7 August, 2010 ”So you really believe that a climate model is just a "working replica of the earth" - only it is made from "mathematical equations" instead of "rock and water and other materials"?... No, of course not. A climate model is designed to simulate energy flows within the climate system. It doesn’t have to simulate “rock and water and other materials”. On the other hand a model could include rock weathering by parameterizing a huge amount of physics and chemistry on silicate weathering, and the relevant properties of water (ocean thermocline; mixing between ocean layers and other aspects of ocean heat transport; ocean surface evaporation; latent heat transfer and so on) can all be parameterized according to empirical physics. ”In the post How reliable are climate models? a big deal is made out of the fact that the models "successfully reproduce the past". Of course they do. That is what they were made to do. But predicting the future is another matter.” There is an element of the Monty Python “what did the Romans ever do for us” about your complaint! “Wot ‘ave models ever predicted...... except (i) the moistening of the troposphere at a time when at least one prominent “skeptic” was asserting that the upper troposphere would dry in a warming world; (ii) tropospheric warming during a long period when erroneous tropospheric measures were indicating the opposite (models predicted correctly again); (iii) northern polar amplification of global warming including a significantly delayed Antarctic response (model predictions from the 1980’s); the extent of warming in response to enhanced greenhouse forcing (models from the 1890’s; from 1975 and Hansen’s projection from the 1980’s discussed earlier); that tropospheric warming would be accompanied by stratospheric cooling and the increased altitude of the tropopause (models from 1980s); enhanced nighttime warming over daytime warming and enhanced winter warming over summer warming (Arrhenius predicted this in the 1890’s!); etc. etc. …..apart from that wot ‘ave models ever predicted!” The reason that models have been rather successful in predicting the Earth response to enhanced greenhouse forcing is that the issue is largely one of addressing the amount and distribution of energy in the climate system. There is a massive amount of well-characterized physics with which to parameterize models (the blackbody Earth temperature, the Earth’s albedo, the origin and magnitude of the greenhouse effect, and the fact that the earth temperature response linearly to logarithmic changes in [CO2] were already known and understood in the 19th century). And as I’ve said before there is a wealth of empirical and theoretical data that informs us that the Earth responds with a surface warming between 2 and 4.5 oC per doubling of [CO2]. In effect this can be considered a highly predictive (all else being equal!) model for projecting future temperatures in response to various CO2 emission scenarios. Global circulation models might be considered to be continuous embellishments of this basic energy relationship. They don’t actually have to be that complicated! It’s not obvious that they actually give us much more info about global warming per se than can be gleaned from the climate sensitivity, but of course (as I’ve said before too!) they allow testing of future projections and a focus on differences between model predictions and real world measurements [which so far have largely been settled in favour of the models (see my Monty Python sketch just above)]. ”I imagine it would be almost as hard as making a model of how the human race will evolve during the next million years.” (referring to how hard it might be to make an accurate climate model of the Earth). I wouldn't say so Argus. Physical models parameterized with well-characterized physics can do a good job of simulating relevant elements of physical systems. Since evolution is fundamentally based on stochastic variability (random mutations in heritable DNA), coupled with interactions at the somatic scale (e.g. mate-selection) under the influence of environmental “natural”-selection, buffeted by non-predictable stochastic (car accidents; fatal illnesses; non-reproduction) and contingent events (war, famine, tsunami’s, volcanic eruptions, earthquakes, floods and all the other nasties that can decimate populations unfairly), evolution is inherently non-predictable. ..weather's difficult too...climate not so difficult broadly speaking. n.b. be sure to click on the Monty Python sketch link! -
Waste heat vs greenhouse warming
RSVP - slow distribution vs. fast distribution? Nah, not an issue. You put 0.028 W/m^2 out via AHF. Perhaps it takes a while to get into the environment - a long slow pipe via a river to the ocean and finally heating the atmosphere. Perhaps it goes out quickly - a short pipe directly via convection in a radiator, which only later heats the ocean by conduction/convection. But you have 0.028 W/m^2 going into the 'pipe' - and you have 0.028 W/m^2 coming out of the pipe. You still have 0.028 joules/sec/m^2 added to the environment. The length of the 'pipe' doesn't matter one bit - the rate of energy deposited in the Earth/air/water system does. On your two-barrel analogy - that would have been better put as looking at a single barrel with alternative filters. The 2 barrels really sounded like your previous arguments that there were two different heat stores, which is simply not the case. Keep in mind, though, that it's a very large barrel, and never gets empty, the Earth won't reach absolute zero. -
Doug Bostrom at 04:20 AM on 8 August 201010 Indicators of a Human Fingerprint on Climate Change
There are many results indicating statistically significant temperature change, Alan. Global observed changes in daily climate extremes of temperature and precipitation Global Trends of Measured Surface Air Temperature Global rural temperature trends Maximum and Minimum Temperature Trends for the Globe Global temperature change and its uncertainties since 1861 Trends in global temperature Global temperature change Global Warming Trend of Mean Tropospheric Temperature Observed by Satellites Quite a few not mentioned. What's interesting is how old many of these findings are yet a lot of people are not aware of them, even so-called skeptics who ought to be the first to go find out what the facts are. A well-armed skeptic should look at everything before making assertions. -
Doug Bostrom at 03:56 AM on 8 August 2010Confidence in climate forecasts
Thanks, Argus. It's notable that your post w/the remarks about "purpose" was discussing scientific research but as you further describe your feelings it turns out your concerns are about what you see as a tone problem in popular media and what you believe is an agenda pursued by the media to drive political action. That's not an argument about science. Your conclusions about popular opinion are also quite interesting. If you look around for scientifically conducted research into public opinion, you'll find that your perceptions put you in a small minority of persons that while varying by year in proportionality appears to show little if any trend. -
Peter Hogarth at 03:38 AM on 8 August 20101934 - hottest year on record
Broadlands at 01:38 AM on 8 August, 2010 Hopefully looking at the latest USHCN chart and data for US annual temperatures might be helpful and answer some of your questions:It ranks 1934 as 3rd highest temperature after 1998 and 2006. As you know this data set has been analysed by researchers (and critics) over many years, and contains a number of corrections and updates, most significantly (from the point of view of older data), “time of observation” adjustments. The corrections are described quite well for version 1 and most recently for version 2 which is used for the chart. The data, fully corrected, time of observation only corrected, and raw, can be downloaded from here
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Argus at 03:27 AM on 8 August 2010Confidence in climate forecasts
doug_bostrom (at 04:32 AM on 7 August, 2010): "What purpose do you believe that to be, Argus?" First, let me say that I am skeptic towards climate models for the same reasons as the signatures Pete Ridley (at 02:23 AM on 7 August, 2010) and johnd (at 11:35 AM on 7 August, 2010), as manifested in their recent comments. They are just expressing themselves far better than I am. "These models make correct predictions because they are based on general scientific principles", Kevin Judd claims about weather modelling programs. Correct predictions - that is quite a statement! And he seems to imply that climate models are just as correct, because "otherwise microwave ovens wouldn't work, aircraft wouldn't fly". He is obviously trying to inject 'confidence in climate forecasts' into the listeners to FM 92.1 (and the readers of this post), by making climate models seem as simple and reliable as "model stream-trains". -- Is it working out? Not for me, but according to doug_bostrom this is only because I am "harboring some misunderstandings about models". As for the question about purpose, I will first give a few examples. Whenever the future of our climate is presented in media, there is too often a tendency to exaggerate: '... warned the world that non-linearities in the ocean-atmosphere system could lead to a whopping 5 meter or more sea level rise over this century' - 'a 5 degree to 8 degree rise in global temperature in the next 100 years, expected by many scientists …' - '… the likelihood of [the glaciers in the Himalaya] disappearing by the year 2035 and perhaps sooner is very high'. I think the purpose behind the use of exaggerated news, is to wake up the masses, alert them so that they will start living more ecologically, and possibly influence their politicians to act sooner (and more forcibly). The alarming predictions are usually based on well chosen climate models, so I think they are influenced by the same purpose. A model that over-predicts global temperatures a bit, or shows a steeper curve, is more useful in this context. Unfortunately, alarming figures and exaggerated predictions do not work well anymore, I think. The public is becoming more skeptic for each new alarming report. I doubt that the purpose of informing the people (which is a good purpose) is served best in this way. New proselytes could possibly be won over more effectively with other methods than serving them half-truths. -
AlanR at 02:12 AM on 8 August 201010 Indicators of a Human Fingerprint on Climate Change
So CO2 continues to rise and water vapour rises to magnify the warming. Unless there's a cloud on the horizon, it can't be long before temperatures rise to statistically significant levels. -
gallopingcamel at 01:56 AM on 8 August 2010Why I care about climate change
kdkd (#112) I was not advocating an approach to energy policy as this web site is not into "solutions". My intent was to point out how difficult it is to change energy policies in the countries that are having the greatest impact on carbon emissions. -
Broadlands at 01:38 AM on 8 August 20101934 - hottest year on record
DOUG... "Given long enough these changes will work their way up through decimal places and emerge. That's exactly what we see in the global record, variability gradually moving upward." But, IS that what we are really seeing, long-term... at least since ~1880? Before 1975 the highest northern hemisphere temperatures occurred in the late 30s, around 1938. Look at Fig. A.6 in the 1976 NAS report "Understanding Climate Change". In 1975 the "normal" zero reference temperature was 14.9°C; the 1938 anomaly was about +0.6. This makes the 1938 NH absolute temperature ~15.5°C (59.9°F). Compare the NAS Fig. A.6 with this chart based on similar data: http://revolution2.us/content/docs/global_cooling/614-615.html Even though 1975 is centered in the current 1961-1990 "normal" base period, the northern hemisphere reference "normal" today is lower by 0.3°C at 14.6°C (58.3°F). With the 2009 NH anomaly around +0.5°C this makes the 2009 NH average only 15.1°C (59.2°F). That is 0.4°C BELOW the measured 1938 highs. Looks like in the ~50 years from 1885 to 1938 temperatures gradually rose, and then they gradually declined back to "normal" in the mid-70s before starting another gradual climb. It looks much more cyclical than the long, gradual upward climb depicted in current charts. [BTW, 59.2°F for the NH in 2009 is more than SIX degrees warmer than the US in 2009 (52.9°F)]. Maybe Tom is right that the US record doesn't matter.] -
DarkSkywise at 00:52 AM on 8 August 201010 key climate indicators all point to the same finding: global warming is unmistakable
(Oops, I hit Submit instead of Preview. Anymoo, the question is still the same.) -
DarkSkywise at 00:50 AM on 8 August 201010 key climate indicators all point to the same finding: global warming is unmistakable
OK, so I really have NO idea where to post this, but since it's the exact opposite of what this thread is about: Reecntly, I was asked (well, gently bullied would be closer to the truth :D) to do a guest blog about climate after providing a couple of answers I stoled from SkS. Since there are already quite excellent articles / sites about "10 most used skeptic arguments" or "10 myths about climate change", my idea was something like "10 key skeptic peer-reviewed studies surviving longer than a few months before being totally trashed". So far I have Friis-Christensen (1991), which isn't really close to 10 yet. Any suggestions? PS @ John & other mods: if you know a better thread to post this, please tell. I really won't mind. :) -
angliss at 00:02 AM on 8 August 2010Three new studies illustrate significant risks and complications with geoengineering climate
Figure 3 has been corrected. -
kdkd at 23:55 PM on 7 August 2010Remember, we’re only human
HR #49 Nice, an argument by complacency. Good work. -
chris at 23:00 PM on 7 August 2010Remember, we’re only human
Come on HR; I’ve pointed out before that quite a bit of your posting is contrived indignation arising from misrepresentation of others posts, and false précis. Your latest example is extreme bordering on the unpleasant! (i) population and “culls”. We don’t know what human population the Earth can support sustainably (we all agree I assume that is the only realizable long term future for humankind). We know that societies which reach a level of economic development that frees parents from producing large families (to maintain subsistence living, for support in old age and to counter high child mortality), tend to stabilize their populations. The UK had a population of 50 million in 1951, and the fact that it’s somewhat larger now is largely due to immigration. If there were imperatives to reduce population sizes this could be achieved (or might well happen naturally) as large populations became unsustainable (as they might…or might not). So you reference to “culls” is a pretty nasty misrepresentation. (ii) Your “strawman" - "one prevalent idea seems to be that the very existence of human beings is a problem" - also seems be to constructed to misrepresent sensible discussion. Throughout the evolution of human societies mankind has addressed problems. It’s one of the things we’re good at and a major impetus for scientific advance. We’ve addressed problems of infectious disease (at least in the developed world if less so in the developing one), energy supply (ditto), and more discrete problems like sulphurous industrial emissions (ditto re developed/developing world), CFC destruction of stratospheric ozone, morbidity and mortality due to ciggie smoking (ditto) and so on. We’re addressing the first of two major looming (and in fact rather helpfully linked) problems: global warming and depletion of fossil fuels, through rather rational considerations of transitions towards sustainable energy production, considering mitigation strategies and so on. I asked you on another thread to briefly outline your vision for the future, given that we both seem to share the ideal for economic and societal advance in poor countries. You declined to respond. But given your assertions that you “aspire to see them have everything we have, and more”, and that “we need to be clear that we still have to consume more”, it is a reasonable question how you consider those aspirations might be achieved in the real world . HumanityRules at 20:33 PM on 7 August, 2010 ”The overshoot is BS! It's been BS for 2000 years! ” Is that supposed to be an argument HR? -
RSVP at 21:43 PM on 7 August 2010Waste heat vs greenhouse warming
KR 194 "If you cannot understand that, and continue to insist that AHF somehow acts differently than solar energy (does it somehow produce a different flavor of joules - chocolate, perhaps?), then you have a conceptual issue I cannot help you with. " The idea of chocolate flavored joules is sweet (no pun intended). Before I go on, sorry for not realizing that you did tie water level to radiative power in your analogy. My apologies. Aside, my two buckets (192) is not a comparison between waste heat with GHG heat as you seem to imply. The point of having two buckets had to do with comparing water discharge rate and silt profiles for two different types of filters. The filters represent effects of higher and lower CO2 concentration. It is a crude analogy only for purposes of focusing on temperature profiles which as per Ned 195 seems to be mapped out fairly well. That said, I am not convinced that there are not "chocolate" joules so to speak. For instance, wind chill factor can make a lot of difference to heat loss... its not that the joules are different, its that they are being transferred at a higher rate due to a moving fluid and evaporation. Likewise, N2 and O2 emissivity being much lower means that these gases radiate much slower than CO2. I have yet to see anyone even after 200 comments (i.e., doug_bostrom #198) address this question squarely. After saying this, of course, someone will now come up with some hoaky comment to simply distract attention from this issue,... please dont make me right (again). Back to "chocolate" flavored joules... What am I talking about? In the same way that wind chill factor affects cooling, radiative emissivity affects the rate for a grey body to cool. And given that N2 and O2 emissivity is much lower than that of CO2, a relationship must exist relating the theoretical waste heat value and apply a E(CO2)/E(N2) or E(CO2)/E(O2) factor and end up with a effective (chocolate) warming factor. The fact that no one has investigated this, does not make this possibility any less real. And from my point of view, in your not wanting in internalize this idea, I could just as easily say that, "you have a conceptual issue I cannot help you with." -
HumanityRules at 20:33 PM on 7 August 2010Remember, we’re only human
48.kdkd Get yourself some optimism. The overshoot is BS! It's been BS for 2000 years! -
GeorgeSP at 20:32 PM on 7 August 2010Has Global Warming Stopped?
By the same token, using excel before thinking is the same as using a calculator without knowledge of calculation by head. The discussion developed after FDykstra used excel is actually a waste of brainpower. The basic question is: are the temp observations during that period representing a rise in temperature or are they random? The proper, formal, based on the 95% confidence interval, answer is: no, and Phil said so. Accordingly, Fdykstra, manipulating statistics is no substitute of knowing what one is doing, as was said in college. Given the percentage Phil gave, actually even more proper, and knowing the low number of observations, that percentage, representing the area of the normal distribution, is pretty high, I would say scaring high, given the convention of 5 or 10% confidence interval. A low number of observations is able to give that high percentage...conclusions are around the corner. -
kdkd at 20:03 PM on 7 August 2010Why I care about climate change
gc #111 "It gets worse. Joe Sixpack is no longer your main problem. Vidya Patel (India) and J.K. Chang (China) want SUVs and electricity (mostly from coal powered plants). They will get what they want no matter how loudly you complain." This circular argument is self-defeating. Also in terms of the Chinese and Indian situation, you're pretty wide off the mark, they (especially China) are taking the development of a renewalble energy economy pretty seriously. On the other hand the Americans do seem to be taking the blinkerd approach you're advocating, at least at the Federal level. This isn't a problem for individuals, substantial differences can only be made by treating it as a collective problem. -
kdkd at 19:55 PM on 7 August 2010Remember, we’re only human
HR #47 "one prevalent idea seems to be that the very existence of human beings is a problem" I'm pretty sure that'a straw man argument. Humanity's over-exploitation of the environment is a problem, and if we don't do something rational about it, the decisions will be made for us. This stuff relating to population ecology dynamics is fairly well understood, and it's pretty clear that we're very likely heading into overshoot. So you can moralise all you like, but I'm afraid that the scientific basis of our knowledge is distressingly amoral. -
HumanityRules at 19:24 PM on 7 August 2010Remember, we’re only human
38.John Russell I wonder if you'd like to suggest the basis on which we start the cull? Or maybe forced sterilization? It seems the rational thing to do. I was going to read your link but the address made me feel sick. We live in a world were one prevalent idea seems to be that the very existence of human beings is a problem. It doesn't mean I have to agree with it. As I said, Malthus was wrong about the natural limits of this planet. I think the present doomsayers are equally wrong. Both are misdirected in were the real problems lie and under-estimate the ingenuity of us. -
Doug Bostrom at 18:11 PM on 7 August 201010 Indicators of a Human Fingerprint on Climate Change
Re #41, the effect of water vapor can be calculated as for any other GHG. After that, you need to look for increased water vapor, and of course confirmation is good to have. Increases in middle atmospheric water vapor as observed by the Halogen Occultation Experiment and the ground-based Water Vapor Millimeter-wave Spectrometer from 1991 to 1997 Increase in lower-stratospheric water vapour at a mid-latitude Northern Hemisphere site from 1981 to 1994 Radiosonde-Based Northern Hemisphere Tropospheric Water Vapor Trends Tropospheric Water Vapor Climatology and Trends over North America: 1973–93 Trends and variability in column-integrated atmospheric water vapor Atmospheric Water Vapor over China Positive water vapour feedback in climate models confirmed by satellite data Global Cooling After the Eruption of Mount Pinatubo: A Test of Climate Feedback by Water Vapor -
AlanR at 17:35 PM on 7 August 201010 Indicators of a Human Fingerprint on Climate Change
One doesn't need to be very sceptical to require an answer to topqquark's question at #41 : evidence for positive feedbacks. -
Doug Bostrom at 17:33 PM on 7 August 2010Monckton tries to censor John Abraham
Monckton News Flash: Viscount Monckton of Brenchley is not and has never been a member of the House of Lords. However, allegations that he has claimed to be a member, and that he has used an emblem resembling the parliamentary emblem, have been drawn to our attention. The House is currently taking steps with a view to ensuring that Lord Monckton does not in future either claim to be a member of the House or use the parliamentary emblem or any variant thereof. FOGT Famed Pink Portcullis to be closed for good? -
Cornelius Breadbasket at 16:30 PM on 7 August 2010More evidence than you can shake a hockey stick at
This is an excellent presentation. Well done. I will add it to my Youtube favourites (my channel is www.youtube.com/user/Herecomesthefatlady - I've collected a decent selection of the best videos about climate change). I have many 'discussions' with people on Youtube - I'll be very interested to see what comments this presentation attracts. -
Doug Bostrom at 16:06 PM on 7 August 2010Confidence in climate forecasts
JohnD, you might want to take a look at what happens w/GCMs when they're challenged w/absurd perturbations such as instantaneous removal of all Antarctic sea ice. What you'll find is that without other simultaneous "knobbing" the effects of such perturbations are transient within a relatively brief time. For instance in the case of Antarctic ice being vanished by a "deus ex machina" the ice returns as of course it ought to do without for instance a massive load of C02 being dumped into atmosphere at the time of removal. This is what's expected from a faithful simulation and is a powerful hint as to how well the models adhere to reality. Stick w/clouds if you want to make a serious case about model limitations, that's my inexpert advice. -
Doug Bostrom at 15:49 PM on 7 August 2010Grappling With Change: London and the River Thames
I think you and I share a problem w/biting our tongues, GC. Often said to cab drivers, random guests at parties, etc.: "Don't get me started." They don't realize the gravity of my advice... :-) -
gallopingcamel at 15:16 PM on 7 August 2010Why I care about climate change
John Cook, As I suspected your really CARE. While I have no problem with that, you have bought into the idea that mankind is causing Global Warming and therefore mankind should be able to mitigate it. The mitigation idea fails on at least two levels. First, the warming is more beneficial than a cooling trend would be and you will never persuade a majority that the contrary is true. Second, you believe that the main factor driving Global Warming is the rising CO2 levels in the atmosphere brought about by industrialisation and rising human populations. Even if this controversial hypothesis is correct you will not be able to persuade Joe Sixpack to give up his "Redneck Cadillac" or his HVAC system. It gets worse. Joe Sixpack is no longer your main problem. Vidya Patel (India) and J.K. Chang (China) want SUVs and electricity (mostly from coal powered plants). They will get what they want no matter how loudly you complain.Response: We'll have to agree to disagree on your two key points:
"warming is more beneficial than a cooling trend would be"
The full body of peer-reviewed research indicates the negatives far outweigh the positives, particularly for the poor and vulnerable countries least equipped to adapt.
"you believe that the main factor driving Global Warming is the rising CO2 levels in the atmosphere brought about by industrialisation and rising human populations"
I wouldn't characterise it as 'belief', this is not a matter of faith. I'm convinced by the multiple lines of empirical evidence. That rising CO2 levels is the main factor is directly measured by satellites and surface measurements that find CO2 is trapping heat and the amount of heat trapped (in other words, the radiative forcing) is greater than any other radiative forcing. This is confirmed by a number of independent human fingerprints on climate change. -
gallopingcamel at 14:46 PM on 7 August 2010Grappling With Change: London and the River Thames
doug_bostrom, (#39) The filibuster only exists in the US senate. A simple majority gets the job done in the House of Representatives. Some people think that a super majority should be needed there too. Sorry, I won't do it again (stray "Off Topic"). -
gallopingcamel at 14:34 PM on 7 August 2010Grappling With Change: London and the River Thames
Michael Sweet (#44), One has to look at the artificial dunes along the Dutch coast to get a feel for the huge scale of what the Dutch have been working on for centuries. Dunes over 25 meters high and running as far as the eye can see. Where rivers emerge into the sea, vast gates are in place to prevent water flowing in the wrong direction. You really have to see it to understand what has been achieved. You are probably right to suggest that creating similar structures to protect Florida may not be an attractive proposition. The perimeter may be too great in relation to the land area to be protected. -
gallopingcamel at 14:19 PM on 7 August 2010Grappling With Change: London and the River Thames
doug_bostrom, Please accept my apologies for encouraging the discussion of something totally irrelevant (individual and economic freedoms). In the past you have often directed me to a more appropriate thread when I stray from the theme. Even though we are clearly from opposite sides when it comes to politics, you may find that we often agree when it comes to actions for protecting the environment. -
johnd at 11:58 AM on 7 August 2010Confidence in climate forecasts
JMurphy at 10:55 AM, whilst the example I have linked to is focused more on seasonal outlooks, and at the moment the results are unusually reasonably well aligned, a check back through the recent archives will demonstrate just how much variation different GCM models can produce in their results. Over a period of time most observers will focus more closely on the results of one model rather than the combined results which more often to not becomes meaningless, especially when the range of results amongst all the models are wide. Personally I believe the experimental coupled GCM from SINTEX JMA of Japan is the most accurate, more so then the combined results of the ensembles. About 3 years ago it went completely against ALL other models that were predicting an imminent and large La-Nina and was the only one to have gotten it right. Modelled Climate and Ocean Predictions on page 2 -
johnd at 11:35 AM on 7 August 2010Confidence in climate forecasts
doug_bostrom at 09:43 AM, a couple of points should be considered. One is that climate modeling, though based on known physics and accumulated data is reduced to combining a number of interacting mathematical equations that is supposed to represent real world conditions, and then project them forward. As many tutors of mathematics will possibly agree, when the expertise of the students (modelers) is examined, it is not whether or not the class as a whole arrived at similar conclusions that matters, but who within that class made all valid assumptions and got the calculations into the correct relationship that determines the validity of the overall equation and the overall result so determined. A number of incorrect assumptions that may end up balancing each other out does not validate each of the processes, but that is what is being asked of us by taking the combined output of a number of different models as being a valid conclusion. Another point is that whilst mathematics is a precise science when dealing with absolute values, when real world data is introduced, the values come attached with varying degrees of margins of error. When such values are being used to establish trends, the margins of error are going to be magnified, increasing the further forward the projections are being made to the point the margin of error makes the projection useless. Therefore it is incumbent upon the modelers to ensure that their inputs and assumptions are free from such errors. Given various models assume different values and inputs, rather than giving more confidence that the science is settled, it only confirms the division that exists. Once we see that the number of models tracked by the IPCC being reduced as the assumptions being made in each are either validated, and so must be incorporated into all other models, or proved invalid so rendering the model itself invalid, then perhaps we can see greater confidence in climate models justified. As I watch the football each week, Aussie rules that is, I am reminded often that the team whose game plan is correct, and whose goal kicking is very precise with very few misses, are at times overrun by an opposition with a muddled game plan and atrocious goal kicking, but one that wins the game because the sheer weight of errors in kicking for goal still resulted in sufficient minor scores to scrape a win. Knowing some such footballers from my schooldays, they had as much trouble explaining how they may have inadvertently produced the right result in maths examinations as they have explaining how they happened to muddle their way to a win on the field. -
JMurphy at 10:55 AM on 7 August 2010Confidence in climate forecasts
johnd wrote : "Whilst the IPCC confines itself to tracking 20 something climate models there are countless other climate models from which they could have chosen." "Perhaps one of the models does accurately track the past and the present, and accurately project into the future, but which one? Only one can be absolutely right, but by being right it then invalidates many of the assumptions made in all of the other models. The only other alternative is that none are right." You should read what the IPCC actually do with the output of the models : Ensembles of models represent a new resource for studying the range of plausible climate responses to a given forcing. Such ensembles can be generated either by collecting results from a range of models from different modelling centres (‘multi-model ensembles’ as described above), or by generating multiple model versions within a particular model structure, by varying internal model parameters within plausible ranges (‘perturbed physics ensembles’). In order to identify errors that are systematic across models, the mean of fields available in the [Multi-Model Data set], referred to here as the ‘multi-model mean field’, will often be shown. The multi-model mean field results are augmented by results from individual models available as Supplementary Material (see Figures S8.1 to S8.15). The multi-model averaging serves to filter out biases of individual models and only retains errors that are generally pervasive. There is some evidence that the multi-model mean field is often in better agreement with observations than any of the fields simulated by the individual models. Ch 8, Climate Models and Their Evaluation The use of ensembles of AOGCMs developed at different modelling centres has become established in climate prediction/ projection on both seasonal-to-interannual and centennial time scales. To the extent that simulation errors in different AOGCMs are independent, the mean of the ensemble can be expected to outperform individual ensemble members, thus providing an improved ‘best estimate’ forecast. 10.5.4.1 The Multi-Model Ensemble Approach And, looking at the number of countries that were involved, it's difficult to see how many other models they could have looked at or used. Do you have any suggestions ? -
More evidence than you can shake a hockey stick at
James - Fantastic. I get tired of the "buried in bull" arguments, great to see such a large collection of actual data, with sources no less. Sometimes, when I'm feeling masochistic, I post something about actual data on JoNova's site. Then I go hide until the spittle level dies down... -
Bern at 09:56 AM on 7 August 2010More evidence than you can shake a hockey stick at
James, that's excellent. The powerpoint slides will come in handy, too, thanks. -
Doug Bostrom at 09:43 AM on 7 August 2010Confidence in climate forecasts
JohnD inadvertently presents an argument indicating the reasonably good utility of models we use. Outputs cluster reasonably well around a pattern of similar conclusions. The notion that variance among exact features of various model outputs is a mark of wholesale failure is actually diagnostic of misunderstanding on JohnD's part. Hypothesizing a myriad of other models does not serve as a functional argument indicating we should ignore the congruence among the models we actually do use. "Absolutely right" of course is not the metric used to determine if models are useful. Thus I think JohnD's endorsement of models is accidentally on the mark. Clouds are a bit of a wildcard but progress is in fact being made in that department and meanwhile folks with more expertise than JohnD (or myself) don't seem paralyzed by the fear that they're going to overturn current thinking. Helps to remember, the folks doing the science are way more circumspect than us in the peanut gallery. -
Jim Powell at 09:25 AM on 7 August 2010More evidence than you can shake a hockey stick at
Line 4 should read "...on the evidence..." -
LewisC at 09:03 AM on 7 August 2010Three new studies illustrate significant risks and complications with geoengineering climate
batsvensson - there's also the factor of first presentation. When Creutzen proposed using sulphates as a replication of volcanoes' emissions with their proven cooling effects, there were only bizarre space-mirrors, etc, and ocean fertilization under discussion, so his seemed like a great idea and, (with the aid of coal-burners who foresaw a cost saving) it gained a lot of traction. In reality, regardless of popular assumptions, sulphates are not the automatic choice as distinctly preferable options have since come into view. Yet this is not to criticize Creutzen, who knows full well the potential catastrophe of the runaway feedbacks - against which even serious global sulphate pollution would be relatively small beer. Regards, Lewis -
johnd at 08:46 AM on 7 August 2010Confidence in climate forecasts
Whilst the IPCC confines itself to tracking 20 something climate models there are countless other climate models from which they could have chosen. All of the modelers have access to the same range of data available as inputs, as well as, hopefully, the same knowledge of "known" physics as well as "unknown" physics, the big one of course being clouds, feedback in particular. Given that the output of most models differ to varying degrees, there are obviously variations in the assumptions being made by the modelers as to the combination of inputs and the relative importance, or weighting, each of the parameters are given in the equations that the model constitutes. The fact that each model differs somewhat is indicative that there is still a large degree of uncertainty and a wide range of opinions as to how all the known physics relates to the real world, and what all the collected data really means. Perhaps one of the models does accurately track the past and the present, and accurately project into the future, but which one? Only one can be absolutely right, but by being right it then invalidates many of the assumptions made in all of the other models. The only other alternative is that none are right. Given that the physics of cloud feedback is still an extremely large unknown, it is just as likely that a model that incorporates negative feedback into the equations has as much chance of being right as those which model positive feedback, given it is not known physics, but opinion only that is the determining factor in the face of such unknown physics. -
Doug Bostrom at 08:38 AM on 7 August 2010Greenland's ice mass loss has spread to the northwest
In the Northwest of Greenland, just another data point: An ice island four times the size of Manhattan broke off from one of Greenland's two main glaciers, scientists said on Friday, in the biggest such event in the Arctic in nearly 50 years. The new ice island, which broke off on Thursday, will enter a remote place called the Nares Straight, about 620 miles (1,000 km) south of the North Pole between Greenland and Canada. The ice island has an area of 100 square miles (260 square km) and a thickness up to half the height of the Empire State Building, said Andreas Muenchow, professor of ocean science and engineering at the University of Delaware. Muenchow said he had expected an ice chunk to break off from the Petermann Glacier, one of the two largest remaining ones in Greenland, because it had been growing in size for seven or eight years. But he did not expect it to be so large. "The freshwater stored in this ice island could keep the Delaware or Hudson Rivers flowing for more than two years," said Muenchow, whose research in the area is supported by the National Science Foundation. "It could also keep all U.S. public tap water flowing for 120 days." He said it was hard to judge whether the event occurred due to global warming because records on the sea water around the glacier have only been kept since 2003. The flow of sea water below the glaciers is one of the main causes of ice calvings off Greenland. More. U. Delaware release here, includes imagery. -
Doug Bostrom at 08:29 AM on 7 August 2010Three new studies illustrate significant risks and complications with geoengineering climate
Because they're desperate, batsvensson. The exact nature of their desperation varies from case to case. One person might want to continue a lifestyle, another an income stream, yet another may be concerned about other problems and failing to think it all the way through. Or a mixture of all three. -
Doug Bostrom at 08:25 AM on 7 August 2010Waste heat vs greenhouse warming
I will do more research before posting further. A contrite acknowledgment from VoltairesDistantCousin that ought to be exemplary, could well stand some emulation. Has the level of rational debate degenerated so much that we are having skirmishes over basic facts such as this? Actually it's much worse than you may think. Read through ~200 comments and you'll get the picture. -
batsvensson at 07:44 AM on 7 August 2010Three new studies illustrate significant risks and complications with geoengineering climate
Why would anyone sane like to suggest to pump something we been working very hard to get rid off for very well known reasons into the atmosphere? -
GeorgeSP at 07:40 AM on 7 August 2010Has Global Warming Stopped?
The analysis of Fdykstra doesn't seem proper to me. Of course, if one adds extra variables, the R2 increases - by definition. R2 should only be interpreted if several models have the same number of variables - without any multicollinearity and heteroscedasticity. Representing a number of observations with any line is no science. The error he mades is that R2 should only be used if one has a theory (explanatory mechanism whatsoever) to be tested - whereas in this case the analysis is aiming at observation - is it getting warmer or not. R2 is then unnessecary - significance level is the only relevant thing and as remarked before, the 5 or 10% significance level is a convention. It are the outer parts of the normal distribution for the number of times somethings is happening. And, as Phil pointed out, the time span is too short to fall within the outer borders of any significance level. I guess that some denialist with good statistical knowlegde has given this question to the reporter. Because everyone knows that the period is short in proportion to the increase of temperature. But Phil gave the possible answer and he stayed within the right area. Right he was, regarding the guns that were targeting him. He couldn't permit any mistakes. -
tobyjoyce at 07:29 AM on 7 August 2010Remember, we’re only human
daisym @43, "The U.S. government seems hell bent on passing Cap and Trade but, without a full-time alternative energy source, how would it force manufacturers to stop using carbon fuels?" If that is a true statement, then why was the Power Bill dropped in the US Senate, without a vote, and without a squeak from the White House? In the 1980s and 1990, "Cap and trade" was touted as the "free market" solution to pollution and global warming. Now it is derided as "cap and tax" and is ideologically off-limits for any aspiring Republican politician, and many Democrats. I thought Jim Hansen has a good proposal in his book Storms of My Grandchildren. This was for a carbon tax to be paid at the point of extraction or import of carbon fuel. The tax would be paid as a dividend to taxpayers, which they could spend as they please (on carbon fuel, for example, if they so wished, but then they gain nothing). An alternative would use the money collected to offset payroll taxes, thereby creating jobs. This version has been adopted in British Columbia, and is working well. Carbon Tax Cap and trade just has too many complexities. Cap and Trade -
VoltairesDistantCousin at 07:13 AM on 7 August 2010Waste heat vs greenhouse warming
Ned, BP: My apologies. Temperature does increase in the stratosphere due, I think to ozone's absorption of UV radiation. I was too quick with my correction. I will do more research before posting further. -
Doug Bostrom at 07:11 AM on 7 August 2010Talkin bout the Skeptical Science phone apps
Buying by scanning? That's nothing; I've been buying by impulse for years now! -
MattJ at 07:03 AM on 7 August 2010Talkin bout the Skeptical Science phone apps
Nokia phones? What about other Symbian phones? They are not all Nokia phones, you know. And as for buying by scanning, that is on both Android and iPhone now. Has been for a while, too. -
Mal Adapted at 07:00 AM on 7 August 2010Remember, we’re only human
BP:No, we are not just any remarkable species, one of millions, but spiritual and immortal souls, an absolutely unique kind, created in the image of God, given freedom and responsibility. We must remember that.
BP's belief, shared by billions, is at The Historical Roots of Our Ecological Crisis. I'm now convinced it's also at the root of his relentless denial of AGW. -
Jim Powell at 06:51 AM on 7 August 2010More evidence than you can shake a hockey stick at
Thanks for this posting, John. The sources of the slides, the script, and a PowerPoint set for the video can be found at my website. As John anticipated, several commenters on ClimateProgress and YouTube noted that I did not spend much time, or any time, or the evidence that humans have caused global warming. But I did cover that in the slide that starts at 1:27 of the video with the chart of carbon emissions, CO2 concentrations, and global temperatures from the Arctic Climate Impact Assessment. I also discuss the significance of that chart on my website.
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