There are some interesting questions being posed at the Which Climate Change Consensus? (Part 2) thread. Following are two questions from Graham Young that interests me. They seems to have been lost amongst the more general policy and economic discussion about Kyoto.
David,
Your quotation from the MIT piece illustrates the problem that you have with your models. You say “a projected 18 percent increase [in CO2] resulting from fossil fuel combustion to the year 2000 (320 ppm to 379 ppm) might increase the surface temperature of the earth 0.5C”. Now CO2 is at 380 ppm and you are claiming a rise in surface temperature of 0.5 degrees.
So far, so good, but as we know that temperature of the earth can and does vary independently of CO2 concentrations, how do you know that the rise was due to CO2 alone? And if it wasn’t, then in fact you may have overshot or undershot by more than the 0.5 degrees. If you overshot, your modelling was completely unsuccessful, and if you undershot, then things are a lot worse than you thought.
The IPCC graph at http://www.grida.no/climate/ipcc_tar/wg1/figspm-4.htm is interesting.
It shows general trends between model and observations reaching more or less the same end point, but with significant divergences along the way. You’d probably get a better feel for this by graphing a rolling average.
But you might well be getting this result by massaging the factors that are programmed in until you get a reasonably good fit, but without those factors necessarily being the right ones if you are missing some ingredients.
I’ve gleaned some of my information from the graphs that Jennifer put up on the site on the 28th November. While you’re explaining your models, could you please tell me what the mechanism is that makes temperature dive just after the peaks in CO2 shown in those graphs?
Graham Young
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Graeme – “While you’re explaining your models, could you please tell me what the mechanism is that makes temperature dive just after the peaks in CO2 shown in those graphs?”
Some of them are just anomolies. Some of them are volcanic eruptions etc. Also at the lower level of CO2 forcing then solar sunspot cycles had a larger influence. AGW forcings however are now ovewhelming these forcings and producing the present steep climb.
Ender, Are you suggesting the next ice age might be just an anomoly?
Jennifer – no the next glaciation that we are actually overdue for will not be an anomoly at all. However if we continue adding to the warming of the planet at this time we may tip the planet into an entirely new climate regime for thousands of years.
A few questions:
1. What has caused previous glaciations?
2. What might cause the next glaciation?
3. How does/should the IPCC deal with the idea that there will be a next ice age?
When I was studying insect evolution, I just accepted climate change. I didn’t bother too much with mechanisms driving climate change. I was interested, rather, in the mechanisms driving speciation, given climate change.
Jennifer – here is a reasonable explanation of Milankovitch cycles that are thought to drive past and future major glaciations.
That post that I asked you to post in for me contains what I think we should do. A low level of fossil fuel use should provide a heat blanket that may stop the worst of the glaciation.
Jen – forgot the link
http://www.aip.org/history/climate/cycles.htm
Jen – I will try again with the link I forgot
http://www.aip.org/history/climate/cycles.htm
Jen
Orbital variations are thought to be the Ice Age mechanism. There are 3 methods of variation.
Read this short description of Ice Age mechanism theory. Then read Hollan and Berger refs. The regular 10,000 year interglacial notion from the last few periods does not have to persist into the future as you can see. We are 10,000s of years from another Ice Age. Not even on the radar according to below:
http://www.ncdc.noaa.gov/paleo/milankovitch.html
Astronomical calculations show that 65N summer insolation should increase gradually over the next 25,000 years, and that no 65N summer insolation declines sufficient to cause an ice age are expected in the next 50,000 – 100,000 years ( Hollan 2000, Berger 2002).
Jen,
Geoscience have no explanations for Ice ages at present, just loosely thought out ideas.
Milankovitch cycles are irrelevant if the LIA is considered, and that was not a ice age but a little ice age where people froze their butts off and could not bury their dead (in Greenland).
That is now interpreted to be the result of the earth probably passing through a meteor swarm, as hinted by the Choson Annals.
Louis – that’s really a very glib one-liner with zero critique – pity about all the paleo data supporting orbital theory – read Ender’s post.
Louis – it appears that John Zillman for one believes in an impact from the “greenhouse effect” – a scientist of some renown also endorsed by Ian Castles.
Of some help perhaps for the lead to this thread from Graham Young:
Graham
On the CO2 warming – see if below helps.
http://www.realclimate.org/index.php?p=220 helps.
Timely new RC post.
On “massaging of factors” – true if they did – but they did not. You only get a match with the record if you include all forcings. These are physics models not statistical regressions.
On your last point about “CO2 peaks” – my answer would be orbital mechanisms changing the amount of energy received from the sun or solar influences.
Phil, a one liner critique is fact WE DO NOT KNOW.
What is your problem?
Louis – there is a substantive case listed by myself and Ender – which you has not provided any critique of at all. Wouldn’t it be convenient to waltz around saying we don’t know to anything in life we don’t care for. This is your new style as a professional Editor ??
Incidentally why do think we laughing about this one “How do we discern a plant CO2 from a oil or coal CO2? ” – no help Ender – we’ve told him before.
Phil,
Thanks, now how about a scientific rebutall than a cheap shot?
Your joint effort as a rebuttal are standard explanations, in another word, plagiarism.
How about you and Ender saying yourselves what caused the last glaciation?
As Jen asked.
Explicitly quoting another source from another institution is now plagiarism. hmmm.. .. OK .. yep .. aha
“Louis – there is a substantive case listed by myself and Ender”.
OK Phil, present it.
I seem to have missed it.
Louis – that’s really a very glib one-liner with zero critique – pity about all the paleo data supporting orbital theory – read Ender’s post.
Ender’s post refers to :http://www.aip.org/history/climate/cycles.htm
A biassed site if there ever was one.
Look above – 2 urls, and other authors quoted from the urls
Phil, it is quite clear from the material that the models do not run on pure physics and they do massage factors to try to get a good fit. If they knew everything the fit would be perfect and they wouldn’t have to keep running simulations to see how close they get. The more I read about climate modelling the hollower David’s claim of superiority over the extrapolations appears. Data appears to be being manipulated in both types of modelling.
You and David are pretending to a much higher degree of accuracy than is actually possible at the moment.
No-one has yet answered my question as to how it is that temperature has historically declined quite rapidly even though CO2 has been at high levels. If you read the material that Ender provided http://www.aip.org/history/climate/cycles.htm it claims that the Milankovitch cycles on their own aren’t sufficient, but that it requires forcing agents like CO2 to create the observed results. But if that is true, for me it makes it even more mysterious that the temperature drops even while CO2 is peaking. But perhaps Ender’s material is deficient? Ender might like to comment.
The American Institute of Physics is a biased site. hmmm .. .. OK .. yep
Does Louis hold a binary vision of everything in the world as either “Natural” or “Other”?
I really don’t understand “keep running” simulations. They have simply shown that single factors alone do not reasonably explain the temperature trend. It’s an elegant experiment.
“Data appears to be manipulated” – it does ? how so?
We are not claiming the models are perfect. They are an experimental tool and most useful for some applications. The analyses are included to show that the models driven with the appropriate forcings represents quite well the pattern of temperature development of the last 100 years.
It’s just 1 of a 100 aspects. Talk to climate modellers and they’ll show you model performance and issues on all sorts of tests and representations of the real world. IPCC are simply quoting a single very relevant result.
On ice age issues. The theory is that an orbital change increases warming and volatilises CO2 from oceans and the biosphere. The CO2 rises sharply but after the temperature. When the orbital forcings change the CO2 warming feedbacks from radiation received are not as strong and CO2 returns to the biosphere and oceans. More slowly than it rose.
Of course there are probably other interplays over this like volcanoes and changes in solar output.
http://www.realclimate.org/index.php?p=13 discusses better than myself.
Graham; as I said privately I don’t give a damn about the models used to explain rising temperatures, CO2 or what ever else we can find on the web. Experience elsewhere has taught me undercurrents act as lags in any system and chaotic energy can be hidden for ages. In all temperature calibration we ever did, waiting a reasonable time for the correct answer becomes pure guess work.
To achieve homogeneous mixing for ICI paint research here in the 1960’s we built our tiny but very high speed agitators in a beaker only in time to discover Silverstone had commercialised their research models in the UK before us. Appropriate mixing before measurement was a universal problem in all modelling back then.
This is an experiment you can all do at home. Grab any thermometer, a bucket of hot water and some ice blocks and try to average that bucket over time. Then repeat the same test after a quick stir with your stab mixer every two minutes. Try again but use the mixer to grind the ice first. Coloured ice is even better.
I bet we each have a different model for starters, but the real issue is what we can see overall.
Note; all the above is much more exciting in a large system where controlling Ph in the volume of water was by using pure acid in a variable stream from a tap. Early mixing provided some surprises.
I should add; for the above reasons I believe our transition to new energy levels on the earth’s surface will be an interesting ride.
So essentially the Taz you are suggesting we can’t model anything fluid or atmospheric where feedbacks and non-linear interactions might be occurring?
Graham – “But perhaps Ender’s material is deficient? Ender might like to comment.”
My material is surely deficient. Perhaps you can ask this of the Real Climate team as it is an interesting question. I answered to the best of my ability. That link I gave is really interesting and I posted my first answer before fully reading it. I was going to post a link to Jim Hansen’s recent work however I cannot find it. If you email me I can send you the PDFs that I have.
“it is quite clear from the material that the models do not run on pure physics”
If they do not run on physics what do they run on. As far as I know they use Computational Fluid Dynamics to model the atmosphere which is a very established branch of physics that is used from modelling aircraft to water flow in drains.
Perhaps some consideration of what the climate models are might be worthwhile:
http://en.wikipedia.org/wiki/General_circulation_model
http://www.metoffice.com/research/hadleycentre/models/modeltypes.html#AGCM
http://www.cgd.ucar.edu/
http://www.giss.nasa.gov/research/modeling/gcms.html
Taz’s example is simple.
Modelling fluid dynamics when the flow is laminar is possible, Navier-Stoke’s equations etc.
When fluid flow reaches turbulence and becomes involved with non-linear processes, it cannot be modelled.
In geophysical exploration the instant we get non-linear feedbacks or drifts in instrumentation, usually from electromagnetic background inputs, the operation stops. No one has been able to model non-linear data. To us it means exploration success and if we could model non-linear data, we would have done so a long time ago.
This is why climate cannot be modelled – it is a combination of a turbulent system (the atmosphere) plus non-linear feedbacks.
This is why sceptics are so sceptical of the climate predictions, because it isn’t possible.
Ender, unlike many (most?) on this blog, I use my real details, so the email address that comes with my name will work.
It’s obvious that the models don’t run on pure physics because there is so much variability between the models. Many of the parameters appear to be manually specified, but just because the operations after that are purely mathematical, it doesn’t absolve the model from the initial guess. And the guesses appear to be fine-tuned so that they equate to reality. Which is fine, except how do we know that another combination wouldn’t have given the same answer? In other words, agreement might be accidental, as it could be with the statistical models.
Wikipedia tends to confirm this when it says: “Three (or more properly, four) dimensional GCM’s discretise the equations for fluid motion and integrate these forward in time. They also contain parametrisations for processes – such as convection – that occur on scales too small to be resolved directly.
Atmospheric GCMs (AGCMs) model the atmosphere and impose sea surface temperatures. Coupled atmosphere-ocean GCMs (AOGCMs, e.g. HadCM3, EdGCM) combine the two models. AOGCMs represent the pinnacle of complexity in climate models and internalise as many processes as possible. However, they are still under development and uncertainties remain.
Most recent simulations show “plausible” agreement with the measured temperature anomalies over the past 150 year, when forced by observed changes in “Greenhouse” gases and aerosols, but better agreement is achieved when natural forcings are also included [1] [2].”
I don’t have a problem with the concept that increased CO2 equals higher temperatures. I just have doubts about the ability of anyone to measure effectively because of the complexity and chaos involved in what we are trying to model. In which case one is thrown back on history and what has historically been the case. This is good enough to work out the risk inherent in the scenario and therefore what one should do about it.
I have a fair bit of experience in modelling of financial systems, which perhaps biases me against climate modelling. The bottom line with financial models is that when they are right, it is often for the wrong reasons. Back of the envelope calculations and heuristics often give the best results.
The complexity of the climate modelling probably detracts from serious debate on this issue rather than illuminating it.
Would a back of the envelope calculation work through the polar amplification story in http://www.realclimate.org/index.php?p=234
One of many such examples.
Graham – “The complexity of the climate modelling probably detracts from serious debate on this issue rather than illuminating it.”
You are probably correct however some people use the uncertainly of models as proof that scientists have AGW wrong as if the ONLY proof of gloabl warming is the GCMs.
Again the distinction needs to be made about AGW and climate change. AGW is pretty well proven science however climate change prediction does depend on somewhat inprecise models. The best anyone can do is give ranges of possible changes and scenerios. This is what most responsible scientists do.
It’s sad that only two people picked up on my simple model. No one tried it? That’s so disappointing to say the least.
Some where in the many threads on climate change, I asked our experts here if the mass of ice parked on land in the Antarctic initially behaved differently to the Arctic which is shown as a red hot anomaly in one of the recent graphs, due to its isolation from the sea.
Given that I have forgotten more physics than most here, a prompt elsewhere on Polar Amplification makes it necessary for me to stress the ice bucket test again.
The ice/water barrier is a pretty big hurdle in physics. Another is turbulence, then there is disrupted system feedback, lag and so on .
In my work with many real systems using water, sludge, webs, gas, fire etc, I developed practical shortcuts based on any local knowledge of a process rather than theory to prove errors and anomalies. I could pick up more clues directly from our plant operators than I could from our designers. Commissioning these monsters was always an art not a science.
We have our differences built in. There is no language to describe my methods because I switched off that part of my brain ages ago particularly for understanding the physical. As I got deeper into my practice the conflict between the verbal and the visual became intense. For me spatial analysis was instinctive. I can navigate round a large bushfire in rugged country in the dark without a torch or compass. Those who relied solely on their OH&S training could not follow.
But we can each be what we want to be by determining how our brain develops it connections. Thinking in the right directions does just that. How? By neurones and dendrites building a web. I could watch my late wife grow them in a Petri dish for some scientist every day.
That’s modelling!
I could also say, we see only what we want to see and that’s sad too
The above post was a rough attempt to outline some problems in integrating many ideas from various disciplines and experiences. If we are ever bound by an agreement it is most likely to come from an accident where everything was scrambled.
To get a revolution in our collective practice we need an explosion under the controls
This time I’m aiming at the economists. How flexible are we at the top?
On Arctic/Antarctica differences – yes experts do expect different behaviour intially and the Arctic to warm faster. Southern Ocean is the key. Also the circumpolar vortex seems to have intensified walling the continent off somewhat. I know everyone will groan saying – oh so warmer now = colder blah blah.
Can I file online?
Here it is possible to have a rest very well.
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