In the same way* that accuracy on the gun range can be expected to improve as distance from the target increases, or that small errors in interest charged disappear when the sums they are applied to go over the million dollar mark….
“Projecting changes in climate due to changes in greenhouse gases 50 years from now is a very different and much more easily solved problem than forecasting weather patterns just weeks from now. To put it another way, long-term variations brought about by changes in the composition of the atmosphere are much more predictable than individual weather events.” [from page 105, 2007 IPCC WG1]
… must model more processes than in a weather model (such as biogeochemistry of vegetation on land and plants in the ocean; sea ice dynamics; aerosol processes; ocean circulation; ground freezing and thawing; snow accumulation and melt and sublimation, etc. – see). For some of these climate processes (which involve physics, biology and chemistry) they are modeled, as with a weather model, by a dynamical core and by parameterizations. These include sea ice dynamics and ocean circulation, which both have advection, pressure gradient and gravitational parts, as well as the parameterization of other effects (such as turbulence, phase changes of water). Some of the climate processes, such as biogeochemistry and biogeography have no dynamical core, and are completely parameterized models.
Thus, a climate model involves more parameterizations with their tunable components than for a weather model, as well as additional new state variables (such as salinity, ice, snow, vegetation type and its root depth etc) for which initial conditions are required for all of these variables.
The climate model also has no real world constraint such as supplied by real-world initial conditions (and for a regional model lateral boundary conditions). This real-world data constrains its predictions. Instead, the state variables required for the dynamic core of each component of the climate model (i.e. the state variables for the atmosphere, land, ocean and continental ice) must be generated from the parameterizations!
The claim by the IPCC that an imposed climate forcing (such as added atmospheric concentrations of CO2) can work through the parameterizations involved in the atmospheric, land, ocean and continental ice sheet components of the climate model to create skillful global and regional forecasts decades from now is a remarkable statement. That the IPCC states that this is a “much more easily solved problem than forecasting weather patterns just weeks from now” is clearly a ridiculous scientific claim. As compared with a weather model, with a multi-decadal climate model prediction there are more state variables, more parameterizations, and a lack of constraint from real-world observed values of the state variables.
Thus concludes today’s scientific consensus moment.
Thankyou.
Vitruvius: Thank you. If we ever find ourselves in the same city at the same time the first beer is on me. However I suspect that you are right that we would find a lot in common in our views of the science of global warming so instead I would suggest a discussion of your list of 50 top documents. It is a fascinating list and while I agree with most, there are some others I would argue need to be included.
Regards,
John
Tenebris said: “Yoop – don’t expect definitive answers to your questions too soon”
Exactly. I wasn’t really expecting any because most answers that might be offered would not be constrained by acceptable parameters. I might expect some WAGs though.
Now, consider this. Those scientists (and I use that term somewhat loosely here) who would like us to immediately change what we are doing (I guess just because they say so) to stop AGW in it’s tracks cannot tell me what caused the last continental glacier to retreat.
Will those same scientists assure me that the solutions they now propose to solve AGW will not trigger another advance of continental glaciation, prior to that time in geologic history when the next one will advance anyway?
Can those scientists, who cannot tell me exactly what happened to the last one, assure me they won’t cause another one?
(Note: recognize that many of the more visible *done deal* proponents of AGW are not scientists nor engineers)
Imagine this: in the year 3007, no land inhabitable north of a line from Toronto to Fargo. In the year 4007 no land inhabitable north of a line through central Ohio, Indiana, Illinois and Iowa. All prior man-made surface features are gone: bulldozed and piled up in Columbus and Council Bluffs.
Here is my comment to my fellow earth scientists: “people, you are f**king with something you do not fully understand. You want me to stop and reverse global warming, but you CANNOT tell me at what average mean global temperature the next continental glaciation will be triggered.”
[You see, I am old and retired, so I can talk that way… 😉 ]
Yoop: Your questions seemed to be about North America and thus I was looking for something relevant (most of the temperature reconstructions I have seen are global). This appears to be relevant and good. Late Quaternary temperature record from buried soils of the North American Great Plains by Nordt (in the February journal Geology).
1) Why did this ice sheet melt and retreat? Due to a warming climate caused by Milankovitch cycles (enhanced by GHG warming).
2) What was the average mean temperature at approximately 12,000 ybp that caused the ice sheet to form? At 12,000 ybp the deglaciation was well under way. Best guess is that they started to form about 116,000 ybp. But answering your question, the mean temperature was about 1.2 C lower than today.
3) What was the average mean temperature at approximately 10,000 ybp that caused the ice sheet to melt? At this time the ice sheets were already well melted, but the average temperature was similar to current temperatures.
4) Over those 2,000 years what was the rate of change of the average mean temperature? Well, there was a lot of up and down but from the average in questions 2 and 3 from above about 0.6 per thousand years.
5) Was the rate of change in the average mean temperature between 12,000 ybp and 10,000 ybp linear or variable? Extremely variable (i.e variations of about 4C).
6) What was the carbon dioxide levels in the atmosphere at 12,000 ybp? About 259.6 ppm.
7) What was the carbon dioxide levels in the atmosphere at 10,000 ybp? About 254.6 ppm.
8) Was the rate of change in carbon dioxide levels over those 2,000 years linear or variable? Fairly linear.
9) Was that change in carbon dioxide levels between 12,000 ybp and 10,000 ybp caused by activities of man? No, although Ruddiman has suggested an anthropogenic change from about 7,000 iirc.
10) How does the highly variable rate of advance and retreat of that period of continental glaciation compare with the advance and retreat rates of glaciers that is being observed today? Over that period there was almost no advance but instead the glaciers were in full retreat. This is similar to current times where we see most glaciers in the world in retreat.
Now, let me ask you, what do you think this means to the current discussion of AGW. I am happy to agree that climate has changed in the past and always will change, the important point is that it must change because of a reason. Are you claiming the reasons then are the same as now?
Yoop: you said Will those same scientists assure me that the solutions they now propose to solve AGW will not trigger another advance of continental glaciation, prior to that time in geologic history when the next one will advance anyway?
From the IPCC AR4 (pg. 453) There is no evidence of mechanisms that could mitigate
the current global warming by a natural cooling trend. Only a strong reduction in summer insolation at high northern latitudes, along with associated feedbacks, can end the current interglacial. Given that current low orbital eccentricity will persist over the next tens of thousand years, the effects of precession are minimised, and extremely cold northern summer orbital configurations like that of the last glacial initiation at 116 ka will not take place for at least 30 kyr (Box 6.1).
So I would not expect an iceage to begin for another 30,000 years. The initiation for an ice age seems to be cooler summers in North America which allows ice to build up. There seems to be no way we could simulate this no matter what happens (baring some far out ideas such as solar shades).
Regards,
John
John Cross
I don’t agree with your logic (you ignore thermal inertia) but your results are actually quite close to what the IPCC gives. Now, in addition to your temperature rise of 1.8C from CO2, estimate the increase due to water vapour (hint, look at the water vapour saturation levels at say 15C and 16.8C).
So you don’t agree with my logic, ok. The arguement up to that point had been that CO2 was the major driver, no apparent need to consider H2O or anything else. The whole AGW bandwagon runs on CO2 inflated tires. I did say that the figures given were with all other things being equal and that those things were not equal.
As for agreeing with the IPCC, yes, the CO2 at 900ppm or so satisfies their busienss as usual scenario. The 1.8 degrees satisifies their massive reduction in CO2 scenario. The IPCC Fourth Assessment Report, Working Group III predicts 660 – 790 ppm by 2060 with a temperature increase of 4.9 to 6.1 degrees C over preindustrial. They predict 350 – 400 ppm by 2015 with a temperature increase of 2.0 to 2.4 degrees C. So yes I agree with the IPCC sort of, if you cherry pick numbers from charts.
How are you using the term thermal inertia?
John,
The difference of 5 ppm between your answers to question #6 and question #7 would (guessing here), fall pretty close to the error limits of that particular applied geochemistry. Therefore, probably can assume relatively the same levels pre and post continental glaciation. What does that mean?
In conclusion you said: “Are you claiming the reasons then are the same as now?”
For the most part, yes. I see no definitive proof that they are not the same reasons. Besides, I see no place within the formulations offered/used by the pro-AGW crowd for the insertion of events common to the *chatoic and unpreditable* nature of geologic events within the earth’s history. For instance the effects of vigorous and sustained volcanic eruptions.
In your next post you reference this comment: ‘From the IPCC AR4 (pg. 453) There is no evidence of mechanisms that could mitigate
the current global warming by a natural cooling trend.’
Again I will point out the obvious, which is exactly what scares me in the assumptions made by the *authors*. Absence of evidence is NOT evidence of absence.
In my long career in an *applied* section of the earth sciences I have seen this to be correct too many times to not to be sceptical of people who are *so absolutely sure of their beliefs*. As far as I am concerned this is NOT a settled science, and those adherents who belive that it is are VERY scary.
In fact, I made a good sum of money just because a fairly large number of highly experienced, diverse scientists said that there was definitive proof that something could not, and did not, exist in a certain area. They were all wrong. 🙂
In an earlier post you reference this paper: “In regards to implications for Canada, this paper is an interesting read: Long-Term Aridity Changes in the Western United States by Cook et al.”
Here is a link to an INTERESTING take on some problems with that paper
http://www.worldclimatereport.com/index.php/2004/10/18/a-tale-of-two-records/
I guess we will just have to agree to disagree. I do not see anything offered yet by the AGW adherents that is *settled science*. Settled politics, yes. Settled grant monies, yes. Settled science (in the true sense of *science*), no.
jnicklin: The argument has always been that a temperature rise resulting from CO2 will cause a rise in water vapour which will increase the warming. It is acknowledged that water will have the larger warming effect.
By Thermal intertia I mean that the climate takes a while to respond to changes. If we were to magically stop CO2 production today, there is still enough inertia in the system so that warming will continue for about 50 years.
John Cross
You said “In regards to implications for Canada, this paper is an interesting read: Long-Term Aridity Changes in the Western United States by Cook et al.” in response to my question “What harm has global warming caused to Canada? Are you refering to the massive retreat of ice 10000 years ago that made it possible for us to live here? So far I haven’t seen any downside to the current warming.”
Long-term aridity changes in the USA may have implications or may not, my question was and is what harm has global warming made in Canada. I’m not looking for predictions, you said in an earlier post that harm has already been done. If so, please tell me what harm and where.
Yoop: I am still confused about how you use the term continental glaciation. You define the start of glaciation as 12,000 ybp and the end of glaciation as 10,000 ybp. I don’t accept these values. Do you have a reference?
Thanks for the link to the WorldClimate Report. Of course its entire analysis is based on MBH99. Are you telling me that you accept this as accurate?
Reagrds,
john
Jnicklin: I am not aware of saying that harm has already been done. Can you direct me to the post. It may have been poor writing on my part, that made you think I said something like that. If not, and I actually said that I may have to eat my words. Won’t be the first time.
Regards,
John
John Cross,
Here’s your statement:
“However I will note that I do not think that it has been shown that Kyoto will cause economic harm to Canada (at least not with the same rigor that global warming has).”
You may have used some bad tenses and I may have misunderstood your meaning.
John said:”I am still confused about how you use the term continental glaciation. You define the start of glaciation as 12,000 ybp and the end of glaciation as 10,000 ybp. I don’t accept these values. Do you have a reference?”
I should have been more specific. Of course the Pleistocene lasted much, much longer than that. I was mainly looking at the late Pleistocene and the surges and retreat of the Wisconsinan glacial stage, which was the last major advance of continental glaciation on the North American continent, and that for which we have the most observable data. Any good reference on Pleistocene geology will give you the details. Carbon dating indicates that final retreat is set at 10,000 years carbon-14 dating before present. I picked the start of that surge as the end of the Sangamon interglacial stage (approx. 100,000 ybp) but somewhat arbitrarily picked 2,000 ybp as the final major surge of the Wisconsian lobe through southern Canada and the upper mid-western US. I could be wrong by a year or two, but not by much… 😉
“Of course its entire analysis is based on MBH99. Are you telling me that you accept this as accurate?”
No more, nor less than anyone else’s analysis. Interesting, is it not, how so many diverse entities can gain so many different inferences from the same data set.
I do think I am done. This thread has gotten too long now. And, tomorrow, another will start on the same subject. And nothing will change…
John said:”I am still confused about how you use the term continental glaciation. You define the start of glaciation as 12,000 ybp and the end of glaciation as 10,000 ybp. I don’t accept these values. Do you have a reference?”
I should have been more specific. Of course the Pleistocene lasted much, much longer than that. I was mainly looking at the late Pleistocene and the surges and retreat of the Wisconsinan glacial stage, which was the last major advance of continental glaciation on the North American continent, and that for which we have the most observable data. Any good reference on Pleistocene geology will give you the details. Carbon dating indicates that final retreat is set at 10,000 years carbon-14 dating before present. I picked the start of that surge as the end of the Sangamon interglacial stage (approx. 100,000 ybp) but somewhat arbitrarily picked 2,000 ybp as the final major surge of the Wisconsian lobe through southern Canada and the upper mid-western US. I could be wrong by a year or two, but not by much… 😉
“Of course its entire analysis is based on MBH99. Are you telling me that you accept this as accurate?”
No more, nor less than anyone else’s analysis. Interesting, is it not, how so many diverse entities can gain so many different inferences from the same data set.
I do think I am done. This thread has gotten too long now. And, tomorrow, another will start on the same subject. And nothing will change…
A quality AGW discussion here on sda. It is what the world needs. Way to go !!
Never seen it in the Toronto Sun or most other Canadian Media outlets.
I realize that the Kyoto Kroud will always keep using the ‘this-time-it-is-different’ argument. New paridigm, and all that.
Ya ya, the climate has changed in the past, but this man-made one will be worse. Why ? Because. Stop questioning it. Watch AIT.
When a situation is ,initially at least, hard to prove either way, proponents will often inject the ‘its-different-now’ take on the subject.
Has been used in the past. Sometimes innocently. Often intentionally, to further one’s cause or $$$s.
The truth will eventually come out-in-the-wash, always does. Too bad that some bystanders will also take a bath.
Nasdaq overheated at 5000 in 1999 ?? Naw, it’s different now, pundits would ensure us on CNN. New paradigm. Will double again by 2007. Came out in the wash (bath) at 2500 … not 10,000. Were the CNN pundits punished ??
Franken foods. Organics have caused a few deaths, not GMOs. Were the greenpeacers punished ?
Will the DDT ban croud be held responsible for millions of malaria deaths ??
Be cautious, be prudent .. yes. There are real dangers out there. But be wary of the fearmongers and the ‘its-different-this-time’ crowd.
jnicklin: yes, poor wording on my part. I meant that the premise that Kyoto would cause harm to Canada has not been as rigorously addressed as the premise that adding CO2 to the atmosphere will cause temperatures to rise. Sorry for the confusion.
ron: Just to keep the record straight, I will never ask you to watch AIT! I will use the “it is different now” argument but I am always willing to back up the “it is different” with “why it is different”.
Regards,
John
Fair enough, John.
As Patrick Moore often says, things are rarely black and white, but shades of gray.
Tobacco was a case of only black. The industries actions were unforgivable. An attempt to dismiss legitimate fears that gave fearmongers strength, IMO.
John: No worries.
Just as a general comment, I would still like to hear what harm GW or CC is doing to us right now as opposed to the horrors of what it might cause. Al Gore says 20 ft sea level rise, James Hansen now says 80 feet which would pretty much require complete degalciation of the planet. Ecosystems are resilient enough to survive temperature swings of 10s of degrees daily and many 10s of degrees annually. Will 1 or even 2 or 3 degrees harm them irrevocably? Habitat is being destroyed, not by GW but by humans looking to find enough firewood to survive another day. Massive habitat loss is being driven by the move to ethanol as an alternative to gasoline. That’s where real environmental damage is being done on a wholesale basis.
jnicklin; “Massive habitat loss is being driven by the move to ethanol as an alternative to gasoline. That’s where real environmental damage is being done on a wholesale basis.”
You got that right !! Especialy when one considers that biofuels take more fossil fuel energy to make them than they will yield. (perhaps, excepting Brazilian cane)
Amazing how so many things in this ole world can take on a life of their own, self perpetuating. Equity markets a good example. Y2K.
Y2K is a good example of bad information taking on a life of its own, the money that little gem cost was immoral at best.
I’m still waiting for any examples of harm done by GW. Forget the sinking of Tuvalu and the Maldives, that’s just BS, no proof there.
Let’s face it, AGW and CC are just fluff to get Al Gore elected in 2008.