How will global warming play out?

Great Debates
41

People keep saying the climate is simple, things like “we understand the physics” or “it’s KNOWN” and the like. This is incredibly naive.

In fact, the climate is one of the more complex, and least understood, systems that we deal with. The global climate system is a chaotic, optimally turbulent, multi-stable, resonant, externally and internally forced, constructal tera-watt scale heat engine, with hundreds of known and unknown forcings and feedbacks. It is comprised of five major subsystems (atmosphere, ocean, cryosphere, lithosphere, and biosphere), with each subsystem having both internal and external feedbacks and forcings.

Climate is far and away the most complex system that humans have ever tried to model, and we’ve only been working on it for a few years. Computer modeling of turbulent systems is in its infancy in all fields of science, not just climate. The idea that our current generation of models represents the climate system well enough to make hundred-year forecasts is hubris of the first order.

Every week we discover something new about the climate. Recently, it was discovered that almost all plants emit methane. Recently, it was discovered that when ocean plankton get too hot, they emit compounds into the air that increase clouds. Recently, it was discovered that animals emit more powerful greenhouse gases in total than all the world’s cars.

Who knew? And how many climate models contain those forcings?

The problem is not in what is KNOWN. It is what is left out, which is that CO2 is only one of dozens of forcings, resonances, constructal forces, and feedbacks in the climate system, and that the effect of many of them is unknown, the nature of their interactions with other forcings is unknown, and for some, their existence is not even suspected. In other words, while we understand the physics, we don’t understand the system.

People keep claiming that “we know the physics, greenhouse gases warm the planet, and we’re adding more greenhouse gases, so it’s KNOWN that the planet has to warm.”

This claim is like saying:

  1. The human body is at 98.6°F.

  2. Adding heat to a system will make it warm up.

  3. Therefore, it’s simple physics, if you put your feet in a bowl of hot water, your temperature will go up.

The physics of the situation is simple, as many people point out, it’s KNOWN … but the response of the system is not KNOWN.
Here’s another example:

In climate models, there is a concept called “water vapor feedback”. The physics of this are clear and well-understood.

  1. An increase in some kind of forcing causes the globe to heat up.

  2. Increasing planetary surface temperature increases evaporation, putting more water vapor in the air.

  3. Water vapor is a greenhouse gas.

  4. The increase in water vapor GHG causes a positive feedback, increasing the effect of the original forcing and making the world even warmer.

Simple physics, right? What could be clearer? Where’s the problem?

The problem is that increased water vapor in the atmosphere also changes the number and type of clouds, which could either cool or warm the earth depending on the number, type and location of the clouds. This might either double the size of the water vapor feedback (or more), or completely cancel out the effect of the additional water vapor.

The amount and size of this effect is one of the many, many unanswered questions in climate science. We simply do not know the size of the effect of the change in clouds, heck, we don’t even know the direction of the effect.

I put this forward as a cautionary tale for those who believe that a rudimentary understanding of a small part of the physics of an incredibly complex system will allow us to make predictions about the future behavior of that system … especially 100 year predications. Yes, there are some facts and physical understandings of climate that are KNOWN … it’s just that they are not sufficient to draw conclusions from.

Is this a recipe for doing nothing? By no means.

What I suggest is that we first conduct a Software Verification and Quality Assurance exercise on the climate models, which has never been done. This is a routine assessment that is done on all high-risk software (e.g., the software in airplanes, etc.), and is a recognized field of study with lots of rules, standard procedures, and guidelines. You are proposing that we bet billions of dollars on the forecasts of software which has not received the most basic verification required for the software that runs a typical subway system.

Next, I suggest that we take a hard look at the inputs to that software. Many GCMs only use a limited set of inputs, yet their forecasts are given equal weight with more complex GCMs. This makes no sense.

Then, I suggest that we set up a suite of benchmarks for GCM performance. These would involve, among many other benchmarks, such things as accurately representing cloud cover, being able to give good results at the continental margins, and matching the radiation levels (particularly in the tropics). Only the results from models that passed those benchmarks would be considered by decisionmakers. As it is, all models are given equal weight, despite major differences in assumptions, parameters, forcings, variables, and forecasts.

To make this clear, let me give you a theoretical example. What would you think of a hypothetical climate model whose benchmark results looked, say, like this:

*Model shortcomings include

• ~25% regional deficiency of summer stratus cloud cover off the west coast of the continents with resulting excessive absorption of solar radiation by as much as 50 W/m2

• deficiency in absorbed solar radiation and net radiation over other tropical regions by typically 20 W/m2

• sea level pressure too high by 4-8 hPa in the winter in the Arctic and 2-4 hPa too low in all seasons in the tropics

• ~20% deficiency of rainfall over the Amazon basin

• ~25% deficiency in summer cloud cover in the western United States and central Asia with a corresponding ~5°C excessive summer warmth in these regions

• absence of a gravity wave representation, as noted above, which may affect the nature of interactions between the troposphere and stratosphere.

• global cloud cover underestimated by 13%.*

Remember that we are looking for the effect of a ~3.7 W/m2 change from doubling of CO2, which corresponds to about a 2° temperature difference.

Now, tropical radiation in the hypothetical model is off by 20 W/m2. Coastal radiation is off by 50 W/m2 … and remember, we’re trying to investigate a difference of only 4 watts/m2 from CO2. A 13% deficiency in the model’s cloud cover is a 19 W/m2 error. It can’t get the rainfall right over the Amazon, a giant and relatively homogeneous chunk of real estate. Summer temperatures over huge parts of the world are too high by 5°.

Would you trust that model enough to bet billions of dollars on its ability to forecast the climate 100 years from now?

The problem is, this is not a hypothetical model. It’s James Hansen’s pride and joy, the NASA GISSEH model, one of the world’s best. And those are not my assessments of the shortcomings of the model. They are the assessments of Hansen and the team of people running the model. It can’t even get the climate right today, and that’s KNOWN.

w.

42

:confused: Who in the world is saying that? Either in this thread or anywhere in the whole global warming debate? I think one of the few things that climate scientists and climate-change skeptics and everyone in between agrees upon is that global climate is a fiendishly complicated set of systems.

And EVENTUALLY, if we keep adding greenhouse gases, it does have to. It’s quite true, as I pointed out earlier, that we don’t understand all the mechanisms that may change the speed or severity of the effect. But AFAIK, there is no serious scientific disagreement that increasing atmospheric CO2 concentrations indefinitely will have severe warming effects. Yes, the models are very fuzzy on the details, but this is not a detail.

More readily than I would bet trillions of dollars and millions of lives on the chance that the model is wrong.

Unfortunately, that’s the only choice we have. We can’t rely on having the luxury of spending a few more decades polishing up the science before we’re willing to commit to any serious policy choices. Yes, it might turn out that there are enough currently-unknown carbon-busting climate mechanisms that we have several decades or a couple of centuries before our continuous carbon-pumping finally puts us at serious risk of dangerous climate change.

On the other hand, it might not. And most climate scientists think that it won’t. Yeah sure, I’d rather be betting on a certainty; who wouldn’t? But this is a case where delaying one’s bet is itself a bet, and one with an even bigger stake.

43

I have no clue if this is true or not. But if it is there’s a very important disinction: the gasoline being burned in the cars has been sequestered in the ground for hundreds of millions of years until we piped it out.

44

I am greatly relieved to see XTisme’s and Intention’s posts.

I was beginning to think that I was the only person who was both unconvinced and uneasy about something that has been adopted with a religious fervour.

My understanding is that mankind’s emissions account for under 10% of total ‘green house gas’ emissions, so even if humanity died out next week, there is a heck of a lot of stuff going out there. And if Nature keeps pumping more and more gas out there then the Earth must get hotter. Well we have had it, we are doomed, doomed.

I’ve no objection to cutting down on pollution, I also think that planting a lot of trees is a rather nice idea, but I get really suspicious when I see people trading CO2 quotas.

As a programmer, and having studied Economics, I’m extremely suspicious of models. I’ll let you in on a little secret, the Bank of England used to, and probably still does, maintain a software model of the economy. It rents it out to other institutions to play with, but I was told by a very reliable source, that it jiggers the model so that the people using it see what the B of E wants them to see, in order to control their behaviour and thereby control the economy.

That may sound conspiritorial, but look at the opposite case, if the model says that inflation will rise to 25% per annum, then it will get out and inflation will take off.

So in 1900 someone said that the Earth was getting warmer, well in the 1970s people were talking about a new ice age. If we get a few crop failures then people will hark back to Malthus - and he changed his mind in his own lifetime.

I can understand scientists supporting GW, from their point of view it is a one sided bet, there is no value to them in trying to prove a negative, and from their point of view it can’t do any harm. Well scientists are a bit blinkered, they don’t realize what opportunists will do if they get their hands on a whip.

I’ll give you another example, my father was tech director of a large bottling company. Some professor in a UK uni had come up with a ‘model’ of stresses in glass bottles. He was hawking it around and the implications for the industry were horrific. I told my father about a demonstration I had seen first hand in Switzerland. It involved shining polarized light through glass then through a prism onto a screen. You could see the stress lines. My father was greatly relieved, if you have a physical way of determining something, then the ‘model’ is superluous. It actually becomes fraudulent.
Exit stage left that opportunistic professor.

Incidentally recycled glass is dodgy, they finally found out why Tonic Water bottles were spontaniously exploding on supermarket shelves. It was down to minute traces of aluminium. Also in the UK there is no market for coloured glass for ‘recycling’ - guess where it goes.

I’m not in favour of recycling glass, we should be re-using the bottles as we used to. And while we are at it we could follow the French in getting rid of plastic bags.

I don’t mind common sense approaches like getting rid of lead in petrol and banning CFCs, I’m also all in favour of chucking money at the Fusion project. What I don’t like is hysterical crowd behaviour - and right now I smell a rat.

45

kimstu, thanks for your thoughts. First, did you read what I said? I never proposed spending a few decades “polishing the science”, that’s your straw man.

What do I actually propose? Why, thanks for asking, because it’s not true that “that’s the only choice we have”, as you claim.

I propose doing what we routinely do for EVERY OTHER CRITICAL PIECE OF SOFTWARE WE USE, which is computer software Verification, Validation (V&V) and Software Quality Assurance (SQA). It’s done for moon shots, for subway control software, for the software that controls the ailerons in the jumbo jets, for the software the air traffic controllers use at the airports … but it has never been done for the climate models. There’s more riding on the climate models than any jumbo jet or subway train, and we haven’t a clue if they’re working right.

You seem to think that a) the models are right and we’re heading for a couple of degree increase in temperature, and b) that will cost trillions of dollars and millions of lives, and c) we have to decide right now. None of these claims have any solid scientific foundation.

Do we have to decide right now? Of course not. None of the predicted catastrophes of increasing CO2 are forecast to occur in the next decade or so.

Will a couple of degrees warming kill millions? There’s no evidence of that, in fact the world has warmed about that much since the Little Ice Age and it’s generally benefitted humans. Cold kills more people than heat, always has.

Will a couple of degrees warming cost trillions? There’s no evidence of that either. While Al Gore raves about 18 foot sea level rises, the IPCC forecasts between 150 and 450 mm rise over the next century. We saw a sea level rise of about 250 mm over the last century … did you notice any headlines about that costing trillions? Did that rise create millions of “environmental refugees” in places like Bangaldesh?

And finally, are the models right?

The answer is, we don’t have a clue, because we haven’t done the computer software Verification, Validation (V&V) and Software Quality Assurance (SQA) necessary to answer that question.

V&V and SQA is not rocket science, nor is it anything new. Software V&V and SQA a standard field of study, taught in colleges, and well understood. No other branch of science or commerce uses any mission-critical programs of the complexity of a climate model without V&V & SQA, they’d be laughed out of the industry or have to explain why their plane crashed.

Here’s a list of some of the things that we don’t have for the models:

(1) Audited Software Quality Assurance (SQA) Plans for any of the computer software that is used in all aspects of climate-change analyses.

(2) Documentation of Maintenance under audited and approved SQA procedures of the ‘frozen’ versions that are used for production-level applications.

(3) Documentation of the Qualifications of the users of the software to apply the software to the analyses that they perform.

(4) Documentation of independent Verification that the source coding is correct relative to the code-specification documents.

(5) Documentation of independent Verification that the equations in the code are solved correctly and the order of convergence of the solutions of the discrete equations to the continuous equations has been determined.

(6) Sufficient information from which the software and its applications and results can be independently replicated by personnel not associated with the software.

(7) Verification that the use of “ensemble averaging”, which is unique to the climate models, actually produces significant results.

(8) Documentation that shows that the codes always calculate physically realistic numbers. For example, the time-rate-of-change of temperature, say, is always consistent with the energy equations and is not the results of numerical instabilities or other numerical solution methods problems.

(9) Documentation in which the mathematical properties (characteristics, proper boundary condition specifications, well- (or ill-) posedness, etc.) of all the continuous equations used in a code have been determined. Do attractors exist, for example.

(10) Documentation in which it has been shown analytically that the system of continuous equations used in any GCM model has the chaotic properties that seem to be invoked by association and not by complete analysis. Strange-looking output from computer codes does not prove that the system of continuous equations possess chaotic characteristics. Output from computer codes might very likely be results of modeling problems, mistakes, solution errors, and/or numerical instabilities.

Invoking/appealing-to an analogy to the Lorenz continuous equations is not appropriate for any other model systems. The Lorenz model equations are a severely truncated approximation of an already overly simplified model. The wide range of physical time constants and potential phase errors in the numerical solutions almost guarantees that aperiodic behavior will be calculated.

(11) Documentation in which it has been determined that the discrete equations and numerical solution method are consistent and stable and thus the convergence of the solution of the discrete equations to the continuous equations is assured. Actually I understand that the large GCM codes are known to be unable to demonstrate independence of the discrete approximations used in the numerical solution methods. The calculated results are in fact known to be functions of the spatial and temporal representations used in the numerical solutions. This characteristic proves that convergence cannot be demonstrated. Consistency and stability remain open questions.

(12) Documentation in which it is shown that the models/codes/calculations have been Validated for applications to the analyses for which it has been designed.

(13) Documentation of independent Verification that the equations used are unconditionally stable for any time step, positive definite, and exactly mass conserving.

(14) Documentation of independent Verification of all “parameterizations” (heuristic equations for parts of the system which are approximated rather than calculated), along with sizes and limits of the various parametric constants used.

(15) Documentation of independent Verification of all “flux adjustments”, which are adjustments made to outputs to keep them within reasonable values, along with justification for their size and form.

There will be more, but you get the idea …

We don’t run airplanes, or subways, or submarines, or airports, or space shuttles without that level of documentation, and we are absolute fools to talk about spending billions based on computer models which do not have that level of documentation.

This does not begin to exhaust the problems with the climate models, however. One problem is that we don’t have the computer horsepower to run a model of the required complexity. You want to see a reasonable model? Take a look at the GATOR-GCMOM model here. Mark Jacobsen has a list there of some 141 things that his model does that no other model does, and it’s a real eye-opener. Unfortunately, this comes at a cost, which is that modeling the globe with this model is very slow. For that reason, you won’t see it listed among the models considered by the IPCC. Instead, we’re using tinkertoy models, because that’s all our computers can run.
Kimstu, a couple of final comments. First, I noticed on another thread that you said you thought you were talking to xtisme, commenting:

No worries, I’m thik skinned. People have said that “deniers” like me should be tried in “Nuremberg style” trials for not believing the revealed wisdom of untested climate models … compared to that, your comments were not out of line, and I took no umbrage. I enjoy your posts, forceful or not. Rage on.

Second, I’d be interested to see some kind of scientific evidence that a couple of degrees of warming would cost trillions of dollars and millions of lives. Increased warming to date has been concentrated in the higher latitudes, during the winter, at night … I don’t see how more warm winter nights will kill millions. The tropics have warmed very little, instead, the isotherms have widened slightly towards the poles. How will that kill millions?

Third, I’d also like to see some evidence that we have to decide right now. Hansen said the same thing in 1988, that it was urgent, we had to decide right away … but obviously we didn’t. Why is it so urgent now that we can’t take the short amount of time to make sure that the models are right?
I know we’re fighting ignorance here, but people’s faith in untested, unvalidated, unverified software and unsubstantiated predictions of future megadeath is a level of ignorance that is truly staggering …

My best to you all, this board is, as always a joy.

w.

46

Yes, and I’ll add that the only time I have ever felt sick in an aircraft was when I was in the cockpit of an A320 chatting to the pilot

He said we have 3 separate computers up there working on things. ( IIRC it was 3 )
I asked ‘what happens if they disagree ?’

  • he said ‘they vote on it’

I felt slightly queasy.

Actually I once met one of the guys who worked on one of the ‘clean room’ Airbus computer systems - I can’t remember whether he was French or Belgian - Air France was using him to check whether I was the real thing - we were mutually impressed.
However I don’t trust software and I don’t trust assumptions.

47

I think your understanding is wrong, though. Yes, non-anthropogenic sources do account for the majority of greenhouse gases (GHGs) that go into the atmosphere. But those GHGs are part of the climate equilibrium that’s been prevailing for the past several thousand years of the current interglacial period. Sure, the earth has been naturally pumping GHGs into the atmosphere for a long time, but it’s also been naturally absorbing GHGs. As a result of that equilibrium, the atmospheric concentrations of GHGs have remained comparatively constant until the sharp increases of the past several decades. It’s the increased atmospheric concentrations that make things hotter.

So the problem is not “OMG! There are GHGs going into the atmosphere!! Oh noes!!!”, but rather “OMG, we are putting enough extra GHGs into the atmosphere to change the natural equilibrium of the pre-existing carbon cycle.”

48

This is one of those statements that is put out there to intentionally confuse you. Yes, it is true that there are large exchanges going on of CO2 between the atmosphere and oceans and the atmosphere and land / vegetation. (See, for example, here.) However, before the industrial revolution, these exchanges were in equilibrium back-and-forth so that the level of CO2 was quite constant since the last ice age ended (~12,000 years ago or so) at about 260-280ppm. And, in fact, from ice core records over the last 750,000 years, we know that going back through several ice age – interglacial cycles, the CO2 levels were always between something like 180 and 300ppm. Our burning of fossil fuels has upset the equilibrium, with CO2 levels now at ~380ppm and rising rapidly (e.g., the level was at ~320ppm back in 1970). These are levels that we know haven’t been seen on earth for the last 750,000 years…and likely for something like the last 20 million years.

Modeling economics and modeling the earth’s climate are quite different. Modeling climate is indeed complicated, but the basic governing rules are well-understood laws of physics. And, one does not have to deal with the sort of psychological feedback effects that you mention above in economics.

Also, we are not just relying on models. We have past climatic events such as ice age - interglacial cycles that allow us to estimate the sensitivity of the earth’s climate to perturbations…and also to allow testing of the models. The models can also be tested against, for example, the short-term cooling in response to the eruption of Mt. Pinatubo in the early 1990s. Many different estimates for the sensitivity of the climate to the known forcing due to a given amount of greenhouse gases (such as a doubling of levels of CO2) seem to be converging to approximately the same value.

Furthermore, different features of the models of the models can be tested: Recently, measurements of the water vapor in the upper atmosphere confirmed that the levels are rising in agreement with what the models predict thus giving us more confidence that we are getting the important water vapor feedback at least approximately correct. And, a recent study by ClimatePrediction.net showed that for what were considered by scientists to be a plausible range in parameters that control things like clouds in the models yielded a range of climate sensitivity values but that none were lower than about 2 C for a doubling of CO2 levels. (By contrast, some ranges of parameters could give climate sensitivities as high as 11 C for such a doubling…although many scientists believe such extreme “we totally f-ucked” scenarios can be ruled out on the basis of how climate has responded to past perturbations.)

It is a myth that there was any sort of scientific consensus on an imminent new ice age back in the mid 1970s. Yes, you can find a few scientists and a few media reports talking about such possibilities. However, at the same time, there was growing concern about the warming effects of greenhouse gases. And, the U.S. National Academy of Sciences [NAS] report in the 1970s was clear about the fact that climate was not yet well-enough understood to make predictions just as the recent joint statement of the NAS and 10 other academies is clear we now know enough to make predictions and to warrant taking action.

I don’t have time now to respond to intention’s points. I’ll try to get to these tonight.

49

Well, healthy skepticism is definitely a good thing. However, by your own admission, you’re evidently so ill-informed and/or confused about the science of climate change that you didn’t even understand the elementary point about non-anthropogenic emissions being part of a pre-existing climate equilibrium, until jshore and I explained it to you. Skepticism is not a cure for ignorance.

I do feel that even we laypeople have an ethical obligation to make a serious effort to understand at least the basic scientific issues underlying important policy questions, rather than just trusting in our skeptical caution or our disdain for “hysterical fervour” and groupthink. It’s certainly true that skepticism and critical thinking are very important when considering science policy. But ISTM that skepticism-plus-ignorance is not really a better recipe for good policy choices than blind-faith-plus-ignorance.

50

Please remind me of the dire predictions after hurricane Katrina; please remind me how this year’s hurricane season has been.

Remind me of atmospheric CO[sub]2[/sub] levels in previous ice ages.

Please let me know when the weather forecasters can accurately predict the weather a week ahead.

I see the usual suspects - Kimstu and jshore are trying the same arguments they tried on me. And the same red herring - evolution - has been tried too.

But we should do something about CO[sub]2[/sub] and other emissions. Because they make the place dirty and smelly. Roll on nuclear power.

51

While there was some hype in the media and such, scientists generally careful to note that global warming does not repeal any thing about year-to-year variability so any changes such as increased intensity of hurricanes (or more hurricanes of high intensity) as warming occurs will not be a monotonic year-to-year increase but will be a general trend accompanied by lots of year-to-year variability.

Ice core data now goes back about 750,000 years, which encompasses about 7 ice – interglacial cycles. During that time, the levels in CO2 have varied between about 180 and 300ppm. At the start of the industrial revolution, they were about 280ppm (i.e., already near the high end because we are in an interglacial). They are now at about 380ppm and I believe the current rate of increase is about 2ppm or so per year.

Forecasting weather and climate are two different things. Because the atmosphere is chaotic, weather forecasts are very sensitive to initial conditions and so models run with slightly perturbed starting conditions will tend to signficantly diverge over a time of a week or so. (In fact, such runs with perturbed initial conditions are regularly performed in order to give forecasters a measure of the confidence in their forecasts.) However, climate is a measure of average weather conditions and, as such, is not so sensitive to initial conditions. When you start climate model runs with slightly perturbed starting conditions, they will not match precisely in all their jiggles but they will all tend to give similar results for a prediction of the climate in 100 years under doubled CO2 relative to the climate in 100 years under a constant level of CO2.

Think of it this way, you may not trust me being able to tell you if it is going to rain where you live next Friday but you will probably trust me at being able to tell you that the average temperature next July will be warmer than it is this month.

It is called an analogy. If one has participated in arguments defending theory of evolution and defending the theory of anthropogenic global warming, one can not help but notice the similarities in the kinds of arguments made against the two theories. I am not claiming that the two are exactly the same and that the level or what we know and don’t know are equal in each. However, the basic issue of people demanding higher and higher levels of evidence when a scientific theory goes against strongly-held prejudices (be they religious or political / economic) is very much the same.

Actually, CO2 itself doesn’t really make things “dirty and smelly”. However, it is worth noting that, even absent climate change, a growing concern about rising CO2 levels is ocean acidification.

Whether nuclear power has a large positive role to play in all this depends on how big you feel concerns are over issues such as nuclear power plant safety (against accident or terrorist attack), long-term storage of waste, and nuclear proliferation. However, if you believe in market solutions rather than big government solutions, you would presumably want to try to correct the market externalities associated with fossil fuel use (in particular, greenhouse gas emissions) and then let the market decide which mix of technologies will best accomplish the goal rather than dictating the solution from on-high.

52

I agree that clouds are the biggest unresolved issue in the GCMs. However, what you are hoping for is that clouds somehow produce a magical cancellation of most of the forcing due to CO2 (along with the positive feedbacks due to increased water vapor, decreases in earth’s albedo due to decreased snow and ice coverage).

There are other ways to get some handle on the extent to which clouds could be acting as such a negative feedback. For example, one can look at whether such a negative feedback would be compatible with the forcings and resulting temperature changes that were produced in the glacial - interglacial transitions or the Mt. Pinatubo eruption. One can look at the extent to which models with the currently understood forcings can model the recent warming if such a negative feedback is assumed. One can study specific aspects of cloud coverage in the tropics and how it is changing over time. One can study how changes in the parameters for clouds in the GCMs affects the results. All of these things are being done…and so far the vast preponderence of the evidence is not in favor of the magic of clouds somehow saving us. In particular, it is really hard to explain the historical oscillations seen in the climate system if the stability implied by a strongly negative cloud feedback is present.

Frankly, this sounds like a large exercise in bureaucracy that, while it may have analogs in the areas you cite, has essentially no analogs that I know of in the physical sciences. In the physical sciences, it has generally been left up to the individual research groups to come up with their own methods of testing their software, with some occasional attempts to have large intercomparisons between models or standard test cases or the like.

At any rate, in my view, if you want to expend the energy, you are welcome to engage in all sorts of such bureaucratic endeavors. However, there is no reason why we should not simultaneously be using the best science at the time to make policy decisions. Because, quite frankly, there is always one more test or one more thing to try. Science is not about striving for absolute certainty. Maybe that is a nice goal to have but in the real world you have to make decisions without being completely certain. And, while it always sounds good to be on the side of more research and testing and study, the fact is that we don’t have the luxury of an infinite amount of time and arguments for more research and testing and study have been around as long as regulation of environmental and health issues has been around. It is what the tobacco companies and sympathetic scientists called for. It is what the Bush Administration has been trying to put in place in various ways to hamper rule-making in the executive branch.

And, look, the sort of policy options that are currently on the table in regards to climate change are generally “no regrets” options that will have lots of side benefits (in terms of reduced pollution, reduced dependence on foreign oil, and so forth). Even if further study shows us that the problem is not quite as bad as we thought, there will be no great loss incurred. On the other hand, the “take no action” crowd is gambling on the current state of the science being overturned and if that does not happen we are going to be faced with a combination of very bad effects or the need to implement measures to prevent them in a much faster and more draconian manner.

The major groups of people who seem to feel there are large regrets if we start down this road are either those with large economic interests (e.g., coal companies and the oil companies like Exxon who haven’t yet come around on this) and people of a conservative or libertarian political persuasion who have a lot of philosophical investment in a “free market” and reduce government regulation.

And, to be honest, I also have a hard time understanding people who uncritically accepted spending hundreds of billions of dollars on a phantom threat of a tin-pot dictator with narry a cry now telling us that we have to be more skeptical in believing what the strong consensus of scientists in a field are telling us. If you were one who was actively protesting the decision to go to war in Iraq, then I apologize about implicitly lumping you in with others…but off the top of my head I don’t know of anyone outspoken in the “skeptic” community who was similarly outspoken about the Iraq war. I think that says quite a bit about their biases and judgement.

A cite here would be helpful so we could see, for example, what version of the model had these deficiencies. However, I am willing to believe that the model has such deficiencies. I do modeling for a living and if I were required not to let my modeling influence any decisions made in the company I work for because of the many known deficiencies of the models, I wouldn’t have anything useful to do. You tell people about the deficiencies and you try to get a handle on the extent to which the deficiencies might affect the results and you continue to work on improving them if you can. It is an iterative process that can essentially go on for ever.

And, it is important to note that, say, a 20 W/m2 deficiency in something in the models as compared to the forcing of 3.7 W/m2 due to doubling of CO2 may sound really bad, it is not necessarily so. For example, if I have a thermometer consistently reads 10 degs high, I am still capable of saying that the temperature in the room today is 2 deg colder than yesterday. I.e., as long as these inaccuracies don’t strongly change in magnitude under the scenerio of doubling CO2, you are still going to get roughly the right answer. In my experience, a surprising number of errors tend to work in this way. Again, if they didn’t, I’d be out of a job.

I think part of the reason that people get so concerned when they start more closely scrutinizing scientific theories, as happens for evolution and AGW, is that they have a naive view of how science works and in particular how uncertainty and making simplifying assumptions comes into science. They don’t realize that if they subjected other scientific theories to the same scrutiny, they would find similar problems…hence my joke about if quantum field theory were publicly controversial, then there would be people laughing about how one could possibly make predictions using a theory that gets these strange infinite divergences!

53

Just to summarize my point, if your vague criterion is that the model “get the climate right today” I can guarantee you that you can define this in a way that the models will never meet that criterion because, after all, they are only models. And, the people who create and produce them will be the ones who are most aware of the remaining deficiencies. After all, science is not about pursuing what you already know…It is about pursuing the areas where you still don’t understand everything.

The question is whether the models seem to be getting things “right enough” to have reasonable predictive capability for the problem at hand. And, that is a judgement that is also best left to those scientists actually working in the field.

54

You are the guys who brought up the word ‘equilibrium’, I see no reason to assume that Earth’s climate is, or ever was, in equilibrium. Heck we are only 12,000 years out of the last ice age.

What is disturbing is that Earth’s climate might not actually tend to self balancing equilibrium - or rather it might be susceptable to sudden rather than gradual change.

Back in the late 1800s people were saying that within a few years London would be x feet high in horse manure. I guess horses give off methane, and just think of those massive herds of buffalo farting their way across the Prairies.

For all we know an extra few PPM of CO2 in the atmosphere will fire off some hungry algae that will cover the oceans and make sea transport impossible.

Being serious, you and JS are asserting that :-
a) there is some sort of equilibrium
b) that mankind’s puny efforts will upset the apple cart

I am agnostic on the subject, but I’m really wary of simplistic explanations of complex systems - the Milton Friedman school of Climatology makes me suspicious.

55

I posted earlier on the gross inadequacies of the GISSE model, one of the very best ones we have. For example, it is off by a whopping 20 W/m2 (5 times the change from a doubling of CO2) over the entire tropics.

Perhaps you could explain, since the “basic governing rules are well-understood laws of physics”, just how the model is getting it so wrong …

At present, there are no models that can successfully simulate the ice ages. So yes, the ice ages “allow testing of the models” as you point out … but you forgot to mention that they failed the test …

Cite, please.

ClimateProduction.net throws out all predictions that show cooling with increasing CO2, on the grounds that they are not believeable … I wouldn’t depend on anything they say, but YMMV. Their model, like all the rest, has not been subject to V&V or SQA, you’re nuts to blindly believe something just because “a computer said so”. What’s next, “as seen on TV” as a citation?

Thanks for your post, jshore, I look forward to your post.

w.

56

You seem to think that the physics of the climate is well understood. In order to show that it is not, I pointed to the fact that cloud feedback might double the water vapor feedback, or reduce it to zero.

Ignoring the point of the example, you somehow come to the conclusion this means that I’m hoping that clouds will produce a “magical cancellation” of the water vapor feedback.

Say what? I pointed out it might double the feedback as well, and we don’t know which. You quoted that but didn’t notice it?

And you seem to think that there is some kind of “magic” feedback out there … I fear you’ll have to discuss magic feedbacks with someone else, I know nothing about them.

Thus far, there is no “vast preponderence of evidence”, there is little evidence of any kind. You ask below which model I was referring to when I gave the list of model deficiencies, even though I had said it was the GISSE (GISS Model E). The GISSE model underestimates the cloud cover globally by 13%. What can that model possibly tell us about the type and nature of the cloud reactions to increasing water vapor, when it can’t even get the basic amount right? That’s why, as I said before, the cloud reaction to increased water vapor is one of the great unanswered questions of climate science. See “Dangerous human-made interference with climate: A GISS modelE study”, J. Hansen et al. for further details about the model. My statements before about model inadequacies were direct quotes from that paper.

Regarding the novel, rash, and unheard-of idea that we should actually do a Validation and Verification (V&V) and a Software Quality Analysis (SQA) on the models to make sure they are working correctly, you say:

Bureaucracy?!? V&V and SQA are bureacracy? My friend, you know not whereof you speak. I suppose, by your reckoning, that we should stop doing V&V and SQA on the software that runs the airplanes, because those procecesses are just “bureaucracy”? Climate change, by your reckoning, is a bigger danger than an airline crash, yet you wouldn’t dream of flying in an airplane without tested and verified software …

Aaah, would that this were true, that the options were “no regrets” options. Canada already has enough regrets about signing up for Kyoto that it’s considering pulling out. Billions have been spent by Canada on Kyoto to date (much of it, ironically, on setting up the bureaucracy to handle the regulation and enforcement of carbon … and we know you don’t like bureaucracy). How can you say that if the problem is not so bad there will be “no great loss” incurred, when billions have been already spent to no avail?

It amuses me to see you and others change course on Kyoto. In the beginning of the discussion, it’s all about saving the world from increasing temperature. Then, when I point out that the effect of Kyoto on the temperature will not be measurable, suddenly it’s not about temperature … now, it’s about developing more efficient technologies.

Look, if you want to develop efficient technologies, let’s put the money into that. As it is, the money is going into creating carbon-regulating bureaucracies, and buying carbon credits from places like Chad. Neither of those do a single thing to develop new technologies.

See, I agree with you about the need for new technologies. I just think the Kyoto Protocol is the stupidest, most expensive, least productive, most ineffective way to promote them that I have ever heard of.

And you speak of the “‘take no action’ crowd” as if I were one of them. I just told you what action we should take, and you called it “bureaucracy”. It is not. It is a vital part of every mission-critical piece of software we use. Proceeding without it, on a mission which is most assuredly critical, is unimaginable hubris.

Not true. Many people think there will be regrets if we take this road. Remember that the US Senate voted 98-0 to turn down Kyoto. Are they all conservatives, libertarians, or in the pocket of economic interests? That’s nonsense.

Oh, please. What does the war in Iraq have to do with climate science. That’s a red herring.

Regarding my quotes about the climate model deficiencies, you say:

If you can demonstrate to me that the models are always off by 10°, I’d agree with you. However, I’ll wait until you can prove that before I make that huge and untested assumption. For example, 19 models used by the IPCC were recently tested to see if they could hindcast the recent (1970-1990) Sahel drought. 8 hindcast less rain in the region over the period, 7 hindcast more rain over the period, and 4 showed no change in the rain.

Remind me again … which one of these models is consistently off by 10°? …

(The study is “A multimodel study of the twentieth-century simulations of Sahel drought from the 1970s to 1990s”, Lau et al., Journal of Geophysical Research 111: 10.1029/2005JD006281)

For a man who thinks that V&V and SQA are “bureaucracy” to claim that other people “have a naive view of how science works” is risible. Other scientific theories have all been subjected to intense scrutiny and they held up, that’s why they are generally believed. Since you seem to have a naive view of how science works, here’s the short course:

  1. Somebody has an idea, and puts it out to the world.

  2. Other people subject that idea to the most intense scrutiny they can muster.

  3. If they can’t find anything wrong with it, it becomes accepted as part of mainstream science.

You seem unwilling to have the ideas of climate science subjected to that same, normal scientific process. Why is that?

w.

57

Intention said

At least one major catastrophe has been predicted by those tree-hugging hippies in the Pentagon, which is a sudden change in the circulation of the Gulf Stream, resulting in a very rapid cooling of the UK, Scandinavia, and most of northern Europe. http://www.thewe.cc/contents/more/archive2004/february/abrupt_climate_change_event.htm
If the predictions are accurate, almost half of the developed world would become more-or-less uninhabitable, or at least unable to sustain present-day agriculture and energy use patterns. If that doesn’t count as a major disaster, what does?

58

A few quotes from th above cite:
BBC News:

From FORTUNE magazine:

Read the whole thing and then tell us why it won’t matter.

59

First of all, I used the term “equilibrium” in a rough sense to express the fact that for the last 12,000 years or so, the rates of transfer of CO2 into and out of the atmosphere have been roughly equal so that the concentration has stayed roughly constant. If one looks at longer timescales, this of course has not always been true.

However, what has been true for at least the last 750,000 years and likely the last 20 million years is that CO2 levels have not been as high as they are currently as a result of the rapid rise in CO2 levels since the beginning of the industrial revolution. This is hardly a “puny effort”; rather, it is a very signficant perturbation to the climate system.

I agree. The fact that the climate is a complex dynamic system seems like a strong reason to me not to be embarking on this sort of global experiment…not a reason not to worry about it! As one climate scientist has put it (and I may be paraphrasing slightly here): “History shows us that the earth’s climate system is an angry beast and we are poking at it with a very large stick.”

The projections of the IPCC assume that the climate continues to respond in an at least roughly linear manner to the perturbation and they are worrisome enough. However, this perturbation is also making it more likely that we will push the climate system past some threshhold that will cause a more dramatic nonlinear change.

Mapache’s posts discuss one of the scenarios, which I would say most scientists in the field would currently consider to have a fairly low probability of occurring (at least to the extreme that he describes it), but could be quite nasty if it did occur. And, as he noted, the Pentagon was nervous enough about it to commission a study for their scenario planning on what the consequences of this would likely be. (By the way, I don’t think it is really correct to say that the folks at the Pentagon are predicting this to happen but rather that they are concerned enough about the possibility to feel it warrants some serious consideration.)

60

I did notice it. However, the point is that, even if true, this is hardly an argument for a policy position of doing nothing to stop the growth of greenhouse gas emissions. After all, if a piano that I think weighs one ton is falling toward my head and then I discover that it in fact weighs 2 tons, this is not going to change my policy decision to try to get out of the way. It would only be if I discovered that it is made of foam rubber and weighs almost nothing that it would impact my decision. This is, by my reading, exactly the point that scientists are making and that is summarized, for example, in the joint statement by the 11 national scientific academies: Yes, we don’t know everything and there are uncertainties, but we are certain enough to know that we need to act.

My point is that the uncertainties that remain will have to all “break” in a very unlikely way for us to later come to the conclusion, “Oh, we can just go along our merry way emitting greenhouse gases without a care in the world.”

Testing software designed for specific engineering purposes is a very different process from testing models in the physical sciences. There are good reasons why software design for the sort of applications that you cite has evolved to have the sort of formalized testing process that you discuss. And, there are also good reasons why the modeling done in the physical sciences has not generally followed such a formal process, while still paying attention to testing how well the model compares to physical reality.

Besides, I would say that your airplane analogy is a poor one…basically backward. A better analogy is that it is you who want to get on the airplane without knowing what might happen because you feel it would be too expensive to make the investments necessary to be sure that this plane is safe (even though there is very strong evidence that it is not). As kimstu pointed out to you, this isn’t the case where we have the luxury of avoiding serious consequences simply by doing what we are doing.

Noone has ever changed course on Kyoto. Noone ever made the claim that simply controlling emissions in some countries for a 5 year period of time would dramatically and magically reduce temperatures all by itself. That is your strawman, not ours. It has always been understood that Kyoto is about beginning a process of stabilizing our worldwide greenhouse gas emissions with the eventual goal of cutting them…and that the only way that is going to happen is to provide the incentives by which the technologies to do this are developed and commercialized.

Well, I suppose one can put money directly into trying to subsidize the development of technologies. However, eventually, in order to get these technologies adopted, you run up against the fact that the market is not correctly calculating the costs of not implementing these technologies because there is no cost associated with using our atmosphere as a free sewer for greenhouse gas emissions.

Well, okay, what exactly do you favor then in order to internalize the externalized cost of our greenhouse gas emissions into the market? Or do you not favor anything to do that and just favor making investments in technologies?

By action, I was talking about action to actually deal with the problem of the buildup fo greenhouse gases in the atmosphere. What you proposed was more research (and in a particularly bureaucratic and unproductive manner from what I could gather). More research is fine but it is not action in the sense of actually tackling the problem.

That vote was now something like 10 years ago and it was not a vote on Kyoto. It was a vote on what our negotiating position ought to be, i.e., that we ought to try to demand that the developing countries have to make emission cuts too. More recently (I can try to dig up a cite later), there was a similar sense-of-the-Senate resolution that supported caps in greenhouse gas emissions.

I explained the relation. It is not what one has to do with the other. It is an attempt to understand how uniformly you apply your skepticism and your need to have strong evidence before undertaking expensive actions. Do you apply this consistently across the board or only when the actions proposed rub you the wrong way because of your own political or philosophical or economic biases?

That is exactly what has happened. And, AGW has become an accepted part of mainstream science. That is clear from the statements that have been made, e.g., by the joint scientific academies, from looking at the peer-reviewed literature, and so forth. Is the belief unanimous? No. But neither is the belief in evolutionary theory. When theories conflict with strongly held beliefs, it is unrealistic to expect to be able to convince everyone. Some people will just have their bar for standard of evidence set very, very high.

It is you who want to go outside of the normal scientific process. The National Academy of Sciences, for example, was set up as part of its mission to advise the government on the current state of peer-reviewed science that is relevant for policy issues. They have done that but you refuse to accept their conclusions.

The IPCC was set up by the UN to advise the world on the current state of peer-reviewed science that is relevant for this policy issue. They have done that but you refuse to accept their conclusions.

The councils of the American Physical Society and the American Geophysical Union feel it is their duty to comment on the current state of the peer-reviewed science that is relevant for this policy issue. They have done that but you refuse to accept their conclusions.

Even BP, Shell, and Ford, for heaven’s sake, have accepted the current state of the peer-reviewed science that is relevant to this policy issue and have started to make changes to their own course. But you refuse to accept their conclusions.