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Predictive Power of Modern Climatological Models


Stochasty

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This is wrong. The problem with these types of arguments is that they only focus on the potential harms of continuing, while ignoring the very real negative consequences of stopping. They also ignoring the possibility that, if we don't stop, we might yet in the future find a means of both controlling the experiment and avoiding the negative consequences.

Bit of a straw man there, Stochasty. There are no negative consequences associated with ceasing the industrial emissions of CO2. There are, of course, very real negative consequences to ceasing all industrial emissions of CO2 right now since there are huge numbers of power plants providing neccessary electrical power and uncountable industrial and agricultural processes that produce these emissions but I'm pretty sure neither tavert or anyone else with half a mind was seriously suggesting that. There is no reason, however, not to begin replacing these processes with alternatives that reduce substantially less CO2 in the most timely fashion possible.

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Key words possibility and might. I didn't mean to imply it would be painless, but there are painless things we can do in the developed world to start slowing emissions down. Energy-efficiency retrofits are a no-brainer, you get a real return and a reasonably short payback period and reduce emissions. Increasing nuclear, as long as we're careful to do it properly. Ramping up renewables won't be painless, but it won't ruin anyone's standard of living either. If the developed world would start going this direction a bit faster, the technology would improve and bring prices down to the point that you can apply the same techniques in the developing world without slowing growth enough to matter.

Exponential growth and finite resources makes for a bad combination.

Edited by tavert
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none of those are direct feedback links between CO2 concentration and temperature, as claimed by AGW believers.

In fact, it has never even been proven that temperature changes follow changes in CO2 concentrations reliably and predictably, rather the reverse has been indicated.

The whole greenhouse idea itself is bogus, it assumes that all CO2 is concentrated in a solid layer in the upper atmosphere, there trapping heat inside.

If you look at the claims, you will also clearly see that energy is counted multiple times, to gain the effect the AGW believers claim the atmosphere would have to generate energy out of thin air (literally).

It goes something like this:

100 Watts impact on the planet. Of this 30W are reflected out, 70W absorbed by the atmosphere, and 30W absorbed by the planet.

Of that 30W, 20W is radiated out into the atmosphere, of which 10W is reflected back down by the CO2 layer.

See how they've just created 30W out of nothing? And that with each iteration they create a bit more?

The glass box experiment fails, I've done it myself. There's no difference in the amount of heating based on different CO2 concentrations, at least nothing more significant than is caused by different placement of boxes with different CO2 concentrations, causing different amounts of energy to impact with the box (and of course diffferences in insulation).

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none of those are direct feedback links between CO2 concentration and temperature, as claimed by AGW believers.

In fact, it has never even been proven that temperature changes follow changes in CO2 concentrations reliably and predictably, rather the reverse has been indicated.

The whole greenhouse idea itself is bogus, it assumes that all CO2 is concentrated in a solid layer in the upper atmosphere, there trapping heat inside.

If you look at the claims, you will also clearly see that energy is counted multiple times, to gain the effect the AGW believers claim the atmosphere would have to generate energy out of thin air (literally).

It goes something like this:

100 Watts impact on the planet. Of this 30W are reflected out, 70W absorbed by the atmosphere, and 30W absorbed by the planet.

Of that 30W, 20W is radiated out into the atmosphere, of which 10W is reflected back down by the CO2 layer.

See how they've just created 30W out of nothing? And that with each iteration they create a bit more?

The glass box experiment fails, I've done it myself. There's no difference in the amount of heating based on different CO2 concentrations, at least nothing more significant than is caused by different placement of boxes with different CO2 concentrations, causing different amounts of energy to impact with the box (and of course diffferences in insulation).

False. False. False.

The albedo of the Earth is around 0.3, this indeed means that around 30% of the energy that impacts the surface of the Earth is reflected back from the planet's surface. With this figure and the incoming solar radiation, one could derive the black body temperature of the temperature (i.e. the temperature the planet would be were there no atmosphere and the Earth were a perfect black-body) using the Stefan Boltzmann Law.

In order to model the atmosphere, one must also consider 1) incoming solar radiation being absorbed the atmosphere 2) reflected solar radiation being absorbed the atmosphere and 3) infrared radiation emitted by the Earth being captured by the atmosphere. Point 3) is particularly important because the Earth's blackbody temperature is obviously much lower than the Sun's it will radiate primarily in the infrared which is more readily absorbed by atmospheric CO2 and other greenhouse gases, helping to trap this heat.

Energy is not being "created" anywhere, if you think this is the case, you are clearly misunderstanding whatever model has been shown to you. Perhaps you are mistaking the radiation emitted by the Earth for this additional energy.

Regardless, I suggest you get a fuller understand of these issues before simply claiming something is "bogus" when the scientific consensus is against you otherwise you are liable not to be taken very seriously.

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Bit of a straw man there, Stochasty.

Touche.

I didn't mean to imply it would be painless, but there are painless things we can do in the developed world to start slowing emissions down.

On this, I agree. I probably came off more strongly in my previous post than I intended.

The point of my reply is that, when you are assessing potential remedies to the problem of CO2 emission, you must factor in both the costs of acting and not acting. This is something often ignored by the environmental activist crowd, who typically argue that we must do something "right now" to stave off some putative ill effect that won't happen for another century. (And, typically, their idea of what we should do is simply to hand them more political power, but that's an argument for a different thread; I'm concerned here more with the science and less with the politics).

Global warming - even if the worst of the doomsayers are right - is a slow process, and fixing it - assuming that fixing it is the right thing to do - will also be a slow process. So, I am entirely in favor of measures to lessen our dependence on fossil fuels - switching to nuclear power is the obvious solution, although it is politically untenable - so long as those methods seek to be as painless as possible. But, if you ask me how much pain I'm willing to endure today to prevent potential ill effects tomorrow - that's where a cost-benefit analysis comes into play, and that's where analysis of the actual predictive power of climate modelling matters.

Right now, personally, the answer to that question is "very, very little." Measures like Cap and Trade or Carbon Taxes definitely fall into the category of "too much." Something to keep in mind when considering this is to remember that the US actually met its Kyoto Protocol CO2 emission target in 2012, without ever making any concerted attempt to do so. Rather, it happened organically, due to a shift to using more natural gas and less coal.

Edited by Stochasty
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While I appreciate the premise of your argument, Stochasty, aren't you effectively throwing the baby out with the bath water? All of science is based on models of one form or another. Those models are tuned and re-tuned as we gain more understanding, but they are only ever models.

Why should climate models be dismissed as nothing more than underdetermined systems of arbitrary variables, tuned with equally arbitrary coefficients to match existing data, when we accept other models such as the standard model of particle physics as gosphel? While it is true that the standard model successfully predicts some amazing and counter-intuitive experimental observations, it still fails to predict plenty of others. Climate models may not be perfect, but they are based on our best understanding of fundamental physical principles.

Much of our standard of living in the developed world is the result of engineering. That engineering is based on scientific models that predict the behaviour of systems, structures, etc. There are occasions where our predictions, based on those models, turn out to be wrong… But that doesn’t mean that we should do nothing because we’re afraid to fail. And certainly, it doesn’t mean that we should be reckless and do whatever we want, damn the consequences, because our models are probably wrong anyway.

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The point of my reply is that, when you are assessing potential remedies to the problem of CO2 emission, you must factor in both the costs of acting and not acting. This is something often ignored by the environmental activist crowd, who typically argue that we must do something "right now" to stave off some putative ill effect that won't happen for another century. (And, typically, their idea of what we should do is simply to hand them more political power, but that's an argument for a different thread; I'm concerned here more with the science and less with the politics).

Global warming - even if the worst of the doomsayers are right - is a slow process, and fixing it - assuming that fixing it is the right thing to do - will also be a slow process. So, I am entirely in favor of measures to lessen our dependence on fossil fuels - switching to nuclear power is the obvious solution, although it is politically untenable - so long as those methods seek to be as painless as possible. But, if you ask me how much pain I'm willing to endure today to prevent potential ill effects tomorrow - that's where a cost-benefit analysis comes into play, and that's where analysis of the actual predictive power of climate modelling matters.

Right now, personally, the answer to that question is "very, very little." Measures like Cap and Trade or Carbon Taxes definitely fall into the category of "too much." Something to keep in mind when considering this is to remember that the US actually met its Kyoto Protocol CO2 emission target in 2012, without ever making any concerted attempt to do so. Rather, it happened organically, due to a shift to using more natural gas and less coal.

One must also the cost of acting now and the cost of acting later. Once we reach some critical value of atmospheric CO2, there suddenly becomes far less scope to actually do anything to combat the problem since actually removing atmospheric CO2 or undertaking some geo-engineering projects is an entirely different problem to simply making sure that dangerous levels of CO2 aren't emiited initially. It's worth remembering as well, that potential geo-engineering methods such as sulphate aerosols might actually cause rather unpleasant climatic effects, which could be almost as dangerous as the warming effects they are seeking to prevent.

Essentially, should you perform a cost-benefit analysis and decide that the problem isn't worth fixing at the moment, you have to be comfortable with the idea that it will never be fixed because the cost is increasing with time and the beneficial effects will likewise be lessened. Effectively, the optimal time to act was a long time before the present but that is hardly an option.

Also, any cost-benefit analysis must naturally consider not only economic consequences but humanitarian and global political considerations. Chances are that within the western world, civilisation will, in some form or another, be able to adapt to a significantly harsher environment. We still have enough of an advantage in terms of economic size per capita that we can buy our way out of trouble - to some extent. On the other hand, climate change could devastate agricultural production particularly throughout many third world and developing nations and the cost in lives could be enormous.

I am personally not so wedded to the idea that any efforts need to be financially painless that I would rather see potentially millions starve in an agricultural crisis on the basis that "I will most likely be okay."

You are correct that the US has been reducing emissions due to increasing use of natural gas in place of coal power. This is a natural result of a de-regulated energy market. The same shift began to occur in Britain in the 1980s with the discovery of North Sea oil and gas and as Margaret Thatcher sought to overcome the power of the unions at the time. The shift to gas is itself a positive development in that it tends to both reduce CO2 emissions as well as reducing prices for the consumer (at least compared to coal).

The shift to gas, however is unlikely to be replicated in the near future by a shift away from gas. Gas performs excellently within the confines of the private sector, where minimal initial capital outlay and ability to maintain ongoing profits become the key goals. It might be, overall, more profitable for a private company to build a nuclear power plant, spend several £billion in construction, then operate it for 40-50 years than to build and operate several gas-fired power plants over the same period but the latter option is seen as safer because a) it doesn't require huge initial investment that will be dormant for 5 years while the power plant is built and B) operating a power plant for 15-20 cost-effectively is inherently more resilient to competition than doing so for 40 or 50.

Fossil fuels are also artificially cheap because the damage that they are doing to the environment is not factored into their actual cost. I would argue that measures such as cap and trade or, as I would favour, a carbon tax are not only not "too much" they are in fact necessary for the functioning of an efficient market. (Much like a command economy, a completely free market promotes perverse incentives and both are fairly equally dangerous).

Anyway, this is an area in which the market is performing entirely self-consistently but not in a positive way for the consumer or humanity as a whole. Intervention, by making nuclear power and renewables relatively cheaper, is likely to not only produce positive environmental gains but equally to actually stimulate economic growth. As I've already noted several times, French electricity is cheaper than in most other western European countries due to the predominance of nuclear power within its energy sector, this is despite the fact that nuclear power has never been built on the kind of scale that we have seen within the fossil fuel sector. More widespread nuclear construction could easily see it become the cheapest form of power generation, an effect which is further amplified when you factor in the likely increase in the cost of gas over the coming years. Energy production is closely tied to economic growth, the two are extremely strongly correlated. It is also reasonable to assume that cheaper electricity would mean cheaper and more cost-effective manufacturing which should lead to further growth.

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Oh crap !

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I unintentionally provided a denialist with a nice soapbox to dump his propaganda from and left it unattended for days.

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So let's untangle this mess. First, note the modus operandi of a typical denialist.

Note how he seizes on each detail to use it as an excuse to sweep everything off table.

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Are you comparing high time resolution data with low resolution data ? Averaging the higher time resolution data is the normal, in fact the only sane thing to do. We all, who have to statistically evaluate data sequences, regardless in which area of science or engineering we are working in, do it almost daily. But what does the denialist do ? Hey ! You --gasp-- Averaged ! That is TAMPERING !!!!111! Off with the head !

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Using some external data to calibrate your model/measurement method/device ? Virtually everything humans came up with needs at least some calibration. But for a denialist, any calibration counts as fudging the data. Off with the head !

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Previous models failed to replicate certain detail the new model replicated successfully ? Denialist says : "see, you are admitting that previous models were all utter hokum ! Off with all the models" (including the new one which actually worked)

And of course, for a denialist there is nothing like overkill, and once he came up to speed on spinning, he switches his engine to the high octane fuel - brazen lies.

"Global warming stopped in the last 15 years"

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Uh no.

Edited by MBobrik
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Why should climate models be dismissed as nothing more than underdetermined systems of arbitrary variables, tuned with equally arbitrary coefficients to match existing data, when we accept other models such as the standard model of particle physics as gosphel? While it is true that the standard model successfully predicts some amazing and counter-intuitive experimental observations, it still fails to predict plenty of others. Climate models may not be perfect, but they are based on our best understanding of fundamental physical principles.

We take the standard model as gospel because, although it is a purely phenomenological model, it works really, really well. Quantum Electrodynamics agrees with experiment to something like twelve decimal places. Compare that agreement with the lack of agreement for the climate models.

The reason why the predictions of the climate models are particularly untrustworthy goes back to a point Brotoro mentioned: extrapolation. Tuned models tend to be reasonably good at interpolation (that is, predicting behavior at intermediate points within your data set) but are notoriously bad at extrapolation (predicting behavior outside of your data set). The reason is that any errors tend to cancel out when examining behavior interior to your dataset, since the dataset contrains the behavior of the model; but, when you try to extrapolate beyond the ends of the data set, such cancellation is no longer assured. Thus, errors tend to accumulate, rather than damp. The upshot of this is that a model that exhibits substantial error over short term behavior when extrapolating is not likely to suddenly improve over the long term, which is why I've been making hay over the failure to predict the last 15 years.

Yes, there are other areas of science which use models just as complicated and just as prone to tuning issues. The astrophysical models Brotoro mentioned are good examples. However, rarely is the output of those models used to inform public policy to mandate sweeping changes to our way of life.

One must also the cost of acting now and the cost of acting later. Once we reach some critical value of atmospheric CO2, there suddenly becomes far less scope to actually do anything to combat the problem since actually removing atmospheric CO2 or undertaking some geo-engineering projects is an entirely different problem to simply making sure that dangerous levels of CO2 aren't emiited initially.

See, I disagree with this. I haven't seen any plausible evidence that there actually is some critical CO2 value after which the problem becomes intractable.

If I accepted your premise here, I would be more willing to act now, but your argument relies on me accepting that, 1) if we don't act now it will be harder to act in the future; 2) the problem won't fix itself if we leave it alone; and 3) failure to fix the problem will lead to catastrophic outcomes. I don't buy any of those three arguments. The pace of technological progress belies point 1), the example of natural gas illustrates that point 2) might not hold, and I have never bought the argument that a warmer, wetter climate would somehow be worse for human inhabitation. Life does well when it's warm, and poorly when it's cold. It's just as plausible that large areas of Siberia become much more arable due to increasing temperatures as it is that areas of Africa desertify. (Desertification has far more to do with wind and moisture patterns than it does with temperature, so it's not clear that global warming would cause desertification.)

I unintentionally provided a denialist with a nice soapbox to dump his propaganda from and left it unattended for days.

Go away. I might have started this discussion based on my argument with you, but the adults are talking now. If you can't contribute except via snark and ad hominem, please leave.

Edited by Stochasty
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Go away. I might have started this discussion based on my argument with you, but the adults are talking now. If you can't contribute except via snark and ad hominem, please leave.

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You are not the boss here and you are not he one who tells what an argument is and not ( you even don't seem to understand what an argumentum ad hominem is ... ) And I am going nowhere, I will stay and expose each and every piece of your propaganda for what it is - shameless spin and lies.

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Exhibit #2 :

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The reason why the predictions of the climate models are particularly untrustworthy goes back to a point Brotoro mentioned: extrapolation. Tuned models tend to be reasonably good at interpolation (that is, predicting behavior at intermediate points within your data set) but are notoriously bad at extrapolation (predicting behavior outside of your data set). The reason is that any errors tend to cancel out when examining behavior interior to your dataset, since the dataset contrains the behavior of the model; but, when you try to extrapolate beyond the ends of the data set, such cancellation is no longer assured. Thus, errors tend to accumulate, rather than damp.

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You are just pulling things from your, ehm, nozzle. If this were indeed a kind of general rule, virtually all modern science and technology would work only under the circumstances it were developed and that's it, because as I already mentioned, virtually anything needs some sort of calibration.

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If I accepted your premise here, I would be more willing to act now, but your argument relies on me accepting that, 1) if we don't act now it will be harder to act in the future; 2) the problem won't fix itself if we leave it alone; and 3) failure to fix the problem will lead to catastrophic outcomes. I don't buy any of those three arguments. The pace of technological progress belies point 1), the example of natural gas illustrates that point 2) might not hold, and I have never bought the argument that a warmer, wetter climate would somehow be worse for human inhabitation. Life does well when it's warm, and poorly when it's cold. It's just as plausible that large areas of Siberia become much more arable due to increasing temperatures as it is that areas of Africa desertify. (Desertification has far more to do with wind and moisture patterns than it does with temperature, so it's not clear that global warming would cause desertification.)

The way that dangerous levels of warming can be locked in is really rather simple, it is simply based on atmospheric CO2 concentrations. Even if we were to completely cease emission of all significant industrial greenhouse gases today, the temperature of the planet would continue to rise until the planet briefly settled into a new equilibrium position before the excess greenhouse gases began to slowly dimish in concentration due to their lack of replacement. Now, the lifetime of various greenhouse gases in the atmosphere is different, CO2 is somewhere between about 30-100 years while Methane only has an atmospheric lifetime of about 12 years. For now though, we can assume that carbon dioxide is the dominant factor and given that emissions are broadly at their highest in history today, we can likewise assume that in some post-greenhouse gas world, it will take between 30 and 100 years for the loss of greenhouse gases to reach its peak from that point of maximal emission.

In reality, of course, we are not going to cease all greenhouse gas emissions immeditely, it is going to take time. Assuming that the curve of carbon dioxide/year added to the atmosphere after the point of maximal emission isn't much much steeper than the curve of emissions that we have followed to get up to this point then we probably aren't even going to see decreased atmospheric concentrations of CO2 for a matter of 150-200 years and consequently no corresponding drop in temperature either.

That is why the maximal point needs to come sooner rather than later, otherwise the atmospheric concentration that will locked in for this period will be sufficient to cause dangerous levels of warming.

Now, on to point 1) I'm a great believer in the power of human innovation to solve problems but I simply don't accept that relying on some marvellous breakthrough solving our problems is very sensible. By taking this approach, we're relying on the exponential growth of technological capability exceeding the exponent of the exponential difficulty of resolving the climate problem. Frankly, I don't care to try and guess what these exponents are but simply hoping that exponent 1 is bigger than exponent 2 doesn't strike me as a very scientific approach, especially when exponent 1 does not have a reliable value.

I actually quite agree with you on point 2), in fact I'd be very surprised if the problem does not resolve itself. There are known mechanisms by which it eventually will as I describe above but human civilisation could have been set back by a good century at the cost of many hundreds of millions or even billions of lives by the time that it does.

Regardless, thinking of global warming as producing a globally warmer and wetter climate is meaningful only a global average basis, it is not meaningful to take these global averages and expect them to apply uniformly to the world. There is, for instance, a huge gap between global average temperatures over the last 100 years and average arctic temperatures (the arctic has warmed consistently by almost double the global average). This will lead to a situation in the near future where the arctic is completely ice free in the summer - the absence of this sea ice could have destabilising impacts upon atmospheric and ocean circulation patterns, this could lead to dramatic local shifts in climate throughout much of the northern hemisphere.

Likewise, the increase in retained energy within the atmosphere is also likely to produce more extreme weather, this is likely to mean increases in the frequency and severity of hurricanes, droughts, etc. These circumstances are not conducive to human civilisation and disproportionately damage the developing world, where it is both more difficult to protect against as well as recover from the costs of such disasters.

I take your point that there may be an increase in arable land within some parts of the world as other parts become unsuited to human habitation but I presume it's not difficult to see the political and humanitarian difficulties that this could present? How are countries throughout the world going to react when millions of refugees arrive on their doorstep expecting somewhere to live in their newly habitable and now valuable living spaces?

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We take the standard model as gospel because, although it is a purely phenomenological model, it works really, really well. Quantum Electrodynamics agrees with experiment to something like twelve decimal places. Compare that agreement with the lack of agreement for the climate models.

Could it be that it works so well only because it has been tuned really well? Physicists experimented for decades in labs and accelerators all over the world to refine the standard model of particle physics. As a result, it does an excellent job at predicting some observations, but it still fails completely at explaining other experimental observations.

The standard model may be more refined than climate models, but they are both based on well understood and experimentally verifiable physical principles. If you can justify tossing out predictions made with one model because they don't fit your selectively chosen data, then why shouldn't you also throw out the other for the same reason?

I fully agree that it would be easier to make decisions that could affect our future well being if we had better data, but we often have to make such critical decisions based on incomplete data. We have to make do with the models we've got, work to improve them, and hope that the decisions we make today that are based on those models won't bite us in the future. That, really, is the art of engineering and it takes me back to my earlier point: It is always reckless to do whatever we want, damn the consequences, because we believe that our models are probably wrong anyway.

Edited by PakledHostage
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Could it be that it works so well only because it has been tuned really well?

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Quantum Electrodynamics does not tell you things you don't want to be true (yet). That's why there is little ideologically or economically motivated denialism directed against it.

Edited by MBobrik
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The way that dangerous levels of warming can be locked in is really rather simple, it is simply based on atmospheric CO2 concentrations.

You say this, but this is the whole crux of the issue, isn't it? What evidence is there of this turning point based on CO2 concentrations other than the models?

I actually quite agree with you on point 2), in fact I'd be very surprised if the problem does not resolve itself. There are known mechanisms by which it eventually will as I describe above but human civilisation could have been set back by a good century at the cost of many hundreds of millions or even billions of lives by the time that it does.

I happen to think that market forces and technological progress will tend to phase out burning of fossil fuels (although we'll probably still use them for plastics until we run out) within a generation or so. I don't have any real evidence for this, just my intuition. To err on the "more warming" side, let's make some ball-park estimates and say that fossil fuel usage largely stops within the next 100 years, and that CO2 peaks no higher than 2,000ppm (so, 2.3 doublings). Assuming that the concept of climate sensitivity holds for concentrations in that range, that gives us between 3 and 10 degrees C maximum warming. The low end is within natural variation over the geological history of the Earth, the high end is just beyond it, and the middle puts us smack dab into the period known as the Eocene Climate Optimum.

Try as I might, I don't see how this is going to cause hundreds of millions of deaths and set back human progress by a hundred years. It's Malthusian doomsaying. Sure, it might cause localized displacements (although, 100 years is a long time in human terms, and people are good at adapting - that's why we're the dominant species) - but the discount rate over a period of a hundred years is awfully large, and localized displacements many decades from now don't warrant drastic changes to our economy today.

Could it be that it works so well only because it has been tuned really well?

K^2 is really the right person to talk to about the standard model - my expertise is QFT in curved space so I don't play with the full particle physics model often. However, I'll give it a shot:

The standard model contains 18 free parameters: 9 fermion masses, 3 mixing angles and one phase, three coupling constants, the Z_0 mass, and the Higgs mass. Its dependence on each of these parameters is relatively simple, and many of them are amenable to independent experimental confirmation. Granted, the form of the model is purely phenomenological, but we have reason to believe that that form is largely correct on physical grounds. Furthermore, the model is much, much simpler than the climatological models, and we have far better quality of data against which to test it. Also, we don't tend to use the standard model for extrapolation (it's generally accepted that the standard model will break down at sufficiently high energies, which is why we continually build more and more powerful particle accelerators to probe for new physics).

So, the answer is that you're right: it works as well as it does because it's been tuned really well. But, we've also pretty much run out of parameter space for the model: if we change any of the parameters, the model ceases to work so well. This gives us indication that the form of the model is probably right. However, these are the right types of questions, and physicists have been asking these questions about the Standard Model for half a century (and we still are; do an arXiv search for "Beyond the Standard Model" physics).

Lastly, the standard model has survived the acid test: it has made predictions which have been born out by experiment. The most recent such success was the discovery of the Higgs Boson.

If the situation were analogous from climate science, I would be willing to trust the models. It's not. The models are more complicated and less well tuned, and the parameter space of the models is not so well understood. The mere fact that we're using models in the plural, rather than Standard Model (singular and capitalized), should tell you something about the relative success (or lack thereof). And, lastly, the climate models have not survived the acid test: they uniformly predicted more warming than was observed for the first decade of the 21st century.

Edited by Stochasty
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The point of my reply is that, when you are assessing potential remedies to the problem of CO2 emission, you must factor in both the costs of acting and not acting. This is something often ignored by the environmental activist crowd, who typically argue that we must do something "right now" to stave off some putative ill effect that won't happen for another century.

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Measures like Cap and Trade or Carbon Taxes definitely fall into the category of "too much."

Of course you have to consider the cost of acting versus not acting. The cost of not acting is much more difficult to predict, and I don't think "letting the free market sort it out" is ever going to work. Better safe than sorry, isn't it? The only thing anyone is suggesting to do "right now" is *start* the process of pushing the market in a safer direction to start pricing in externalities that have at least some possibility of being very very bad. I very much disagree that cap and trade or carbon taxes are too much. Energy is still cheap by developed world standards, thanks in part to the recent significant shift to natural gas. This reduces the carbon intensity of energy, but doesn't much slow down the inevitable growth in fossil-fuel energy use. A little bit of nudging here could go a long way.

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And, lastly, the climate models have not survived the acid test: they uniformly predicted more warming than was observed for the first decade of the 21st century.

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Temporary slowing down ( not stopping, as my link shows, the oceans are still taking up heat ) was due to exogenous factors like very sub-average solar activity and increased volcanism. No model of earth's climate is expected to model solar activity and a model of Earth's tectonic processes as well. Summarily dismissing models because of things they weren't supposed to take account of in first place is very unfair, and evidence of your ideological bias.

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You say this, but this is the whole crux of the issue, isn't it? What evidence is there of this turning point based on CO2 concentrations other than the models

There needn't be any turn point in the mathematical sense of the word, the derivative of atmospheric concentration can be continuous and in the same direction it is the absolute quantity that matters. Should a turning point be reached, such as a dimishment in CO2 emissions then the absolute concentration will still not reduce below a dangerous level for a long period of time. I mean, this is basic mathematics, all you need do is look at potential decline curves in CO2 emissions/unit time and compare that to prior emissions to see how quickly emissions need to come down.

If you don't see the danger of between 3 and 10 degrees of warming, I don't see how this debate can reasonably continue. I mean, how much you want? By the time you're getting to the middle-upper scale of this range, many of our major population centres are completely under water, much of the developing world is uninhabitable, the rain forests are likely collapsing rapidly. Sure, there's no danger to "life on Earth" as a whole but humanity becomes a scattered remnant. In general, large scale changes in the climate throughout Earth's geological have coincided almost perfectly with mass extinction events. Humanity is probably resilient enough to survive such a thing on a small scale but say goodbye to billions of Humans.

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If you don't see the danger of between 3 and 10 degrees of warming, I don't see how this debate can reasonably continue. I mean, how much you want? By the time you're getting to the middle-upper scale of this range, many of our major population centres are completely under water, much of the developing world is uninhabitable, the rain forests are likely collapsing rapidly. Sure, there's no danger to "life on Earth" as a whole but humanity becomes a scattered remnant. In general, large scale changes in the climate throughout Earth's geological have coincided almost perfectly with mass extinction events. Humanity is probably resilient enough to survive such a thing on a small scale but say goodbye to billions of Humans.

See, it's the rampant, wild speculation like this that makes me so distrustful of those on your side of the argument. Other than the problem of sea level rise, you cannot tell me that there is a shred of evidence supporting your claims. Rain forests collapsing due to an increase in the areal extent of tropical weather? Rendering the developing world uninhabitable? Seriously? Regarding mass extinctions, while many mass extinctions have coincided with changes in climate, there have been numerous changes in climate which have not coincided with extinctions. Otherwise, we would see mass extinctions coinciding with each and every onset of glaciation over the last 3 million years.

The one place where you do have a point is regarding sea level rise; were the Antarctic Ice Sheet to melt completely we would be looking at a sea level rise of about 60 meters (drawn out over the course of a century). While this would be bad, there's no reason to think that a mere 10 deg rise in temperature would cause the complete melting of the Antarctic Ice Sheet. Going by IPCC estimates, the worst number I can find is about 3.5 meters over the century, but let's say that a catastrophic scenario plays out and we get 20 meters worth. Bad, right? Except, it's drawn out over a century, so we're looking at ~20cm per year. That's still a lot, and it would be a continual, long term drag on our economy over the century, but it's not so fast that we couldn't adapt to it.

Now, were we able to prove that such a catastrophic scenario were in our future, I'd be willing to implement measures now to prevent it - although, the discount rate for a century is quite large, so I'd want to look long and hard at the cost effectiveness of the proposed measures before I was willing to jump onto the bandwagon.

But, that's only for the worst case scenario I can imagine: a 10 degree rise in temperature causing substantial melting of the Greenland and Antarctic Ice Sheets. And, let's look into the assumptions we made to get to that worst case scenario: first, that humanity would keep producing CO2 for a much longer period than I think is plausible; second, that the long term predictions of the climate models are substantially right; and third that the real climate sensitivity is at the top end of the model-derived range. Can you see now why I'm skeptical of the doomsaying?

Then, when I step back and look at things, not only am I forced to come to the conclusion that not only is such a scenario unlikely, it's unfounded. It's based on accepting numbers for climate sensitivity from models that have no proven predictive power. If we consider only the raw climate sensitivity for CO2 in the absence of feedbacks (which, believe it or not, I would be willing to accept as the null hypothesis), then even in my crazy 2000ppm CO2 scenario we're looking at about 2.7 degrees C of warming, which, according to IPCC estimates, puts us in the 1-2m sea level rise range - not so catastrophic at all.

Edited by Stochasty
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Then, when I step back and look at things, not only am I forced to come to the conclusion that not only is such a scenario unlikely, it's unfounded. It's based on accepting numbers for climate sensitivity from models that have no proven predictive power.

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yeah right. no proven predictive power. Except a couple of fulfilled predictions, no predictive power. Nothing to see here, move along... no model could ever reach your goalposts with a strap-on transwarp drive, so why bother with models. Wonder whether you drive like that - driving straight forward until 100 % proven you are going to crash without swerving.

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See, it's the rampant, wild speculation like this that makes me so distrustful of those on your side of the argument. Other than the problem of sea level rise, you cannot tell me that there is a shred of evidence supporting your claims. Rain forests collapsing due to an increase in the areal extent of tropical weather? Rendering the developing world uninhabitable? Seriously? Regarding mass extinctions, while many mass extinctions have coincided with changes in climate, there have been numerous changes in climate which have not coincided with extinctions. Otherwise, we would see mass extinctions coinciding with each and every onset of glaciation over the last 3 million years.

If you think that present day climate zones won't shift due to warming at even the lower end of the scale, you're living in fantasy land. Do not expect temperatures to simply increase with no knock-on effects. I'm fairly sure that one of your arguments is about how vastly complicated comprehensive models of the climate are and how difficult it is to actually perform such calculations accurately, yet you apparently think that you can calculate in your head that climate change will simply lead to increased temperature and humidity in the rain forest with no other associated effects?

You cannot simply take a global time evolution and use the average to derive conclusions about local behaviour of a complex dynamical system. I'm sure you know this already, of course, so why are you even proposing it?

Anyway, let's look at ways that climate change might affect the rainforest. Drought is a major factor, as I previously mentioned it is becoming more prevalent and will become increasingly prevalent with increasing temperature. In the last 10 years the Amazon has suffered two major droughts of greater in scale than all preceeding droughts for the prior 100 years. Both of these occurances led to the Amazon becoming a net carbon source of carbon dioxide rather than a carbon sink (releasing, I believe, around a decades worth of carbon at its typical rate of removal of CO2 from the atmosphere), note that this is a positive feedback effect.

Changes in precipitation patterns are also likely to cause forest loss. Climate models indicate that precipitation in the amazon is likely to decrease moderately with increasing temperature. Increased temperature and reduced rainfall both suggest increased risk of forest fire which can cause further dramatic forest loss. Additionally, zones of savanna, which are likely to replace areas of lost forest are themselves much more susceptible to forest fire than the rainforest they are replacing.

Now, to respond to the other point. Sea level rise certain represents one of the major dangers to the developing world. Again, the rate of sea level rise is less significant than the overall quantity of land lost due to this sea level rise. As soon as you begin displacing large populations in the developing world, humanitarian problems become major concerns. Much of the remaining land, often being in equatorial climates, again become at risk of desertification while increased frequency and severity of natural disasters further hinder the agricultural productivity of these regions. As if this wasn't bad enough, in order to try and cope with these conditions, the land must be more heavily irrigated which leads to increased soil salinity and a degredation of the productivity of the land, further amplifying the desertification of such regions.

It is by no means unreasonable to suggest that even relatively modest changes to global temperature are likely to cause significant shortfalls in food production, especially within these regions. The scale of the temperature rise obviously determines the severity of these effects, with the damage ranging from significant based on expected climate scenarios to absurdly deadly in your ridiculous 10 degree scenario.

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If you think that present day climate zones won't shift due to warming at even the lower end of the scale, you're living in fantasy land.

Yes. But they've changed before, and they'll change again, whether or not we release carbon into the atmosphere. Greenland became briefly habitable before refreezing, and that had nothing to do with humans. The time scale of that change was no different than the time scale discussed here; if there was a catastrophe involved, it was the refreezing, not the warming.

Anyway, let's look at ways that climate change might affect the rainforest. Drought is a major factor, as I previously mentioned it is becoming more prevalent and will become increasingly prevalent with increasing temperature.

Changes in precipitation patterns are also likely to cause forest loss. Climate models indicate that precipitation in the amazon is likely to decrease moderately with increasing temperature. Increased temperature and reduced rainfall both suggest increased risk of forest fire which can cause further dramatic forest loss. Additionally, zones of savanna, which are likely to replace areas of lost forest are themselves much more susceptible to forest fire than the rainforest they are replacing.

Drought is caused by shifts in wind patterns, not by temperature. Climate change might cause local changes in precipitation patterns, but you're cherry picking here. For every area that sees less rainfall, there will be one which sees more. You can't count only the disasters and ignore the blessings. There is every reason to believe, based on the history of the Earth, that the Earth is more habitable when it is warm. You've even admitted so yourself, in a previous post.

This belies your claim of food shortages. For every bit of arable land that is lost to desertification, there will be as much or more new arable land available. Net effect on food production should actually go up, since most potentially arable land is located in regions whose climate would benefit by an increase in temperature (Canada and Russia being prime examples).

Yes, there will be local disturbances - but, on human scales, these disturbances are slow. A century is a damned long time, by human reckoning.

This same principle applies to sea level rise, too: a two meter rising in water level is a disaster when it happens over a few hours; it is background noise when it happens over the course of a hundred years. Many coastal cities - New York, for example - have already experienced comparable effective sea level rise over the last century as a result of land subsidence. You'll note that the people of New York failed to evacuate - and, for that matter, failed to notice.

This is the problem: you're using scare tactics here, not rational scientific thinking. Each of the issues you name is a localized, slowly manifesting issue, and humans have more than enough capability to adapt to those problems as they occur. Even in the ludicrous 10 degree scenario we could adapt, although I'm willing to admit that the costs of adapting there would be significant.

So, the proper response here is not to run about like chicken little shouting that the sky is warming. It is to identify what the actual effects would be under each scenario, identify the costs of adapting to them as they occur, and identify the costs of trying to prevent them from occurring by acting now. If the cost of acting now is greater than the cost of acting in the future, then the proper response is to do nothing. Even were I willing to grant you all of the negative effects associated with global warming that you claim, I'm not willing to grant that it is obvious that we should act.

Edited by Stochasty
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Drought is caused by shifts in wind patterns, not by temperature. Climate change might cause local changes in precipitation patterns, but you're cherry picking here. For every area that sees less rainfall, there will be one which sees more. You can't count only the disasters and ignore the blessings. There is every reason to believe, based on the history of the Earth, that the Earth is more habitable when it is warm. You've even admitted so yourself, in a previous post.

This belies your claim of food shortages. For every bit of arable land that is lost to desertification, there will be as much or more new arable land available. Net effect on food production should actually go up, since most potentially arable land is located in regions whose climate would benefit by an increase in temperature (Canada and Russia being prime examples).

Yes, there will be local disturbances - but, on human scales, these disturbances are slow. A century is a damned long time, by human reckoning.

There are many possible causes of drought, deviation from expected precipitation being a dominant factor though there are any number of potential causes. Regardless, no, I'm not cherry picking. There is no reason to believe that there will remain any kind of habitability equilibrium as global temperature increases, certainly not for humans anyway. You have no automatic right to assume that if one region becomes less habitable another one will become more so. It is quite possible that, as a global average, the conditions become less suited to the kind of environment that humans are accustomed to living in.

I quite accept, however, that there will be regions of Canada and Russia, as examples, that will likely become relatively productive arable land but continental climates like these are inherently prone to extremes of temperature, both in terms of heatwaves and extended cold spells, both of which can significantly hinder agricultural output. Essentially, a world with lower crop yields and a smaller proportion of arable land would be additional things that we'd have to adapt to.

The problem would be significantly dimished were human society efficient at actually operating collectively for the good of the species. Do you really think that when millions of people are displaced from developing countries they are going to be welcomed with open arms in the new arable regions of Canada and Russia? What incentive do the governments of those countries have to actually share those benefits with these displaced refugees rather than to keep them for the benefit of their own citizens? What will the cost of dealing with these refugees be and where will they live? This is a massive problem and one that I've mentioned repeatedly but you keep neglecting.

I shouldn't even respond to the point about New York but I'll bite: I have already made it clear several times that humanitarian costs would be focused around locations within the developing world that are less able to adapt to and recover from changing circumstances. It is hardly meaningful to argue that a city with one of the highest city GDPs in one of the world's wealthiest countries has had few problems adapting to one of the dangers posed by climate change. Even if New York were an example of a highly at-risk location, one item does not a representative sample make. Again, you know this.

If you think I'm using scare tactics, however, I would have to argue that you simply don't comprehend the threat facing us, a fact that is reinforced by the idea that you think that human civilisation could adapt to a world with 10 degrees of warming. I mean, I suppose it depends on your definition of adapt. Like I said, I'm sure that some people would survive but its going to be struggle to actually support the number of people that are predicted to be in the world in the next 50 years, that's before we even consider moderate climate change nevermind some ludicrous 10 degree scenario.

I'm also curious anyway why you think that acting now to prevent climate change is so expensive. The cost is primarily political, the energy sector can be decarbonised painlessly provided that construction of new power plants is properly regulated or CO2 emissions are appropriately taxed and this represents the single largest source of greenhouse gas emissions. Electric and, to a lesser but potentially more useful extent, hydrogen vehicles are making steady progress and both show plenty of promise. Many industrial processes can be switched over to electrical rather than thermal processes, which provided decarbonisation of the power sector is in progress does not present any problems of its own. Aviation and agriculture are a little trickier but again there are promising avenues and if you make up the slack in some of the easier to decarbonise sectors of the economy, more leeway can be allowed within the more difficult ones.

The proper approach in this matter is indeed scientific rational thinking. It is to identify how to prevent this problem from occuring via the most beneficial means. The cost of acting now is not nearly so horrendous as many would have you believe. An appropriate term for those who prophesise doom at the cost of the reforms that decarbonising our economies would take could indeed be "scaremonger." A crude analogy to illustrate this might be a medical condition: if you experience some abdominal distress, do you go to the doctor and see if you need to have your appendix removed or do you simply wait for it to burst and deal with the consequences afterwards? The first represents a rational approach to dealing with the problem and is clearly the most efficient, some people chose the second because they are afraid of what the doctor might say.

I'd also appreciate it if you would clarify your position. Initially you were arguing that current climate simulations weren't accurate as a basis for modelling the future atmospheric behaviour of the planet, now you seem to be arguing from a position that climate simulations might be accurate but that the dangers aren't worth worrying out. Given that these are quite distinct topics of independent scientific research and you appear to hold views that conflict with the scientific consensus on both of them, it really makes me question your intellectual objectivity in this matter. You should be approaching this from a cold analysis of the available facts and drawing your conclusions on this basis, not entering the argument with a predefined agenda which you are attempting to argue to promote.

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Funny how this guy summarily rejects all climate simulations as insufficient, yet he seems to know exactly, how the ecosystems and human societies, which are orders of magnitude more complicated and difficult to model, will react to drastically altered climate. Without need of any models at all !

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I think that a simulation of him would not be hard to write

void main() {

while(true) {

mouth.insert(foot);

}

}

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