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Old 03-26-2014, 06:46 PM
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Originally Posted by Sam Stone View Post
The best you can say about current climate models is that they can predict with some accuracy the value of sequestered past data. But since climate is a complex adaptive system, tuning a model to the past climate and then predicting other values generated by that climate is not the same as predicting the future state of the climate system.

I'm not saying they are necessarily wrong - the errors in their predictions are still within the range of natural variability in the climate. A sudden turn to abnormal temperature increases due to variance could put them smack in the middle again. But that hasn't happened, so the predictive power of these models is still uncertain.

In every other field I'm familiar with, the value of 'tuned' models in predicting future states of complex systems is treated with a high degree of skepticism. Even in economics, most economists will freely admit that the predictive power of their models is highly dubious, but they use them anyway because that's the best they've got. The real value of these models is generally found to be in helping to understand such systems - not to predict their specific state in the far future.

If anything climate modeling is even more difficult than economic modeling, or computer models of immune response or brain activity. Climate operates on geologic time scales, the interactions between elements are very hard to determine, and measurement problems are very difficult. Yet we claim much more certainty in our understanding of climate change than we do of immune responses or how a specific ecosystem will respond to a shock, despite these systems being much easier to measure and change happening on much shorter time scales so we can learn from our model failures.
Nonsense, you are recycling denier talking points. If that was the whole truth, then people like Lindsen would had the same rate of success than other climate modelers.
I have mentioned the ice ages since this is a "natural experiment" that we use, not to forecast the future, but to build understanding of climate processes and to validate the tools that we do use to forecast the future -- that is, our climate theories embodied in mathematical models. Are there any other such natural experiments? The answer is "yes there are many," the two most prominent being (1) episodic volcanic eruptions which throw dust in the stratosphere that reflects for a few years a few watts per square meter of solar energy that otherwise would have reached the lower atmosphere and (2) the seasonal cycle. Let's consider volcanic eruptions first. Volcanic dust veils should cool the planet. In fact, the last major eruption, Mt. Pinatubo in 1991, was forecast to cool the earth's lower atmosphere on the order of several tenths of a degree by a number of climate modeling groups -- in advance of the actual data to confirm -- and indeed, that is roughly what happened. However, it could be argued that a few tenths of a degree cooling, or warming for that matter, might be a natural fluctuation in the earth's climate system, and indeed, fluctuations of that magnitude are a part of the natural background "climatic noise." How then could we distinguish the climatic signal of the volcanic eruption from the noise of the natural variability? In any one eruption it is difficult to do so since the signal to noise ratio is about one, i.e. the magnitude of the cooling expected is about equal to the magnitude of the natural fluctuations in non-volcanic years, and therefore for any one event we cannot have very much confidence that a signal has been observed. So the fact that the Pinatubo results showed up about as predicted doesn't, by itself, give a lot of confidence, although as a circumstantial bit of evidence is quite useful. However, another volcanic eruption in 1983, El Chich¢n, was also followed by several tenths of a degree cooling, as was the effect after Mt. Agung in 1963 or Mt. Krakatoa in the Victorian period.

In other words, by looking at the results of several volcanic eruptions and compositing, a number of scientists (including Mass and Schneider, 1977) used this technique and discovered that indeed there was a clear and obvious correlation which suggests that when a few watts of energy over every square meter of the earth is removed by volcanic dust veils in the stratosphere, the lower atmosphere will indeed cool by a few tenths of degrees -- the very magnitude predicted by the same computer models that we use to forecast the effects of a few watts per square meter of sustained heating from global warming.

What other natural experiments might we have to test climate sensitivity? My favorite is one that happens every year -- the seasons. Winter predictably follows summer, being some fifteen degrees colder in the Northern Hemisphere and five degrees colder than summer in the Southern Hemisphere. The reason the Southern Hemisphere has a smaller seasonal cycle is because it has much more ocean than land, and water has a higher heat retaining capacity than land or air. Since a season is not long enough for the planet to reach an equilibrium temperature change, therefore, the more land dominated Northern Hemisphere has lower heat capacity and thus a larger seasonal cycle of surface temperature. How well do the climate models do in reproducing this change? The answer is "extraordinarily well."
The thing here is that until recently I had not paid much attention to the models as on the whole they are not used exclusively by the experts to report that warming is coming thanks to the dumping of global warming gases into the atmosphere. But then as I found on searches while discussing this issue recently, I have concluded is that most of the items pointed by contrarians are really silly or not at the levels of the distrust they want to make of.

As it turns out it was thanks to Carl Sagan and Cosmos that I found in his last update to his original show that he pointed that computer models also work very well with the climate of other planets.

And then with that insight I found this:
Climate change models used to analyze changing conditions on Earth can be applied to at least one other planet in our solar system — Mars, a new study reveals.

Earth-based computer models can predict the age and location of glacial features on the Red Planet, scientists say. This extra-planetary generalization suggests that climate change models aren't so as inaccurate as they're sometimes portrayed, said study researcher William Hartmann, a senior scientist at the Planetary Science Institute in Tucson.

"Some public figures imply that modeling of global climate is 'junk science,' but if climate models can explain features observed on other planets, then the models must have at least some validity," Hartmann said in a statement.
So, since it is not junk science, one has to then conclude a few things:

1) You are still drinking a lot from the wellspring of the denier information.
2) The blind can not lead the blind. You have to be aware that the same makers of the "computer climate models are junk" say so are also recommending the "solutions" that are just the same as the think thanks that told us how to deal with the tobacco companies.
3) You still forget about the ants.

No, really, you are like an owner of a barn that has found an infestation of carpenter ants and he is being told that a few skeptics out there to do nothing as some models predict the ants will move away and he is accepting that over what the pest control experts recommend. Problem is that most models do predict the undermining of the walls of the wall if nothing is done. But imagine here if this is no problem for the barn construction companies that funded those skeptics.

Yes, that last bit is not what what the barn companies are doing, but it applies to the forces that are funding politicians and think thanks that are telling us to do nothing.

Last edited by GIGObuster; 03-26-2014 at 06:48 PM.