Yes, and that’s why you can even attempt to build a computer model. But you seem to be assuming that a climate model can actually simulate all those processes on a relatively fundamental level, and that isn’t the case.
When you set out to build a model of a large, non-linear system you’re confronted with a list of tens of thousands of known processes that might be important. Adding them all to your model would take millions of man-hours, and make it so big no computer could possibly run it. But you can’t just take the most important-looking processes and ignore the rest, because the behavior of any non-linear system tends to be dominated by unexpected interactions between obscure parts of the system that seem unrelated at first glance.
So what actually happens is you implement rough approximations of the effects the specialists in the field think are important, and get a model that outputs crazy nonsense. If you’re honest, the next step is a long process of trying to figure out what you missed, adding things to the model, comparing the output to reality, and then going back to the drawing board again. There’s no hard, known-to-be-accurate physics modeling involved here, because that would take far more CPU power than any possible system could provide. Instead it’s all rules of thumb and simplified approximations, stuck together with arbitrary kludges that seem to give reasonable results.
Or you can take that first, horribly broken model, slap on some arbitrary fudge factors to make it spit out results the specialists agree look reasonable, and declare your work done. Then you get paid, the scientists can proudly show off their new computer model, and the media will credulously believe whatever predictions you make because they came out of a computer. But in reality all you’ve done is build an echo chamber—you can easily adjust such a model to give any result you want, so it provides no additional evidence.
In the case of nuclear winter there was no preexisting body of climate science that predicted a global catastrophe. There was just a couple of scientists who thought it would happen, and built a model to echo their prediction.
Yes, and that’s why you can even attempt to build a computer model. But you seem to be assuming that a climate model can actually simulate all those processes on a relatively fundamental level, and that isn’t the case.
When you set out to build a model of a large, non-linear system you’re confronted with a list of tens of thousands of known processes that might be important. Adding them all to your model would take millions of man-hours, and make it so big no computer could possibly run it. But you can’t just take the most important-looking processes and ignore the rest, because the behavior of any non-linear system tends to be dominated by unexpected interactions between obscure parts of the system that seem unrelated at first glance.
So what actually happens is you implement rough approximations of the effects the specialists in the field think are important, and get a model that outputs crazy nonsense. If you’re honest, the next step is a long process of trying to figure out what you missed, adding things to the model, comparing the output to reality, and then going back to the drawing board again. There’s no hard, known-to-be-accurate physics modeling involved here, because that would take far more CPU power than any possible system could provide. Instead it’s all rules of thumb and simplified approximations, stuck together with arbitrary kludges that seem to give reasonable results.
Or you can take that first, horribly broken model, slap on some arbitrary fudge factors to make it spit out results the specialists agree look reasonable, and declare your work done. Then you get paid, the scientists can proudly show off their new computer model, and the media will credulously believe whatever predictions you make because they came out of a computer. But in reality all you’ve done is build an echo chamber—you can easily adjust such a model to give any result you want, so it provides no additional evidence.
In the case of nuclear winter there was no preexisting body of climate science that predicted a global catastrophe. There was just a couple of scientists who thought it would happen, and built a model to echo their prediction.