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>Chaos doesn't mean you have to throw your hands up and give up on making any long term predictions at all about a system. But we can't tell what the weather w
by Produce 14y ago
>Chaos doesn't mean you have to throw your hands up and give up on making any long term predictions at all about a system.
But we can't tell what the weather will be in 45 days in New York.
One of the attributes of chaotic systems is their self-similarity. The behavior on one level is similar to the behavior on another - in this case weather is similar to climate. We can make predictions about the weather in the next few days, just as we can with climate, but in the next few months or years (or centuries or millenia for climate) is another story. The tiny pertrubations in the system which we do not model (the butterflies) end up throwing our predictions off in the long run.
- xyzzyz 14y agoYes, and that's why nobody is claiming to be able to predict the weather in the long run. Nevertheless, some things still can be predicted, even in chaotic systems. What is your point?
- Produce 14y agoMy point is that pollution should be reduced, climate models should still be developed and that at the same time we shouldn't take their predictions as dogma and continue to question them.
- scarmig 14y agoI agree with all of what you say above and am skeptical of the models as they exist now, as another comment of mine elsewhere suggests. I'm more interested in the theoretical question here, though. I'm unconvinced that self-similarity in chaotic systems means that since weather is a chaotic system, climate is itself a chaotic system that's unpredictable in the long term. One way of thinking about chaos is that at some point in the future, a system's position in phase space will become wholly uncorrelated with the system's initial position. So for weather, tomorrow's weather is correlated with today's weather, but weather two weeks from now (or whenever) is wholly uncorrelated. But with climate you do end up with persistent correlations, year on year, decade on decade, millenia on millenia. Temperate regions show (anti-)correlations of deviation from annual average temperature between 180 day periods, and daily solar energy impingement is correlated with positive deviation from global mean temperature. I've always made a mental analogy between that and a gas (the n-body problem): even though the positions of gas molecules rapidly become uncorrelated from their starting position, certain statistical properties--e.g., the pressure the gas exerts on the walls of its container--are highly correlated from one moment to another. Not just initially but into the indefinite future. I'm open to arguments that that analogy is flawed and could see some assumptions that I'm not 100% confident in, but I don't see any obvious flaws. What's going wrong here, in your view?
- MaysonL 14y agoThe point is, while the models are inaccurate, the data (and there is a lot of data) indicate that warming is happening. This is shown not merely in temperature measurements; but in ice coverage changes, both in the Arctic Ocean and at mountaintops; and in biological change: increased growing seasons, earlier spring flowering, earlier bird migrations (and in some cases increased overwintering bird populations), increased ranges of species, including pests; not to mention permafrost melting and increased droughts and other severe weather anomalies in many areas.
- deleted 14y ago[deleted]