Models say only what the modeler tells them to say.
Do you have any evidence for this? Are you implying that climate change isn't happening?
Do climate models predict extreme weather?
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Re: Do climate models predict extreme weather?
#22Models say only what the modeler tells them to say.
So in this case the modeler just needs to tell the model to (1) accurately calculate the degree to which the Earth's climate will change in the next few decades and (2) give a comprehensive global forecast of the accompanying extreme weather events.
Re: Do climate models predict extreme weather?
#23Models say only what the modeler tells them to say.
modeling an infinitely fractal set of chaotic systems can only do exactly this
Re: Do climate models predict extreme weather?
#24I believe in climate change, but if you look into how the climate change computer models are written, it really makes me feel like it is contrived. Here's the problem with climate change modeling, you are modeling a complex chaotic system, you just cannot do it accurately. You have to be honest about it.
This is a pretty extreme claim to make without references. Have you looked at climate change computer models? Which ones what are your credentials in making this sort of "code review"? Etc.
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Re: Do climate models predict extreme weather?
#25One of the things about "extreme weather attribution" that makes me uncomfortable is the asymmetry of it. To be clear: I'm in no way an expert (or even educated) in the area. To give an example. Let's say there's a 1% chance every year that there will be a catastrophic wildfire in some particular area. Now let's say climate change increases a chance of drought in that area. Then we get a wildfire one year and the att…
That's why in these discussions it's usually better to talk about specific statistics like 'the chance of a wildfire has gone up by 20%', or perhaps more clearly 'the average time between extreme floods has gone down from once every 100 years to once every 60' (which I find communicates the point a bit more clearly).
That said personally I think that should be as far as the discussion goes, talking about a specific event and asking whether it's because of climate change is silly and leads to counter intuitive results because by nature extreme weather events are mostly caused by bad luck.
Climate changes the frequency of extreme events, but talking about the frequency of a singular specific event is impossible. And talking about just 1 or 2 of them isn't quite enough either, events will occur at a rate far above or below that predicted by the best weather models simply because of (bad) luck.
I sometimes get the feeling that people try to attribute extreme weather to climate change because it improves the narrative, or as proof that climate change has happened. But personally I find this a bit silly since the fact that the global average temperature has increased and the effects this has on weather shouldn't be all that controversial.
Re: Do climate models predict extreme weather?
#26I believe in climate change, but if you look into how the climate change computer models are written, it really makes me feel like it is contrived. Here's the problem with climate change modeling, you are modeling a complex chaotic system, you just cannot do it accurately. You have to be honest about it.
It’s complex and chaotic, sure. But as you increase time horizons, and area of simulation larger and larger, that complexity and chaos starts to average out. So you can’t take a singular datapoint from a climate model, and make any concrete statements, but you can take thousands to millions of them and start making probabilistic statements.
Additionally it’s not like these models are untested. Their predictions are continually compared to actual reality, including by taking know data, and asking the model to predict more known data. Pretty basic stuff for testing the capability of any model, and guess what, that data shows these models are pretty darn good.
Everything in this world is complex and chaotic, how cars behave in collisions is complex and chaotic. But no one doubts our ability to use computer models to design safer cars. Equally most people generally trust the one week weather forecast, despite the fact that it’s substantially more difficult to predict weather than it is to predict climate.
Re: Do climate models predict extreme weather?
#27Earlier quoted context omitted.
Extreme weather can occur in both directions. A year with more rain may be less prone to fire but more prone to flooding. It also does not take natural disaster to notice extremes. People who have lived in the same area awhile will know if there is an unusually wet, dry, hot, or cold year.
> Extreme weather can occur in both directions. Of course that's true. What I guess I was trying to say is that a change in climate doesn't necessarily mean more extreme weather (in every instance, I mean). A change in climate could cause something to happen more or happen less . But no one is going to study a given year and a given place that doesn't have an extreme weather event.
Discrete events are a human construct but the underlying data is continuous. I'm not sure the attribution of individual events is that meaningful and the article suggests for a variety of reasons the models aren't really built for that purpose anyway. So I think in a sense you are right, but this doesn't necessarily imply any problem for the predictive value of the models or research going into them.
Re: Do climate models predict extreme weather?
#28I believe in climate change, but if you look into how the climate change computer models are written, it really makes me feel like it is contrived. Here's the problem with climate change modeling, you are modeling a complex chaotic system, you just cannot do it accurately. You have to be honest about it.
It’s complex and chaotic, sure. But as you increase time horizons, and area of simulation larger and larger, that complexity and chaos starts to average out. So you can’t take a singular datapoint from a climate model, and make any concrete statements, but you can take thousands to millions of them and start making probabilistic statements. Additionally it’s not like these models are untested. Their predictions are c…
Can you give me another example of a chaotic system that can be correctly forecasted years out?
Re: Do climate models predict extreme weather?
#29I believe in climate change, but if you look into how the climate change computer models are written, it really makes me feel like it is contrived. Here's the problem with climate change modeling, you are modeling a complex chaotic system, you just cannot do it accurately. You have to be honest about it.
Examples? This is a pretty dubious claim.
Just simple extrapolating logic. Climate is chaotic. Chaotic systems cannot be forecasted years out. Therefor a computer model for climate forecasting is not going to be accurate.
Re: Do climate models predict extreme weather?
#30We are taking a system that was in equilibrium and we introduce a huge disturbance (+ multiple degrees C). Hell yes it will be unstable until it reaches the new equilibrium (whatever that equilibrium will look like - catastrophic for life or not).