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Arthur T Knackerbracket has found the following story:
Last month, as much of the United States shivered in Arctic cold, weather models predicted a seemingly implausible surge of balmy, springlike warmth. A week later, that unlikely forecast came true—testimony to the remarkable march of such models. Since the 1980s, they’ve added a new day of predictive power with each new decade. Today, the best forecasts run out to 10 days with real skill, leading meteorologists to wonder just how much further they can push useful forecasts.
A new study suggests a humbling answer: another 4 or 5 days. In the regions of the world where most people live, the midlatitudes, “2 weeks is about right. It’s as close to be the ultimate limit as we can demonstrate,” says Fuqing Zhang, a meteorologist at Pennsylvania State University in State College who led the work, accepted for publication in the Journal of the Atmospheric Sciences.
Forecasters must contend with the atmosphere’s turbulent flows, which nest and build on each other as they create clouds, power storms, and push forward cold fronts. A tiny disruption in one layer of turbulence can quickly snowball, infecting the next with its error. A 1969 paper by Massachusetts Institute of Technology mathematician and meteorologist Edward Lorenz introduced this dynamic, later dubbed the “butterfly effect.” His research showed that two nearly identical atmospheric models can diverge widely after 2 weeks because of an initial disturbance as minute as a butterfly flapping its wings.
-- submitted from IRC
(Score: 2, Informative) by Anonymous Coward on Tuesday February 19 2019, @10:38AM (12 children)
Just to pre-emt those inevitable comments saying "see, we can't predict weather for merely a month, so how could we predict climate over decades", let me make it immediately clear that climate is not the same as weather.
I can't tell if in Washington, Jan 10, 2020 will be colder or warmer than Jul 13, 2020. But I'm willing to bet that on average in the US, winter 2019/2020 will be colder than summer 2020.
(Score: 1, Insightful) by Anonymous Coward on Tuesday February 19 2019, @11:50AM (5 children)
So you are willing to bet on imaginary number like average temperature of an entire country that probably includes people experiencing a range from -20 C to +20 C at any given time? Average temperature of an entire country the size of the US doesn't mean anything.
Now, perhaps you actually want to be measuring something in Joules? Total energy content of the first 2 meters of atmosphere or something? That would be a real number.
(Score: 3, Touché) by khallow on Tuesday February 19 2019, @01:55PM (4 children)
What's imaginary about it? Integration is a well-known thing.
(Score: 1, Insightful) by Anonymous Coward on Tuesday February 19 2019, @04:38PM
You can plug any numbers into an equation, doesn't mean the results have physical meaning.
(Score: 0) by Anonymous Coward on Tuesday February 19 2019, @04:46PM (2 children)
If I measure the energy content of two regions A and B, I can add A + B to get "total energy". Can I do that for temperature?
(Score: 2) by fritsd on Tuesday February 19 2019, @05:09PM
Probably [wikipedia.org], but I don't remember how to do it.
Eventually the black body radiation of the two bodies will have warmed up the one and cooled down the other to equilibrium.
(Score: 1) by khallow on Tuesday February 19 2019, @07:01PM
That's not even wrong territory. The existence of addition doesn't tell you anything about whether the values in question are real or imaginary in an existence sense. But if we were to add average temperatures in a sensible way, the way to do it would be the average temperature of A times the area of A plus the average temperature of B times the area of B divided by the total area of A and B.
(Score: 2, Insightful) by Anonymous Coward on Tuesday February 19 2019, @01:20PM (1 child)
Weather and climate are not the same, but not completely different either.
The weather models predict that it is likely to rain and generally where and when. This means predicting averages over the next few days. Not exactly when and where for each drop.
The article points out the Butterfly effect where random variation limits how far in the future a prediction can go. Given initial knowledge of the state of the system the models can only predict so far in the future.
That limit aside, there seem to be restoring forces in the weather which pull the random variations back to statistically measurable long term weather patterns.
Perhaps these long term weather patterns are the climate.
If they are predictable remains to be seen. In the last 50 years, the weather predictors have seen numerous 10 day weather cycles in detail. They have used these to tune their models to their current state. Still, the models are far from perfect in their ability to say if it will rain or not.
Climate prediction seems a similar problem, only the data set includes more things which are just constants to the weather models. The pattern cycles lengths are much longer. (It's been quite a while since the last ice age, but not so long since the last El Nino.) Mankind hasn't been around to see these cycles and can only glimpse at a few clues from the last one. (For example ice cores.) Given this, there seems no reason to expect a anything like the finely tuned weather model for the climate.
That said, one can still try. It is possible to gather more and more of the current state of the system. This includes especially the sea flows. It seems likely that we might not be able to predict, but will be able to better know the current state. For a climate scientist to call this prediction seems dishonest and discredits their field. This probably limits any response that these folks are hoping to see.
(Score: 2) by HiThere on Tuesday February 19 2019, @06:14PM
Of course, the problem is that as the climate warms, poles melt, etc. we are moving into a area where we don't have the relevant data. The models make predictions, but we have no idea how accurate they will be when the climate is, say 2 degrees warmer. All we know is that it will be hotter, and that water will evaporate more quickly. Moving into a modified Venus scenario is not impossible...though doing so quickly is, since that depends on a lot of photo-dissociation. Still, a large increase of water vapor in the exosphere is not desirable by any means. Etc.
The really dire scenarios are believe to be less likely than, say, a large meteor strike setting of another "Siberian Traps" chain of volcanoes and cooling everything back down again, but that's a guess. And the intermediately unpleasant scenarios which are deemed more likely are also guesses. My real guess is that we'll either have an AI Singularity or a nuclear war before the poles finish melting...which will cause global warming to cease to be a problem in one way or another.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: -1, Troll) by Anonymous Coward on Tuesday February 19 2019, @01:39PM (3 children)
You didn't preempt jackshit. Climate, according to the 90's IPCC report itself, is a complex, dynamic, chaotic system And, quote, long term prediction of climate is impossible. Gee, something changed?
Complex systems are sensitive to initial conditions, and they are completely unpredictable.
Climate models were invented to study by experimentation, not to predict. They are pure futuristic bullshit.
Climate Change is bullshit.
Global Warming is a bullshit gibberish theory, based on only one predictable factor, CO2.
Anybody really interested should read Freeman Dyson's intro to a CO2 report here:
http://www.thegwpf.org/content/uploads/2015/10/benefits1.pdf [thegwpf.org]
Here, if you have an hour's time, is atmospheric scientist Richard Lindzen, calmy and dispassionately taking the bullshit theory apart:
https://www.youtube.com/watch?v=X2q9BT2LIUA [youtube.com]
And take your bullshit scientific consensus and shove it. Politics is consensus, science can be single individual being right with correct data e.g. Copernicus, Galileo, Einstein.
(Score: 4, Insightful) by fritsd on Tuesday February 19 2019, @05:12PM (2 children)
No, that's what we call "weather".
You're confusing weather with climate :-)
Do you own swimming clothes? If so, why?? It's freezing outside, you can't predict that it will become warm enough to swim in 6 months!
(Score: 2) by HiThere on Tuesday February 19 2019, @06:17PM
That's short term climate prediction. I'll agree that long term climate prediction is impossible. But long term is measured in at minimum thousands of years. Short term climate prediction is nearly as good as weather prediction, and in some ways better. (Summer is always warmer than winter, but noon isn't always warmer than midnight.)
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 0) by Anonymous Coward on Wednesday February 20 2019, @07:03AM
You really have no knowledge there, do you. You are talking seasons, not climate decades ahead. Way to prove your ignorance. You know of the famous/infamous Butterfly Effect. That's bloody weather, unpredictable, same with climate. Even more complex system. BTW, Comples, Chaotic are technical terms and if that what climate is it means it's inherently unpredictable, fucking perios. Same as earthquakes. There is not going to be any fucking long term future knowledge of climate unless you are psychic.
IPCC climate scenario oh we base it on:
prediction of future temps, prediction of future technology prediction of future populatiin numbers, prediction of future Dun activity, prediction of future cosmic rays, and we make readonable scenarios.
No, you fucking morons. You are bullshitting innocent people that you have knowledge that nobody can have, you dirty imbecilic liars.