Discussion > We are wasting our time; all of it.
If climate is so chaotic and as unpredictable as the stock market, how can I say with certainty that July will be warmer than January in London this year, next year and in 100 years?
What are you trying to say Raff? That July in London being warmer than January in London is evidence that we can predict what the climate will be 100 years from now?
Martin A
Why dont you tell us what YOU think Raff instead of asking people idiot questions?
Dung
If climate is so chaotic and as unpredictable as the stock market, how can I say with certainty that July will be warmer than January in London this year, next year and in 100 years?
Raff, the information that you seek may be one of the following. Tell us what you think.
Something to do with all such predictions in the past having invariably been proved correct?
Something to do with the fact that the Earth's axis is inclined and its orbiting the Sun is a periodic, non-chaotic process?
splitpin
Martin, I just gave you what you wanted:
"evidence that we can predict things that will happen in the future to a system that, at best is partially understood, whose initial conditions are unknown, and is known to be chaotic*."It is based on the physics of the system. It shows that the climate reacts in predictable ways to forcing even though it is chaotic. We can predict this behavior even without knowing detailed initial conditions because it is not an initial value problem. This shows that we are not clueless as you like to tell yourself in predicting the future climate.
Raff
Splitpin, they didn't predict snow at Lord's in July 1888.
michael hart
Splitpin, they didn't predict snow at Lord's in July 1888.
michael hart
Splitpin, they didn't predict snow at Lord's in July 1888.
michael hart
The Captcha is strong today.
michael hart
Ralph, the state of a dynamic system at some future time t is determined by its current state and the external inputs to it between now and t. Of course, this depends on the validity of various assumptions: stability, non chaotic behaviour, that it is deterministic, and so on. People involved in the analysis, simulation, control, and design of dynamic systems work on that basis.
I am curious to know if your belief that future states of the climate system can be determined without knowledge of its present state applies to future states at all timescales - eg one hour from now, one year from now, and so on. Or does it only apply to the very remote future?
Would the method of predicting future states without knowledge of the current state give a different result for, say, 100 years from now, if we were currently in the middle of an ice age? Hard to see how it could.
Martin A
Martin, before you dart off down a rabbit hole, lets just clear up your previous assertion - that we cannot "predict things that will happen in the future to a system that, at best is partially understood, whose initial conditions are unknown, and is known to be chaotic". It is pretty clear that we can. Please confirm that you agree or explain exactly why not.
Raff
Rafa please explain why this is wrong.
"In sum, a strategy must recognise what is possible. In climate research and modelling, we should recognise that we are dealing with a coupled non-linear chaotic system, and therefore that the long-term prediction of future climate states is not possible. The most we can expect to achieve is the prediction of the probability distribution of the system's future possible states by the generation of ensembles of model solutions."
IPCC TAR WG1 14.2.2.2
geronimo
Raff I already gave detailed examples of climate NOT following forcing (at least according to your understanding of the forcing),
Why don't you scroll up?
Dung
Geronimo, it is Martin who says that is wrong - that not only can't we produce a probability distribution but we can't even assume not knowing means a flat distribution. He says we can predict nothing that will happen to a system that is chaotic etc (I'm surprised he didn't use your favorite "coupled non-linear chaotic system"). But we can - I just predicted that July 2100 will be warmer than January 2100 and nobody is going to say that is wrong.
Dung, did you? I don't see it.
Martin, please confirm that what you said is wrong. If you think initial conditions are so important, do you think that if you plonked a planet with arbitrary initial climate conditions in place of earth with the same orbit, orientation etc, that winters and summers would not occur in the same way they do on earth?
Raff
Raff Matin, as he usually is, is correct. Of course you can produce PDFs but they're meaningless unless you're data is correct and you, understand the interactions, can you point me to anything in the literature that provides an explanation of cloud formation and how that relates mathematically to the amount of water vapour in the atmosphere, the rate of change of the water vapour and the temperature? I don't think so, yet clouds are alleged to reflect 22% of the incoming heat from the Sun, the whatever the imbalance is (it's currently 0.2% of the TOA energy from the Sun), so it is impossible either to figure out what the clouds will reflect. and what the energy budget imbalance would be.
"But we can - I just predicted that July 2100 will be warmer than January 2100 and nobody is going to say that is wrong."
You are wrong, you haven't taken into consideration all of the facts. I take it when you said "we" you weren't implying that you're a climate scientist. It will be much colder in the entire Southern Hemispher below 23 degrees South in July than it is in January and seasons between the tropics (23 degrees North and 23 degrees South) do not match either the Northern Hemisphere or Southern Hemisphere notions of Summer and Winter. Instead, it is hottest in Spring and Autumn, with Summer and Winter are the coolest seasons.
You see your answer is right for only 1/3 of the planet.
geronimo
I forgot to mention that at the equator the temperatures are the same for every month of the year.
geronimo
Hi Raff, still here?
If you think initial conditions are so important, do you think that if you plonked a planet with arbitrary initial climate conditions in place of earth with the same orbit, orientation etc, that winters and summers would not occur in the same way they do on earth?
I'm trying to understand the point you're trying to make. And I assume that you are actually attempting to make a point, rather than a simple piss-take.
As somebody said previously, summers and winters are a result of the Earth's axis about which it turns not being at a right angle to the plane in which it orbits the Sun. I don't think this is open to dispute. Notice that the words 'initial conditions' are not present in the previous sentence. Does that answer your question?
The general focus now seems to be on climate in decades or centuries ahead, given various assumptions on CO₂ emissions. I have assumed that when you talk about future climate, that's the sort of timescale you have in mind. Am I right?
My own opinion is that efforts to predict future climate with meaningful accuracy are doomed to failure for a handful reasons, any one of which on its own would be a show-stopper.
But forgetting about that, help us all to understand how you think it is possible to estimate the climate some decades from now, without making use of information about the current state of the climate system. Answers such as "the answer is called physics" really don't help.
In particular, help us to understand how the prediction of the climate a century from now given that 'current climate' = 'little ice age' can be different from the prediction if 'current climate' = 'late 20th century climate' and if, as I understand you to believe, current conditions have no bearing on the predictions.
Martin A
Geronimo, your nit-picking about hemispheres just proves the point. You can predict with confidence that summer will be warmer than winter in 2100 whichever hemisphere you refer to. And by the way, equatorial temperatures are not the same every month.
Martin, why are you so reluctant to confirm that you were wrong in your assertion - that we cannot "predict things that will happen in the future to a system that, at best is partially understood, whose initial conditions are unknown, and is known to be chaotic"? Clearly we can as the example of seasonality demonstrates.
By "things that will happen", did you perhaps not mean things like seasons? Seasons are obviously predictable. Starting from northern hemisphere summer, reduce NH insolation by a large amount (let's call it N Watts/m2) and you'll get winter, sure as winter follows summer. And the fact that temperature will drop doesn't depend on initial conditions - start from NH winter and reduce NH insolation by another N W/m2 and you'll get another drop. No doubt about that, is there? So what if we drop the insolation of the whole planet by, say 8W/m2? Again, initial conditions don't matter - we'll get a drop in global temperatures, enough to enter an ice age by some reports, maybe a 5-10K drop (some people here seem quite concerned about that possibility from a change in insolation at the solar minimum of only maybe 1W/m2). All of that seems beyond doubt. So are you going to tell me that if we raise insolation by that 8W/m2 we wont get warming, whatever the initial conditions? And why would it be any different, in principle if not extent, if instead of increasing climate forcing through changes to insolation we increase it by doubling CO2 - producing about 4W/m2. Can you really say you now have simply no idea what effect that would have, not even the direction, whatever the initial conditions? You'd be the only person on this site who is so unsure (alright, maybe geronimo too).
Raff
Rafa it isn't nitpicking to show something is wrong. Even the statement summer is always warmer than winter wherever you are on Earth is wrong, as I've pointed out above.. In any event that''s not what you said, you said you could safely "predict"* that July would be warmer than January, don't you think it's important to be accurate? In, two thirds of the planet that forecast is not true. When presented with the data that you were wrong you call it "nitpicking", this characterises your whole approach to this issue, which is base on belief rather than looking at the evidence.
You got the simple forecast of January and July temperatures wrong, but even if it were true, how do you think that proves that you can model the future state of a coupled non-linear chaotic system (It's the scientific term for systems where small difference in the initial conditions can make massive differences in the output, not a phrase I've picked up and used as my favourite as you snidely remarked) in defiance of the known science that the future state of coupled non-linear systems cannot be forecast.
*Forecast are prediction of events and telling us that Tuesday follows Monday isn't a forecast, or in Yorkshire July will be warmer than January isn't a forecast because July and January are the names we give to months in which known events occur i.e. warm days and cold days in summer and winter respectively. If you choose to make what you describe as a forecast don't make one a bookie wouldn't take a bet on. And you still got it wrong.
geronimo
Raff, you have at last - and so charmingly - made clear what you were on about: that a doubling of atmospheric CO₂ would have the effect of increasing global mean temperature. Have I finally got it right now?
Previously, I had thought you were talking about much more precise and specific predictions. Until you started spouting banalities like 'July will be warmer than January', and then I thought you were just raving.
No, sorry.
I think it's by no means certain what the effect on global mean temperature of doubling CO₂ would be, or whether it would even be detectable in the presence of other simultaneous changes.
Even the sign of any detectable change in global mean temperature is uncertain for various reasons, one of which is that 'mean temperature' is physical nonsense. It does not provide a measure of any physical property of a system. You could easily concoct a system in which an increase in thermal energy resulted in a decrease in 'mean temperature' or vice versa.
And don't forget that 'radiative forcing' is a simplified nonphysical idealisation dreamed up in an attempt to quantify the effects of atmospheric trace gases. It is not a directly measurable physical quantity, so equating W/m² of insolation to W/m² of 'radiative forcing' does not provide an appeal to simple and indisputable physics.
Last time I checked (perhaps 3yrs ago), satellite measurements of incoming and outgoing terrestrial radiation were not precise enough for their difference to have any meaning, so validation of calculations done using the 'radiative forcing' concept was something that remained to be done. Presumably that is still the case. As I have said before, the 'travesty of the missing energy' perhaps provides a clue that the concept of radiative forcing does not provide the precision it has been believed to provide.
Martin A
The warming man can do pales in comparison to the cooling Nature can do. In the long run, man's pitiful little aliquot of warming and greening fossil carbon will be recognized for the thin layer of fat against the cold that it is.
And the Raffs will be for laffs.
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kim
A theoretical system in which "an increase in thermal energy resulted in a decrease in 'mean temperature'" is diversionary nonsense, unless you think the earth resembles such a system. Does it? No you won't answer that of course - it is not your style.
Radiative forcing may not be a measurable quantity, but as a means of estimating influences on the climate it is accepted by everyone, even by skeptics such as Lindzen. The forcing from a doubling of CO2 of around 4W/m2 (or 3.7 actually) is also universally agreed. Your position really just boils down to sophisticated denial of the greenhouse effect.
Raff
A theoretical system in which "an increase in thermal energy resulted in a decrease in 'mean temperature'" is diversionary nonsense, unless you think the earth resembles such a system. Does it?...
Could be. Not impossible, depending on how 'mean temperature' is measured.
If the temperature rose 2 deg in areas where there is little or no temperature monitoring (over the oceans, for example) and, because of changed cloud effects, it fell 1 deg in areas where monitoring is dense, what effect would that have on the measured mean temperature?
Radiative forcing may not be a measurable quantity, but as a means of estimating influences on the climate it is accepted by everyone, even by skeptics such as Lindzen.
Everyone? Really? And how would that validate calculations made using it?
I imagine that The Virgin Birth is accepted by all Catholic bishops.
The forcing from a doubling of CO2 of around 4W/m2 (or 3.7 actually) is also universally agreed.
And is the resulting global mean temperature change also universally agreed? Not that I have heard.
Here are a couple of facts:
- GCM's are crap at predicting climate change.
- 'Everyone' accepts that GCM's are better than radiative forcing calculations for predicting climate change.
"Radiative forcing is more to inform the public and penniless climate scientists who don't have access to a GCM."
Bottom line: radiative forcing calculations of climate change are crap++.
Your position really just boils down to sophisticated denial of the greenhouse effect.
If you say so. Seems to me that it's a big jump from understanding and accepting that the greenhouse effect exists to predicting the effect of a change in a minor atmospheric component on the overall climate system.
Martin A
It is clearly true, as you say, that >"it's by no means certain what the effect on global mean temperature of doubling CO₂ would be"That is what the climate debate is largely about. It is also true, as you say, that you can construct (and GISS/BEST/HADCRUT etc may have constructed) a false global 'mean temperature' that is not the same as the true global mean temperature (a theoretical average of temperature measured at every point on earth). Neither of those facts has any bearing on whether CO2 does indeed raise true global mean temperature, though you seem to think they do. Measurement issues just increase our level of uncertainty - they make the long tails of probability fatter.
And is the resulting global mean temperature change also universally agreed? Not that I have heard.Again, that is what the climate debate is largely about and why there are different estimates of likely effects. And because of all the uncertainty, they are not point estimates but distributions with tails that indicate significant probability of many degrees of warming. You can't get away from that.
The more you talk up uncertainty, the more you emphasize the very non-zero probability of dangerous change that you want to deny. That is ironic, although I imagine you don't see it that way.
Raff
" DungOh Noooooees NOT Green Sand?
I never dreamed he would risk shopping at Liddle!"
Ah hem, on this I can only refer to the late, great Alan Coren:-
"Always welcome a Sainsbury's, helps keep the riff raff out of Waitrose."
Pity about his daughter and partner, but we can never dictate how our descendants should live but some seem to be spending their lives attempting the impossible.
Green Sand
**sigh**
You really are not the sharpest tool in the box, are you? Even chaotic systems can be cyclical. However, you are now making a direct comparison of climate with the stock market, which is what was not done; the stock market was being used as an analogy.
Oxford English Dictionary:
Analogies are often used to look at an explanation from a different perspective, or as a way of explaining a complex concept in more easily understood terms, such as using water piping as analogous to electricity; the pipe width is the resistance, the pressure is the volts, the flow rate the amps, etc… Unfortunately, analogies will ultimately fail in the detail, and I have little doubt that you will now try to waste several postings on picking apart the water piping/electricity analogy.
As for your assurance that this July will be warmer than it was in January, please tell us by how much, and how it will adversely affect us (as you do seem to be convinced that any increase in temperature will be harmful). Also, remember 2012, when the March was considerably warmer than much of the rest of the year.