Do AGW models account for natural cycles.?

[Iceberg]

A favourite aunt of the sceptics, that gets dragged out in every argument.

So, What evidence do you have that the AGW thoery does not take natural cycles into account. ?.

To start it off I know for a fact the Climate models such as the Hadley one, show a cooling period in 10-15 years time completely due to natural cycles.

I know that the IPCC report and models include natural cyclical variability in solar input.

I know that the models include natural ocean overturning and other decadal practices.

So please explain to me why AGW thoery is rubbish because it's all just a natural cycle.

[VillagePlank]

It depends if you are prepared to learn what Fourier Analysis is. Are you? If you're not then you must take someone's word for it, and your job becomes the selection of someone who you feel is most likely to tell you the truth of the matter.

[Iceberg]

VP I know your not trying to cloud the issue, but what are you saying ?.

That AGW theory does take natural variation into account ?

That models take natural variation into account ?

That we can't possible take natural variation into account ?.

That it's a valid argument to say because we don't know everything, we can therefore no nothing ?.

That it's a fluke that models when ran from the year 1900 model climate and it's natural forcings quite well.?

I can grasp the basics of Fourier Analysis, but not the implemention of it.

[VillagePlank]

I can grasp the basics of Fourier Analysis, but not the implemention of it.

Yes, I'm the same; although I'm trying . . .

As I understand it climatic patterns are (mainly - but not exclusively) identified using Fourier Analysis. This technique is quite good (but not perfect) at identifying sinusoidal patterns.

We must therefore assume that there is some linearity to natural climatic patterns as it this form of analysis, is by definition, plottable in a y=mx+c format.

Are climatic patterns subject to standard linear mathematics? I don't know. The only patterns that fit this have, I suspect, already been found, and one's that don't are extremely hard to find, if they can indeed by found by modern analytic methods - that is not to exclude them. They might indeed by there.

So the answer to your question is, I guess, I haven't got the foggiest.

Edited February 14, 2007 by VillagePlank

[Devonian]

I don't understand it either - but I think I know someone who does. Try this post for example from an excellent blog by a mathematician/astronomer who can communicate. It seems that we need to move on from Fourier to wavelets

That said models must take natural factors into account - they'd give pretty odd outputs if they only included anthro ghg's...

[Guest Daniel]

A favourite aunt of the sceptics, that gets dragged out in every argument.

So, What evidence do you have that the AGW thoery does not take natural cycles into account. ?.

To start it off I know for a fact the Climate models such as the Hadley one, show a cooling period in 10-15 years time completely due to natural cycles.

I know that the IPCC report and models include natural cyclical variability in solar input.

I know that the models include natural ocean overturning and other decadal practices.

So please explain to me why AGW thoery is rubbish because it's all just a natural cycle.

I still strongly think that most if not all the current warming is down to the natural cycles. Let us not forgate we have been warm before in the mediveal warm period and yet that ended and cooled into the little ice age age. It is utter rubbish to say that man made warming now only controls climate. The fact that we in the U.K are warm now does not mean we be warm for ever. there a real chance that after 2010 as the sun goes quite quite we will see a strong cooling pattern begin in the U.K and the world. I would also like to point out that we are now at the end of our warm period between true iceages and that should be a long term woory. that one day we will enter a new full ice age.

[Devonian]

I still strongly think that most if not all the current warming is down to the natural cycles. Let us not forgate we have been warm before in the mediveal warm period and yet that ended and cooled into the little ice age age. It is utter rubbish to say that man made warming now only controls climate. The fact that we in the U.K are warm now does not mean we be warm for ever. there a real chance that after 2010 as the sun goes quite quite we will see a strong cooling pattern begin in the U.K and the world. I would also like to point out that we are now at the end of our warm period between true iceages and that should be a long term woory. that one day we will enter a new full ice age.

I think, Daniel, you need to look in the SPM (page 4) at the relative importance of various climate forcing. Specifically it's not the sun that is doing it atm.

[eddie]

You don't need to fully understand fourier analysis to know that isn't a magical thing that will tell you all about natural climate cycles. Fourier anaysis is ok but you need have to have a data set worth analysing in the first place and you also need to know what the results actually mean.

We haven't been recording acurate, global temperature records/ocean currents/wind direction/cloud cover/etc/etc. for very long at all, certainly not long enough to spot some of the more subtle cycles. Also, just because you think you have isoloated an individual temperature signal from the climate 'noise' doesn't mean you have any idea what caused it or if it will continue in the same way.

I'm sure the climate models do try and take some natural cycles into account but I bet they aren't doing a very good job. Please understand that I'm not arguing against the existence AGW or the need to do something about it. I just think we don't know very much about natural climate cycles.

[Mondy]

I still strongly think that most if not all the current warming is down to the natural cycles. Let us not forgate we have been warm before in the mediveal warm period and yet that ended and cooled into the little ice age age. It is utter rubbish to say that man made warming now only controls climate. The fact that we in the U.K are warm now does not mean we be warm for ever. there a real chance that after 2010 as the sun goes quite quite we will see a strong cooling pattern begin in the U.K and the world. I would also like to point out that we are now at the end of our warm period between true iceages and that should be a long term woory. that one day we will enter a new full ice age.

Good Daniel, good lad!

I trust you read page 3 of this thread http://www.netweather.tv/forum/index.php?s...36353&st=34 whereby i hope you agree with the points i've raised, as you're obviously the same mould as me.

[parmenides3]

For those who wish to get an idea of what the models do: http://www-pcmdi.llnl.gov/ipcc/diagnostic_subprojects.php

The answer to the question is ; yes, of course they do. Which is why we can be confident that natural cycles don't explain AGW.

[Admiral_Bobski]

Perhaps the question isn't "do AGW models take natural cycles into account" but rather "do AGW models take natural cycles sufficiently into account?" I wouldn't deny for a second that the climate models do attempt to incorporate natural cycles, but have they given these cycles their appropriate degree of "oomph"?

More later

C-Bob

[Mr Sleet]

Perhaps the question isn't "do AGW models take natural cycles into account" but rather "do AGW models take natural cycles sufficiently into account?" I wouldn't deny for a second that the climate models do attempt to incorporate natural cycles, but have they given these cycles their appropriate degree of "oomph"?

More later

C-Bob

Fact is that the models can't possibly take natural cycles into account with complete confidence, probably a lot of room for error IMO. How arrogant we are.

[Iceberg]

I still strongly think that most if not all the current warming is down to the natural cycles. Let us not forgate we have been warm before in the mediveal warm period and yet that ended and cooled into the little ice age age. It is utter rubbish to say that man made warming now only controls climate. The fact that we in the U.K are warm now does not mean we be warm for ever. there a real chance that after 2010 as the sun goes quite quite we will see a strong cooling pattern begin in the U.K and the world. I would also like to point out that we are now at the end of our warm period between true iceages and that should be a long term woory. that one day we will enter a new full ice age.

But the thing is scientists do know what caused the MWP and the little ice age, our understanding of forcings can account for these. Our understanding of forcings though cannot account for the current warming without the antropogenic effect.

No body is saying that man made warming now only controls climate. This is why the models as I indicated early show a cooling period.

You don't need to fully understand fourier analysis to know that isn't a magical thing that will tell you all about natural climate cycles. Fourier anaysis is ok but you need have to have a data set worth analysing in the first place and you also need to know what the results actually mean.

We haven't been recording acurate, global temperature records/ocean currents/wind direction/cloud cover/etc/etc. for very long at all, certainly not long enough to spot some of the more subtle cycles. Also, just because you think you have isoloated an individual temperature signal from the climate 'noise' doesn't mean you have any idea what caused it or if it will continue in the same way.

I'm sure the climate models do try and take some natural cycles into account but I bet they aren't doing a very good job. Please understand that I'm not arguing against the existence AGW or the need to do something about it. I just think we don't know very much about natural climate cycles.

I agree with some of what your saying Eddie, we don't know everything and never will do in my life time. However the consistance of the models is rather telling. Even when you add in the various drivers such as aerosols or even when they start to add in the effects of ice sheet behaviour the end result is almost always the same.

Perhaps the question isn't "do AGW models take natural cycles into account" but rather "do AGW models take natural cycles sufficiently into account?" I wouldn't deny for a second that the climate models do attempt to incorporate natural cycles, but have they given these cycles their appropriate degree of "oomph"?

More later

C-Bob

um..... but we can assume that without any evidence what we don't know will suddenly save the planet and lead to a natural world again. ?

Fact is that the models can't possibly take natural cycles into account with complete confidence, probably a lot of room for error IMO. How arrogant we are.

So until we are completely 100% confident that we have hte entire climate system nailed down, AGW can't possibly be happening ?.

[Gray-Wolf]

Didn't fissure eruptions in Iceland cause the little ice age?

[Admiral_Bobski]

But the thing is scientists do know what caused the MWP and the little ice age, our understanding of forcings can account for these. Our understanding of forcings though cannot account for the current warming without the antropogenic effect.

Our scientists can explain what caused the MWP and the LIA, but this isn't the same as knowing what caused them. We can create models that recreate past events quite well, but the way this is done is by running a model with a particular dataset, comparing the results with actual records, then tweaking the input dataset to give a better match in the subsequent run. It's like someone giving you this sum: x+y=10 and asking you to figure out what he intended x and y to be - he may have said 9+1=10, but you can reach the same answer with other numbers. You can go back to the guy and say 3+7=10 and have a valid sum, but this doesn't mean that you have answered the question correctly. Furthermore, if you are asked to predict future results by continuously adding y to your result then you'll find dramatic divergence in your results the further you progress the series. ({10, 11, 12, 13...} compared with {10, 17, 24, 31...})

um..... but we can assume that without any evidence what we don't know will suddenly save the planet and lead to a natural world again. ?

I didn't say that - I was answering the question posed at the start: "Do AGW Models account for natural cycles?" As I said, I think they may try to, but I don't think they take them enough into account, which exaggerates the man-made forcings (if the total forcings were to equal, say, 10 then a smaller "natural" figure must lead to a larger "man-made" figure to balance). Please don't put words in my mouth - there's not enough room there for any more... But, having said that, you are implying that it is possible for us to "save the world" and that the current state of things somehow makes it an "un-natural world", and I would disagree with both sentiments. But if you accept that mankind can damage the climate system through ignorance then you must also accept that he can damage it deliberately - if our "concensus" understanding of climate is wrong, and natural cycles cause most or all of the change, then doesn't it follow that tinkering with it could be detrimental?

So until we are completely 100% confident that we have hte entire climate system nailed down, AGW can't possibly be happening ?.

No, it's not that it "can't possibly be happening" - it may be happening or it may not be happening - it's that there is a degree of uncertainty involved.

C-Bob

PS...

Didn't fissure eruptions in Iceland cause the little ice age?

They may be an example of what could have caused the LIA, but not necessarily the cause.

[Methuselah]

As far as I can determine, the current climate models take account of the Earth's natural cycles, to the best of our understanding???

I fail to see how the can ever be expected to do any more than that...Like all models, they can only evolve in response to new understandings; they cannot pre-empt them. They are only models afterall...

[Mr Sleet]

Didn't fissure eruptions in Iceland cause the little ice age?

No, it was sunspots ( or lack of them).

[Devonian]

Our scientists can explain what caused the MWP and the LIA, but this isn't the same as knowing what caused them. We can create models that recreate past events quite well, but the way this is done is by running a model with a particular dataset, comparing the results with actual records, then tweaking the input dataset to give a better match in the subsequent run. It's like someone giving you this sum: x+y=10 and asking you to figure out what he intended x and y to be - he may have said 9+1=10, but you can reach the same answer with other numbers. You can go back to the guy and say 3+7=10 and have a valid sum, but this doesn't mean that you have answered the question correctly.

Sure, but until or unless you offer some evidence and another theory that it's that it's 3+7 rather than 1+9 why should I not go with the theory and the pile of evidence it's 1+9? You're asking me to run with the least backed up answer, I for one am not not going to do that, especially as the answer it's 1+9 has stood the test of a considerable amount of time.

But, you're saying it's not 1+9 so why is 3+7 a better answer???

[VillagePlank]

Ignoring the ignominous arguments going on elsewhere on this thread (yes, we've heard them all before, but thanks anyway) I'd like to re-write the question:

Do AGW fully account for natural cycles?

[Devonian]

Ignoring the ignominous arguments going on elsewhere on this thread (yes, we've heard them all before, but thanks anyway) I'd like to re-write the question:

Do AGW fully account for natural cycles?

I'm not sure that's a question that needs to be asked since, until we have time travel or perfect knowledge, it's got an obvious answer. So what are you driving at?

[VillagePlank]

I'm not sure that's a question that needs to be asked since, until we have time travel or perfect knowledge, it's got an obvious answer. So what are you driving at?

Well, the obvious answer, I think, is No, the models do not fully account for natural cycles. I'll leave it to the reader to draw conclusions on what the answer means, and doesn't mean.

There are lots of variations on this question and I wanted to point out that subtle differences in the wording of question naturally bias what will end up being the consensus answer after a lot of heated debate.

This particular question is loaded toward the AGW camp as is demonstrated by the the sub question in the poll. All that is required for a yes answer is proof that one AGW model accounts for two natural cycles; which is not really any sort of burden at all, is it?

[Admiral_Bobski]

I'm not sure that's a question that needs to be asked since, until we have time travel or perfect knowledge, it's got an obvious answer. So what are you driving at?

There's a big difference between attempting to account for natural cycles and accurately accounting for natural cycles. As I said earlier, I don't deny that they make some efforts to account for natural cycles, but I don't think they give the natural cycles enough credit. My straight answer (ie, without nit-picking) to the original question is "Yes", but my straight answer to VP's altered question is "No" (or, more accurately, "I sincerely doubt it.)

Sure, but until or unless you offer some evidence and another theory that it's that it's 3+7 rather than 1+9 why should I not go with the theory and the pile of evidence it's 1+9? You're asking me to run with the least backed up answer, I for one am not not going to do that, especially as the answer it's 1+9 has stood the test of a considerable amount of time.

But, you're saying it's not 1+9 so why is 3+7 a better answer???

I think you're focusing too closely on the maths analogy here - what I'm saying is that it is, of course, possible to make models that seem to accurately simulate past events, but that there are many models that could do the same thing, and that we can't be certain (by any stretch of the imagination) that we have the correct solution. Of far greater importance is this: "But if you accept that mankind can damage the climate system through ignorance then you must also accept that he can damage it deliberately - if our "concensus" understanding of climate is wrong, and natural cycles cause most or all of the change, then doesn't it follow that tinkering with it could be detrimental?"

To summarise, my point is that we need to know whether it is 1+9 or 7+3, otherwise how can we attempt to "combat" the "problem".

C-Bob

PS - VP, what parts of the thread were you referring to as being ignominious?

[Devonian]

Well, the obvious answer, I think, is No, the models do not fully account for natural cycles. I'll leave it to the reader to draw conclusions on what the answer means, and doesn't mean.

There are lots of variations on this question and I wanted to point out that subtle differences in the wording of question naturally bias what will end up being the consensus answer after a lot of heated debate.

This particular question is loaded toward the AGW camp as is demonstrated by the the sub question in the poll. All that is required for a yes answer is proof that one AGW model accounts for two natural cycles; which is not really any sort of burden at all, is it?

Of course it is no. But, so what? Do you need to have all the puzzle finished to see what it is? Imo, the loaded question is to imply that because we don't know everything what we don't know is enough to make a significant difference to the predictions, or, worse, to imply we don't know very much when it's clear we know a lot.

Anyway, what is the unloaded question?

To summarise, my point is that we need to know whether it is 1+9 or 7+3, otherwise how can we attempt to "combat" the "problem".

C-Bob

Of course. What do you think climatologists and modellers have been doing for decades . As the link I gave says knowledge has grown enormously over recent years. Still no sign of that illusive major natural forcing that disproves the models...

[Admiral_Bobski]

Of course. What do you think climatologists and modellers have been doing for decades . As the link I gave says knowledge has grown enormously over recent years. Still no sign of that illusive major natural forcing that disproves the models...

Granted that climatologists have been trying to refine the models but, to further emphasise what I'm saying, 1+9 and 7+3 (to continue the analogy) would be indistinguishable from one another over short time frames. They simply wouldn't know that they've attributed the forcings inaccurately until they've accumulated more data.

C-Bob

[Iceberg]

I don't have much time, but it's more complicated that x+y = 10 becuase you also have x/y= 3.5 and y-x = 3.5 as well. It's makes the end answer a lot easier.

Matt