General Climate Change Discussion.......

[weather eater]

My understanding is that the scientists do take natural cycles into consideration, but that many of them are poorly understood and poorly represented in climate models (which form the main basis for making projections into the 21st century).

The IPCC's temperature rise graphs do not appear to take natural cycles into consideration but I think that's for purposes of simplification so that the graphs are easy to digest and the main point gets across. Natural variability will, of course, be superimposed on any warming trend, be it due to AGW or something else, but that is difficult to represent on a graph. However perhaps the IPCC should be more vocal in saying "natural variability will occur either side of the mean" to cover their backsides against people assuming that they've presented AGW as over-riding everything else.

Thanks TWS in other words you think the IPCC are presenting us with an idiots guide and not treating us as adults and giving us the whole picture. Given the vociferousness of the sceptics, as they are perfectly entitled to be, you would have though that the IPCC would be at pains to make it clear as to how natural cycles were factored in to their models and estimates, I do, as I said, find it difficult to believe that natural cycles are not being accounted for in future model projections when the scientists behind AGW theory will also be responsible for much of what we know about natural cycles as well. It would be great to have one participate in this thread to answer some of the criticisms.

Edited July 21, 2009 by weather eater

[jethro]

Speaking as one of those sceptics who point to natural cycles, I'll try to explain my take on this....

I'm not of the opinion that scientific theorys behind natural cycles is to be believed without question, quite the opposite. Our knowledge of natural cycles is so scant, we can be certain of nothing. My criticism of the IPCC on natural cycles is primarily because our knowledge is so scant.

Leaving aside the CO2 debate for one moment; oceans cover roughly 70% of the Earth's surface, primarily they are storage heaters, gobbling up energy to redistribute around the globe. This they do in a cyclical manner. We have very little idea of how or why or when these ocean currents switch phases. We've had heat content, wind shear, African dust amongst other things mooted as being the cause, but we don't know.

Water vapour, the primary GHG by a long, long way - again our knowledge of the hydrological cycle is scant.

So, we have 70% of the Earth's surface covered by water which we don't understand and the major GHG which we also don't understand. And we're supposed to believe we know what will happen (roughly) in the future?

When it comes to what was included/excluded in the IPCC reports, well that's open to a lot of criticism too. Without going down the blogosphere snipe fest.... To reach the conclusions they reached, the IPCC had to say that additional CO2 would lead to positive feedbacks. The largest of which are clouds, they need clouds to produce this positive feedback in order for the models to project the warming by the addition of CO2. They do say, they don't really know but working on what is known, this is what they think will happen. Fair enough I hear you all say, it's something which needs further study. Until that is you start looking for info on clouds to try and understand the uncertainty and you find this: http://www.sciencemag.org/cgi/content/abstract/243/4887/57 A study published in a scientific journal way back in 1989, it says amongst other things Thus, clouds had a net cooling effect on the earth. Did they miss this? If so how?

Now let's look at the future, we're told they're something like 90% sure based on model projections, that we will warm by X amount by X date. There has to be criticism of this, not least because a model is only as good as the data input. Even leaving that criticism to one side for a moment, there still has to be doubt. Why? Because we're told the only way to replicate the recent warming is to introduce CO2 into the models. They've put in all they know about natural cycles but it still doesn't show what has happened, add CO2 and Voila! it does.

It's only an Eureka moment if nothing else can create that result. As we don't know if there's anything else, how can we possibly judge? Unfair criticism I hear you all say. We don't have time to sit and wait, we're never going to know everything, we know enough already, if CO2 creates the profile, that's enough for me.....

I'll pose a question to demonstrate my scepticism....if we are so certain of the future, based on what we know today then why can we still not replicate the warming in the earlier part of the 20th century? The Earth is configured in the same way, the Sun hasn't changed much, our Orbit hasn't changed much.

Edited July 22, 2009 by jethro

[Admiral_Bobski]

If I could just add something related to Jethro's post, and also to the Arrhenius Greenhouse Law:

One should not, however, take these carbon dioxide concentrations as the last word. The sensitivity of the climate to a doubling of carbon dioxide concentration could be in error. The change in forcing due to a change in carbon dioxide concentration is given by

ΔF = α ln(C/C0) w/m2,

where C0 and C are the initial and final carbon dioxide concentrations. Since 1990, the estimate by the Intergovernmental Panel on Climate Change (IPCC) of the coefficient α changed by 15% (Δα/α = 0.15) and “implicitly include the radiative effects of global mean cloud cover” [12], and estimates of the radiative effect of clouds are quite uncertain. If the actual sensitivity is significantly lower than current estimates, that would elevate the concentration of carbon dioxide needed to extend the current interglacial.

(source: http://www.aps.org/units/fps/newsletters/200804/marsh.cfm)

So it would seem that the effect of CO2 is still open to revision.

CB

[Methuselah]

If I could just add something related to Jethro's post, and also to the Arrhenius Greenhouse Law:

One should not, however, take these carbon dioxide concentrations as the last word. The sensitivity of the climate to a doubling of carbon dioxide concentration could be in error. The change in forcing due to a change in carbon dioxide concentration is given by

ΔF = α ln(C/C0) w/m2,

where C0 and C are the initial and final carbon dioxide concentrations. Since 1990, the estimate by the Intergovernmental Panel on Climate Change (IPCC) of the coefficient α changed by 15% (Δα/α = 0.15) and “implicitly include the radiative effects of global mean cloud cover” [12], and estimates of the radiative effect of clouds are quite uncertain. If the actual sensitivity is significantly lower than current estimates, that would elevate the concentration of carbon dioxide needed to extend the current interglacial.

(source: http://www.aps.org/units/fps/newsletters/200804/marsh.cfm)

So it would seem that the effect of CO2 is still open to revision.

CB

Thanks for that, CB...Something I can understand. And, I agree with your conclusion.

Interestingly, but not surprisingly, it also shows that the logarithmicity (Should that be a word?) of the relation is already within the IPCC's calculations; and, as such IMO, it also implies that our repeated discussions over whether-or-not it is logarithmic a tad superfluous?

PS: I've always considered net cloud-feedback to negative. Which is why I tend towards the lower end of the IPCC's projected future temperature-increase range.

[weather eater]

So it would seem that the effect of CO2 is still open to revision.

CB

Up or down, under calculation seems as likely. Well we will find out, sooner or later, the facts of the matter are that for all the talking and a few initiatives by governments there is no real possibility of global CO2 emissions being curbed in any meaningful way. So far all we have seen is a lot of hot air and attempts by politicians to sound right on and look like they are doing something.

[Thundery wintry showers]

Re Jethro's post, it certainly strikes me that there is too much acceptance among the scientific "mainstream" that the models can be taken as gospel, which in itself remains my main basis for maintaining some degree of scepticism. Perhaps the IPCC would be much better off saying "certainty is 90% if we assume climate models as givens", but I think the consensus view among the "mainstream" is to try and downplay the uncertainty when conveying the message to the general public- something I have my doubts about, but there is a lot of defensiveness over that view.

Interesting points about CO2, which I wasn't previously aware of- so there is uncertainty over that as well.

[Guest North Sea Snow Convection]

I don't think anyone can say that understanding of the natural drivers is watertight by any means or that associated natural feedbacks can be predicted with absolute confidence in the way that it has recently been suggested about sceptics on here. I have repeated and criticised many times the need for such same absolute statements and over confidences to dissist within the AGW sector, so I would hardly ascribe to it within the sceptic sector already either.

The 90% confidence thing with the IPCC is rather clumsily worded and doesn't help to detract from the over progressive impression that is created from within many areas of the AGW movement. I agree that there should be a footnote of some kind to the effect that they are assuming that their models are correct in terms of suggesting this rate of confidence . And we know that models are only as accurate as the selected information that is put into them. They can't on the one hand suggest 90% confidence and then on the other point to all the feedback uncertainties that exist, as they do. The clouds positive feedback hypothesis is reckoned to account for up to 75% of the projected induced warming over the next century as modelled by the IPCC, and bearing in mind there is already some doubt over whether the assumed positive feedbacks to account for this warming even exists (at the expense of potential negative feedbacks) then the maths is already looking dodgy. And that is just one of the assumed feedbacks that are counted amongst the scientific research. They can't have it both ways.

On the other hand, I don't think that any absolutes can be placed regarding major natural feedbacks in the form , for example, of solar minimum either - this is very much a wildcard feedback imo that could change the outlook considerably within the climate change debate over the coming decade. But trying to put 70,80,90 (whatever) percentages on this would be as foolhardy as the IPCC 90%. I'm not sure that many climate sceptics have given any official figure apart from some suggestions at the more progressive sceptic end as to how we might need some of this surplus CO2 to keep us warm in the event of naturally induced significant global cooling

I think that what many average sceptics are suggesting however, and that very much includes myself, is that solar amongst other major natural feedback systems, is taken much more seriously by many global climate scientists (very much including the IPCC) who navel contemplate AGW hypothesis too much.

Edited July 22, 2009 by North Sea Snow Convection

[Iceberg]

The problem though is that there is not a stread of evidence that anything accept a major major solar downcycle is going to have anything but a tiny effect on global temps. See the current solar downcycle (and before anybody mentions anything I am still awaiting a paper which says that ALL or most of the negative effect takes years to kick it), simply it doesn't. We've been at the low end of the solar cycle for 2 years now and EVERY paper I've ever read says that most of the effect is in the first 2 years.

The IPCC make it very obvious that they have an almost "ceterus paribus" attitude to things like solar and volcanism.

The 90% mark is also being taken out of context they are saying that there is a 90% certainty that global temps will rise by 0.5C by 2080. TBH this is pretty likely unless some major as yet undiscovered negative driver creeps in. As more and more feedbacks get counted in (most of them postive) the certainty goes down and down.

They are not saying that they can predict the temperature in 80 years time, but they are saying that they have a pretty good idea of the direction it will go in.

Much like pushing a stone down a hill, I can say it will go down the hill but at what speed and at what point it stops it becomes more difficult.

As for the 75% cloud vapour figure, just to make clear the 75% is only for the extreme IPCC temperature predictions of 6-8C of warming.

[Guest North Sea Snow Convection]

The problem though is that there is not a stread of evidence that anything accept a major major solar downcycle is going to have anything but a tiny effect on global temps. See the current solar downcycle (and before anybody mentions anything I am still awaiting a paper which says that ALL or most of the negative effect takes years to kick it), simply it doesn't. We've been at the low end of the solar cycle for 2 years now and EVERY paper I've ever read says that most of the effect is in the first 2 years.

The IPCC make it very obvious that they have an almost "ceterus paribus" attitude to things like solar and volcanism.

The 90% mark is also being taken out of context they are saying that there is a 90% certainty that global temps will rise by 0.5C by 2080. TBH this is pretty likely unless some major as yet undiscovered negative driver creeps in. As more and more feedbacks get counted in (most of them postive) the certainty goes down and down.

They are not saying that they can predict the temperature in 80 years time, but they are saying that they have a pretty good idea of the direction it will go in.

Much like pushing a stone down a hill, I can say it will go down the hill but at what speed and at what point it stops it becomes more difficult.

As for the 75% cloud vapour figure, just to make clear the 75% is only for the extreme IPCC temperature predictions of 6-8C of warming.

Two years and still counting. No-one knows where this is going to lead over the next decade or more. There is a definite risk of further major solar downturn. And the prognosis for C25 is further down. Put that into the IPCC projection equation over the coming 80 years?? You cannot begin to say that the solar min is already discounted in terms of its effects. Crikey, if that represents the IPCC view as well then there is some really serious questioning to do!!

Solar could well be that very, as you put it, 'undiscovered negative driver'. Such dismissive tone of words reflects well just how sure you seem to be about all this. So the sun is not a big enough driver for you!?

That 90% is not being taken out of context. You are viewing things on the basis that all the suggested positive feedbacks to go on and produce all this warming are correct and present. Even taking into account a lower benchmark solution of warming less than the 6 to 8C it is a big ask, based on the uncertainties of major feedbacks (like clouds) . What happens if a negative feedback exists instead of a positive one? For those of us who aren't anywhere near as sure about the existence of these feedbacks, and/or, alternatively don't have the same confidence in terms of how they will interact with natural factors, then the rates of return you suggest are nowhere near as clear cut as you see them. Indeed a reversal is possible.

[Admiral_Bobski]

We've been at the low end of the solar cycle for 2 years now and EVERY paper I've ever read says that most of the effect is in the first 2 years.

This article refers to a study that found a 10-30 year lag. (1st hit on a Google search for "Solar Lag Climate".)

http://www.innovations-report.com/html/reports/earth_sciences/temperature_response_altai_lags_solar_forcing_124878.html

CB

[Methuselah]

I get the impression that some of the extreme sceptics are misquoting: where, in the IPCC's reports, is a probability of 90% ascribed the projections' upper limits of temperature? Judging from the error bars and elementary statistics, <5% looks to be nearer the mark for both the higher and lower extremes?

Not that I buy any of the upper limits anyway!

My apologies, if I'm barking up the wrong tree.

[Admiral_Bobski]

Here's a quote from a piece by Theodor Landschiedt (so a lot of people will reject it, but still... )

The lag of the temperature data suggests that some of the excess energy linked to solar activity is stored and accumulated in the climate system by processes taking years. The thermal inertia of oceans may offer an explanation. White et al. (1997) have shown how the oceans respond to excess insolation caused by solar forcing and why there is a lag of several years depending on the length of the involved cycles of solar activity. According to Wigley (1988) an 80-year cycle of irradiance would yield an atmospheric temperature response with a lag of 7 to 9 years. The secular cycle of solar activity, modulating the intensity of the 11-year cycle, has a mean length of 80 - 90 years.

(Source: http://www.mitosyfraudes.org/Calen/SolarWind.html)

CB

[Guest North Sea Snow Convection]

I get the impression that some of the extreme sceptics are misquoting: where, in the IPCC's reports, is a probability of 90% ascribed the projections' upper limits of temperature? Judging from the error bars and elementary statistics, <5% looks to be nearer the mark for both the higher and lower extremes?

Not that I buy any of the upper limits anyway!

My apologies, if I'm barking up the wrong tree.

Yes you are barking up the wrong tree. And where is any extreme scepticism - that seems to be being pointed at me?

Not sure that is at all helpful, bearing in mind my post highlighted the unwise use of taking any of the science AGW or natural as watertight. Yes I am pretty sceptical as it goes, but I am trying to avoid the use of richter scales,swingometers and measurements and the like. Don't see how it helps any.

CB's posts just now touch on some of the myths about solar lag times.

Lets be aware that NASA for eg, have not been able to predict short term solar behaviour regarding C23 and C24 with any degree of accuracy over the last couple of years, so how we can make statements about how the current solar min is already discounted I will never know. They have already backtracked over when C24 is likely to start and already downgraded its potential strength. What say C25?

Edited July 22, 2009 by North Sea Snow Convection

[Admiral_Bobski]

Here's one which suggests a time lag of about 10 years:

http://www.mps.mpg.de/dokumente/publikationen/solanki/c153.pdf

CB

[Methuselah]

Yes you are barking up the wrong tree. And where is any extreme scepticism - that seems to be being pointed at me?

Not sure that is at all helpful, bearing in mind my post highlighted the unwise use of taking any of the science AGW or natural as watertight. Yes I am pretty sceptical as it goes, but I am trying to avoid the use of richter scales,swingometers and measurements and the like. Don't see how it helps any.

No NSSC. It wasn't aimed at you...I'm not even about to argue with your post.

[Admiral_Bobski]

This one suggests a 3-year lag, and comments how this is close to a 5-year lag proposed by Scafetta and West:

http://icecap.us/images/uploads/Solar_Changes_and_the_Climate.pdf

CB

Lag of up to 10 years:

http://cat.inist.fr/?aModele=afficheN&cpsidt=1712261

CB

[Methuselah]

As I was one suggesting a substantial time-lag for CO₂'s possible effects on the oceans, I'll make the same suggestion for Solar effects, As the articles point-out, thermal inertia will make a time-lag a near certainty IMO. Much like the extra time required to heat a house, when it's been empty for a week?

[Admiral_Bobski]

Anything between 10 and 40 years depending upon the solar phenomenon responsible:

http://books.google.co.uk/books?id=-YgNB19jJlsC&pg=PA529&lpg=PA529&dq=solar+lag+climate&source=bl&ots=PEkLmb_MrV&sig=DH_0wzhKmp25mcw3-H0MLArxFE8&hl=en&ei=AitnSp-RG92ZjAfExOiYAQ&sa=X&oi=book_result&ct=result&resnum=1

CB

EDIT - sorry Pete, I wasn't ignoring you! I was too wrapped up in pulling up all these papers and articles

I agree wholeheartedly with you - thermal inertia is a proven phenomenon, and yet we're supposed to believe that it barely happens with the climate? There seems to be plenty of evidence for lags on the decadal scale, so there's plenty of time for the Sun's recent quiet period to start having an effect.

:lol:

Edited July 22, 2009 by Captain_Bobski

[Methuselah]

Anything between 10 and 40 years depending upon the solar phenomenon responsible:

http://books.google.co.uk/books?id=-YgNB19jJlsC&pg=PA529&lpg=PA529&dq=solar+lag+climate&source=bl&ots=PEkLmb_MrV&sig=DH_0wzhKmp25mcw3-H0MLArxFE8&hl=en&ei=AitnSp-RG92ZjAfExOiYAQ&sa=X&oi=book_result&ct=result&resnum=1

CB

Thanks for those, CB.

[Admiral_Bobski]

Thanks for those, CB.

No problem, Pete. (Looks like I was a bit late editing my last post!)

CB

[Guest North Sea Snow Convection]

So, taking the IPCC eighty year plan, then a lot can happen wrt to solar alone to blow the myriad of warming projections off course. With such a range of possible lag times, does this not highlight the point about this aspect of the science being taken more seriously? C24 has not 'played ball' with predictions so far and with C25 perhaps deeper (none of which will be likely be modelled in as possibles by the IPCC) then it's anyones guess?

[Admiral_Bobski]

So, taking the IPCC eighty year plan, then a lot can happen wrt to solar alone to blow the myriad of warming projections off course. With such a range of possible lag times, does this not highlight the point about this aspect of the science being taken more seriously? C24 has not 'played ball' with predictions so far and with C25 perhaps deeper (none of which will be likely be modelled in as possibles by the IPCC) then it's anyones guess?

Absolutely, NSSC. Whether there are many lags occurring or there's just one lag, the duration of which is uncertain, the fact is that there is a lag.

More research is needed to aid our understanding of this phenomenon and how it fits in to AGW theory.

CB

[Guest North Sea Snow Convection]

Absolutely, NSSC. Whether there are many lags occurring or there's just one lag, the duration of which is uncertain, the fact is that there is a lag.

More research is needed to aid our understanding of this phenomenon and how it fits in to AGW theory.

CB

Thanks for those links regarding lags. They would have fitted aptly in my original post.

As for your last sentence - amen to that!

I think this factor, and the wildcard potential big negative feedback contained therein, is a good example of where the acting on what science we (apparently) DO know can shoot one in the foot. We might not understand this complex natural forcing (the sun) as well as we would like, but we can't ignore the possible feedback implications of deep minimums just because they are unknown. And even more so, we can't ignore the lags therein.

If models are going to be operated and run and run to try and give us every idea of what our climate might look like in eighty years time, or whenever, we STILL have to reflect ALL the possible feedback possibilities and not cherry pick the one's that are THOUGHT to have most confidence in. Hence this is one big reason alone why I just don't buy into this 'we can't afford to wait , act now' stuff. If so much is unknown, or, more dangerously, prematurely discounted then what alternative pickle in eighty years time after we have put all eggs in one basket to tackle a problem foreseen through AGW eyes, and we end up with something very different and unforessen through natural causes?

How much time is then available to deal with the unforeseen after so much time, energy (and money) has been expended on the, apparently, foreseeable?

Edited July 22, 2009 by North Sea Snow Convection

[Solar Cycles]

Yes you are barking up the wrong tree. And where is any extreme scepticism - that seems to be being pointed at me?

Not sure that is at all helpful, bearing in mind my post highlighted the unwise use of taking any of the science AGW or natural as watertight. Yes I am pretty sceptical as it goes, but I am trying to avoid the use of richter scales,swingometers and measurements and the like. Don't see how it helps any.

CB's posts just now touch on some of the myths about solar lag times.

Lets be aware that NASA for eg, have not been able to predict short term solar behaviour regarding C23 and C24 with any degree of accuracy over the last couple of years, so how we can make statements about how the current solar min is already discounted I will never know. They have already backtracked over when C24 is likely to start and already downgraded its potential strength. What say C25?

Funny how warmists expect instant cooling from solar minima, but are prepared to adopt a sit and wait attitude, to any warming that is supposed to happen. As for the IPCC and their stance on solar minima. Well it's pretty obvious, they are dismissive of natural factors over riding their beloved theory. We are in the midst of being able to witness solar minima, and it's impact on temperatures. For some of us it's what we thought all along, natural forcings dominate what drives our temperatures. For others it's going to be a long road of denial!!

[Admiral_Bobski]

<snip!>

How much time is then available to deal with the unforeseen after so much time, energy (and money) has been expended on the, apparently, foreseeable?

I think you're spot on. This is why I think, and have said before (as have many others), that we should spend some time, effort and money on mitigation - certainly insofar as sustainability is concerned - but we should really be thinking more about adaptation, since regardless of the causes we are going to have to adapt!

An even spreading of eggs would certainly be the most sensible way forward

CB