quote:

Originally posted by Son of Mulder:

He seems a reasonable and moderate sceptic to me. Others might say he sits on the fence.

quote:

Thus at bottom, it is very difficult to separate human induced change from natural change, certainly not with the confidence we all seek.

Wunsch wrote that in March 2006. Here's the latest of his I've found which doesn't strike me as sitting on the fence at all.

http://www.abc.net.au/lateline/content/2007/s1977366.htm

QUOTE

Is there is no proof? Well, there is no proof, but science is very rarely about proof, science is about plausibility. Most of the people who work in this subject without guaranteeing anything will say, "It seems very likely that we are seeing human induced warming because it is taking place on time scales that nature does not normally produce". There is the argument in that film that it's all due to the sun. There is absolutely no evidence, apart from the distortions they made in the graphs in that film in the version that I saw, there's no absolutely no evidence that what we're seeing is due to solar forcing.

Will I guarantee what we're seeing is due to anthropogenic causes? No. Do I think it's very likely that it is due to anthropogenic causes, and we should react on that basis? Yes, I do, it's very worrying.

UNQUOTE

I think you should quote more of Wunsch's statement.

quote:

Thus at bottom, it is very difficult to separate human induced change from natural change, certainly not with the confidence we all seek. In these circumstances, it is essential to remember that the inability to prove human-induced change is not the same thing as a demonstration of its absence. It is probably true that most scientists would assign a very high probability that human-induced change is already strongly present in the climate system, while at the same time agreeing that clear-cut proof is not now available and may not be available for a long-time to come, if ever. Public policy has to be made on the basis of probabilities, not firm proof.

which seems perfectly reasonable to me too.

quote:

Originally posted by Steve_M:

which seems perfectly reasonable to me too.

I hasten to add that was Mulder cherry picking! Hope I don't get accused of that.

BTW I thought that you only got proof in maths anyway.

Realprimate

quote:

I hasten to add that was Mulder cherry picking! Hope I don't get accused of that

Not true all I did was Google Wunsch and the first article up was the one I read and quoted.

The point being that he says "certainly not with the confidence we all seek".

Now I seem to recall that most pro-AGW comment is that "they've moved beyond such a position.... They are confident.... The science is certain.... Time to move on....".

So has Wunsch's position changed since March 2006? If so what was his tipping point?

quote:

Originally posted by Son of Mulder:


So has Wunsch's position changed since March 2006? If so what was his tipping point?

Durkin?

I think Wunsch is talking about the confidence scientists have on the relative importance between Anthropogenic effects and Natural variations compared to the overall effect of the combination of A&N.

A subtle difference but the bottom line is that Carl Wunsch is "very worried". I wouldn't call him a sceptic myself. Cautious maybe, reasonable certainly.

Realprimate

quote:

Durkin?

I doubt it - what has the documentary or a film maker got to do with the actual science?

I think Wunsch is talking about the confidence scientists have on the relative importance between Anthropogenic effects and Natural variations compared to the overall effect of the combination of A&N.

Isn't that what this whole debate is about? I don't think many would categorically believe that CO2 has absolutely no influence on climate

quote:

Originally posted by Son of Mulder:

I don't think many would categorically believe that CO2 has absolutely no influence on climate

And if CO2 was at a higher concentration in the atmosphere than at any time in the last million years wouldn't most people accept that that would have a significant impact on the earth's climate?

quote:

Now I seem to recall that most pro-AGW comment is that "they've moved beyond such a position.... They are confident.... The science is certain.... Time to move on....".

I would say that the position is this:

It is certain that adding CO2 will result in a warmer climate than would have happened otherwise, and it is certain that there are risks from the impact of a warmer climate. The risks can be mitigated, and the sooner we start, the better.

Just because natural variability makes it is hard to attribute all of the current climate change to humans, and to predict the amount and rate of future change, does not mean that the risk goes away.

Legjoints

quote:

And if CO2 was at a higher concentration in the atmosphere than at any time in the last million years wouldn't most people accept that that would have a significant impact on the earth's climate?

Well sceptics don't accept it will be a significant impact (if by significant you mean overall damaging).

Steve_M

quote:

I would say that the position is this:

It is certain that adding CO2 will result in a warmer climate than would have happened otherwise, and it is certain that there are risks from the impact of a warmer climate. The risks can be mitigated, and the sooner we start, the better.

Just because natural variability makes it is hard to attribute all of the current climate change to humans, and to predict the amount and rate of future change, does not mean that the risk goes away.

There would be change but quantifying the costs and benefits moves from the climate debate to an economic / political debate.

Should the worst AGW fears prove to be -

Is an arctic without ice worse than a Europe without being covered with forests as we caused over the last 1000 years? Is an uninhabitable Siberia better than a temperate Siberia? etc etc. To me it's just different and this time round we'll have advanced technology to make any transition easier

quote:

There would be change but quantifying the costs and benefits moves from the climate debate to an economic / political debate.

An economic / political / science debate, but I know what you mean.

But the technology that can defend against the impacts is expensive to deploy and cannot be afforded by all countries - not even the US can afford to properly defend its cities and roads. The problem is that modern societies live far too close to the edge.

I doubt it - what has the documentary or a film maker got to do with the actual science?

Cumon Mulder perhaps because Durkin threatened to sue Wunsch after he complained about TGGWS. Interestingly I've heard that Wunsch is not on the new improved version of TGGWS. Not that I'll watch it.

But you got that right. TGGWS and Durkin have NOTHING to do with the actual science.

I think Wunsch is talking about the confidence scientists have on the relative importance between Anthropogenic effects and Natural variations compared to the overall effect of the combination of A&N.

Isn't that what this whole debate is about? I don't think many would categorically believe that CO2 has absolutely no influence on climate

Don't sound so naive. Newsweek's been exposing the way the baddies emphasise the "science is uncertain" angle. Please read the comments section of the following link. The rant brigade are practically accusing climatologists of taking the May day salute with Pol Pot and that Kim Il Sung.

http://www.msnbc.msn.com/id/20122975/site/newsweek/

We've a long way to go mon frere.

Realclimate

quote:

Cumon Mulder perhaps because Durkin threatened to sue Wunsch after he complained about TGGWS. Interestingly I've heard that Wunsch is not on the new improved version of TGGWS. Not that I'll watch it.

Well by your reckoning Wunsch would be in for a payout wouldn't he?

quote:

Isn't that what this whole debate is about? I don't think many would categorically believe that CO2 has absolutely no influence on climate

Don't sound so naive. Newsweek's been exposing the way the baddies emphasise the "science is uncertain" angle. Please read the comments section of the following link. The rant brigade are practically accusing climatologists of taking the May day salute with Pol Pot and that Kim Il Sung.

I assume some supporters of both sides rant, some supporters of both sides spin, some just blindly believe .... but what about those who are trying to really understand what the risk and exposure from all this really is? Not knowing what to believe as fact, not knowing how valid the assigned probabilities are to the various outcomes.....not knowing what political dealing and double dealing is contributing to the reported picture.

I've tried to identify strengths and weaknesses in the science because all around it is the usual smog of pro and sceptic lobby groups, individuals after the quick buck....

I know that real data over the next 10 years is what is most likely to convince me one way or the other.

Son of Mulder.

Quote.
From reading what Wunsch has to say on Royal Society

He seems a reasonable and moderate sceptic to me. Others might say he sits on the fence.

quote:
Thus at bottom, it is very difficult to separate human induced change from natural change, certainly not with the confidence we all seek.
EOQ.

Any substantial scientist with International connections is likely to be subjected to International pressures. His 'other' quoted comments in this thread on "public policy" ring alarm bells with me. Public policy is the domain of politicians and sits incongruously with science. Anyway, I think this is an aside.


If a paper properly describing "greenhouse effect" were ever to be published, the main subject would be the prohibition in convection of (and I hate to repeat myself) water vapour and radiation would take a 'back seat'.

Regards, suricat.

Suricat

quote:

If a paper properly describing "greenhouse effect" were ever to be published, the main subject would be the prohibition in convection of (and I hate to repeat myself) water vapour and radiation would take a 'back seat'.

I don't understand this point you make - surely any heat that leaves earth to maintain a balance has to be as radiation (apart from the occasional space craft).

Son of Mulder.

Quote.
I don't understand this point you make - surely any heat that leaves earth to maintain a balance has to be as radiation (apart from the occasional space craft).
EOQ.

I was alluding to the subject of this thread, not IR leaving Earth atmosphere!??

When you get down to the true reasons that a greenhouse is warmer than the garden, you can begin to see striking similarities between a greenhouse and the troposphere. Do you want me to expand on this?

quote:

When you get down to the true reasons that a greenhouse is warmer than the garden, you can begin to see striking similarities between a greenhouse and the troposphere. Do you want me to expand on this?

Ok I think I see the point you're making - the big issue is increasing convection to counteract any warming.

Suricat (and Steve_M) So let's focus on convection for a while. There's a nice diagram in balance

which I referenced before that shows Thermals removing 24WM^-2 from the surface at equilibrium.

So what is understood about how this varies with surface temperature. Consider the analysis which looks at a theoretical atmosphere with no CO2. About 30 deg C cooler at the surface. But what would happen to the value of Watts removed from the surface by thermals with no CO2? If earth's temperature at the surface rose by 1 deg C from current average what would the change in the thermal wattage be?

The experts say that the balance between overall in and out is +1 WM^-2 causing warming. How accurately is the convection part of the equation understood (or is it parametrised in the models based on assumptions)?

Son of Mulder.

Quote.
OK I think I see the point you're making - the big issue is increasing convection to counteract any warming.
EOQ.

Not quite. Convection which includes water vapour (i.e.. within the troposphere) masks a hidden energy level.

Quote.
Suricat (and Steve_M) So let's focus on convection for a while. There's a nice diagram in balance
which I referenced before that shows Thermals removing 24WM^-2 from the surface at equilibrium.
EOQ.

This is gibberish! It is impossible to make radiative calculations that originate from the surface of the Earth! Water vapour mostly commutes 'radiative theory' out of the troposphere! The primary 'effective' thermal transfer agent changes with altitude!

Quote.
So what is understood about how this varies with surface temperature. Consider the analysis which looks at a theoretical atmosphere with no CO2. About 30 deg C cooler at the surface. But what would happen to the value of Watts removed from the surface by thermals with no CO2? If earth's temperature at the surface rose by 1 deg C from current average what would the change in the thermal wattage be?
EOQ.

Why? The effect of CO2 is minimal at the surface! Water evaporates and dumps the energy at the top of the troposphere! Water is the "primary 'effective' thermal transfer agent" medium as 'passive refrigeration' in the troposphere, where IR radiation is saturated! Thermal biasing of primary energy carriers is necessary with changing altitude. For example, as the troposphere expands the area of radiation from the 'passive refrigeration' zone is increased (and that's a negative feedback). I can't quote well on a "1 deg C from current average", but if that's an assumed 1 deg C's worth in radiation leaving Earth atmosphere, it means a ½ deg C change at boundary level. Otherwise, a 1 deg C increase at Earth surface would invoke a 100% increase of IR above the troposphere (e.g.. 2 deg C's worth of outgoing IR radiation). The vapour pressure of a passive refrigeration system always falls to the midpoint of in/out energy movements of the system (that's why it's a crap system for 'thermal recovery' within industry).


Quote.
The experts say that the balance between overall in and out is +1 WM^-2 causing warming. How accurately is the convection part of the equation understood (or is it parametrised in the models based on assumptions)?
EOQ.

Don't have a clue! Steve_M may be better placed to offer insight into this, but 1 W per cm seems over the top (or, that's + 100 W/M^2? [+1 W/ M^-2?] ).


Do you want me to expand my point?

Regards, suricat.

Son of Mulder.

We clearly have a 'standard notation' problem here!

I understand 2M^-2 to perhaps mean 'two square centimetres', or even 'two centimetres' (two X [1 meter raised to the power of ten to the minus two] ). The IPCC also uses this style of notation and I find it confusing. I better understand 2m^2 to mean 'two square metres' (M is usual notation for mega [10^6, or 1 X 10^6] and not metre). I don't want to seem rude, but do you agree?

I think you'll find a better graphic than the one you offered on the IPCC web site

Http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Pub_Ch01.pdf

See page 96.

Regards, suricat.

quote:

Originally posted by Steve_M:
I think you should quote more of Wunsch's statement.

quote:

Thus at bottom, it is very difficult to separate human induced change from natural change, certainly not with the confidence we all seek. In these circumstances, it is essential to remember that the inability to prove human-induced change is not the same thing as a demonstration of its absence. It is probably true that most scientists would assign a very high probability that human-induced change is already strongly present in the climate system, while at the same time agreeing that clear-cut proof is not now available and may not be available for a long-time to come, if ever. Public policy has to be made on the basis of probabilities, not firm proof.

which seems perfectly reasonable to me too.

Let's also revisit Wunsch's statement on climate modelling, as he expressed it in TGGWS

quote:

"Even within the scientific community, you see, it's a problem. If I run a complicated model, and I do something to it, like, melt a lot of ice into the ocean, and nothing happens, it's not likely to get printed. But if I run the same model and I adjust it in such a way that something dramatic happens to the ocean circulation, like the heat transport turns off, it will be published. People will say this is very exciting. It will even get picked up by the media. So there is a bias, there's a very powerful bias within the media, and within the science community itself, toward results which are dramatisable. 'The Earth freezes over', that's a much more interesting story than saying, well, you know, 'it fluctuates around'. Sometimes the mass flux goes up by 10%, sometimes it goes down by 20%, but eventually it comes back. Well you know, which would you do a story on? I mean that's what its about."

which seems to me to be a perfectly reasonable assessment of climate modelling from an acknowledged expert.

Suricat, Just back from the Test Match so back to reality, WM^-2 is watts per square metre. Given your certainty on so much of the science I'm surprised you're not familiar with such a standard notation. I'm beginning to suspect that your certainty masks uncertainty, which is no problem to me because I'm happy to confess uncertainty. What is clear to me is that no matter how simple and obvious it seems to Steve_M & Cobbly Worlds - it aint.

I'M happy to admit that additional CO2 will cause heating but how the rest of the variables react is a mystery and anyone who is certain is conning themselves.

Son of Mulder.

Quote.
WM^-2 is watts per square metre. Given your certainty on so much of the science I'm surprised you're not familiar with such a standard notation.
EOQ.

Just checking that you understand, I'm old school and I don't like these 'newer' changes. Wherever you see change, disruption always follows. Changing pounds sterling to 100p instead of 240d was bad enough, but changing scientific notation evokes ageism in the community and is a barrier to the greater 'wisdom' of a 'knowledgeable society'. I am with you on this, but I don't like it (it's a bit like the argument between engineers and mathematicians on the 'origins of pi').

Quote.
I'm beginning to suspect that your certainty masks uncertainty, which is no problem to me because I'm happy to confess uncertainty. What is clear to me is that no matter how simple and obvious it seems to Steve_M & Cobbly Worlds - it aint.
EOQ.

SOM. I always try to expect the unexpected. However, (I'm sure you know the rest). In science, certainty only exists until the next proof! As an engineer I'm always 'pawing' over sums and running checksums to make sure there is no mistake. 'Observation' is most important, that's why I use my 'specs'.

Quote.
I'M happy to admit that additional CO2 will cause heating but how the rest of the variables react is a mystery and anyone who is certain is conning themselves.
EOQ.

I concur. However, mysteries are there to be demystified.


The link I gave in my last post (I know it's the IPCC again, but!) at least shows that the middle atmosphere has its own characteristics and that overall, the system is more complex than most people 'give credit'. I hope you are comfortable with this.

On that graphic you will see that 78w/m^2 is their equivalent IR radiative rate for evapo-transpiration (and latent heat [or, 'enthalpy of transformation' to the newly initiated] ). All well and good that it fits in with their 'mean energy balance', but their 'evapo-transpiration rate' doesn't seem to fit in well with the 'average annual global precipitation' figures. These two series of data should be almost identical and corroborate one another (what goes up, must come down).

I know that the annual average precipitation rate of about 1,000 mm is an estimate, but I'm also sure that the IPCC's 78w/m^2 is also an estimate. What are we to understand as 'true'? The discrepancy is about 6w/m^2. Only an 8% error if you accept precipitation figures, but 6w/m^2 extra 'ground radiation transport' (biasing to the tropopause) seems large. Yet another thing to be queried on data accuracy, or should that be metrics.


Your previous quote.
The experts say that the balance between overall in and out is +1 WM^-2 causing warming. How accurately is the convection part of the equation understood (or is it parametrised in the models based on assumptions)?
EOQ.

Does this post offer insight to your question?

Regards, suricat.