Now it's 2°C climate change target 'not safe'

We can seriously promise an average 2 degrees Celsius less for sure and without the need of carbon sequestering . 🙂

Which of the many climate prediction models will be used to determine CO2 quantity needed to raise the (adjusted) temperature by 2 degrees?

“… with a rate of [sea level] rise of between 60 to 90 centimetres per decade — more than double that recently observed”
Yeah, right. Slightly more than double. LOL. Trying to imply that someone has recently observed sea level rises of 30-45 cm per decade? It really is unbelievable that two professors can present information with this degree of inaccuracy.

Professor Chris Turney:
“Most recently I’ve been scientific advisor on a new Channel 4 TV series Man on Earth, presented by Tony Robinson, looking at the impact of past climate change on our ancestors.”
That will be Tony Robinson of Blackadder which was written by Richard Curtis. I seem to recall hearing that Richard Curtis has written another comedy recently. Was it a success?
http://eureferendum.blogspot.com/2010/10/enemys-true-face.html
http://www.guardian.co.uk/environment/blog/2010/sep/30/10-10-no-pressure-film?showallcomments=true#start-of-comments
It seems NOT!

Exeter is a nothing uni in the SW of england and this rubbish confirms that assessment. My god these people are arrogant and thick as two short planks.

Does this not smack of a typical “negotiation strategy” commonly employed when bargaining, given the coming Mexico summit? Go in with inflated demands, and eventually, after a suitable “tough approach” settle for what was always on the table. This way policy makers can claim that “they wanted more”, but we reached agreement on x, thereby (hopefully) appeasing/BS-ing opponents. There’s also a lot of the usual “estimates” and “appears”, together with the obligatory “fear factor” – it’s worse than we thought. Well you know what thought did?

Maybe yes and maybe no but man had no hand in the last interglacial and does not appear to have much of one in the present one. Hubris is perhaps a little kind for anything thinking humanity has more then a marginal, if that, influence on global climate. I suggest if we are truly concerned about sea level rises we should do two things. First get out the shovels and pumps. Second move our collective butts to higher ground. Lets see how that sells in the world of politics.

60 to 90 millimeters per decade would be double recently observed rises, right?
Fairly sure water levels haven’t been rising by 1 foot/decade where I live.

Anything to get your name in the media , I suppose !!!
I remember reading in Der Speigel that the 2C figure was “plucked out of the air” by a top German climatologist who did it for the politicians. They had said that all the scientific detail was too hard to use in selling the message. We need a catch phrase or simple “fact”, they said to him. So the guy said use 2C. He had the honesty to tell the interviewer in Der Spegel that he could not scientifically verify the figure.

Everybody wants to draw parallels between 125,000 years ago & today for the scary stuff, while totally ignoring the most important item – the planet warmed, naturally, all on its own, there is GW without the A, and it’s a normal cycle.

What are geographers doing in the geological sphere? Geography means drawing a map of the earth. Geography is an anachronism like alchemy without the latter’s knowledge of science. I remember as a geology student back in the 60s a geography student came over to the geology department to get some data on the glacial history of North America for his thesis. A professor of quaternary geology found that the fellow was several courses short of understanding the material he was asking for. He wound up switching to geology where he picked up courses in math, chemistry and physics along with sedimentology, glaciology, etc and then went on to obtain his degree in geology. It is a geographer from my alma mater (Manitoba) who is running around charting rotten ice – remember him. Geography is fine for school kids who need to learn that Colombia grows coffee and has such and such a population but otherwise it should be given a decent burial. If supposed real scientists seem to make a ballsup of climatology, we surely don’t need liberal arts researchers to help. Imsuspiciouss that it is the U of Exeter, where down the hall we have the meeting of the global temp osterizers deciding whether they were doing a good job or not. Watch for the outcome of this meeting to be that we missed a decimal point in one of the temps and other few small errors but this doesn<t alter the trend of the last 100 years significantly – and Gee new research suggests we have already reached our 2 C limit.

I have a problem when they say that while the temperature at the equator does not go up much, the temperature at the poles goes up a lot.
Now polar air below zero does not contain much heat, and so requires a tiny amount of heat to change the air temperature a considerable amount. But tropical air above zero contains a lot of moisture, and so requires a lot of heat to change its temperature.
So , isn’t the whole concept of an average global temperature, based on measurements of the temperature of air, not too relevant?

“a rate of rise of between 60 to 90 centimetres per decade — more than double that recently observed.”
I can beat that easily…….
The last time I went to the beach, sea levels rose by 3 metres in just six hours!
Don’t these people realise the enormity of the problem?

Since the thirty year trends for MSU ( middle and lower, UAH and RSS ), Land Ocean ( CRU and GISS) and SST are all at or BELOW 1.7 C per century,
it looks like doing nothing has got us below 2 C!!!!!

So “world temperature” was nearly 2 Kelvins higher during the (uncivilized) last interglacial, but civilization must be responsible for any warming during this one?
Do these folks even read what they write?

“Critically, the warmer temperatures appear to have resulted in global sea levels some 6.6 to 9.4 metres higher than today, with a rate of rise of between 60 to 90 centimetres per decade — more than double that recently observed.”
This is obviously being promoted by a cabal of boat & inner tube manufacturers.

“the planet will be allowed to warm…”
I wonder if the person who wrote this copy actually read it back, out loud?
…planet….allowed…
…8 world leaders…will…allow the planet….
…allow the planet?
Huh?

So now these pointy heads are ‘telling’ the climate how much it’s ‘allowed’ to warm? I have to go outside and tell my grass how tall it’s allowed to grow – because I’m tired of cutting it.

Hahah! That is great! He even admits its happened before (2x as fast as today?)! Why is this a bad thing? Means its going slower right? Why presume different! This makes me happy.

I don’t mean to sound condescending, but these are professors of geography. Do most people know “climatologists” are relegated to the geography departments of most universities. Not that these people are stupid, but…
Ok. I’m not going to question their mental abilities–just their outlandish conclusions as already pointed out by several of the comments above.

Why do our politicians listen to this crap?
Only the idea that humanity is able to control the temperature of our oceans and our atmosphere is too stupid for words.
It exposes our political elite as incompetent and their policies as a total fraud.
Vote them out of office at the first possible opportunity, fight them and prosecute them for treason of their country and their electorate.
These people belong behind bars.

One of the key concepts used in present day efforts to quantify MSL via satellite altimetry, is that of the geoid. In simplified terms it is an artificial construct which attempts to portray what the oceans’ surface would be if all the planet’s land masses were totally pervious to the water in the oceans, with the variations in surface height due to the small variability in the planet’s gravitational strength. Most representations of the geoid give the range of gravitational strength as +/- 50-60 milliGals. When plotted in terms of absolute surface height that results in a range of 250 to over 300 METERS. In other words every milliGal variation in gravity strength corresponds to a change of surface height of 2-3 meters. Efforts have been made for decades to create models of the geoid. Many have been produced, each different in not insignificant ways from the others. The GRACE satellite and the similarly tasked European sat, whose name I’m blanking on at the moment, have revealed over their short lives that the Earth’s gravity is not constant over even a minutely brief period in geologic time.
The point of all this in the present context is that, even if we stipulate to the thoroughly dubious notion that these folks’ paleoreconstruction of Ancient sea levels is as accurate as they claim, without a similar reconstruction of the Earth’s gravitational properties for the same time period, which is at least a match for present observational data, no conclusions about what created those sea levels are justified.

People, please welcome homo superbus (arrogant man) the species that can control the temperature of our world.
They walk amongst you!
But rest easy the UN is appointing an ambassador to facilitate their integration and I am doing the only sensible thing possible and opening another bottle! Today has been amazing, this and 10:10. Whoever is writing this script needs to change whatever it is that they are on.

That’s where the meeting that specifically excluded people such as Pielke Sr. took place… Says it all.
A drastic reduction in breathing organisms is next…

more than double that recently observed.
recently observed sea level rise is betweeen 2.8-3.2mm year which is 2.8-3.2 cm per decade, which is 20-30x less than the 60-90 cm/decade trotted out in the article.

We’re back to controlling the climate, again? Well, at least from this is something most people can get a laugh. While they’re at it, can they send some rain this way? We’ve been a bit dry for a week or so and the dust on the roads are getting a bit much. Ego-maniacs and lunatics.

It is now beyond ridiculous for these smiling fools to release their “findings”, and proceed to simply lie about such simple facts as the rate of current Sea Level Rise.
And never a correction.
It’s just a lie and they do it with a smile.
No more snake oil.

“”” Lady Life Grows says:
October 1, 2010 at 1:50 pm
The planet was 10 degrees C warmer than today for 300 million years since the Cambrian. That is, 22 degC, exactly room temperature. That is probably optimum. It is also a maximum as feedback mechanisms prevent it from rising any higher than that. “””
Well by all accounts the present Temperature is close to 288 K or +15 deg C so +22 is only seven degrees C higher than today.

” “The results here are quite startling and, importantly, they suggest sea levels will rise significantly higher than anticipated and that stabilizing global average temperatures at 2˚C above pre-industrial levels may not be considered a ‘safe’ target as envisaged by the European Union and others. The inevitable conclusion is emission targets will have to be lowered further still.””
It is just amazing the range of authority attained by a Geographer .
Shouldn’t he be out measuring a mountain somewhere to see of it conforms to the terrain map ?
And then cutting or adding some dirt to match it?
Instead he is pronouncing himself judge, jury, climatologist, and UN General Secretary, dictating the allowable rise in sea level ( over which we have no control) to the governments of the world.
It is offensive already. I would not trust this liar with directions to the airport.
The humble Geographer.

help,
it was 47f this morning and 94 at the present – how will I ever survive?

Without in any way meaning to lend support to this article, I presume the sea level rise of 6 – 9 cm a year is a journalistic slip up. In the paper they say sea level is
“rising some 6–9 mm a−1 (Kopp et al., 2009) – at least double the current global average.” so I don’t think it’s fair to criticise/ridicule Turney on those grounds.
What troubles me more is the mixing of campaigning with science. OK, Chris Turney is a populariser but he has written campaigning articles on CAGW (e.g. We must acknowledge global warming, and act, The Times, 21 December 2007;
Time we acted on climate-change warnings, The Press, 21 February 2007). We can only be ourselves and if as scientists we are convinced (trying not to use the word ‘believe’) of the importance of some issue it’s understandable that we might contribute to the media in some way, I suppose even campaign for a cause. But (and its a big but) once you do that how do can you go on to pursue objective science?
In my research I try hard to run multiple working hypotheses (mwh), try to argue against what my current understanding suggests is true, argue against my own convictions. I suggest that unless an individual pursues mwh (and if we’ve strong convictions about something then there’s the greater need to aggressively pursue mwh) then dodgy science is the result.
The stronger your convictions, the more you think you are right and the less necessary mwh seem to be. Individually it’s not easy and corporately it is even tougher to question the ruling paradigms as the team fights against you, (with dirty tricks and all as witnessed by ClimateGate) though I take comfort that truly great individuals (e.g. Steve M) can prevail. On the other hand it’s even more dangerous to play onside, egos are flattered, mwh seem unnecessary and all manner of rubbish slips through if you say the right things. It’s a lesson for WUWT. And if climate scientists (if that’s what they are) had pursued mwh we’d have been saved a lot of grief, including being beaten about by hockey sticks or the hubris of believing we can agree “to the historic deal setting 2 degrees Celsius as the maximum limit for global temperature rise.”

On reading this, I had a picture of a king, drawn by Bulwer, standing on the sand commanding the tide. YCMTSU!

Also read: Your Tax dollars at work, US Fish Wildlife Service issues über alarmist report.
http://www.heliogenic.net/2010/09/30/your-tax-dollars-at-work-u-s-fish-wildlife-service-issues-uber-alarmist-report/

“I presume the sea level rise of 6 – 9 cm a year is a journalistic slip up. In the paper they say sea level is
“rising some 6–9 mm a−1 (Kopp et al., 2009) – at least double the current global average.” so I don’t think it’s fair to criticise/ridicule Turney on those grounds.”
Has a correction been issued ?
Am I reasonable to assume that Dr Turney reads his own glowing press ?
IS saying one thing to professionals and then another to the public at large
a strategy or an error ?
Unless a correction has been released I assume the former.

Ammonite says:
October 1, 2010 at 5:27 pm
Whatever the shortcomings or otherwise of the abovementioned study, there is a welter of information indicating a doubling of CO2 will likely lead to a global average temperature increase in excess of 2C. Please read a review of various approaches by Knutti and Hegerl 2008 at http://www.iac.ethz.ch/people/knuttir/papers/knutti08natgeo.pdf.
An “interesting” paper. Based on my own, admittedly brief, perusal of it, I’d have to say that the climate sensitivity to a doubling of atmospheric CO2 could be 3C… or it could be a bologna sandwich. I rate it a pick’em.

A disclaimer is required. That no science was used in the production of this (sciency )product. On reflection, as a WUWT contributer suggested weeks ago, the 1st rank of AWG shills are in full retreat. To cover their retreat they encourage the 2nd raters and useful idiots to publish in support of the great cause.Hence strange claims such as this.

E.M.Smith says:
October 1, 2010 at 6:56 pm
So let me get this straight… In the last interglacial, all on its own and without the help of people making CO2, the planet got 5 C hotter than now, then plunged back into ice. And during this interglacial, even though we are approaching the end of it, and are several degrees cooler than then; warming is unprecedented and it’s our fault? And the answer is to reduce CO2 production? Because that was involved how last time?
Something is not adding up here for me…
========================
The only variable at this point is, the profit motive.

Is the University of Exeter the new East Anglia?

Of course, in the run-up to Copenhagen last year Dr. Stefan Rahmstorf of Germany’s Potsdam Institute declared that a two-meter sea-level rise [over the next 300 years] had now become almost ‘unstoppable’ unless we could extract enough CO2 from the atmosphere to cool the planet. I suppose we will all just ‘go with the flow,’ whatever that might be.
Just for reference; as the anthropogenic contribution to the CO2 in atmosphere is assumed to be on the order of 110 ppm, to anthropogenically double the current CO2 concentration in the atmosphere, we would need to find and burn almost four times as much fossil fuel as has already been done in the last 100 years. I assume that burning carbon recovered by plants from the atmosphere would not count.

Spector says: October 1, 2010 at 9:02 pm
“we would need to find and burn almost four times as much fossil fuel as has already been done in the last 100 years. I assume that burning carbon recovered by plants from the atmosphere would not count.”
Burning carbon recovered by plants from the atmosphere would not count?
Where exactly do you think the carbon in fossil fuels originally came from?
Are you saying that if you rake the leaves and then burn them it is ok, but if you toss the leaves in a bog and burn them 250 million years later it is not ok?
Both cases are simply recycling CO2, which is the entry point for all carbon onto the food chain on earth, back into the food chain. Same same.

Kan says:
October 1, 2010 at 10:29 pm
It would help if these Professors would tell us, or maybe discover, what humans did 125,000 years ago to make the temperature stop increasing – obviously it was not the cessation of burning coal.
======================================
The wisdom of the ages.
-Chris

Robert of Ottawa says:
David Wendt, “even if I accepted your “doubling increases 2 centigrade” theory; two piddling centigrade will make no darn difference whatsoever.”
Hi Robert, I believe David was responding to a post in which I cited Knutti and Hegerl 2008, a climate sensitivity meta-analysis which provides wide ranging evidence for a likely climate sensitivity of 3C (+/-1C). The paper covers ten separate methodologies for arriving at this estimate along with their strengths, weaknesses and uncertainties. David has applied penetrating analysis to the paper’s findings, likening the results to a “bologna sandwich”. I have arrived at a different conclusion, namely that we are
headed for +3C.
I recommend Mark Lynas “Six Degrees” to how a +2C, +3C global temperature increase might unfold. In many places it has the potential to push agriculture regimes outside norms established for much of modern human history. Tag this as “alarmist rubbish” or read the book – your choice.

About Professor Turney mixing up metric units: The 60-90 cms are just as wrong in his blog which refers to an article in Nature from last year which says the following: “When global sea level was close to its current level (≥-10 m), the millennial average rate of global sea level rise is very likely to have exceeded 5.6 m kyr-1 but is unlikely to have exceeded 9.2 m kyr-1.”. 5.6-9.2 meters per millennium, that’s 5.6-9.2 centimeters per decade.

It hurt my eyes: “never”
Sorry big fingers on the iphone

The discrepancy between the paleo sea level in the last interglacial and the present situation does imply that is is worse that we thought; i.e., the overstating of the present warming in respect to past warm periods is apparently more greatly exaggerated than many may have thought and thus does not replicate the past sea level.

Christopher Hanley:
“A future temperature of 2°C above “pre-industrial levels” would presumably have to be maintained for several hundreds of years to effect the predicted sea level rise.”
Yes, and it would only be after the altitude of the Greenland ice sheet had been significantly reduced that the melting and sea level rise would accelerate. The paper could just as easily have been spun and reassuring, since our lower rate of sea level rise shows we are not at that climate stage yet, and even in the unlikely event we are at that rate of rise in 100 years, we can address any concerns then, when we are wealthier, more technological capable and hopefully understand the climate a little better.

About these 2°C:
Can ANYBODY tell me
1) the starting year of this calculation, and what the temperature was then?
2) how much of these 2°C has humanity “used up” up to 2010?

“I’m a Professor of Physical Geography at the University of Exeter where I’m focussing my efforts on … To do something positive about climate change, I’m a Director of a small company called Carbonscape which has developed technology to fix carbon from the atmosphere and make a host of green bi-products, helping reduce greenhouse gas levels.” – Professor Chris Turney
Hello everybody, could you do me a favour and forget what you’ve all seen here the past few moments? Thanks. Seems somebody is infringing on my IP. Just some lawyer stuff.

edmh says: October 2, 2010 at 2:26 am
… • Man-made CO2 is less than 7% of total atmospheric CO2 = ~0.087 deg C
edmh, your chain of reasoning assumes the water vapour content would not be affected if all other GHGs are removed from the atmosphere. This is not the case. Your conclusion is flawed.

Since our resources and leaders are focussed on minor warming and have put much resources and research into this, what happens if the BIG FREEZE starts to occur?
Will they recommend buying condos in the Keys as our only choice?

John Marshall says:
October 2, 2010 at 1:33 am
“Why did the temperature rise then? Not CO2!!! And are we constrained about a 2 deg. rise? or is a 2 deg. fall ok. I would rather it was a rise as I hate cold. CO2 never caused climate change in the past! Why now?”
Milankovitch forcing followed by CO2-CH4-WV feedback.
BTW folks – in the UK, Glaciology/Quaternary research tends to come under the wing of “Physical Geography”. Geology departments deal with the pre-quaternary stuff. Hope that clears that up!
Cheers – John

What the……………….!
“with a rate of [sea level] rise of between 60 to 90 centimetres per decade — more than double that recently observed”
I think the measured rate is less then 60 to 90 cm per CENTURY… not decade.
Probably a typo, but is is so typical. Climate science is just sloppy in every respect.

Am I the only one who reads these articles and then feels like they got hit by a truck at their conclusion? The last interglacial showed sea rise way above the current trend and was much warmer. So manmade CO2 could not have been the culprit. But then WHAM!!! manmade CO2 IS the culprit and we must do everything to lower it.

Vorlath says:
October 2, 2010 at 8:05 am
“Am I the only one who reads these articles and then feels like they got hit by a truck at their conclusion? The last interglacial showed sea rise way above the current trend and was much warmer. So manmade CO2 could not have been the culprit. But then WHAM!!! manmade CO2 IS the culprit and we must do everything to lower it.”
Well, that’s the thing about feedbacks, you see. They kick in once an initial forcing agent tips things. Milankovitch forcings affect insolation, especially in the N Hemisphere. Plate tectonics affects weather-patterns e.g. drifting a big continent to occupy the area of the South Pole creates a very dry and very cold place, but with moist fringes with lots of precip there. CO2/CH4 feeds back if Milankovitch forcings cook the permafrost. After that, water vapor follows suit.
This time – uniquely, outside of the armageddon-style Siberian Traps type events of volcanism on a quite mind-boggling scale, we are the primary forcing agent as a long-life GHG generator. What we are doing is unprecedented in geological history – in fact, the last time an Order of life affected CO2 concentrations so drastically was in the Devonian, when land-based vascular plants went forth and multiplied. That time of course it meant that CO2 levels went down. Antony has posted the graph before.
It’s a Dirty Harry-style experiment we are performing with our future, and the geezer saying “do you wanna make my day” ain’t Clint. It ain’t Antony, it ain’t Richard Curtis (people should, senso stricto, only explode on Monty Python sketches), and is sure as hell ain’t me. It’s the biosphere.
Cheers – John

“Peter Miller says: October 2, 2010 at 12:00 am
The article below is from the October 2008 edition of New Scientist – note the comments by Turney. This strikes me as being one of the goofier types of green technology being touted around today.
“The world’s first commercial plant that uses microwave technology to capture carbon dioxide from the atmosphere to help reduce the effects of global warming has started operating in New Zealand.
One way to sequester this carbon before it’s released is to turn plant waste into charcoal. “It’s a stable form of carbon and can last tens of thousands of years,” says Chris Turney of the University of Exeter, UK.
Carbonscape, based in Blenheim, New Zealand, has developed technology that turns organic waste, such as wood and wood chips, into charcoal using microwaves. Turney, who advises Carbonscape, says that at full capacity the plant can produce a tonne of charcoal a day. And even when the plant is using electricity generated by conventional non-renewable sources, the process will result in a net reduction of one tonne of CO2 in the atmosphere every day, claims Turney.”
—————————————————————————-
What Turney is saying that this company can make a ton of charcoal with a process hat uses electricity off the power grid. He is also saying: “even when the plant is using electricity generated by conventional non-renewable sources, the process will result in a net reduction of one tonne of CO2 in the atmosphere every day”
This is the classic perpetual motion machine. Coal burning power plants can be modified to burn charcoal just fine. Using Turney’s process, we can make more than a ton of charcoal by burning less than a ton of coal in a power plant.
FANTASTIC!!

John Mason says:
“Plate tectonics affects weather-patterns e.g. drifting a big continent to occupy the area of the South Pole creates a very dry and very cold place, but with moist fringes with lots of precip there.”
—
I hope you’re being sarcastic. I’ve done modelling of the Earth with respect to the seafloor age. New seafloor production has actually been even or going down for the last 30 million years. This production is under water. So there is no drifting of big continents. We’re talking 120,000 years since the last ice age. Not millions required for significant plate movement. And I’m not sure what to say about the rest of your comment except WOW!

Ammonite says:
October 2, 2010 at 3:02 pm
From their opening paragraph, “various observations favour a climate sensitivity value of about 3 °C, with a likely range of about 2–4.5 °C.” The 10 differing approaches assessed all centre around 3C.
——————–
Show me one set of actual observations that results in 3.0C per doubling.
I’m talking about temperature and CO2/GHG observations (historical or recent).
That is the problem with these papers, there is no actual data in them. There is a chart that somehow shows 3.0C per doubling and this is just accepted as evidence. However, when looks into any set of actual observations that the chart is based on – it is a mystery where the 3.0C per doubling came from because the math does not work.

I am very skeptical about the ability of climatologists to determine with accuracy the temperature 125,000 years ago from the settling of sediments and especially to determine the ocean rise of 60 to 90 centimeters per decade. I am surprised that they use such rough estimates to suggest that 2 degrees Celsius climate change is unsafe.

Smokey says:
October 2, 2010 at 9:22 pm
What is “UHI” in this context?

Rob Potter says:
And the whole 6-9 m of sea level rise will take just 100 years……. Wow, the resolution of their historical reconstruction is fabulous!
That would require 6-9cm per year. Or 60-90 mm/year, 600-900mm/decade…
I’m thinking 6-9 mm per decade is what they meant, based on a 6-9 m rise over a millennium (which they might just be able to resolve).
6-9mm per decade would mean that the 6-9m change would require 10,000 years.
Which is plenty of time for plenty of other processes to alter the level of the land.

Ammonite,
Hegerl and Knutti are just presenting a review of the literature, and the published literature, mostly model based, does generally agree on a climate sensitivity of 3 degrees C. But there is more to be learned from reading paper and its references than that. Consider for instance that they don’t discuss the model diagnostic literature. Since all the AR4 models have correlated error in several different diagnostics, including representing less than half the observed increase in precipitation (Wentz), failing to reproduce the amplitude of the observed response to the solar cycle (Camp and Tung) (Lean), more than 3 W/m^2 globally and annually averaged bias in surface albedo feedback (Roesch), errors in tropical radiative suggestive that the net feedback is negative while the models have it positive (Spencer) (Lindzen), etc., Hegerl and Knutti failed to discount the model based results. I don’t see how they can be discounted in a way which has them significantly and credibly contributing to the final conclusion. Please note that in their discussion of “various observations” they admit, not only model dependency, but dependency on just one climate model. It was just slab ocean model, by the way:
“The main caveat is that all three studies are based on a version of the same climate model and may be similarly influenced by biases in the underlying model.”
Let’s now consider the model independent estimates of climate sensitivity. Upon closer examination, we find that much of it is actually model dependent, one of the papers of Annan for instance, that claims to arrive at a model independent estimate, uses models to evaluate the maunder minimum and (if I recall correctly) the Holocene optimum and a previous glacial/interglacial transition.
Note another limitation disclosed by Knutti and Hegerl:
“The concept of radiative forcing is of rather limited use for forcings with strongly varying vertical or spatial distributions.”
This does not come as a revelation to those who have thought much about nonlinear dynamic systems. So which forcings have strongly varying vertical or spacial distributions? Well, solar for one, couples more strongly to the stratosphere and surface including 10s of meters of the ocean than it does to the troposphere. The well mixed GHGs couple mainly to the troposphere, with H2O having an uneven distribution, and aerosols couple to the troposphere is a vertically and spatially varying way. For the purposes of the AGW hypothesis, it is climate sensitivity to CO2 and the other non-H2O well mixed GHGs that is over interest. There is no reason to assume that the climate sensitivity to CO2 is the same as that to solar or aerosols, so we can eliminate those estimates based upon solar and aerosol forcings.
Next we can consider the paleo estimates of climate sensitivity to CO2. The errors in estimates of temperature from proxies and CO2 levels are both high, and the estimates of climate sensitivity based on long term equilibrium responses are of questionable relevance to what will happen in the next century or two, because they either involve a crossover to a different climate mode, or because higher estimates of climate sensitivity require time frames in which significant melting of the Greenland ice sheet can occur. All the glacial outlets of the Greenland ice sheet would have to be galloping continuously at rates only seen infrequently for hours at a time and the elevation of the top of the ice sheet would have to be considerably lowered.
Rather than just summarily rejecting all these studies, lets also try to understand why the estimates of climate sensitivity might be high. The model diagnostics help here, because they show that the models under represent the observed response to the solar cycle variation. Models that under represent solar might need to be excessively sensitive to CO2 in order to reproduce the recent warming despite the fact that solar activity was at a grand maximum during the latter half of the 20th century. Furthermore, the models might also need excessively high sensitivity to CO2 because they were unable to reproduce the multi-decadal climate modes that were in the positive phases during the recent warming. The under representation of the negative feedback of the water cycle and the questionable positive tropical cloud feedback might be how they achieve this higher sensitivity.
Lets look at why the estimate of climate sensitivity to solar radiative forcing might be high. Solar variation is admitted by the IPCC FAR to be poorly understood and possibly off by a factor of two. If variation in solar radiative forcing is actually higher, the sensitivity required to explain past climate variation is lower, most studies just use Lean’s estimates without allowance for that uncertainty. But I think the real reason that estimates of climate sensitivity to solar radiative forcing is likely to be too high, is because the climate response to solar is not just to radiative coupling to the climate but to other nonlinear coupling mechanisms. Solar UV variation couples chemically to the stratosphere and a lesser extent to the troposphere through chemistry, the creation of the greenhouse gas ozone. It was already being understood in 2008 that solar UV varied by several percent over the course of a solar cycle. Recent work in the current extended minimum show that these minima are not like the shorter solar cycle minimum. UV varies even more greatly, perhaps by an order of magnitude. Therefore models might have required much higher sensitivities to solar radiative forcing to understand the maunder and dalton minima and the medival warm period because the climate response was not just due to radiative forcing but to this other nonlinear coupling which they didn’t represent.
The models implement radiative coupling similarly for solar and CO2, for instance CO2 is usually coupled to the whole mixing layer of the oceans even though it barely penetrates microns into the surface while solar penetrates 10s of meters. Similar treatement of the CO2 and solar wavelengths occur at the land surface as well. Therefore model implementations which amp up the response to solar radiation in order to explain past climate response which was due to coupling that wasn’t just radiative, will also have amped up the response to CO2 radiative forcing.
Past aerosol forcing is poorly understood and is so poorly constrained that it supplies most of the explanation of how models with more than a factor of two difference in climate sensitivity can “match” the same climate. The Pinatubo eruption aerosols are probably better understood, but estimates of climate sensitivity from this event are usually also tainted by models.
Basically, there is practically no model independent evidence of climate sensitivity to CO2 in the current climate regime. The direct effects of CO2 can only explain about a third of the recent warming and a climate sensitivity of 1 to 1.1 degrees C. Anything more requires net positive feedback. Recent model independent evidence suggests that the net feedback might actually be negative (Lindzen) (Spencer) and at the very least that the models have another important conflict with the observations.
The science is not settled.

Ammonite says:
October 2, 2010 at 6:25 pm
————
The last interglacial period, which this thread was started on, actually invalidates all those papers you cited (which I have read thoroughly before). Temperatures rose 2.25C above the most recent interglacial yet all of the forcing factors that the papers are based are exactly the same between the two periods. CO2 increased enough to cause about 1.6C of warming (at 3.0C per doubling) in the last interglacial yet temperatures increased 7.0C.
The Lorius paper starts out by defining the planetary energy balance N as:
N = (1 – Albedo)/4*Solar – 0.96 * 5.67e-8 * (Temp Surface)^4
– from there, one can determine all kinds of sensitivities including the CO2 sensitivity because we know Solar, we know most of the Temp Surface numbers, we know CO2/GHG forcing numbers: yet not a single climate paper ever provides what Albedo estimate they used. How can you determine the change in total forcing and energy balance and the sensitivities without it. Well, one can just use whatever estimate one wants to [And they do – It is the major fudge factor in all the paleo climate model reconstructions – basically they just choose to use an Albedo number which gives them 3.0C per doubling of CO2/GHGs].
Covey’s 1996 paper contains the following quote (in reference to the simulation of the Eocene, a period in which there was no sea ice and no Greenland or Antarctic glaciers) –
“Covey et al. (1991) estimated that 2 to 3 W m -2 radiative forcing would
result from the complete disappearance of sea ice from the present-day Earth, but
we have excluded sea ice changes from our definition of [change in] Q because we want to include such changes in the feedback processes measured by the paleocalibration technique. Accordingly we consider only the remaining contributor to changes in surface albedo, namely higher sea levels and the resulting decrease in the fraction of relatively high-albedo land areas.”
– ie we just changed our previous estimate so that we could use “the paleocalibration technique” – they just ignored something that is -3 watts/m2 (almost the same number Hansen uses for the forcing change from all the ice and vegetation changes in the ice ages) – which is itself incompatible with the Covey 1991 estimate of losing just sea ice since the ice sea ice and glaciers should be something like -15 watts/m2).
– etc. etc.

It’s a pity really – think of the manure potential for the veg-garden!
As a lad, I was very fortunate to be taken under the wing of Prof. F.W. Shotton, who was something of a big-hitter on the Quaternary of the UK. He used to take me on his research-trips and they were a major education into how the UK had changed from glacial to interglacial and how the resultant deposits & fossil faunas developed as a consequence.
I know a lot of regulars on here are hostile to my take on climate change, but I’m happy to put that to one side if you are, and to discuss any questions of a more geological nature. My background is in mineralogy & precious metals exploration primarily, but also in the geological evolution of the British Isles, which has some of the most diverse geological history for any comparably-sized landmass around the world. The events of late have again reminded me that, in the climate debate, both sides screw up at times: however, that should not prevent us from talking about the scientific method and the need to apply it rigorously. For all the posts that I have read on here attempting to rubbish climate science, I still stick with what I see as the overwhelming balance of evidence on that front, which is counter-wise to what most posters on here seem to think, but in geology I am happy to drop in and contribute to less controversial topics, from time to time. Apart from anything else, I think it is important to engage with people, rather than the “traditional” wars between “warmists” and “deniers”. We’ll know either way who was right on that within a few years, after all.
Cheers – John

Bill Illis says: October 3, 2010 at 7:00 am
“yet not a single climate paper ever provides what Albedo estimate they used”
Thankyou for your response Bill. I will take this as a reading assignment (no sarcasm).

Passed the point of arguing how many angels can dance on the head of a pin
– reached the stage of mandating the maximum number of them that will do it

Ammonite,
Yes, you are correct that the annually averaged surface albedo bias documented by Roesch is extremly small, however, at about 3W/m^2 it is comparable in size to the Anthropogenic greenhouse forcing and more than 3 times larger than the energy imbalance of less than 0.8W/m^2 that Hansen calculated was being stored into the oceans during the 1990s. The 20th century warming was a small difficult to detect phenomenon, so it should be no surprise that climate models are not up to the task of attributing and projecting the phenomenon yet.
You sound as if you aren’t familiar with the Wentz publication in the journal science showing that none of the models produced as much as half of the observed increase in precipitation. Not only does correlated under representation of a key negative feedback by more than a factor of two create a credibility and validation problem for attributing and projecting warming, it calls into question all the model based conclusions that there will be increased risk of droughts, that are being funded by countries, states and regions and reported without discussing the model diagnostic literature. The money is just too hard to turn down.