What BBD apparently fails to appreciate is that a so-called consensus opinion changes over time: that is why e.g. the RS re-issued its viewpoint in the document Climate Change: a summary of the science as recently as September 2010 rather than sticking by the viewpoint it issued in 2007.

The so-called consensus opinions linked to in BBD's link are pretty-much out of date. But hey, no need to spoil a good story by revising a "consensus opinion".

In a couple more years, it is just as likely that the consensus view will have shifted yet again - climate science is nothing if not evolving - but the direction of change is generally towards acceptance that there may be many more previously unconsidered drivers of climate, rather than fewer, that climate sensitivity may be less than previously estimated, that the world may be about to enter a cooling period rather than accelerated warming.

Those who cling to the old consensus will simply be left behind.

Your reflexive denial that CO2 is a serious problem going forward is the problem with this conversation. As is the case with Shub, Hilary, Mike and others.

Ah, I get the picture (minuscule, inaccurate and irrelevant as it is) ... there can be absolutely no doubt whatsoever that "CO2 is a serious problem" simply because our resident zealot-for-all-seasons (and some might say beyond-all-reason) says so!

Maybe someone could explain to me how our resident zealot's postulations, prognostications and pontifications have any relevance whatsover to the topic of this thread.

Oh, wait ... I get it ... the zealot has diverted and once s/he has chosen to divert, the actual topic is no longer a matter deserving of consideration because - let's face facts, folks - the only thing that matters in a thread in which the zealot has graced us with her/his presence is paying attention to her/his postulations, prognistications and pontifications. (viz inordinate number of her/his "comments")

[cue whining from zealot]

Hilary

Please inform Philip that his contributions to this thread are unwelcome.

Thanks!

matthu

Only you could fail to appreciate how absurd it is to argue that the scientific consensus is not focussed on the effects of CO2 on climate.

I'm sorry but you've wasted enough time on this. Believe what you like; it makes no difference to the facts.

Conversation over.

Philip

No problem - I enjoyed the papers and am still considering their implications. I do not entirely agree with you however:

The suggestion is that not only does snowball/hothouse correspond to jumps and round-the-side routes on this surface; the Federov et al finding of different T for the same sunshine, geography and CO2, corresponds to taking different routes; sudden changes at glacial->interglacial etc correspond to taking a jump rather than an easy route; the Cenozoic change from gradual erratic cooling to wild oscillation corresponds to a movement into a more folded part of the surface; the step discernible in UAH/RSS corresponds to a jump; as do the discontinuities in slope discernible in the HADCRUT record.

The point about Cenozoic climate is that it represents a long cooling. The ice-free Early Pliocene with its perennial EN was a legacy climate state from a deep past of much warmer states. The elevated GAT was forced by low cloud albedo and high atmospheric WV content, both consequences of the perennial EN.

Once the Ma-scale cooling caused NH ice sheets to form around 3Ma ago, the ice-albedo feedback began to drive the pronounced glacial/interglacial oscillations. There is no need to elaborate on this essentially straightforward evolution of physical processes.

Holocene climate is at the bottom of a U curve in sensitivity variation. Push it hard enough left or right, and you get a snowball or hothouse Earth. Push it so just so far and you get a glacial or a Pliocene-like climate. Federov et al. suggests that the latter is a possible outcome from CO2 forcing on a centennial scale.

F&G apparently agrees.

I disagree that Koutsoyiannis has anything btw. And when I asked him to explain how his ideas actually integrate with physical processes (specifically including RF from GHGs) he refused to answer and terminated the conversation.

What's the link to the .jpg supposed to mean? Baffled ;-)

Of course the consensus is focussed on CO2.
CO2 was mentioned in my 3 line summary of the consensus.

RF? Not sure exactly what you mean here.
increasingly important factor? I am not sure whether it is even an important factor. Certainly this is not the scientific consensus.

You are a time-waster. Conversation over.

BBD
What you have on your hands, is a lot of ideas which resonate to perfect pitch with the consensus (not a problem by itself) , and a handful of current topics that run on this blog, just like any other blog.

Why do you have to fill in threads and threads of copy-pasted material from climate science papers, and your concerns, when you virtually don't have anything to add to any thread otherwise? Staying topical, adding an on-topic comment, and following a path to a slow, but sure transformation (of those who are listening to you) - is that such a bad thing?

In other words, what you need is a blog. Your blog. I'm pretty sure you have the material to run it, and the readers who will be interested. I don't know whether you've thought about it, but it is not a big deal - as long as you run it on your own terms ( and let it not take over your life) - if that is what you are concerned about.

What you fail toi realise is that the importance of CO2 is subject to a lot more uncertainty now than it has been in the past.

Climate scientists are recognising many other factors previously unconsidered by the IPCC.
Global temperatures have tended to level off since the end of last century, despite a 33% increase in CO2 emissions. (US temperatures have actually been falling.)

Shouldn't any of these recent developments affect the level of certainty that you attach to CO2 as a dominant driver of climate? Well they have - that is why the consensus opinion has changed and is continuing to change.

You fail to see this and resort to ad hominem attacks.
Attack the messenger. Repeat the mantra.

By the way, BBD, regarding your snipe about RF:

New studies on climate forcing agents not conventionally considered have, however, raised doubts as to the continued viability of the radiative forcing concept. For example, the climatic effects from light-absorbing aerosols or land-use changes do not lend themselves to quantification using the traditional radiative forcing concept. Aerosol effects on clouds are difficult to describe in terms of simple radiative forcing. These challenges have raised the question of whether the radiative forcing concept has outlived its usefulness and, if so, what new climate change metrics should be used.

http://www.nap.edu/openbook.php?record_id=11175&page=R7

Sure, the suggestions are only that. The point I was interested in was the general idea of the earth responding non-linearly to imposed changes, and what that implies for its likely behaviour. I'm pleased that the researchers involved in the papers I pointed at all seem to express similar reservations to mine.

I haven't explored Koutsoyiannis' work too deeply yet. My understanding has been that one of his findings has been scaling in temperature series. If you look at this paper, you will see that Lovejoy/Schertzer also find scaling, and (amongst other things) use it to provide yet another indication regarding the Hockey stick, figure 9 and section 4.3. I don't know if the Bishop is aware of this argument?

"What's the link to the .jpg supposed to mean?" - Sorry about that, just a slightly whimsical joke. Either me or the world hanging on by its finger tips, take your pick. BTW, I assume (hope!) you didn't mean to name me in your 1:07 comment to Hilary? Had me worried for a moment until I spotted your 1:32!

Shub

Why do you have to fill in threads and threads of copy-pasted material from climate science papers, and your concerns, when you virtually don't have anything to add to any thread otherwise?

Eye-watering hypocrisy. Your commentary on this thread has been 100% content-free trolling, purely designed to disrupt the conversation and smear me.

I know the current exchange I am having with Philip is over your head. Please let it proceed without yet more personal attacks and interruptions.

Because you have an agenda - delegitimise me. Well, it isn't working, although you have committed a messy and prolonged credibility suicide.

What is hilarious about all your (and others') crap about me derailing this thread is that it was started by Zed. You know - Zed the hated troll.

Further amusement derives from the fact that I did not derail the thread as you and your fellow delegitimisers wrongly claim.

Zed accused the majority of contrarians of a moral failing. Then she immediately started up with crude renewables boosterism - which is a gross moral failing. So I took her to task for dual standards.

But her original question informs the discussion even now - she asks whether denying the influence of CO2 on present and future climate is immoral. Before we can address this, we must decide whether CO2 does or does not have an effect on present and future climate.

That is what is going on. This thread remains on-topic.

This is all just too subtle for you, isn't it?

Philip

Sorry for the confusion re 1:07. My point was that Hilary is (as ever) trying to shut me down. But logically, she must also include you in the process as we are in dialogue. I was pointing to the unfortunate consequence of her not having thought her tactics through (again).

As you just might have noticed, I am under constant attack by certain commenters. They have to be kept in check. It's tedious and time-consuming, and if you find their antics annoying, please tell them so.

BBD - sorry if you think I am attacking you.

But I do think (for the avoidance of doubt) it is only fair that you now declare what your position is on RF from CO2 since you asked me to I declare my position.

Presumably you do still think it is an increasingly important factor? (By the way, this would probably put you some distance away from the current consensus).

Philip

The problem with Koutsoyiannis' and several other alternative takes on short and long-term climate variability is that they are essentially non-physical.

Thus they provide contrarians with an irresistibly convenient way of avoiding any discussion of the role of RF from GHGs in the physical processes that underpin and drive climate variation.

This is classic misdirection as practised by lawyers and stage magicians.

matthu

You have attacked me ever since joining this thread. You know my view on the role of RF. Stop scratching away trying to get a reaction.

Your continued insistence that concern over the effects of CO2 on climate is not central to the scientific consensus is wrong. End of conversation.

matthu @ 2:13pm

You should read the sources you reference:

The committee began its discussions with a good dose of skepticism about the continued viability of the radiative forcing concept. In the end, however, one of our major findings is that the concept retains considerable value.

Whoopsie!

BBD - you misunderstand me. Perhaps deliberately.

"retains considerable value" is hardly the same as "is an increasingly important factor".

"Retains considerable value" suggests that at least some of the value has been diminished i.e. the consensus about its importance is not as rock solid as once may have been the case.

matthu

Oh wow.

Look: you're out of your depth. You've just made quite a funny mistake with quoting a source which undermines your 'argument'. Unwisely followed by a pitiful attempt to cover up what you've done.

Please understand something. I am not stupid. I see through your nonsense. Time to stop now.

You claim the RF is an increasingly important factor.

The major finding of a committee of scientists is that while RF may retain considerable value, the concept needs to be rehashed and at the same time they admit previously unacknowledged uncertainties in forcings and climate effects from conventional and nonconventional agents and that they need to improve their understanding of the relationship of radiative forcing to climate change.

This hardly amounts to consensus knowledge, even to a layman.

By the way - any idea what nonconventional agents are?

matthu

The BASC report that you unwisely misused does not find any real problems with the current understanding of RF from GHGs. See here:

Whereas the level of understanding associated with radiative forcing by well-mixed greenhouse gases is relatively high, there are major gaps in understanding for the other forcings, as well as for the links between forcings and climate response. Error bars remain large for current estimates of radiative forcing by ozone, and are even larger for estimates of radiative forcing by aerosols. Nonradiative forcings are even less well understood. The potential for large and abrupt climate change triggered by radiative and nonradiative forcings needs to be explored.

Rather it is part of the process by which the error bars on iconic representations such as this one in AR4 WG1 SPM are being tightened.

You are misrepresenting your source. The scientific consensus is and remains that CO2 is the main cause of recent warming and that it will drive future warming until the climate system reaches approximate radiative equilibrium.

You seem to have some personal beef here. What is it?

BBD

Your attitude in this thread smacks of an arrogance that is totally alien to the norm on BH, however that does not mean your views have no relevance.
Zed's question:
But her original question informs the discussion even now - she asks whether denying the influence of CO2 on present and future climate is immoral. Before we can address this, we must decide whether CO2 does or does not have an effect on present and future climate.

Answer:

The IPCC itself stated that the relationship between atmospheric CO2 and global temperature is logarithmic not linear. Since all sceptics also believe that, can we then take it as read that it is the consensus view?
That opinion implies that there is a finite amount of warming that CO2 causes and that above a certain level of atmospheric CO2, adding more CO2 to the atmosphere will have no effect.
There is no consensus about the level of CO2 above which it becomes irrelevant in terms of warming.
However the ice core records give huge weight to the argument that we are already well past the level at which CO2 is actively warming the planet.
It is a fact that atmospheric CO2 is at high levels during very recent climate history (although it is dangerously near to the level at which current vegetation can not survive). Given that levels of CO2 are currently higher than existed in the last 6 interglacial warmings in the current ice age, it is relevant to examine what happened in those interglacials when temperatures were similar to today.
What happened was that the planet cooled even though CO2 was rising (sometimes for as long as 2000 years after the cooling started, Idso et al) in every one of those interglacials. These facts strongly suggests that current levels of CO2 are not warming the planet.
The IEA report is based on the assumption that CO2 IS currently warming the planet. It seems to me that calling people who do not agree immoral is a joke since there is evidence to suggest it is NOT warming the planet and not one shread of evidence that it IS warming the planet.

Nothing personal.

I have simply been exploring why you continue to cling to an outdated consensus that no longer applies, opinion having moved on, uncertainties being greater than previously acknowledged and many more factors playing a part than were properly considered in 2007.

A substantial body of scientists today acknowledge that there is a significant risk of material cooling over the next 20-30 years. That by itself is enough to undermine the previous consensus of ever-increasing temperatures unless we bring CO2 under control.

matthu

I have simply been exploring why you continue to cling to an outdated consensus that no longer applies, opinion having moved on, uncertainties being greater than previously acknowledged and many more factors playing a part than were properly considered in 2007.

All you are doing is misrepresenting the facts. While there are always uncertainties, one of the least uncertain aspects of the scientific consensus is that CO2 is the main driver of recent climate change etc (see 100x above).

This is agenda-driven BS. You want to deny the central role of CO2, and think - mistakenly - that endless repetition of nonsense will get you somewhere. Think again. Why don't you look at the relative forcings as set out in the WG1 SPM? It's as plain as day that you are wrong.

A substantial body of scientists today acknowledge that there is a significant risk of material cooling over the next 20-30 years.

Really? Name some names.

And what about the 30y+ time-frame?