Monday, February 28, 2011

What do we know? Is it enough to start action?

In a previous comment, I asked the following question: "The problem is climate - we don't understand exactly how and why it changes and what that means. Or do we?" Our estimated contributor Andreas responded and points to a discussion of exactly these questions. He writes:
"Zeke on Lucias blackboard and J. Curry at her blog tried to summarize the results in connection with their personal estimation of likelihood. Zeke writes about his motivation:
"My personal pet peeve in the climate debate is how much time is wasted on arguments that are largely spurious, while more substantive and interesting subjects receive short shrift. While I’m sure a number of folks will disagree with me on what is spurious vs. substantive, I think it would be useful to outline which parts of the debate I feel are relatively certain, are somewhat uncertain, and quite uncertain."

Andreas suggests that in case we agree upon certain facts, we could move forward to the next question: What kind of climate policy do we support and what is the basis of our differences?


Anonymous said...

Vielleicht sollten wir uns erstmal im Klaren darüber sein, was wir unter "Klima" verstehen.

Lassen Sie uns doch einen "modernen" Universalienstreit führen, der "mittelalterliche" wäre für Herrn Grundmann sicher zu primitiv.


sien said...

Roger Pielke Jnr, Bjorn Lomborg, Richard Tol, Nordhaus and other seem to address exactly this question.

I'm a 'lukewarmer' and more skeptical of claims of many Climate Scientists than they are but I'd be quite happy to accept a 10 EURO per ton tax in the developed world that was used in a hypothecated fashion to research alternative energy including nuclear.

The question is, why haven't any politicians gone with this suggestion?

Anonymous said...

@werner krauss

Hans von Storch pointed out my last sentence to be flawed.. I agree and I'm not happy with my last question any more.

I think, Zekes und Curry's estimations of likelihoods could be an excellent idea to sort out, where the parties differ and why.
It's not supposed to lead to reconciliation, but maybe to a better understanding of each other.

My last question was not supposed to justify or postulate a special political response, e.g. a 2°C-goal. But if we can agree on some scientific basics, we could focus on the important discussion:

What kind of climate policy do we support and what is the basis of our differences? In my opinion the main reasons for the differences are of political nature.

Anonymous said...

Sorry, #3 was my post.


Roddy said...

sien #2 - you don't need a tax. Just take the subsidies/taxes (FiTs) used currently for solar and wind in Europe alone and you get plenty o'plenty of billions.

Werner Krauss said...

@Andreas #3: I changed the post - does that fit better now?

Anonymous said...

Back to square one?

We are right in the middle of an debate, having a critical view at a lot of different issues and you start to call for action - before even someone agrees on an answer to Zekes's and J. Curry's question "which parts of the debate are relatively certain"?!

If the differences would be just of of political nature, as you say - what they are clearly not - what kind of action should be taken?

Cut CO2 emissions by half until 2050?
In China? India? in the USA or just in Europe if the others won't follow?

Trust the "sorcerer's apprentices", the geo engineers and their remedies like ocean iron fertilization, space mirrors, cloud reflectivity enhancement, painting our (solar) roofs white?

Anyway, the earth's atmosphere is not a broken machine to be repaired by engineers and quite a lot of things could happen in such a long periode of time, besides that we might reach peak oil long before and run out of oil, gas and coal.
If just one important volcanic eruption occurs - like the Mount Tambora eruption of 1815 - we would live another "year without a summer", followed by cooler periods like the ones after 1816.
What to do then?

Mit Brecht:
"Ja, mach nur einen Plan
sei nur ein großes Licht
und mach dann noch 'nen zweiten Plan
gehn tun sie beide nicht"

Besides that: there is a lot of good reasons to reduce our consumption and the dependency on fossil fuels, coal and gas. A big challenge for R&D.
I can't see any solutions yet to be practicable - but a lot of money wasted on inefficient, intermittent and unreliable energy sources.
If we look back in history, a marginal warming is not a problem that needs to be tackled. Cooling would be a serious one.


_Flin_ said...

@Roddy #5: A Feed-In-Tarriff is neither a tax nor a subsidy. It is a shared cost that results from the contractual guarantees given to investors to make them invest in renewable energy sources.

It is no discretionary spending, is not part of any public budget and therefore is not money that is somehow available.

Furthermore it is a contractual obligation and cannot be stopped just because an interested party feels like it. You might stop FiTs and therefore not give any new guarantees, but the existing ones are pretty much untouchable.

Concerning climate policy:
In my opinion the most important part of climate policy is twofold:
1. Accepting that CO2 is a greenhouse gas, warms the planet and that this outcome is dangerous or at least risky, although the exact amount of danger and risk is uncertain.
2. putting a price on a ton of CO2 and pursuing all measures that are below this price. Even if the price is very low, e.g. 10 US-$ / ton of CO2 (maybe even 0?), the statement "we try to save CO2 by all means that cost less than x" would be an improvement, at least in the USA.

For Europe, esp. Germany, I'd like to see an end of the partisan "hü-hott", esp. concerning nuclear. Furthermore I'd like to see longterm regulatory goals, openly communicated, so the industry can calculate with it (e.g. concerning CO2 output for the fleets of car manufacturers).

Anonymous said...

@ werner krauss

Thank you. Feel free to remove all grammar and spelling mistakes you find ;-)

@ ralph

First of all I would agree mostly with Zekes ratings. Furthermore I regard the AR4-WG1 as an excellent and correct summary of climate science (in 2007).

I don't know much about WG2 and WG3, but from an paleoclimate perspective (note: I mean up to billion of years, not the last 2000) our ongoing "experiment" is disconcerting and breathtaking.

Hence in my opinion we should reduce CO2-emissions.

All further actions I can't explain by science, now we enter the field of political and philosophical convictions (precautionary principle, sustainability etc.).

I would prefer a goal of 90% reduction for Europe until 2050.

You ask: "In China? India? in the USA or just in Europe if the others won't follow?"

That's my problem: We have to show, that the way to reduction works without economical frictions.
But what if others don't follow?
I suggest: Subscribe to a very ambitious short-term goal (10-20 years) and keep further goals open for further negotiations. If these will fail, well, then there's no much sense in ambitious EU-reductions.

What's your point of view?

Ich halte solche Diskussionen für wertvoll, weil sie helfen können, das Verständnis für die andere Position zu entwickeln oder zu vertiefen und möglicherweise auch das Gesprächsklima entgiften. Es ist aber Illusion zu glauben, wir könnten einen Konsens oder Kompromiss finden, was politische Ausgestaltung von Klimapolitik angeht, dafür sind die Unterschiede einfach zu groß.

Warum sollten wir auch? Ist es nicht eher normal in unserer jungen Geschichte der Bundesrepublik, dass wichtige Entscheidungen im größten Dissens getroffen wurden und sich erst langsam und allmählich zu einem gesellschaftlichen Konsens umwandelten? (Beispiele: Aufbau der Bundeswehr, Brandts Ostpolitik, Nachrüstung, vielleicht sogar Hartz4?).

Es gibt nur eine Stelle, wo Konsens erforderlich ist: Bei den UN-Klimaverhandlungen.

Ich schätze ebenfalls an der Klimazwiebel, dass man sich respektvoll mit dem "anderen Lager" austauschen kann.


Günter Heß said...

As a democrat I do not need to agree, if the majority decides I respect that. So, if necessary our government can act, even if I don’t agree. Decision making doesn’t need consensus, only democratic procedure. Consensus is for people who don’t want to be responsible, if their decision is wrong. Therefore I think the call for agreeing is spurious. We need a majority to act, but of course respect the rights of the minority according to our constitution.
As I scientist I will always acknowledge uncertainty as a possibility. So, I am aware that each decision is made under uncertainty and might be wrong. So, we should not be afraid of being wrong.
As a scientist and engineer I will always object to actions that are neither verified nor validated or not removed if proven wrong or harmful. For me that is the most important part. I do see a lot of acting “Aktionsmus” and lip service , but not enough verified and validated actions.
My second big problem. I do not trust people who call others “denier”, those guys are not credible to me. In order for me to agree to things that are not validated, but deemed necessary to be explored, I like to see such people removed from advisory boards to our government. As a democrat I will object to such advisors.
Best regards

Anonymous said...

I think that the uncertainty in climate science is pretty much irrelevant for the small term policies someone prefers, and becomes increasingly relevant for the longer term.

Within the realm of realistic outcomes, GHG reductions are equally necessary (or unnecessary, dependent on how someone views the nature of the problem in connection with their broader worldview). Since no serious measures to reduce emissions globally have been enacted so far, the trajectory of emission reductions will begin the same in all cases. It’s only further down the road, when serious mitigation action has started, that it starts to matter for the optimal policy portfolio what the exact climate sensitivity is for example.

In short: If it’s bad, it’s really bad. If it’s good, it’s still pretty bad (where “bad” obviously is a subjective term). So for the steps to undertake (initially at least), it doesn’t matter much precisely how bad it will be. We’re driving in a snowstorm and it’s advisable to reduce speed. Whether 30 or 60 km/h is the optimal speed is perhaps not certain, but we know that continuing with 120 km/h is not a wise option for the long term.

As Herman Daly said: “if you jump out of an airplane you need a crude parachute more than an accurate altimeter.”


Anonymous said...

@ Andreas

"I regard the AR4-WG1 as an excellent and correct summary of climate science (in 2007)"

To cite another than a sceptical source, here's the report of the BMO and the HC. Just read what is presented on uncertainties and open questions (models) etc.

"I don't know much about WG2 and WG3"
That's where the mess really begins ...

"we should reduce CO2-emissions"

OK, that would be an option if it was binding for all countries. Apparently China, India, the US and other nations don't follow and all these areas are emitting much more CO2 than the rest of the world including Europe. CO2 and the climate ignore borders ...

"I would prefer a goal of 90% reduction for Europe until 2050"

Do you have any idea of how to achieve that target (technically) and at what costs? (meanwhile the rest of the world continues...)

"We have to show, that the way to reduction works without economical frictions"

Precisely! Unfortunately we can't - yet.

"Ich halte solche Diskussionen für wertvoll"
Me too.

About "agreeing" ...

Here's Pielke Sr. on Zeke's post at Lucias Blog:


Anonymous said...

... here's the missing/forgotten BMO/HC link:

@ Günther: thank you for that post! More than nice to discover democratic convictions in this debate.


Harry Dale Huffman said...

The scientific consensus, or even a compromise agreement largely accepting that consensus, is the problem, not the solution. Climate science (and the insufficient understanding of those promulgating a new agreement) is not robust, but thoroughly incompetent, founded upon theoretical sand and biased interpretations of untrustworthy, noisy data, by untrustworthy scientists and a political, ideologically biased organization, the IPCC. There has been no statistically observable warming for a decade or more (contrary to consensus predictions) and the basic science of the consensus is under fire from knowledgable scientists in a broad range of scientific fields. Everyone is frustrated to see positive change, but you can only truly go forward together by first coming together in understanding, not by trying to legislate blindly and against the will of all those who disagree with you.

_Flin_ said...

@Harry Dale Huffman: Generalizations and talking points are not very helpful in the discussion, neither are statements about "incompetence" and "ideological bias". The question was about agreement on scientific facts. It is impossible to read any agreement out of your statement. Neither is it possible to identify any precise points, except for "there is no warming as predicted".

So my questions to you are:
- Is CO2 a greenhouse gas?
- If yes, to what extent?
- If no, which forcings are responsible for the rise of average global temperature anomaly from 1970-2010, and to what extent?

Günter Heß said...

So CO2 is a greenhouse gas, but since we do not know the spatial and temporal change of cloud cover in the 20th century, we do not know how much is caused by CO2, or do we?

_flin_ said...

@Günter Heß: I do agree that climate reacts to changed variables in the system. CO2 is a variable, clouds are a variable.
Is the forcing of CO2 itself really that disputed?
Isn't it the feedback of clouds that is disputed (and whether it's a feedback or a forcing)?

Günter Heß said...

Clouds modulate incoming and outgoing radiation. Therefore can be forcings and feedbacks. In a short period like 1970 to 2010 (not even two climate values) with unknown cloud cover change your question “to what extent?” cannot be answered from a scientific point of view at least according to my opinion. You can easily deduct what I said from the IPCC AR4 or the ISCCP webpage. I had this discussion before with NF on Eike and with a Herr Bessel on science skeptical or with Stefan Rahmstorf at the Klimalounge. Before the two of us have this discussion again, please check the conversation over there.
I think the answer from many climate scientist I usually encounter is that cloud cover is supposed to be fairly constant or its effect averages out. But this is an assumption without data support.
For my opinion therefore, two hypotheses might explain the warming from 1970 – 2010. For me as an experimental scientist this matter remains open until somebody comes up with a new conclusive reanalysis or with cloud cover change data within the 21st century.
I am not a supporter of consensus in science and therefore do not see the need to agree on one of the two hypotheses.
But as a citizen I think we have enough information to decide about sensible and validated actions about our energy supply chain. However, I do not think that many green activist will share all my conclusions and my decisions.
Best regards

Günter Heß said...

Clouds modulate incoming and outgoing radiation. Therefore can be forcings and feedbacks. In a short period like 1970 to 2010 (not even two climate values) with unknown cloud cover change your question “to what extent?” cannot be answered from a scientific point of view at least according to my opinion. You can easily deduct what I said from the IPCC AR4 or the ISCCP webpage. I had this discussion before with NF on Eike and with a Herr Bessel on science skeptical or with Stefan Rahmstorf at the Klimalounge. Before the two of us have this discussion again, please check the conversation over there.
I think the answer from many climate scientist I usually encounter is that cloud cover is supposed to be fairly constant or its effect averages out. But this an assumption without data support.
For my opinion therefore, two hypotheses might explain the warming from 1970 – 2010. For me as an experimental scientist this matter remains open until somebody comes up with a new conclusive reanalysis or with cloud cover change data within the 21st century.
I am not a supporter of consensus in science and therefore do not see the need to agree on one of the two hypothesis.
But as a citizen I think we have enough information to decide about sensible and validated actions about our energy supply chain. However, I do not think that many green activist will share all my conclusions and my decisions.
Best regards

Anonymous said...

@ günter

Maybe we can find a consensus, that cloud cover is an issue of rather high uncertainty (as noted in AR4).

The next (nonscientific) questions would be:
Can this uncertainty justify a delay of political action?
How to deal with uncertainties?

Remember the financial crisis 2009:
How much political action and money was spent for actions because of economical predictions, which were rather poorly based. What, if policy hat waited for better economical theories or data? I don't know.
Or more fundamental:

I would be curious to see your summary compared to Zeke's or Curry's.

Best regards,

eduardo said...


This is not directly related to the webpost but I think it requires clarification.

'Clouds modulate incoming and outgoing radiation. Therefore can be forcings and feedbacks'
This sentence is not correct. That clouds modulate incoming and outgoing radiation does not make them a forcing for the climate system. What is a driver and what is a feedback may be a matter of definition, but in some cases the question is quite clear. Roughly speaking a forcing is an external driver of the system that is not affected (back) by the system itself, for instance solar irradiance: the output of the sun is a forcing and does not depend on the Earth temperatures. In the case of CO2 the answer is more ambiguous and concentrations may be a forcing or a feedback, depending what is the definition of 'climate system'. If 'climate system' includes the carbon cycle, then CO2 concentrations are a feedback, and the driver are anthropogenic carbon emissions. If 'climate system' does not include the carbon cycle, the CO2 concentrations is a driver.
Clouds are most certainly a feed-back. Even if one considers the possibility that cloud formation is modulated by solar wind, cloud cover will be always influenced by available water vapor and therefore by temperature. It cannot be a forcing.
For clouds to be considered a forcing, one would have to envisage an external agent that would completely control cloud cover and this external agent should be independent of climate. I cannot imagine any such mechanism.

"I think the answer from many climate scientist I usually encounter is that cloud cover is supposed to be fairly constant or its effect averages out. But this an assumption without data support."

This is incorrect. Cloud cover is not assumed to be constant. Cloud cover depends on many factors, in the real world and in models, and it changes with temperature and with the dynamics of the atmosphere and even with the availability of cloud condensation nuclei (natural and anthropogenic dust and marine dimethyl sulfate). In climate simulations cloud cover varies substantially. The problems is that it changes differently in each model, and this is one of the reasons why each model displays a different climate sensitivity.

Günter Heß said...

Dear Eduardo,
Thanks for reminding me. I was summarizing a couple of discussions I had and might have skipped some arguments. However, I only intended to communicate to Flin where I can agree and where not.
I did not want to discuss cloud cover change too much again.
I was talking about the real world not about models. In my textbook about radiative transfer and in the IPCC AR 4 “cloud radiative forcing” is defined as a forcing. I do know that the IPCC defines radiative forcings differently.
In my honest opinion if you want to answer to what extent CO2 “warmed” the real earth from 1970 – 2010 you have to consider cloud radiative forcing and cloud cover change in the real world, if you choose to call it forcing or not I don’t care too much.
However, if I read sentences like: “CO2 caused the main part of the warming from 1970 – 2010”, I assume that the writer implicitly considered cloud cover change constant or having no influence without telling the reader. I call that a hidden assumption. As long as we don’t have better cloud data, it is not getting better than that.
Actually, I checked my line of argument about cloud cover change with Prof. Joel Norris per email, who said that it is correct in principle, but that he believes that cloud cover change in the ISCCP data from 1983 to 2006 are spurious according to his opinion.But he said explicitly believe, since he had no evidence.
I can respect this answer and it actually reconciled me with climate science. That is why I
I understand very well that one has to use certain assumption to be able to work. But it is also necessary if you talk to people outside your field to get your definitions across and communicate your hidden assumptions and pay attention to detail. Therefore thanks for reminding me to write more clearly what definitions I use.
Best regards

_Flin_ said...

@Günther Heß: Well, you state "this question cannot be answered", which is easy. Giving a list of forcings and/or feedbacks and the uncertainties for these forcings is the hard way.
Noone actually said "CO2 caused the main part of the warming from 1970-2010" in this thread. I asked for forcings/feedbacks and their extent (as a response to a poster calling all climate science biased, untrustworthy, etc.).
Like CO2, methane, aerosols, water vapor, cloud cover, solar radiance, albedo, land use, net primary production, blackbody radiation, long term oscillations, change in ocean circulation systems etc.

The point is that there needs to be an alternative theory that explains the observed warming of the planet.

A current paper of A. Dessler from Texas A&M puts cloud feedback at 0.54 +- 0,74 W/m2 per degree warming. Which, as a layman, I interpret as the scientific equivalent to: "at the next crossing turn right, then drive about 20 miles further, then ask again."

So, as an alarmist, I agree to "clouds might be a negative feedback".

But then I am just an "alarmist".

So far in this thread noone from the "skeptic" camp has actually agreed to anything. Which is... well... just the usual state of affairs.

Günter Heß said...


I never said what you imply.
But anyway it is my fault that you misunderstood me completely. It is funny but where did I mention that somebody is not trustworthy.

On one point maybe you read my lines again and bring it in perspective.
Moreover, you could check out the definition of cloud radiative forcing for a change, instead of misinterpreting my words.

I gave you an honest anwser to your question, but get the usual party line. Sorry, I guess this is my fault. So excuse me.

Anyway, one can also easily calculate from the ISCCP Data that cloud cover change could explain a huge part of the warming from 1970 - 2010.


Günter Heß said...

A lot of my arguments about clouds you could read in Rob Ellisons(ChiefHydrologist) post. And I think Tomas Milanovichs Argument fit in nicely. But you might know that my main argument is about scientific method, since I guess you read my arguments at science-sceptical.
As I said. There is no necessity to delay action, if we go through parliament, because we disagree about attribution.

Anonymous said...

@ günter

Just one thought:
Zeke summarizes with the categories "extreme likely", "very likely" etc.

How would you classify the possibility of a negativ cloud albedo feedback with these categories?

Indeed I know a some interesting dicsussions you were involved. I see your point "scientific methods", but I'm not sure, if it's rather a problem of scientific communication of results.

Best regards

eduardo said...

Dear Günther,

I agree that the concept of forcing may be sometimes a matter of definition and semantics. But I think that in your explanation about whether or not clouds may be a forcing and whether the effects of clouds may compete with CO2 in the explanation of temperature rise, is unclear to me.

In the IPCC statement that CO2 is mostly responsible for the temperature rise, the effects of changes in cloud cover is indeed taken into account. They are not implicitly assumed to remain constant. If I understand your point of view correctly, you believe that type of attribution is made by calculating the external forcing exerted by CO2 and somehow transformed to increase in temperature. In this way one would estimate what percentage of warming is attributed to CO2.
Am I correctly depicting your reasoning ?

However, this is not the way that the attribution is done. The fundamental problem in your approach would be that increases in CO2, or increases in solar irradiance for that matter, change the temperature and the change in temperature changes cloud cover. So it is impossible to disentangle which part of the observed changes in cloud cover are due to the effect of the external forcings and which part is due to the effect of a putative autonomous change of cloud cover ( I think, this is what you would call cloud forcing, which is different what the IPCC would call cloud forcing). When you state that cloud cover exhibits a trend and that this trend may explain part of the temperature rise, we do not know whether or not the observed trend in cloud clover is ultimately due to the increase of CO2.
This is the rationale of defining external forcings (those that are not effected by the climate) and feedbacks, which may be also affected by the climate (temperature) itself.

The attribution of temperature rise to CO2 must be done with model simulations, in which you compare simulations with all known external forcings (CO2, solar volcanoes, etc) and simulations with all forcings except CO2. In all these simulations all the feedbacks (water vapor, clouds, etc) are free to evolve as the model equations require. Only the comparison between both types of simulations can lead to an attribution.

Now, in one thing you are right. The models do not agree in the changes in cloud cover they simulate when driven by an increase of CO2, and therefore a very important feedback is not being correctly captured by some or by all models. And so, I think that an attempt to attribute changes in cloud cover to CO2, as in the Min et al paper, would fail - but I am just guessing.

Also, cloud cover could change autonomously, i.e. not driven by any external forcing. In climate science parlance, this would be called a mechanism for internal variability - also a difficult issue, I gather that you are referring to this type of 'forcing' specifically. Basically I would translate your claim as that part of the observed temperature increase has been possibly caused by internal mechanisms, in this case cloud cover. But as I said, there is no use way to keep apart these changes from the externally forced changes (to attribute so to say), using only observations. The thorny issue would be to explain how cloud cover can change on multidecadal timescales on its own

Anonymous said...

@ Eduardo

A lot of words just to keep the door a narrow gap open to the dark chambers of guessing.

Meanwhile Flin is asking the agnostics for a proof that god doesn't exist. Could ask him vice versa for a proof that walruses don't sing when the feel unobserved.

Cloud cover IS the problem in all model equitations.

"How cloud cover can change on multidecadal timescales on its own"

Just like lottery or roulette numbers use to do?
Any patterns to see there - but a lot of people would be interested in finding some.


eduardo said...


Well, this not a scientific explanation. There is no randomness in nature, apart from the quantum realm. If things happen is because there is a cause. Otherwise the world would be magical. We have discussed this already in other posts. There are no null hypothesis: if the sun rises and sets every day is because there is a cause, and not because 'it has always been like this'.

We cannot predict a particular outcome because we lack enough information to do so - as in the case of the lottery or cloudiness in a particular day. But if I observe that there are cycles or trends in the numbers that come out of the Lotto, I would immediately suspect that something unusual is going on, and I will try to explain it. In the case of cloudiness, if I observe a long-term trend, there must be an underlying mechanism for this trend. This mechanism may be natural or anthropogenic, but one there must be.

If I would accept your explanation, science would be impossible. Why do temperature rise: random effects. why do apples fall down? random effects, etc, etc.

As one of the problems of climate prediction is that models are not perfect, and actually they are undoubtedly lousy, the main problem of the climate skeptics is that apparently they have no physical explanation for the observed warming other than 'random effects', and this is no explanation. Günther suggested one: trends in clouds. Maybe but my question is entirely justified: which physical mechanism ?
And with this we return to the topic of the blog entry. If each camp just would honestly recognize that both may have a point...

Howard said...

I am skeptical that Climate is a big problem. However, I do believe that now is the time to begin decarbonization of energy.

I think CO2 targets and a CO2 "market" are mistakes. It will result in states like China and India having a large incentive to not participate and Goldman Saks will make the most money from trading.

Having a type of Apollo Project for energy makes more sense. Tax all energy, no matter the source. Take some of the defense budget as this is a security investment. Offer a mix of R&D grants and prizes for development of carbon-free energy. Fission and Fusion should be the priority. Renewable sources should be quickly reduced down to the most practical.

Money should be given for short periods say up to a max of 5-years. Only renew the contracts for the projects that seem to be working.

Any geoengineering should be limited to increasing organic carbon in soil and growing back the world's rainforests.

ghost said...

hm... meiner Meinung nach ist es völlig egal ob irgendwo likely oder very likely oder maybe steht. Die Entscheidung was zu tun ist eine politische Entscheidung. Roy Spencer sagte mal, er würde an den menschlichen Einfluss auch nicht glauben, wenn es eine Erwärmung um 6 Grad geben würde. Nun ja. Also: die Politik und Gesellschaft muss auf Basis von Unsicherheiten entscheiden.

Und erst wenn die Entscheidung getroffen ist, was zu tun, kommt das likely wieder ins Spiel. Denn dann muss man entscheiden, wie wann was zu tun ist, um das Problem effektiv und effizient zu lösen oder die Auswirkungen abzumildern. Das finde schon schwieriger.

Aber zum Einfluss von CO2. CO2 hat einen niedrigen Einfluss, wenn die Strahlungstransfertheorie völlig falsch ist, oder wenn es große unbekannte oder bisher völlig falsch berechnete, negative Feedbacks bzw falsch berechnete positive Feedbacks gibt. Ist das richtig so? Wie wahrscheinlich ist das?

Anonymous said...

@ Eduardo

"Well, this not a scientific explanation"

You are right of course. It's not and we still try hard to find one.

"if the sun rises and sets every day is because there is a cause"

Difficult to compare well explained orbital mechanics with cloud cover change in a dynamical, chaotic and non-linear atmospheric system.

"the main problem of the climate skeptics is that apparently they have no physical explanation for the observed warming"

They have quite some. Maybe the idea of identifying one main culprit is wrong. There might be different causes and feedbacks, not all of them understood yet. How to explain the Medieval Warm Period? The roman optimum? Natural variations of climate found in the ice core records?

"If each camp just would honestly recognize that both may have a point"

I agree with you.
Here's some interesting new points from a recently presented EGU paper ...

"The values for the global climate sensitivity published by the IPCC [3] cover a range from 2.1°C – 4.4°C with an average value of 3.2°C, which is SEVEN TIMES larger than that predicted here"


Günter Heß said...

we have to acknowledge that we are individuals with different scientific educations.
If you are an experimental chemist or experimental physicist you might prefer data over models. If you are climate scientist or a computational chemist or a theoretical physicist you might prefer differently for your evaluation. So, if you evaluate the presented results you always do this based on your scientific education.
For the period 1970 – 2010 the ISCCP data support the hypothesis that the observed warming is caused by cloud cover change.
Models and other attribution studies say that CO2 might be the main cause for the warming between 1970 – 2010.
Studies from other climate scientists like Roger Pielke Sr. suggest that there are several influences the cause between.
For me the question therefore remains open, until somebody comes up with data that show the cause unambiguously. I don’t see a scientific reason to change my opinion, since I have not read a convincing study that points to CO2 unambiguously.
I also consider labels like “likely” as tools to make a decision in a decision making process, but not as categories for a scientific question. So your question for me is invalid in a scientific discussion.
And for a political decision, I don’t need to answer your question, but rather other questions. I can judge the proposed actions based on hard facts, like safety for people, energy efficiency, costs, and effectiveness. However, I guess we all judge the people that give advice or propose actions based on how they present their results and their conclusions and how we judge their credibility.
What I observe in the literature though is that Lindzen and Spencer presented evidence for negative feedback, whereas models or Dessler and others provide evidence for positive feedback. So this question remains open to me as well. However, the video discussion between Dessler and Lindzen, although interesting because of the content, did leave the impression with me that also the scientific discussions in climate science have a strong political bias. On most of the blogs I get the same impression. I read a textbook about “Klima und Klimadynamik” that had the sentence:
“We don’t know the cause, but it might be some unknown anthropogenic factor.”
Tell me, what does that mean to me as a reader. My conclusion: I therefore trust only my own judgement as a scientist and agree only to observations and conclusions that are based on hard data.
But I agree with ghost, it is not necessary for a political process to wait. We can make our decision any time based on uncertainty.
Best regards

Günter Heß said...

My point is simple. ISCCP data as part of spatial and/or temporal variations could as well explain the temperature change as does CO2 forcing. So I read two hypotheses so far that might explain the temperature data between 1970 and 2010. I have not seen unambiguous “proof” or “disproof” by data. For me therefore the question is open.
But I think the IPCC defines cloud radiative forcing as: “Cloud radiative forcing is the difference
between the all-sky Earth’s radiation budget and the clear-sky
Earth’s radiation budget (units: W m–2)”, which includes a spatial and temporal modulation of the incoming and outgoing radiation. Integrated over a finite period of time this can explain an observed warming in a nonlinear system that shows spatial and temporal chaos.
Best regards

eduardo said...


That cloud forcing is brought about by a change in cloud cover. Why can we rule out that that change in cloud cover is not (partly due) to the increase in temperatures caused by the CO2 increase ? Actually, it is very reasonable to think that changes in temperature will cause changes in cloud cover.

Anonymous said...

@ eduardo

"Why can we rule out that that change in cloud cover is not (partly due) to the increase in temperatures caused by the CO2 increase?"

A rhetorical question ...
Why indeed should we rule out that "change in cloud cover is (p a r t l y due) to the increase in temperatures caused by - the human made (to be precise) - CO2 increase"?

There are at least some other 15 pawns in the game, so why especially exclude this one?
It would not be "reasonable" as you say.


eduardo said...

I am not excluding any other reason.

Günther is arguing that the cloud forcing is comparable to the CO2 forcing in the last 30 years, and thus he is separating both .

I am arguing that it is not possible to separate them solely based on observations, and therefore his argument is not valid. My argument applies also to all other pairs:

solar forcing-cloud forcing
land use changes- cloud forcing
volcanic forcing-cloud forcing

I would like to know how the forcing on the right side can be separated from the forcings on the left side, as each forcings listed on the left side produces an unknown change of cloud cover.

Anonymous said...

Herr Heß,
ich bin fast Ihrer Meinung.
Zwei Dinge stören mich persönlich.
1.Von "observed warming" können wir nicht sprechen, es müßte doch "calculated warming" heißen?
Sind nicht alle globalen Temperaturtrends nur errechnet und weder beobachtet oder gemessen?
2.Ich denke eine politische Entscheidung kann zwar auf unsicheren Erkenntnissen basieren. Um aber den Boden der Verfassung nicht zu verlassen, muß auch eine unmittelbare Gefahr bestehen und nicht erst in 50 Jahren für möglich gehalten werden. Es wäre dann eher Willkür?

_Flin_ said...

@Günter Heß: You never called anyone untrustworthy, that was Mr Huffman.

Actually I appreciate your sober observations and arguments about the issues you raise.

My "party line" is only that I want scientific explanations that fit in with the rest of science.

Considering the topic of this thread, which is about the search for agreement on scientific fact as a prerequisite to a climate/energy policy, I was just probing for things skeptics and alarmists can agree on. But there isn't a single footstep towards agreement from the skeptic side. Ever.

And this is where I have my main issues with most skeptics, because there is just nothing that skeptics agree to. Neither observations (like temperature record or CO2 measurements) nor models, neither single forcing/feedback effects nor paleoclimate data, neither to the measured effects of infrared absorption nor the shrinking of arctic sea ice, neither to the effects of higher temperatures on water vapor in the atmosphere and relations to precipitation nor on the acidification of oceans etc. pp.

And my impression is that the same is true for policy. Anything except for "all is well, nothing to see, move on" is unacceptable. Every measure is only "job-killing", "hurting the economy", "expensive", "unreasonable" or the always welcome "tax increase". Except if it involves digging for oil or gas, or if it involves building nuclear power plants. Even the most reasonable strategies, like energy efficiency or insulation, create furor.

But then this is only a personal impression, maybe in reality things are different and there is a broad agreement and just a dispute over the fine print.

Hans von Storch said...

I do share this observation of _Flin_ to large extent. The willingness, which I have perceived among skeptics about agreeing on a knowledge base and criteria for sorting out questions, was unfortunately rather limited.

Anonymous said...

@ _Flin_
@ Hans von Storch

Diesen Eindruck habe ich nicht gewonnen. Ich kann freilich nur begrenzt auf meinen Blog darauf verweisen, mich mit Wissenschaftern, "Skeptikern" und "Realisten", "AGWlern" und "Nicht-AGWlern" unterhalten zu haben.

Beschimpft, wenn man so will, wurde ich, wenn, dann von Alarmistenseite.


Anonymous said...

@ Flin & Hans von Storch

Do you look at sceptics as a homogeneous group of people? Are they all the same? Any differences to see between them?

There is scientific dissent (or there are sceptical views) in all the issues mentioned in Flin's post, from temperature records to the acidification of oceans.

And there is much more dissent since climategate and the errors discovered in AR4 became public as well as the exaggerations of some of the AGW supporters (massive sea-level increases etc. etc.).
Not to mention in detail the peer review gate keeping and all the uncertainties that seem to be forgotten sometimes.

It will take much more time than a year and a little bit more to clean up the damage - that hasn't been done by sceptics by the way.

Much time was spent to investigate and realize what had happened. The affair(s) throw us back for years. It will take more time to bring back the public trust in science - and building trust between scientists.

Does science speak with one voice? Is there really a broad consensus among experts as it's often claimed? I doubt it ...

Back to the thread question: "Is it enough to start action?"
There is a lot of work that needs to be done first, before we will be able to answer the question with less uncertainties and with conviction. Just to mention the BEST project for instance ( ).

Call me a sceptic - but just don't call me a "denier".


Hans von Storch said...

Ralph, the skeptics I know of are all very different; many of them, however, adopt the point of view, that an opponent of any alarmist is somebody who deserves support.
The fact that they are all so different makes it difficult to agree on certain procedures to test certain hypothesis and claims. If we could, then we would be able to reduce the number of problems a bit and possibly identify the key issues, and not always talk about a broad mix of problems of very different legitimacy.

Anonymous said...


the "broad mix" is a problem. But wouldn't it be rather unconvincing to blame just the sceptics for that as long as there are flawed claims published at all kinds of levels?

J. Curry and Zeke Hausfather tried to "to reduce the number of problems a bit and possibly identify the key issues" to define “What we know with confidence”, ranking the degrees of certainty.
( )

JC on an earlier thread: "The size of this warming is broadly consistent with predictions of climate models, but it is also of the same magnitude as natural climate variability. Thus the observed increase could be largely due to this natural variability, alternatively this variability and other human factors could have offset a still larger human-induced greenhouse warming. The unequivocal detection of the enhanced greenhouse effect from observations is not likely for a decade or more"

If she's (quite) right, how to answer the political questions: "What kind of climate policy do we support" and "Is it enough to start action"?

... or better go back to work, trying to regain what could be called the "lost years"* in climate science?


* I know that they are not completely lost, not all of them and not in all of the fields but some parts of science have been seriously affected by exaggeration, biased thought and dogmatism

Günter Heß said...

Thank you for the clarification and the discussion.

@_Flin_ @Hans von Storch
I do think the issue is just that human beings are different individuals. Let me start with how I feel and think.
I do not see a reason to agree on scientific facts with you or anybody else. I will argue with you about data and interpretation or even facts, but I do not need you to agree with me. I don’t think science needs agreement.
It is sometimes nice, if we come to the same conclusion, but if we come to a different conclusion I respect that. I might argue with you, I might consider your conclusion wrong, but I accept if you come to a different conclusion.
Interestingly enough, I would phrase my “line” differently.
I search always for a scientific explanation that is thermodynamically consistent and explains all the data.
I guess you meant the same, but the difference to your “line” is very subtle, but explains, if you meant it literally, the difference between our way of thinking.
During grad school in Germany I observed that students from applied sciences that leaned towards geography used the concept “I understand” differently. Geography students would tell me that they understood something when they could reproduce the wording in their textbooks, whereas physics student would say “I understand” very often only if they could derive the explanation for themselves from first principle. Moreover, the arguments in geography seemed to me more along “certain schools” and mainstream explanations compared arguments between physicists. I can understand both from the respective needs and point of view of both scientific disciplines. Therefore, I think “agreeing” is not something we can strive for, since our scientific education might be different.
I addition, I think it is more productive to disagree. In the last quarter before I finalized my Ph.D. work one of my expert reviewers told me in a joint seminar he did not agree to my scientific conclusion, because I miss a crucial experiment for his opinion. At first I was disappointed, but it forced me to my best experiment ever. So, I am still grateful to a true “sceptic”, I guess he could have chosen "consensus". Therefore I think science needs disagreement more than agreement.
Best regards

Günter Heß said...

@Anonymous # 38
Zu ihrem ersten Punkt:
Ich denke alle Daten sind im Prinzip nur errechnet, analog oder digital. In der Metereologie werden meines Wissens schon immer synoptische Daten benutzt. Das heißt, wenn ich es richtig verstanden habe, dass die rohen Messdaten von einem ausgebildeten Metereologen bearbeitet und in Wetterkarten umgesetzt werden. Heute machen das eben Computer. Das scheint mir in Ordnung, aber selbstverständlich muss man die Algorithmen einer Qualitätskontrolle unterziehen und immer wieder skeptisch hinterfragen. Aber sie nicht zu verwenden, hieße ja nie Daten zu verwenden die irgendwie noch analog oder digital errechnet wurden. Auch ein normales Thermometer ist nichts anderes als ein kalibrierter Analogrechner der Ausdehnung in Temperatur umrechnet. Ein empfindlicher Detektor hat ja meistens auch einen Vorverstärker und Verstärker, die auch Analogrechner sind.
Zu ihrem zweiten Punkt:
Ich bin ihrer Meinung, dass das Bekämpfen einer vermuteten und möglichen Gefahr mit Massnahmen die nur möglicherweise wirken keine gute Handlungsgrundlage ist. Das Vorsorgeprinzip lehne ich ab, weil es alles rechtfertigt. Das Prinzip der Verhältnissmäßigkeit muss aber laut EU selbstverständlich auch beim Vorsorgeprinzip angewandt werden und eine Kosten/Nutzen Analyse erstellt werden, so dass man es eigentlich nicht braucht.
Mit freundlichen Grüßen
Günter Heß

Günter Heß said...

Eduardo #37,
I only argue that both hypotheses could in principle explain a large extent of the warming alone.
Therefore we cannot assign the root cause to one of them. Without independent cloud measurements we will not be able to assign the root cause. But of course even with cloud measurements we might not be able to separate feedback and forcing in a nonlinear system.
We might never know. But that is one thing you learn in experimental science. Mother nature is always a step ahead. I worked hard to know that I know only a little about nature.
I guess it will stay that way although we strive to and do learn every day.

Anonymous said...

Herr Heß,
danke für Ihre Antwort. Wer sich mit analogen Rechnern und analogen Regelkreisen auskennt, weiß wie schwierig es ist diese zu beschreiben.X-verschiedene Ursachen führen oft zu gleichen Ergebnissen, die wiederum so gut wie nie ihre Ursachen beweisen. Ich vermute mal, die Natur ist der komplizierteste analoge Regelkreis , den wir kennen.
Roger Pielke sr. hat auf dem International Workshop on Downscaling 2011 seine Meinung zum Stand der Erkenntnis gesagt:
"Statistical Downscaling From Multi-Decadal Global Model Projections Does Not Add Spatial and Temporal Accuracy Of Value To The Impacts Community"
"The bottom line is that vast amounts of money are being spent for both dynamic and statistical downscaling predictions for decades from now that have absolutely no demonstrative skill. Policymakers are being provided information that is at best, no worse than one that can be achieved by using historical and recent paleo-climate information and/or worst case sequences of climate events. At worse, however, these predictions could be significantly misleading policymakers to the actual threats that our key resources of water, energy, food, human health and ecosystem face in the coming decades."

ghost said...

to start action, hm my two cents

1. IMHO we have enough evidence to know why we should start action. Not one "skeptic" could show to me that climate change is not happing and why increased greenhouse effect won't affect the climate considerably. On the other hand, "mainstream science" could show this to me to a certain point.

2. However, I am not sure if we really know what we should do first or which action is effective and efficient. Of course, trying to lower the CO2 emissions and maybe build higher dams, water reservoirs, re-forest, save energy etc. But is this all enough and sustainable? Do we use the most efficient techniques? Do we really do the right adaptations? I do not say, we should go back to zero. I mean, renewable energy is great, but just building wind turbines and solar panels are not enough. Can we leave this to the market alone? Is this possible? CO2 does not have a natural value.

They were some failures, like recently the E10 gas in Germany, that does not help at all to start action, real action.

Furthermore, is it possible to solve the problem technically? Or does the society have to change, too? I mean, the energy hunger won't decrease in the future, and we must try to give the complete world at least a living standard like ours. Huge problems.

If I compare this to the Ozone hole problem, I think the CFC prohibition was really simple.

Well, but I think, we are still on point 1 and mostly on the level of the discussion between Knut Angtrom and Arrenhius... yeah. Over 100 years research lost in the political debate.

Anonymous said...

@ ghost

"we have enough evidence to know why we should start action"

No idea where your confidence is coming from.

"Not one 'skeptic' could show to me that climate change is not happing"

It is happening of course and it happened and will happen all the time - even without humans living on this planet.

"... and why increased greenhouse effect won't affect the climate considerably"

It does affect the climate but we don't know the extent of the so called "greenhouse" effect.
While CO2 emissions grow, the observations of the last 12 or 15 years do not show the predicted increase of temperatures.
We just don't know. The warming potential of CO2 could be hidden - or exaggerated.

"what we should do first"

More research in climate physics as well as in energy research. But the hope in a technical fix can be deceptive: don't trust the promises too much.
This is not just about oil peak. We are running short in quite al lot of other things.

Societies change indeed - but not at the behest of scientific or governing authority as you can see in north africa.

"CO2 does not have a natural value"
Of course it has! you don't have to be vegetarian to accept the benefits of carbon dioxide.


ghost said...

"No idea where your confidence is coming from"

I read a bit about it, I trust the observations and try to understand their limits and I tried to understand the basic. I still failed a bit... At least, I tried.

Well, AFAIK there is a consensus about the pure CO2 influence: 1.2Degrees/double CO2. it is also clear, that the humankind is responsible for the CO2 increase and how much it is increasing. Now, if CO2 does not have a significant influence, we will need a very low sensitivity (much below 1K/Wm-2) to radiative changes. And nobody could convincingly show this until now. At the same time, many, many different works with totally different approaches showed the sensitivity in the IPCC range. Approaches were GCM, based on modern observations or on reconstructions from different periods of the past. Therefore, it much more likely for me that CO2 has a big influence than not.

"It is happening of course and it happened and will happen all the time - even without humans living on this planet."

this argument is quite hollow. Of course, that is totally right, but climate science does want to know WHY. And again: models of skeptics totally failed to explain todays as well as past climate variations. Here is a try to use Dr Spencers "model" for the last century: IMHO, many "skeptical" works are pure fitting the elephant exercises. Not all, but the number is quite high.

of course, everything has a lot of uncertainty. Furthermore, I am not convinced if the projections are always good enough to choose the right way to adapt and to show what exactly we have to expect.

"While CO2 emissions grow, the observations of the last 12 or 15 years do not show the predicted increase of temperatures."

Who actually predicted the last 12 to 15 years? What does this mean? Isn't this a bit short? Actually, if one compares the temperatures with the models, it could look like that:

Not to shabby, bit on the lower side, and one must consider: it is a short time.

I am pretty much convinced by science, and not really impressed by the work of the "skeptics". Of course, this is just my layman opinion, any expert could destroy it, I suppose.

Anonymous said...

As an interested layperson, I find it extremely difficult, even with a background in physics, to judge the validity of arguments in the climate discussion. So my judgement is guided very much by the status of experts, by their consensus about some of the main points and - I must admit - by emotional and social questions - which are in the climate debate a really driving factor.
I think in 1995 the German Physical Society send out an official statement that this is happening.Since then I did mainly read in nature or science about confirmational results, my conclusion is that it is time to act and to use ressources more economically. For my understanding of ethics it is conceivable to think about the wellbeing of those after us, in 50 or 100 years.

Anonymous said...

@ antoroblog

You seem to support the the AGw hypothesis and the precautionary principle.

Do you have an idea of the costs to achieve the so called two degree goal - which some of us think to be so eminently important?
Besides the fact that only Europe, contributing to about 14% of the worldwide CO2 emissions, is determined to cut down (mainly) the increasing concentration of one of the "greenhouse gases"? forcing some european industries to emigrate to Asia - where nobody will care about these emissions as long as we are importing the goods produced in these countries.

Even if you ignore these points- do you really think, we would control the earth's nature and the atmosphere? "global temperatures"?

If you "think about the wellbeing of those after us, in 50 or 100 years" - how about thinking about all those living in the presence, in our times?
The people living in (North ) Africa, Australia, Pakistan, New Zealand, Haiti, Japan etc.
How to guarantee their wellbeing with all the desasters they had and have to go through?

What will happen in the next 20 or 30 years? some more earthquakes, in California or elswhere? some major volcanic eruptions - not to think about a high level meteor impact?

Do we have the resources to do both: help the people suffering from poverty, shortage of water, food, education, underdevelopment and natural disasters - and to cut down our - and their - most important energy supply the same time?

I doubt we can. Meanwhile we are losing our heads over a white middle-class problem in western countries.


Anonymous said...

these are many points and I will reply the last point first: no, I do not think that climate change is just a white middle class problem in western countries. It will concern much more the poor people in the least developed countries, which have not the means to adapt.
And I am not wishing that they remain poor, but I would rather opt for a downgrade in material consumption on our side, which will not mean a downgrade in life quality. (Yes, I do drive a bicycle and no car, it keeps me healthy);
I think investing into new technologies is investing into future markets and Europe will win in the long term reducing efficiently carbon dioxide emissions.

And I do not think that we can "control" global temperatures. But apparently since industrialisation, we influence the atmospheric mix of gases and even small changes there can add up to have consequences. We might not understand everything yet, but yes, as a precaution, we should act.

Anonymous said...

@ antoroblog

"I do not think that climate change is just a white middle class problem in western countries"

First: "climate change" - a new and a human made problem? There are no natural variations known?

Second: "It will concern much more the poor people in the least developed countries, which have not the means to adapt" - Exactly! If they are not allowed to use the energy supplies they can afford.

"Yes, I do drive a bicycle and no car, it keeps me healthy"
Great to read that. A typical white middle class problem in western countries.

"I think investing into new technologies is investing into future markets"

I agree. But "investing into (developing) new technologies" is one thing - investing into the application of inefficient technologies is something different. We are wasting quite a lot of money, aren't we?

"Europe will win in the long term reducing efficiently carbon dioxide emissions"
Meanwhile most of the other countries just don't care and contribute with about (growing) 85% of the emissions.
Do you think reducing 20 or 30% of the european contribution (14%) at whatever price will be important anyway? exporting european factories and the production of goods to east asia - just to preserve a good conscience on "our" CO2 footprint?

By the way: where is your bike coming from?

"... but yes, as a precaution, we should act"

Again: what to tell the japanese or the haitian people? in Pakistan? New Zealand? Australia?
How to follow the precautionary principle?
Getting save from what? From nature? from human technologies?
Do you think there will be a "green dot"-sheme to clean up all the desasters - and for living on in these areas?