Thursday, January 14, 2010

Three hypotheses

Several comments have mentioned Pielke Sr.s (et al) recent piece in EOS. However, so far this has not been given the attention it deserves. The paper presents thee mutually exclusive hypotheses:

Hypothesis 1: Human influence on climate
variability and change is of minimal
importance, and natural causes dominate
climate variations and changes on all time
scales. In coming decades, the human influence
will continue to be minimal.

Hypothesis 2a: Although the natural
causes of climate variations and changes
are undoubtedly important, the human influences
are significant and involve a diverse
range of first- order climate forcings, including,
but not limited to, the human input of
carbon dioxide (CO2). Most, if not all, of
these human infl uences on regional and
global climate will continue to be of concern
during the coming decades.

Hypothesis 2b: Although the natural
causes of climate variations and changes are
undoubtedly important, the human influences
are significant and are dominated by the emissions
into the atmosphere of greenhouse
gases, the most important of which is CO2. The
adverse impact of these gases on regional and
global climate constitutes the primary climate
issue for the coming decades.

These hypotheses are mutually exclusive.
Thus, the accumulated evidence can only
provide support for one of these hypotheses.
The question is which one?
The skeptical position is the first, the IPCC is 2b. The paper makes the case for 2a saying that it is best supported by the available evidence.
Unfortunately, the 2007 Intergovernmental
Panel on Climate Change (IPCC)
assessment did not sufficiently acknowledge
the importance of these other human climate
forcings in altering regional and global
climate and their effects on predictability at
the regional scale. It also placed too much
emphasis on average global forcing from a
limited set of human climate forcings. Further,
it devised a mitigation strategy based
on global model predictions.
Instead, argues the paper, a borader analysis of factors is needed, which includes the regional level:
Because global climate models do not
accurately simulate (or even include) several
of these other first-order human climate
forcings, policy makers must be made
aware of the inability of the current generation
of models to accurately forecast
regional climate risks to resources on multidecadal
time scales. For example, how
the water cycle responds to the diversity of
climate forcings at the regional level will
be important information to policy makers
seeking to mitigate risks to water resources.
Read the paper in full here. It raises important questions, not only on how to position yourself in the debate, but also what is the right way forward. Should there be models with regional prediction? Should these be taking into account many more variables? If so, should this be done through the IPCC?


Hans Erren said...

Thanks for bringing this up.
Let me show you a significant antropogenic warming effect which is not CO2
Here is a Landsat image of the Eastern Netherlands (Arnhem to Enschede) of Jan 4 2002, with a snow cover

The snow is not covering forests, towns and roads, most of them did not exist in 1900.
Indicating that land use change - particularly in winter - has a huge impact on albedo.

Unknown said...

I think the paper is strange: first, it says we have to broaden the IPCC approach, and then it only focuses on broadening the modeling approach and saying that the politics has to know models are bullshit.

I would accept the paper, if it says: yes Greenhouse gas emissions have to be reduced, because they cause a change of the Greenhouse effect and will finally change the climate every where with different effect. That may be quite unpleasant. But, we have to make sure not to forget other things that are already well known problems: good example is the Sahel zone, where traditional re-forestation can help a lot. And this has to be shown in the IPCC report, too.

But IMHO the authors do not say this. They see only models and limitations and try to delay any action.

One question: what is you opinion Reiner?

Unknown said...

one additional remark: I do not think 2a and 2b are mutually exclusive. Do you think they are, Reiner?

Werner Krauss said...

In my opinion as a cultural anthropologist, Pielke's suggestion 2a has the additional advantage of helping to really localize climate change (and climate science). Climate change indeed happens locally, and it does so differently in each specific region. Scientific models of regional climate change have a greater chance to be embedded and integrated into the real world where real people live.
The global models suffer from this reality check - Copenhagen dealt with a kind of virtual model world, which was discussed in a pretty artificial world forum. The regional models instead can be located in a world of municipalities, regions or nations; there we find people, institutions and organizatios which indeed can discuss these regional models with the scientists. This already happens in many places, and it is here where climate change becomes an integral part of social, cultural and economic activities (in sometimes very productive ways).
Global models helped to raise alarm and awareness; downscaling helps to localize climate change in the real life world. This is exactly where it is possible to find more appropriate solutions to handle this global problem.

Hans von Storch said...

Werner, the dichotomy of global vs. regional is indeed significant. Global points mostly to mitigation, while regional towards adaptation. The political "correct" response to the perspective of man-amde global change is to "stop" it (which we know is impossible, only a significant slowing of the change is conceivable) by reducing emissions, and preferrably changing lifestyle - thus any attempts to adapt are counterproductive efforts reducing the willingness to help "stopping"; thus, the issue is kept on the global level, with some regional examples (usually in remote areas, people do not really know) to demonstrate the severity of the implication of "unstopped" climate change.

See also Stehr, N., and H. von Storch, 2003: Micro/Macro and soft/hard: divergence and converging issues in the physical and social sciences. Integrated Assessment 3, 1145-121, 2002 (have no pdf, unfortunately).

Werner Krauss said...

and I would suggest that even mitigation needs an effective regional component; the production of low carbon etc energies and products is always located somewhere. Specific regions can develop new strategies in a realistic way, based on their possibilities, while global treaties tend to produce abstract limits which end up in failures (such as the Kyoto treaty).
Furthermore, from an anthropological standpoint it is interesting to notice that the scientific model of climate change does not really match with the reality we live in. It is an interesting philosophical question to find out where exactly climate change does happen.
This is a question that global climate change models alone cannot answer; to localize climate change is foremost a societal process. This is true for adaptation and mitigation.

Hans von Storch said...

True, Werner - but successful efforts of regional or local mitigation (in Hamburg, for instance, giving up Moorburg) can not experienced by people, apart of reading numbers (about emissions and concentrations) and of demonstrationg politial clout, while adaptation - reducing of vulnerability - has a direct impact on people's way of life.

Werner Krauss said...

Hans, right, except when mitigation efforts lead to the creation of new jobs, for example. Or, weatherization of houses means less heating means less emissions means less money spent - pretty direct experience. Investing into improving infrastructures is also something that is immediately felt; all these fine smart grids etc are a pretty immediate attachment to mitigation efforts, don't you think so? I wouldn't hang this distinction in respect to immediate experience of mitigation and adaptation too high; people love doing things even for abstract reasons.
In Greensburg, Kansas, which was almost completely destroyed by a tornado, they rebuilt their town in a model low carbon / green etc style; most of its inhabitants are conservative Republicans. They don't talk about climate change very much, by the way, because this is completely politicized. Instead, they connect their newly discovered identity to their religion and to their rural past, and it works out fine. They adapt as good as possible to future weather events, and they are proud of being leaders in low carbon lifestyle. Nothing wrong with that.

Hans von Storch said...

Agree, Werner, the consequences of mitigation measures, or the impact of climate protection policy, is immediately "felt" - but not the effect on climate, and the vulnerability to climate impact (say tornadoes).
The Greensburg case - what did they do to reduce their vulnerability? "Low carbon" does not necessarily shield from the impact of a tornado, I would assume.

Werner Krauss said...

They improved building structures, but they live in the tornado alley and have no illusions concerning protection from future devastating tornadoes. 'Low carbon' is a new business for them, it is a new identity and a reason to stay there in the middle of nowhere. Greensburg turns into a model city. You don't have to believe neither in climate apocalypse nor in magic (emission reduction helps to protect from tornados? Nobody, I guess, believes this in Greensburg) to do the right things.

@ReinerGrundmann said...

ghost @2,3
I think 2a and 2b are mutually exclusive. Focussing everything on CO2 leads to different research programmes and policies compared to a broader approach (2a). 2a has the advantage of avoiding dead ends like the hockey stick. If you believe in 2b you have a very strong bias to believe in 'unprecendented' warming. But what if you cannot prove it? Then you would be left with 1 =:-((
The symmetry of both approaches is stunning.

On the other hand, following 2a you can do many things on a regional level that make sense anyway and do not have to wait for some (elusive) 'proof' in the future. I don't think 2a is prone to delaying action. 2b is delaying action as everyone waits for a global carbon treaty to emerge.

Inadvertently the AGW alarmists have steered themselves into a deadlock with the skeptics, thereby stifling action. They may have been convinced that time will tell and time will be on their side. In the meantime you have to tweak the data. ;-)

Unknown said...


tweak the data? Hm, right, similar to the smoking gun which you loved so much... funny.

first, 2a and 2b say: humans have a significant share on the climate change. And the changes, if land usage, dust, aerosols, environment pollution, dams, deforestation, or Greenhouse gas emissions and so on, of the last 100-200 years dominate all other human changes before. I think, it is natural because the population exploded and we industrialized. Thus, both scenarios would lead to a hockey stick and unprecedented whatever. ;)

For me personally, I do not care about 2a and 2b. I see Greenhouse gas messing as long term, global threat. That must be stopped. Sooner is better. But, that is (almost) orthogonal to mitigations and adaptations on local and regional level. Can you tell me an example where an "alarmist" said, we must stop regional projects to get the global solution? I do not know any. Actually, I love simple solutions, like the example in the Sahel zone showed.

the global greenhouse effect is more inconvenient (haha ;)) because it shows we are also responsible for changes in Africa or in the Pacific. I think Pielke Sr (et al) tried to weaken this fact with their artificial classification.

Hans von Storch said...

Ghost/12 - yes, Al Gore did so several years ago. The other day, a journalist confronted me with that claim. He must have had it from somewhere.

Unknown said...


Ouch, okay, IF Al Gore did this, i do not agree with him, it would be idiotic.

IMHO, global CO2 reduction programs and other actions must not compete. I think it should be possible.

Oh oh, I live in a dream world, I admit it.

@ReinerGrundmann said...

"Thus, both scenarios would lead to a hockey stick and unprecedented whatever. ;)"

You do not seem to get the point. Of course we have many hockey stick shaped time series. But the one about temperatures is specific to the IPCC (and skeptics) claims. Both believe that IF current temperatures are within historically observed variability then there is no justification for political intervention. This is a slight exaggeration, as only the skeptics make the point explicit. The IPCC shares it implicitly as they dedicate so much energy on the establishing of this claim. Do you agree with the IPCC on this?

Hans von Storch said...

Ghost: "IF Al Gore ...." - somewhere in my files, I have a better quote, but maybe this Reuters News from 2006 is already good enough: I just googled "Gore adaptation".

Unknown said...


thanks, Gore said: he is against "adaptation INSTEAD of prevention". I think that is right. But, if he tried to say, adaption is not necessary and not urgent, then he is wrong, IMHO. You said that very well in your student answers. Okay. I am not a fan of Al Gore, I do not want to defend him. Is the question is: can we do it both? If not, what first? Adaption is necessary anyway. Hope, we will do this at least after the Copenhagen failure.

IMHO, the temperature hockey stick became to much an icon of climate change and climate change debate. I do not know, if the IPCC is still that focused on this point. In the last report, it already changed, didn't it? I do not think the hockey stick proofs the greenhouse theory or a non-hockey stick will disproof it. The reconstructions are important but, the hockey stick discussion became totally political. I think some scientists have their share on this state...

If the IPCC really thinks, it must show that we already outside of natural variability, then it is wrong. It must show why is the state of climate as it is now. Why was it in the MWP as it was then. But I think it does that. But I must say, it is easier and tempting to show a hockeystick ;). But it is also easier to attack.

Hans von Storch said...

Ghost - I referred to "Gore said he was worried that adaptation to climate change could serve as an excuse for not reducing the global warming pollution and solving the climate crisis.", which of course needs verification. Let me see if I find the quote, which rumours somewhere in the back of my mind.
-- Do you know anybody who had argued for "adaptation INSTEAD of prevention"?

Unknown said...


not really, but I do not really read "skeptic" works ;),... I believe that you have the quote, I do not agree with Al Gore.

You said, adaption would quite nicely work, if the change is slow and not so big. If we assume, the "models" (I hate that term ;)) are right and we have really a sensitivity of 2.5K or 3K regarding to doubling the CO2 concentration. Is it possible to "compute" which mixture of adaptation and prevention (of further warming based on more Greenhouse gases) is the best? Are there works about this or projects? Of course, it depends on the actual problems that come with the warming. Okay, good night.

Hans von Storch said...

such cost-benefit analysis have been made. A classical one was Nordhaus, W.D., 1991: To slow or not to slow: the economy of the greenhouse effect. Econ. J. 101, 920-937, who dealt with an equilibrium problem. We later extended that - Tahvonen, O., H. von Storch,and J. von Storch, 1994: Economic efficiency of CO2 reduction programs. Clim Res. 4, 127-141 - to a transient situation. See also Hasselmann, K., S. Hasselmann, R. Giering, V. Ocaña, H. von Storch, 1997: Sensitivity study of optimal CO2 emission paths using a simplified structural integrated assessment model (SIAM). Climatic Change 37, 345-386. In Oberle, H.J., H. von Storch and O. Tahvonen, 1996: Numerical computation of optimal reductions of CO2 emissions in a simplified climate-economy model. Numer. Funct. Anal. and Optimiz. 17, 809-822, we determined the states, which would be reachable with mitigation efforts.

But all these studies are just sketches of how it could be done, if it were possible to determine the expected costs. But that, again, is a complex issue, and massively influenced by vested interests (e.g., Lord Stern). Maybe Richard Tol will comment on this (or even provide an article on it?); he knows what has happened in recent years; our work took place in the 1990s, which is NOW ages away.

eduardo said...


I think that, at least for some countries, to not seriously plan for adaptation is out of question. Take for instance the example of Spain. The IPCC projections under scenario A1B are about 30% reduction of precipitation in the Southern region, where even now shortage of water is a problem in some years, and consumption pressure is high. With higher temperatures, say 4K increase and 30% precipitation reduction that region may become inhabitable with present technology. Should small countries like Spain live happily and blindly trust that the US and China will eventually reach a timely agreement on emissions ? No, that would be foolish. They should use their resources for adaptation, since their emissions make globally no difference. If one believes those IPCC projections, the path to follow should be clear. I surmise, however, that no politician really believes them.

Unknown said...

thanks, I will look definitely into it. I have also found a letter in the nature news about this topic too.

hm, your Spanish example is nice. First, they must adapt because CO2 emissions cannot be reduced fast enough. But it shows also: adaptations are not enough. We must reduce the Greenhouse emissions, pretty soon and fast. There are areas in the world that cannot adapt anymore at a certain level. Should we sacrifice these areas? I think not.

regarding to your last two sentences, I like it. I found a quote at

After all, what's the use of having developed a science well enough to make predictions, if in the end all we're willing to do is stand around and wait for them to come true. (Sherwood Rowland)

Stan said...

Too many weasel words. "minimal", "dominate", "important", "significant", "of concern" How one views them affects everything.

Also, there is an entire spectrum of opinions and a divergence among them on different subpoints. I'm not sure how herding different viewpoints togther into 3 large holding pens does anything to clarify the picture.

If one wants to assess positions on various scientific or policy matters, it would be best to survey regarding each matter.