This is a copy (do I say, “reblogged”?) of a comment made by Andrew Lacis1 at Climate Etc (cite) just recently. As DA replied, its a breath of fresh air, but probably won’t fare well there. So I’ll give it more prominence (ha!) here. There’s also a followup: Lacis: What is it that determines the terrestrial climate and how it changes?
A Lacis | May 25, 2014 at 3:22 am | Reply
I know Lennart Bengtsson as one of the reviewers of a paper of mine that was published in Tellus B a year ago. This was a paper was part of the Bert Bolin Symposium held in Stockholm in May 2012. In this paper I describe in detail why it is that atmospheric CO2 is the principal LW control knob that governs the global surface temperature of Earth. For those interested, this paper is available via the GISS webpage at http://pubs.giss.nasa.gov/abs/la06400p.html
In writing this paper, I wanted to formulate the discussion of the global warming problem in terms of the basic physics involved, rather than presenting it as just another climate modeling exercise.
The other reviewer of this paper was Ray Pierrehumbert. Lennart Bengtsson is a classical meteorologist with decades of experience in that field; he also has a good understanding of atmospheric physics. Ray Pierrehumbert is known as an outspoken climate scientist; his recent book Principles of Planetary Climate describes well his credentials as a knowledgeable expert in climate science. Both reviewers had numerous criticisms on various aspects of my original manuscript. These criticisms led to a much improved paper, and I stated so in the acknowledgments. The kind of review that I wouldn’t like to see is one that says “Great paper! Publish as is!” To me, a review like that would be a clear indication that the reviewer most likely never read the paper, or simply did not care enough about the topic to express an opinion.
At 25 pages, the paper is a bit long, but it is composed of six distinct sections that are largely self-contained. RP thought the paper was at best a review paper with little new material; he thought that my comparison of the terrestrial greenhouse effect and those of Mars and Venus was weak; he objected to my describing the greenhouse effect as being driven by solar radiation; he liked the section demonstrating the fast-feedback response of water vapor feedback; but he thought that the section on radiative transfer was unnecessary and should have been deleted; and, RP was unhappy with the way I characterized of the run-away greenhouse aspect of ever increasing CO2 in the terrestrial atmosphere.
LB, on the other hand, rather liked the radiative transfer section and thought it provided a useful description of how radiative transfer was calculated; he wanted more discussion of how the greenhouse effect could be evaluated by direct observation; he also wanted more discussion on the nature of feedback effects, and thought that cloud feedback effects were handled poorly, in particular the cloud solar albedo component. LB also raised the issue of transient climate sensitivity vs equilibrium sensitivity. (The paper addresses the equilibrium sensitivity, and not the transient response, except in demonstrating the fast-feedback response of water vapor).
Both reviewers suggested multiple improvements to get the historical facts about the greenhouse effect described and referenced more accurately. Neither reviewer questioned the validity of the main theme of the paper, i.e., that atmospheric CO2 is the principal LW control knob of the terrestrial climate system.
Addressing all of these concerns and criticisms resulted in the quality paper as it now stands. Accordingly, I have absolutely no criticism to direct toward Lennart Bengtsson. What the current GWPF-Bengtsson brewhaha is all about, I really don’t know. And, I am not sufficiently motivated to investigate further. I have seen it pop up on Foxnews, and can surmise that Foxnews would not hesitate to spin and inflate any minor incident into another “climategate” conspiracy.
There are more than a few topics in the climate system where uncertainty abounds. But there are also some aspects of the global climate system that are quite well established and documented, such as the human-caused increase in atmospheric CO2, and the radiative effect of this CO2 increase to intensify the strength of the terrestrial greenhouse effect, thus causing global warming and the accelerated melting of polar ice that will eventually make all coastal areas uninhabitable. This is the consequential and serious climate problem that needs to be addressed sooner rather than later.
In Lennart Bengtsson’s remarks on his view on climate research, there is one telling sentence that summarizes Lennart’s perspective on climate change. Lennart states that “Climate is nothing but the sum of all weather events during some representative period of time.” Superficially, the statement is quite correct. But fundamentally, that statement is flat wrong. This is because climate is a boundary value problem in physics, while weather is an initial value problem. The physical nature of these two problems is quite different, so also is the numerical approach that has to be taken in order to model climate change, and to forecast the changing weather.
In my Tellus B paper, I described the ongoing global warming as a cause-and-effect problem in physics. Understandably, Lennart Bengtsson might be inclined to view the global warming problem from his meteorology perspective in terms of changing weather patterns. But there is a reason why summer weather is warmer than winter weather. And there is a similar physics-based reason why global warming will change the weather patterns as the global temperature rises. There is substantially more uncertainty in how the local and regional weather patterns will change than in how the global temperature will change. So, when it comes to discussing regional climate change, as opposed to global climate change, there is far more room for differences in opinion.
As for Lennart’s joining GWPF, then resigning – I have not formed an opinion. Perhaps Lennart Bengtsson was hoping to instill some rationality to an organization that could benefit from an improved understanding of climate. Perhaps Lennart’s colleagues then persuaded him that that objective would be a hopeless endeavor.
If I really thought that I could instill some common sense regarding the nature of global climate change to such organizations like the Cato, Heartland, and George C. Marshall Institutes (among others), I too would be more than willing to go talk to them. But their goal and agenda (on behalf of the short-sighted interests of the fossil fuel industries) is to spread disinformation about global warming, rather than to seek a clearer understanding of global climate change. Thus, I don’t think that they would really want to hear from me. So far, they have succeeded in deceiving, duping, and brainwashing a significant fraction of the American public into believing that global warming is some sort of hoax perpetrated by the climate scientists.
This unfortunate nonsense needs to be counteracted by continuing to repeat ever more clearly the basic facts and physics of global climate change. As the climate effects of global warming become ever more apparent (increases in larger weather extremes – droughts, floods, forest fires), the public awareness will shift in favor of the science and away from the climate deniers.
Climate etc. denizens should keep in mind that the consequences of global warming are not a question of “if”, but of “when”, and that the climate modeling uncertainties are not one-sided, but cut both ways. Thus, the nasty stuff in ecological disruption and the rise in sea level that is predicted to happen by the end of the century could be arriving a lot sooner than expected, accompanied perhaps by totally unanticipated maladies.
Follow up by Lacis
I would say that AL’s words largely fell on deaf ears, no great surprise there. But he felt moved to reply, so I’ll copy it in here:
Some remarks regarding some of the comments from above
The universe – and the terrestrial climate system – both operate according to the laws of physics. That means that even the chaotic looking climate system variability is ultimately the result of cause-and-effect physical processes subject to the conservation of energy. That makes climate modeling possible, and understandable. Things don’t just happen for no reason at all.
nottawa rafter –
Climate is best understood as a problem in physics. The natural variability of the climate system is too large, and the documented climate record is too short to enable a clear understanding of climate change in terms of its statistical variability alone. By the way, I am not looking for enemies. By definition, climate skeptics are those who do not yet have a clear understanding of the climate problem at hand. Climate deniers are those who have made up their minds without taking the time to consider the relevant facts and physics. You should not be so trusting as to automatically believe everything that is said in the public forum either for or against the ongoing global climate change. There really are organized efforts out there to deliberately spread disinformation about climate change. Climate change is a matter of physics. If you stay focused on the basic physics of global climate change, you will be less likely to become misinformed.
Whether or not a discussion is productive depends on the expectations of the participants, and I suppose, the expectations of any onlookers as well. I have set the bar rather low for myself in that if I feel that I have made my point clearly enough, then my expectations have been met. If anybody else finds my statements informative, then I am gratified beyond my expectations. Also, I don’t harbor expectations that any of my comments will positively advance the understanding of climate by Climate etc. denizens – that way I will never be disappointed. Occasionally, there are comments made here by some people that are useful and informative – that is a plus. But at this point in time I am more interested in the science of global warming, and much less about all the possible options and costs of adaptation, mitigation, and/or geoengineering countermeasures to counteract global warming.
Steve Fitzpatrick –
Glad to hear that you are not influenced by the likes of Heartland and Cato Institute propaganda. But I would not say that makes you have a good understanding of the basic physics relevant to global warming. Try reading that Tellus B paper I mentioned above. It is not just me who is blaming the fossil fuel interests for spreading climate change misinformation – the Koch brothers efforts in this effort have been well documented by many others. As for MY failure to convince people, I tend not to blame myself too much, being satisfied for the most part in just placing my climate research material out in the public forum. How about YOUR failure to understand the basic aspects of the global warming problem? Who do blame for that?
Don Monfort –
I don’t really care that much what some climate dissenters may or may not think about global climate change – they all have the Constitutional right to believe whatever their hearts may desire to believe, even if their beliefs are totally contrary to reality. But when people make deliberately erroneous public statements regarding the nature of global climate change, then we do have an obligation to make an effort to correct those misrepresentations – that’s part of our job. Then too, the climate system could not possibly care less whether some public opinion poll is 57% against with 13% undecided. The climate system responds only to the laws of physics, and to the fact that atmospheric CO2 has continued to increase.
Rud Istvan –
While the EPA and WMO are both respectable government supported organizations, why on Earth would you take as the Gospel Truth their arbitrary definition that climate is weather averaged over 30 years? Relying on the basic physics approach taken for weather forecasting and climate modeling provides a far more reliable assessment. As you may know, weather forecasts begin with an accurate characterization of the reference pressure, wind, temperature, and humidity fields. Hydrodynamic modeling calculates how this atmospheric reference state evolves with time. After about a week of simulated time, the unresolved eddy energies will have overwhelmed the initial wind field configuration, and the weather forecast will have totally exhausted its predictive capability. In climate modeling, while the evolving weather patterns are continuously being calculated, it is only the statistical distribution of these weather patterns that is of interest. There is obviously a reference atmosphere that serves as the initial modeling starting point, but it does not define the final equilibrium state of the modeled climate – that is defined by all the radiative forcings that define that particular climate change simulation. A notable example of climate forcing in action is the seasonal change from warm weather in the summer time to cold weather in the winter time, driven the seasonal shift in solar irradiance. Over longer time scales, it is the radiative flux imbalance at the top of the atmosphere due to changes in greenhouse gases, solar luminosity, or aerosol distributions that drive the climate system toward a new energy balance equilibrium.
It is very important to distinguish between the natural variability of the climate system (in particular the local and regional variability) and the steadily rising global warming component (which is the long-term problem that we need to worry about). Droughts, heat waves, and floods have many contributing factors. So it is not really a proper inference to state that a particular extreme weather event either was, or was not, caused by the increase in atmospheric CO2. Suffice it to say that with global warming, the sea surface temperatures are warmer and the atmosphere can hold more water vapor (the principal fuel for weather activity). Climate models suggest that a more strongly activated hydrological cycle arising from global warming enhances weather extremes such as droughts, floods, and heat waves. In regard to the likes of Cato, Heartland, and Marshall Institutes, what makes you thing that these “Institutes” are really interested in understanding global climate change. Typically, the publications that they produce do not pass objective scientific muster, and are not designed to inform but rather are designed to confuse and obfuscate climate science issues. Take for example their NIPCC report, total garbage compared to the far more objective analysis of climate science as reported in the series of IPCC reports.
R. Gates –
The climate modeling runs in the 2013 Tellus B paper were designed to simulate the equilibrium climate response over a wide range of CO2 concentrations. So, the ocean heat content was never an issue. Proper accounting of the ocean heat content is an important issue for transient climate simulations over the recorded surface temperature period. For those climate simulations a fully interactive coupled atmosphere-ocean model is used with the full SW and LW radiative effects of all major volcanoes included. A detailed description of such climate simulations for the 1880-2003 time period with the GISS climate GCM can be found at via the GISS webpage at http://data.giss.nasa.gov/modelE/transient/climsim.html
It might appear that the global warming problem merits little urgency since the rise in global temperature is slow in coming and sometimes even exhibits pauses in the steady rise in global temperature. The climate indicator that you should be watching is the unending rise in the atmospheric CO2 concentration (now topping 400 ppm compared to the interglacial maximum of 280 ppm). Failure to address that problem serves only to make fixing the climate problem that much more difficult. This will surely make life that much more miserable for future generations. But perhaps that does not concern you.
I am sure that you will not be disappointed if continued global warming brings more fire and drought episodes to the outback. Same here for your conservative Foxfriends in the southwest. As the polar ice keeps on melting at an accelerating pace, the sea level has nowhere else to go but up. If you happen to reside on high ground, then you have nothing at all to worry about. It is just us low-lifers here in New York, Miami, and New Orleans that might need to be thinking about re-locating before this century runs out of time.
Modeling climate is indeed a boundary value in physics. But the radiative forcing at the top of this atmospheric boundary is actually NOT constant. That is why we have a climate problem. It appears that it is the desire of the humans to want to keep burning 10 cubic km of fossil fuel per year so as to increase the concentration of atmospheric CO2. This upsets the radiative energy balance of the Earth causing the global surface temperature to rise, the polar ice to melt, the sea level to rise, etc.
Jim D –
If understanding could be so easily achieved, I am sure that a great many of us would be more than willing to engage in discussing climate issues with Cato and Heartland denizens, even Congressional Republicans. But I hardly think it rational to expect good things to happen when there is so much irrationality to overcome to deal with.
Sour grapes – buying or selling?
David Young –
Bob Woodward resolved the Watergate problem by adopting the approach of “follow the money”. In modeling climate you need to adopt a similar recipe, except that in climate you “follow the energy”, and make damn sure that energy (also mass, water substance, angular momentum, and vorticity) stays conserved at every single modeling time step.
Steven Mosher –
Interesting contemplations about improving the climate discourse. Like the saying goes, you can bring horses to water, but you can’t make them discuss climate in any productively rational manner. Would discussions with climate skeptics and climate deniers actually accomplish anything useful? I suppose that we will never know, if we don’t try. But I remain skeptical that Pat Michaels would even care to read my comments here on the Climate etc. blog. The principal objective of any meaningful discussion would be to first establish a clear understanding of just what are the relevant facts and physics of global warming. But that is a topic that the climate skeptics tend to avoid – because they can’t win their case on that topic.
Climate modeling, as it is performed with current state-of-the-art climate GCMs, is basically a problem in physics, and not one of statistics or abstract mathematics. You should look at the Hansen et al. (1983) paper http://pubs.giss.nasa.gov/abs/ha05900x.html which describes the primitive equations that are being solved to simulate the atmospheric dynamics. There is also the current GISS ModelE2 version at http://pubs.giss.nasa.gov/abs/sc02500z.html Or, for a simplified conceptual overview, but with a more detailed description of the radiative transfer modeling, there is my 2013 Tellus B paper at http://pubs.giss.nasa.gov/abs/la06400p.html There are also a great many climate modeling simulations generated with the GISS ModelE version at http://data.giss.nasa.gov/modelE/ with more than a superficial resemblance to real-world climate variability.
I think you are viewing the climate science landscape through the wrong end of the telescope. I would characterize most climate scientists as being quite objective as to the basic nature of climate change. And I tend to see the “skeptics” as being stuck in their dogmatic views, unable to comprehend the basic facts and physics of global warming that are really quite well understood. At the same time it is also well known that there are some aspects and areas of climate modeling that have significant degrees of uncertainty. The climate system is after all quite complex. But that doesn’t mean that nothing can be understood if there are some aspects that are less well understood. I do tend to view organizations such as GWPF, Cato, and Heartland as having a set dogma and agenda on global warming with a distinct reluctance to accept or address the basic facts and physics. Can holding discussions with these guys really lead to improved understanding?
What makes you think that fossil fuel industries don’t have interests?
Fernando Leanme –
The recent paper by Hansen et al. (2011) available from the GISS webpage at http://pubs.giss.nasa.gov/abs/ha06510a.html should provide a good description of the Earth’ energy imbalance and its implications.
1. At least, I assume its by him. I have no way to verify this2.
2. I now know it really was him.