Tuesday, January 08, 2008

scientific consensus

I'm not against the concept of scientific consensus. Some science is well established and non controversial. All scientists agree about how bodies will fall to the earth in given conditions. Scientific revolutions and paradigm shifts as described by Kuhn do happen and are very important but they are dramatic punctuations to the steady state of most known things about science.

I was pretty much persuaded by Peter Norvig's article (The Global Climate Change Consensus) that there was a consensus within peer reviewed articles by scientists about global warming about the following fairly moderate but important IPCC hypothesis:
Human activities ... are modifying the concentration of atmospheric constituents ... that absorb or scatter radiant energy. Most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations.
Although very far from alarmism this hypothesis is important because it does say humans are responsible for "most" of the observed global warming. So, that might throw us into a brand new situation, unprecedented in human history.

However, Norvig's article was written in 2004 and there are now new peer reviewed studies that do dispute the so-called consensus. I thought this article was well argued: “Consensus”?What “Consensus”?Among Climate Scientists, the Debate Is Not Over by The Viscount Monckton of Brenchley

I had to laugh at the end though, where it is revealed that the author is a former policy advisor to Margaret Thatcher during her years as Prime Minister of the United Kingdom. But then if a right winger puts up a good argument then we shouldn't dismiss it just because they are a right winger, agreed?

The articles does quite a good job at:
  • discrediting aspects of the original Naomi Oreskes article which originally claimed the consensus
  • exposes the false linkage between Oreskes' moderate consensus position and the alarmism promoted by Al Gore in his movie - the difference between the sea rising 2 inches compared with 20 feet
  • raises what seem to be some valid contextual questions, but which I haven't researched yet
  • concedes that "most climate scientists probably believe that humankind has caused 0.2C of the past half-century’s 0.4C warming"
  • outlines the results of a new review of peer review papers since 2004 in which 7.3% either explicitly or implicitly reject the consensus
  • exposes some alleged important mistakes made by the IPCC about sea level rises
The article however misses out on Peter Norvig's point about Dr. Benny Peiser, you would have to read the Norvig original and follow the links. The Viscount seems to have missed the Norvig article

So, the majority of peer reviewed scientists support a moderate human caused global warming hypothesis. But there is not a consensus and there is not strong case for alarmism based on the peer reviewed literature.


Bill Kerr said...

mmm ... more about Christopher Monckton, 3rd Viscount Monckton of Brenchley and his vigorous and controversial opposition to global warming alarmism in this wikipedia entry

He is upfront about his right wing political views. I think that is the main issues, declaring your biases or predilections publicly and more importantly to yourself so that you are self aware about how it might be affecting your scientific judgment

btw Monckton has challenged Al Gore to an internationally televised debate on climate change but the former U.S. Vice President did not respond. In my view such debates are the way forward to raise awareness and consciousness

Anonymous said...

Out of curiosity, have you ever seen a PBS Nova show called "Global Dimming"? If not, I think you might find it worth watching. I don't want to spoil that show for you.

Unknown said...

I am reminded about the debate about teaching intelligent design in schools.

The creationists believe that they are gagged by an orthodoxy where only evolution theories are discussed.

Creationists can produce many highly qualified experts who believe creationism over evolution. The orthodoxy disounts intelligent design as a credible science.

Fortunately we can examine the evidence and draw our own conclusions of the credibility of the 2 positions.

With global warming, the central argument is that anthropogenic greenhouse gases produce about 0.7C warming at present rising to 4C at the end of the century. The current level of warming is too small to be able to reliably detect against the natural climate variability. All arguments about the current climate are peripheral, the central argument is about our ability to predict the global warming resulting from a given CO2 increase.

The modelling is way beyond the power of computers at home so the masses are not in a position to assess the merits of the 2 positions. This is why global warming cannot be evaluated by ordinary people in the way evolution can.

Unknown said...

Bill argues that progress and sustainability may be incompatible.

There are two reasons why our desire to progress should be tempered by sustainability considerations:

2)intergenerational equity

Anonymous said...

Hi Bill. I've been meaning to comment on this issue, since it's one I've been concerned about, but I've been extremely busy since December.

I would like to address your point about scientific consensus. There is such a thing in practical reality, but it's lamentable because it's tended to hurt the credibility of science rather than help it. Scientific truth comes from many scientists being able to reproduce experiments or empirical observations. Maybe this is what you meant by "consensus", but it's not a matter of scientists agreeing that something is true. It's a matter of the evidence itself showing that something is true, and many scientists seeing the same empirical results. This is different from what's going on with science and theories of global warming right now.

Several years ago I began to hear about the anthropogenic theory of global warming. I looked for opportunities for the scientists who claimed this theory was true to make their case. I found a few opportunities, but I was disappointed. I analyzed what they said, and the best I could make out was that the evidence showed the Earth had warmed in the past 30 years. When it came time to explain the cause, the best they could do was, "There's no question that man is causing it." There was no exposition of evidence for the cause. At best their position was arrived at by inductive reasoning, a kind of process of elimination, which in science is a risky position to take, because there's the possibility that there's a conclusion that models reality better that hasn't been considered or discovered yet. I got no sense that they had found a positive cause that could be proven scientifically.

What I find bothersome as well, as someone who is trained in computer science, is whenever anyone asks how scientists know that anthropogenic CO2 is causing it, they point to computer models. In college I majored in CS. If there's one thing I know to be true it's that you can get a computer to say ANYTHING. It's dumb. It only does what it's told to do.

I also took some atmospheric science courses. As a child I once wanted to become a meteorologist/storm chaser. I ultimately skipped that and chose to go into computing whole hog. What I know is that Earth's atmosphere is a chaotic, non-linear system.

I also took a course in economics while in college. There I learned that economists often run computer models on the economy. The difference is they do not use them to make direct predictions. Rather they use them to get ideas about the effects of things like inflation, Fed policy, tax policy, etc. Even so, the results are considered to be very rough estimates, because it's understood in the profession that the economy is a chaotic, non-linear system. No credible economist would say, "The economy is going to go into a depression because our computer models say so."

From my CS training I know that such systems are very difficult to model with accuracy on computers. Digital computers are above all deterministic, and things tend to be implemented on them in a linear fashion, though concurrent, asynchronous processes can be modelled. Computers are able to model the weather a few days out, but beyond that they are terrible. The reason is that in the short term, the difference between the variability in the atmosphere, and the variability the computer is able to model is close enough that the prediction is reasonably accurate. As you go out further in time, the permutations of the variability become so large that computers can't model it with reasonable accuracy.

As years have passed I've been hearing about problems with the computer models used to make global warming predictions. For example the famous "hockey stick" graph produced by an early computer model that showed a sudden, unusual rise in the Earth's temperature in the 20th century was shown by an independent statistician to have some serious flaws. The algorithm used produced a graph that showed a rise in temperature at the end of the data series no matter what data was fed to it. In one test it was given a totally random data set, and it still produced something resembling the hockey stick. This showed that the model had a hard-wired bias. This model was the centerpiece of the 2001 IPCC report. Secondly, there were gaps in the original data set the model used, which were found to have been filled by repeatedly using old data. In the end, the model had absolutely no credibility. Yet it had been peer-reviewed and accepted by a cadre of scientists. It just goes to show that peer review is not immune to groupthink.

I have since heard from climate scientists who have been willing to talk about the use of climate models. It sounds like the models are at best no better in quality than the models that economists use to model economies. They contain some well-known equations, but they also make assumptions. For example some climate models assume that relative humidity is the same all across the globe. Climate models have real trouble modelling the cycle of water evaporation and precipitation. This is critical, because water vapor is the major greenhouse gas on Earth. In terms of effect it dwarfs CO2.

The IPCC report acknowledged that the very computer models they were using to make their predictions had difficulty with reproducing historical climate with accuracy, given historical inputs. If we're going to use climate models to make predictions about future climate they should at least be able to accurately (though not precisely) model historical climate. I mean, how else are we going to validate them?

I've also heard from people who were once on the IPCC, but who have since been willing to come on camera and reveal how they make their reports. They say that the reports are political, not scientific. In the report released last year, the IPCC released its summary, which contained NO scientific data, but which made predictions about the effects of warming. It also said rather blatantly that the scientific data would be released several months later, and that the data report would basically be made to agree with the summary. This is not science.

Geologists have been chiming in as well, saying that according to fine grained studies of ice cores, the empirical data shows that historically rises in CO2 do not cause rises in temperature on Earth. It is a powerful greenhouse gas, but its concentration is so low, 36 parts per million right now, its effect is basically background noise when compared to other factors. What the evidence from the cores has shown is that historically the temperature rises, and then the CO2 levels rise. There is a causal link between the two, but it's temperature that causes the rise in CO2, not the other way around. The delay between these two is on the order of hundreds of years. The CO2 rise we're seeing today is probably the result of the climate rising in temperature out of the Little Ice Age, which ended in the 19th century.

The natural question to ask is, "If CO2 is not the cause, what's causing the temperature to rise, then?" A relative few scientists are exploring this question. No one definitively knows the answer yet, but there are some promising leads.

Empirical data also shows that there is no measurable rise in average atmospheric temperature right now, which is what should be happening if CO2 is causing the temperature to rise. However, according to the data we have, surface temperatures have risen. A relative few scientists are exploring this phenomenon as well. A theory that some are exploring is that the warming is caused by our land use decisions (ie. the growth of our cities), not CO2 production. One scientist who is exploring this is Roger Pielke Sr. at CU Boulder. The reason this doesn't get big news is that while this is true science at work, there's not much funding in it.

One cause of the purported surface warming that can be pointed to right off the bat is a report that came out recently showing that 70% of the U.S.'s ground temperature monitoring stations do not meet standards. There have been temperature sensors which have been found positioned right near central AC exhaust vents. Other examples are ones positioned at lower than acceptable heights above concrete parking lots, and on black tar roofs. This situation produces a distorted overall picture of surface temperature. Secondly, NASA recently admitted that it messed up 7 years worth of its temperature data, which it has since corrected. Now, according to the official historical record of temperature, the hottest year on record was in 1934, not 1998, which begs the question, how come there was global warming in the midst of the Great Depression, when industrial activity was at one of its lowest ebbs?

It is up to the global warming alarmists to prove their claims. They must answer the counterveiling evidence using scientific methods in order for their conclusions to be valid. Unfortunately all I've seen from the alarmists is scientists acting like political activists, all the while cloaking themselves in their scientific garb, as if they were giving objective truth. In my view this is shameful behavior on their part. They are not acting like scientists, but rather people who "play ones on TV". It is also my view that what is happening, unfortunately, is that highly reputable scientists, the ones we often hear about, have been drawn into a situation that is not unlike the fable "The Emperor Has No Clothes". It's an embarrassment to the profession.

Bill Kerr said...

hi tekkie,

Freeman Dyson says this about the computer models:

"But I have studied the climate models and I know what they can do. The models solve the equations of fluid dynamics, and they do a very good job of describing the fluid motions of the atmosphere and the oceans. They do a very poor job of describing the clouds, the dust, the chemistry and the biology of fields and farms and forests. They do not begin to describe the real world that we live in"
- source

About the CO2 lagging the temperature rise, Real Climate, seems to have responded to that:

the lag b/w temp and CO2

I'm back at work now and unfortunately don't have time to fully research this topic. My main worry is that both alarmists and deniers may have agendas that cause them not to present the science objectively - and this is magnified by what the media chooses to report and how they report it.

Anonymous said...

Hi Bill. I didn't emphasize the ice core stuff too much, because I have heard some contrary evidence which suggests that scientists may not be reading them correctly at all in terms of their time scale. One story I heard on the radio recently was that pieces of an airplane were found at a depth in the ice that scientists say should've been thousands of years old, or something. So obviously that is a major screw-up in the data set. In my eyes what is undeniable is the consistent pattern in the ice record of temperature preceding CO2, no matter what timescale you're talking about.

The article on RealClimate I think filled in the picture some on the ice core issue, but I found it confusing. It starts out by saying there's no doubt that CO2 leads temperature, but then goes on to say later that there is a lag in the record, where temperature comes first, and then CO2 comes later. It basically suggests though that "this is old data" (I've heard this explanation many times), and that "we know CO2 is causing warming" in our modern era, because our burning of fossil fuels is "overwhelming" the natural processes. Where is their data to back up this assertion? The author doesn't provide a link to any. He just makes assertions.

He also links to an earlier article which attempts to explain the lag, where temperature precedes CO2. The author acknowledges that yes, the ice core record shows this pattern, but he contends these records only go up to the end of the last ice age, and that CO2 "could" (his word) be responsible for the warming we've seen since then. That's as far as he got: CO2 "could" cause the rest. That's a shaky position to hold on to. It suggests that this is not proven, but the author just chooses to believe it.

In the conclusion of the article you referred to, it ties it all back to predictions made by computer models, and what the IPCC says, saying that they and the data are in total agreement. As I said before, I don't trust these models to make accurate predictions, and I don't trust the IPCC reports as far as I can throw them, because it's not run as a scientific organization. To rely on it is folly, in my view.

I have read articles on RealClimate in the past, and I don't find them trustworthy. I do feel they have an agenda. They also rely a lot on computer models to justify their positions. I cited one computer model that many climate scientists hung their hat on, and it was debunked. There have been many others that have not been independently validated, mainly because the scientists who create them refuse to submit them for independent review. They'll share them with their colleagues for peer review, but they keep them "inside the family", as it were.

This is probably idealistic, but in my view real science is open for review by anyone. The data/results should speak for themselves. All this talk about, "We can't trust person X, because he got money from the oil companies" should be rebuked in the scientific community. It shouldn't matter where a scientist's money comes from. It's the data/results that should do the talking. If upon independent review it stands up, it should be accepted. If it doesn't, the research project should be sent back to the drawing board. End of story. That's the way science works.

One of the things the RealClimate article says is that regardless of what the ice core records say, there's no doubt that our temperature now is influenced by the CO2 from industrial activity (again, he provides no data/link to back this assertion), which in the historical scheme of things is very recent. The empirical atmospheric evidence says otherwise.

One of the complaints I've heard from the "denialists" (for lack of a better term) is that in the alarmist community there is very little reliance on empirical evidence. So much of what they're talking about relies on computer models. They complain that this is not typical scientific practice. I have to agree. I was taught the scientific method and one of the pillars of it is data gathered from observation. Building a model and watching it run is not observation. It can be useful for understanding a dynamic in isolation. Alan Kay has talked about this, that it's an educational tool. Done right, it increases our understanding of a phenomenon. It's entirely another matter to make a real world prediction that you're going to base societal decisions on using such models. That's what bothers me about all this. The alarmists expect us to take what their computer models say and use that as a basis for upending our whole societal framework. It smacks of a very naive, but common notion in our society that "because a computer said it, it must be true." Anyone who has done any programming on a computer knows this assertion is false. I find this attitude both unscientific, and unacceptable, particularly for scientists, who should know better.

I heard about a series of videos on a presentation given by Australian scientist Bob Carter. He presents what I think is some
good information on the issue. You can see it at:

Part 1: http://www.youtube.com/watch?v=FOLkze-9GcI

Part 2: http://www.youtube.com/watch?v=vN06JSi-SW8

Part 3: http://www.youtube.com/watch?v=iCXDISLXTaY

Part 4: http://www.youtube.com/watch?v=bpQQGFZHSno

The reason I am concerned about this is not that I am against us getting off of fossil fuels. I like the idea of us getting off of oil in particular, because of national security. I don't like wasting energy either, so the news that companies are trying to become more energy efficient is great as far as I'm conerned. What I'm concerned about is what the alarmism around this issue is doing to science. Modern civilization needs to be able to trust science to provide reliable, sober answers to what is going on in our world. This whole issue strikes me as a giant "cry wolf" scenario. I feel like these scientists had BETTER be right. If we follow their lead and their theories are shown to be wrong (eventually the truth will be known), then science itself could lose credibility. That will be bad news for modern civilization, because what will we have left to rely on? Rumors and superstition. I do not care to see us slouch back to Medieval thinking.

Anonymous said...

I had the thought that I should also suggest watching a BBC Channel 4 program I watched on the internet called "The Great Global Warming Swindle". You can find it on Google Video if you search for it. It's about an 1 hour, 20 minutes long (either that or just 1 hour). The show talks to about 2-3 scientists who used to be on the IPCC. I found it to be a very interesting presentation on the topic, and some new research which I think is promising, and beautiful. The reason I say "beautiful" is it suggests that our climate is influenced in large part by what's going on in our solar and/or galactic "neighborhood". In that sense it makes sense to me. We are a part of the universe, so why shouldn't what's happening out there influence what's going on here? The show acknowledges that the theories they show, which suggest answers for where changes in our climate come from, are new and at this point thinly researched, but the "leads", as I referred to them earlier, look promising.