Posted by: climatewonk | December 24, 2009

CRU Emails — What’s Really There

A very good summary from the Yale Forum on Climate Change on the gist of the emails in a post by Zeke Hausfather titled “The CRU Emails: What’s Really There?

From the post:

The release of the Climatic Research Unit e-mails is a blow to the reputation of many of the climate scientists involved, at least over the short run and perhaps among the public at large, if not necessarily among serious climatologists. They have been cast in a far different light from the general perception of scientists as impartial and impassionate.

Given the prominence of the scandal that has unfolded, it is unlikely that the whole affair will just fade away without anything changing. Indeed, there are growing calls for more openness and transparency in climate science research:  Climate scientists likely will have to accelerate efforts to be more open about their processes and data (though, to be fair, this is much further along than often thought).

It is unfortunate, if perhaps not surprising, that the quotes from the e-mails that have gotten the most publicity from skeptics and in some media strongly distort the views and actions of the scientists in question, contributing to a perception of collusion to manipulate the climate data itself.

Nothing contained in the e-mails, however, suggests that global temperature records are particularly inaccurate or, worse, that they have been manipulated to show greater warming. The  certainly troubling conduct exposed in some of the e-mails has little bearing on the fundamental science that strongly indicates that the world is warming and that anthropogenic emissions of greenhouse gases are the primary cause.

For the scientists involved and for many of their professional colleagues, that is the “bottom line.” Whethere the public and its elected and appointed policy leaders reach that same conclusion remains to be seen. [my emphasis]

Hausfather does a good job of going over each of the five main points raised in the emails:

  • Scientist Kevin Trenberth’s remarks on scientists’ inability to account for lack of warming;
  • Phil Jones’ comment on using a “trick” to “hide the decline”;
  • Encouraging editors of Climate Research to resign after the publication of Soon and Baliunas (2003);
  • Discussions among scientists surrounding efforts to avoid citing two skeptical papers (Kalnay and Cai (2003) and McKitrick and Michaels (2004)) in the IPCC Fourth Assessment Report; and
  • Perhaps most damning, comments by Jones encouraging others to delete e-mails to avoid releasing them to freedom of information requests from climate skeptics.

In the author’s assessment, only the final point is troubling because while some of the others might appear to be damning, the reality is that threats aside, nothing came of it.  Articles were published and included in the IPCC reports despite the voiced intentions of the authors to prevent both. The “trick” is just a handy means of splicing the instrumental temperature record onto the paleoclimate proxy record, and “hiding the decline” merely refers to the “divergence issue” which is well known in the dendro communities and was discussed in the paper in question. The “lack of warming” does not reveal that scientists know AGW is a fraud, but that the models do not have the ability to account for short-term variability in climate.

So, yes, the emails do reveal the all-too human nature of scientists. The public might think they are dispassionate disinterested and wholly objective, but they aren’t. Luckily, the system is set up so that no on scientist or small group of scientists can pervert the entire venture.

Posted by: climatewonk | December 20, 2009

Science and Engineering – a digression of pure speculation

I’ve been reading over at Climate Audit now for a couple of years. When the talk about global warming started to pick up on my radar screen, about a dozen years ago, I pretty much accepted what I read from the IPCC. One feels the weight of scientific opinion when numerous science bodies come out and make strong statements about global warming that there must be a lot of strength to the research.

When I first heard of the global warming skepticism and skeptics, such as Steve McIntyre and Climate Audit, I went there and hoped to learn for myself if there was anything to the skepticism or whether it was just another example of industry trying to cast doubt over the science for its own financial gain — which I had studied in university courses on the history and philosophy of science. I took McI seriously at first, tried to read his blog and papers and see if he was on to something. I read over at Real Climate. I read Anthony Watts. I read Lucia. I read Eli and Tamino and Deltoid and Revkin and Ice Cap and DeSmogBlog and Bishop Hill.

I do believe in the sincerity of many of those who label themselves “skeptics”. I think they truly believe that climate science is a sham, the scientists are crooked and the data has been “adjusted” and fudged. For the most part.

However, I feel very strongly that the opposition to climate science and global warming theory comes from a political / ideological / general orientation to reality rather than a scientific place. Many of those over at CA and other places appear to be computer, math/stats or engineering types and with all due respect, they are a different kettle of fish than pure scientists or research scientists.

There is some social scientific research to back this up so it isn’t just me blowing smoke. When I read the posts of many of the engineers, one of their biggest complaints is that the code isn’t up to speed, that the math isn’t up to snuff, and that there are too many uncertainties in the science for any policy to be premised on it. They want engineering quality code and specs. I believe that this stems from their orientation to their occupation and work.

Engineers apply science to design things and build things and blow shit up. Scientists explore. They imagine. They seek the novel. They work in uncertainties. They try to make them less uncertain. They ask questions. Engineers solve concrete and applied problems and while the two fields are very close, there is a fundamental difference between the two.

I suggest that there is a fundamental tendency among engineers and computer science types to be more concerned with certainty and less tolerance for the kind of exploration and imagination and novelty when compared with scientists. Engineers talk all the time about having to have the calculations perfect so that a building doesn’t fall down and kill a thousand people or a plane fall out of the air or a machine not function properly.

That is completely different than a climate scientist thinking about the variables and factors that affect tree growth and how there are connections between climate and growth that might give us important information about global warming. Sure, it’s not the kind of analysis that you can use to build a locomotive or space shuttle or launch a rocket, but it’s the kind of thinking that pushes the frontiers beyond practical application, as important as that is for our species.

I’m not dissing engineering or engineers. We owe so much to their exacting demands for their own profession. I’m just saying that I feel a lot of the animosity I see voiced towards climate scientists from the “skeptics” — especially the engineers and computer scientists — is due to a wholly different understanding of the world, an orientation to knowledge and a different sense of exploration. They don’t understand the other’s POV — it is almost an anathema.

Scientists have to think beyond the box in order to make those intuitive leaps that allow those revolutions in science to occur. Science and art have one very important aspect in common — a vision of possibility beyond that which is given in the world. Of creative imagination.

Sure, there are lots of uncertainties in climate science as there are in any science. In the normal course of things, those uncertainties become certainties, through the scientific method, peer review and the progress in research.

And yes, there is a lot of creative problem solving in engineering, but engineers require a degree of certitude that is just not expected nor beneficial in the pure sciences.

The reason the uncertainties in climate science became so visible — and contentious — is because of the implications of the findings about climate and CO2 and greenhouse gasses from burning fossil fuels. The clear implication is that burning fossil fuels leads to increased CO2 in the atmosphere which leads to enhanced greenhouse gas effect which leads to warming and perhaps, to a new much warmer climate. That has political and economic and social consequences far beyond that of most sciences. Once the political and economic and social implications became apparent, the certainties and uncertainties in the science became all the more an issue.

I understand the skeptical concern with uncertainties. This is mighty important stuff. It might necessitate big changes in our societies. Can we base decisions regarding the ordering of our economies on sciences with all the uncertainties? It will be up to the engineers to design systems that will help mitigate climate change and help us adapt to what seems certain to be over 2C warming. We will need their penchant for certainty when they are designing their systems, but when it comes to science, by its very nature, we need to preserve and encourage that exploratory intuitive bent so that the unimaginable is imagined and the dark corners of the universe are explored.

In other words, engineers should not be auditing or judging science for if they are the arbiters of what is valid science, it will be diminished. Scientists should not be judging engineering for it will be found lacking vision and buildings will fall. Let the two shine in their own domains.

Posted by: climatewonk | December 10, 2009

500 Canadian Scientist Sign Petition

500 Canadian scientists signed a petition to Canadian leaders at the Copenhagen conference, which you can read at the WWF website.

Posted by: climatewonk | December 10, 2009

free counters

Posted by: climatewonk | December 5, 2009

Climategate — Victory?

Of course, it doesn’t matter what the truth is — there is so much spin going on out there in denialoblogisphereland that it would be virtually impossible to sort through the dreck to find the facts.

This is the key to manufacturing uncertainty — most people are not able to rise above their own biases to read a document with objectivity. It takes a really self-aware person — aware of their own biases — to even approach an unbiased view of some event, especially if it is linked to a cause they believe in.

Thus, in the world of the climate wars, each side sees the hacked emails the way that best reflects on their own position. We have denialists claiming this is the death knell of climate science and cheering that the rogues will lose their jobs, etc. or — as I read in one blog — be put into jail with a big hairy smelly roommate. Others are claiming that the emails mean nothing and it will all come out in the wash, but I beg to differ. I think this is really serious, not because of the real truth to the notion that climate science is a sham, but due to the harm this has done to its public perception and image.

That is what the climate wars are really all about — convincing the general public — and through them, the politicians — to its side of things so that there will be/won’t be action on climate change.

But I already had come to the conclusion that no real action on climate change will occur any time soon. There are just too many very powerful stakeholders with their hands in the pants of politicians for it to happen.

We had better hope that the climate scientists warning about the possibilities of a wholly new climate in the next century are hoaxers and charlatans.

Posted by: climatewonk | December 3, 2009

Climate Gate Post 3 — PCA, BCP, OMG!

We left off yesterday with the M&M paper attempting to cast doubt over the methods and choice of bristlecone pines in the MBH98 600 year paleoclimate temperature reconstruction.

So what exactly is the problem with MBH98?

Three things: Principal Component Analysis (PCA), bristlecone pines and the divergence problem in dendroclimatology.

Real Climate has a post on PCA, which defines it thusly:

A procedure by which a spatiotemporal data set is decomposed into its leading patterns in both time (see ‘Principal Component’) and space (see ‘Empirical Orthogonal Function’) based on an orthogonal decomposition of the data covariance matrix.

Phew!

From the Wikipedia entry, a bit more detail:

Principal component analysis (PCA) involves a mathematical procedure that transforms a number of possibly correlated variables into a smaller number of uncorrelated variables called principal components. The first principal component accounts for as much of the variability in the data as possible, and each succeeding component accounts for as much of the remaining variability as possible.

PCA is the simplest of the true eigenvector-based multivariate analyses. Often, its operation can be thought of as revealing the internal structure of the data in a way which best explains the variance in the data.

PCA is the simplest of the true eigenvector-based multivariate analyses. Often, its operation can be thought of as revealing the internal structure of the data in a way which best explains the variance in the data. If a multivariate dataset is visualised as a set of coordinates in a high-dimensional data space (1 axis per variable), PCA supplies the user with a lower-dimensional picture, a “shadow” of this object when viewed from its (in some sense) most informative viewpoint.

PCA is closely related to factor analysis; indeed, some statistical packages deliberately conflate the two techniques. True factor analysis makes different assumptions about the underlying structure and solves eigenvectors of a slightly different matrix.

Simple enough?

What’s going on with this paleoclimate research?

The instrumental record only goes back a century and a half or so, so we have no way to judge if temperatures today are warmer, colder or similar to those in the distant past. We need temperature proxies to help reconstruct the climate of the past. Now some might say this is a fool’s game, but there are many things we could not measure directly that required some kind of proxy measure. The climate is one of them.

Based on research on the relationship between environmental conditions and tree growth, dendroclimatology attempts to examine tree growth patterns and their relationship to climate variables today and in the past. This is done to better understand the science of tree growth, but especially in order to create a temperature reconstruction of past climate. Tree ring characteristics are considered to be proxy measures of past climate.

The assumptions, in very simplified language, are:

1. Tree ring width and density are related to environmental variables such as temperature, moisture, insolation, and site conditions such as aspect and location.

2. The relationship between ring width/density and temperature, in environments in which temperature is the limiting factor, is constant over time, in that x increase/decrease in temperature will result in y increase/decrease in width/density.

3. By calibrating tree ring width/density to the instrumental temperature record, it is possible to determine the temperature of the past by examining tree ring width/density from tree cores of living and fossil trees.

Seems logical and for the most part, it seems to hold true. Of course, there are always problems with any set of assumptions about physical phenomenon. Are there other factors that may affect tree width/growth and what effect do they have? How much individual variation exists? Do different species respond more or less to temperature fluctuations? What is the best way of collecting representative samples of trees so that any conclusions drawn from the research are valid or reliable? What possible errors exist in the methods and analysis?

MBH98 and 2000 used PCA to construct a paleoclimate temperature reconstruction using dendro data, in particular, tree rings. The actual method is quite complicated, and I am not a statistician, but suffice to say that when McIntyre went looking at MBH98 and 2000, he brought up a number of criticisms of the work in question.

Here is an excerpt from the abstract of their paper in Geophysical Research Letters:

Their method, when tested on persistent red noise, nearly always produces a hockey stick shaped first principal component (PC1) and overstates the first eigenvalue. In the controversial 15th century period, the MBH98 method effectively selects only one species (bristlecone pine) into the critical North American PC1, making it implausible to describe it as the “dominant pattern of variance”.

In response, various papers and enquiries looked into the PCA analysis in MBH98 and 2000. For example, Wahl and Ammann (2007) argue that:

Our examination does suggest that a slight modification to the original Mann et al. reconstruction is justifiable for the first half of the 15th century ( ∼ +0.05–0.10◦ ), which leaves entirely unaltered the primary conclusion of Mann et al. (as well as many other reconstructions) that both the 20th century upward trend and high late-20th century hemispheric surface temperatures are anomalous over at least the last 600 years.

So, the problem was the way PCA was used in the research to create a temperature reconstruction. M&M argue that the method MBH used relied too heavily on a small subset of the data, in particular the bristlecone pines, to do the reconstruction and that they are not reliable for use because of the problem of divergence.

More on divergence later.

For now, there have been a number of investigations into the contention of M&M that the methods used in MBH98 and 2000 were biased towards creating a hockey stick graph and that its conclusions are therefore flawed and do not support the contention that surface temperatures in the last half of the 20th century were warmer than any time in the past 600, 1,000 or 2,000 years.

The National Research Council conducted an investigation in 2006, and its report, Committee on Surface Temperature Reconstructions Over the Past 2,000 Years, concluded:

The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on ice caps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years.

In other words, the NRC report concluded that while there were some small issues with the use of PCA in the 1500 ca data, the basic conclusions about unprecedented late 20th century warmth held.

The report concludes:

Surface temperature reconstructions for periods prior to the industrial era are only one of multiple lines of evidence supporting the conclusion that climatic warming is occurring in response to human activities, and they are not the primary evidence.

Next: Wegman and Divergence

Posted by: climatewonk | December 2, 2009

The Real “Climategate”

People around the world are reading headlines with provocative titles, most of them suggesting that the hacked CRU emails betray some kind of fraud or conspiracy among climate scientists to hide or fudge data and oppress the poor “skeptics” who disagree with them. Some bloggers, meanwhile, are trying to point out what the real climategate scandal is — the cozy relationship between so-called climate skeptics and various astroturf front organizations funded, at least in part, by the petroleum industry and their concerted effort to publish shoddy papers and avoid the peer-review process in established science journals.

The goal of this strategy, as articulated by one very famous tobacco executive “denier” is to cast doubt:

“Doubt is our product since it is the best means of competing with the ‘body of fact’ that exists in the minds of the general public. It is also the means of establishing a controversy.”

From “Defending Science“.

An example of bloggers who are trying to point out the real scanda is a recently posted discussion at Deep Climate . The post documents a particularly odious example of the incestuous relationship between industry and “climate skeptics” and their intent to cast doubt on established science– The Friends of Science, in which the links between the CRU hack and the real climategate is revealed and discussed.

From the post:

For the first time, we can confirm both financial and logistical support from an Albertan oil company, Talisman Energy, along with circumstantial evidence of the early involvement of a second, Imperial Oil (ExxonMobil’s Canadian subsidiary). We’ll also look at the key roles played by the de Freitas brothers, geologist Tim and climate skeptic Chris. And the story leads right to the heart of a key controversy reignited by the stolen CRU emails, namely the ongoing perversion of the scientific peer review system by “skeptic” scientists.

It’s good reading for all, but especially for Canadians who may think the controversy is all down in the USA.

Posted by: climatewonk | December 2, 2009

Climate Gate Post 2 — The Hockey Stick

Our last episode ended with a retired minerals consultant/consultant to big oil and his sidekick, economics professor and fellow at the right-wing think tank The Fraser Institute, getting all hot under the collar about a graph adapted from an article by Mann, Bradley and Hughes (1998) used in the TAR: the infamous “Hockey Stick”:

They lamented the absence of the medieval warm period. To them, it contradicted an older less precise (by a long shot) graphic used in the First IPCC Assessment report.

In 2003, McIntyre and McKittrick published an article that challenged the methods and findings of the MBH(* paper used in the TAR.

From the paper:

The particular “hockey stick” shape derived in the MBH98 proxy construction – a temperature index that decreases slightly between the early 15th century and early 20th century and then increases dramatically up to 1980 — is primarily an artefact of poor data handling, obsolete data and incorrect calculation of principal components.

Note that the article was not published in a peer-reviewed journal listed in the JCR – Journal Citation Reports.

In response, Mann, Bradley and Hughes published a corrigendum in Nature, a very well-recognized science journal.

Next is M&M’s response, published in GRL, “Hockey Sticks, Principal Components and Spurious Significance” in which they critique the use of Principal Components Analysis.

From the article:

“Through Monte Carlo analysis, we show that MBH98 benchmarks for significance of the Reduction of Error (RE) statistic are substantially under-stated and, using a range of cross-validation statistics, we show that the MBH98 15th century reconstruction lacks statistical significance.”

So, we see some back and forth between Mann et. al and others in the climate science community and M&M over the use of certain statistical analysis, PC, to analyze paleoclimate data. Not only did they reject the use of PC analysis, but also the use of a specific set of paleoclimate data, Bristlecone Pines.

More on that in another post.

Posted by: climatewonk | December 2, 2009

Where’s the data?

In the interest of debunking some of the lying dreck that poses passes for skepticism, I thought I’d post a link to Real Climate’s post that provides masses and masses of data that would keep any and all retired minerals consultants busy for the rest of their lives doing climate science audits, if they so desired.

You might think that, given all this data and code, a semi-retired minerals consultant might write something, you know, scientific and publishable that would actually overturn existing research and show it to be just plain wrong.

But no.

Posted by: climatewonk | December 1, 2009

7 Answers to Climate Contrarian Nonesense

From Scientific American. I couldn’t have said it better myself.

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