In some followup discussion with Barry Bickmore (by email) and Kevin C (at Skeptical Science) it became clear we were missing something in the analysis of Roy Spencer's climate model. Specifically, Bickmore's Figure 10:
differed significantly from Spencer's 20th century fit even though he was ostensibly using the same parameters. If you look at the year 1900 in particular, Bickmore's Figure 10 has a temperature anomaly slightly above zero, while Spencer's is pegged at -0.6 C. Bickmore did use a slightly different PDO index than Spencer for his 1000-year graph (figure 10) - but more importantly, he took Spencer's -0.6 C temperature as the starting point in the year 993 AD, rather than as a constraint on temperature in the year 1900, as it actually was in Spencer's analysis. It turns out that to actually match Spencer's 20th century temperature fit the starting temperature in 993 AD needs to be extraordinarily, far beyond impossibly, low. We'll get to the details shortly.
BYU geologist Barry Bickmore recently reviewed Roy Spencer's recent book, "The Great Global Warming Blunder", finding a number of true "blunders" by the author. In particular he found some very peculiar properties of the simplified physical model that Spencer made a central feature of the book, finding that Spencer's curve-fitting allow infinitely more solutions than the one Spencer somehow settled on, and a number of related issues.
I tangled with Spencer over an earlier model like this which he was promoting more than 3 years ago. What he didn't seem to realize about that first model was that it was essentially trivial, a linear two-box model with two time constants (a subject I explored in detail here a while back). I tried explaining this, but he seems not to have gotten my point that such a model inherently contains no interesting internal dynamics, just relaxation on some (in this case two) time scales. Which seems to go completely against the point I thought he was trying to make, that some sort of internal variability was responsible for decadal climate change.
So it was something of a surprise to me that Spencer based his "Great Blunder" book on an even more simplified version of this model, with just 1 effective time constant. He even tried to get a paper published using this essentially trivial model of Earth's climate. As Bickmore outlined in his part 1, the basic equation Spencer uses is:
(1) dT/dt = (Forcing(t) – Feedback(t))/Cp
where T is the temperature at a given time t, Forcing is a term representing the input of energy into the climate system (there is a standard definition for this in terms of radiation at the "top of the atmosphere") and Feedback is a term that itself depends on temperature as
(2) Feedback(t) = α (T(t) - Te)
with α a linear feedback parameter and Te an equilibrium temperature in the absence of forcing (Bickmore and apparently Spencer don't actually use absolute temperature T and equilibrium value Te, but rather write the equations in terms of the difference Δ T = T - Te, which amounts to the same thing, but obscures an important point we'll return to later).
The final term Cp is the total heat capacity involved. Each of forcing, feedback and heat capacity is potentially a global average, but would normally be expressed as a quantity per unit area, for example per square meter. Since the bulk of Earth's surface heat capacity that would respond to energy flux changes on a time-scale of a few years is embodied in the oceans (about 70% of the surface), Cp should be defined essentially as 0.7 times the heat capacity of water per cubic meter, multiplied by the relevant ocean depth in meters (h):
(3) Cp = 0.7*4.19*10^6 J/(m^3 K) * h = c * h
where c = 2.9 MJ/(m^3 K) (Spencer and Bickmore seem to have forgotten the factor of 0.7, so use a slightly larger value for c, which means their h values are probably smaller than the actual ocean depth such a heat capacity would be associated with).
Growing up, my mother seemed to worry about everything. What we ate, how we exercised, school grades, future employability, crossing the street. Trees creaking in a storm, us climbing trees and rocks, my father's driving, the least speck of dust in the house, all seemed to her signs of impending disaster. Perhaps it was in reaction that I acquired such a worry-free attitude about life in general, and in particular about the future. To me just about every step to the future seems a wonderful bright beacon to a better purer world, where human beings are fully valued for what they can really contribute, where drudgery is gone, abuse of other humans and the natural world are a thing of the past, all are enlightened and wise...
Now, I don't consider myself a techno-utopian like Ray Kurzweil. I've critiqued his hyper-optimism elsewhere - if Kurzweil is doubly-exponentially optimistic about the future, I'd limit myself to a single exponential, or even (as I think we eventually must) a power law. But I still think overall the future has to be, on net, more positive than negative. Maybe it's just in my nature.
Andy Revkin has a nice interview with optimistic "World-Changer" Alex Steffen, whose latest book "Worldchanging 2.0" (an expanded edition of the first version, of which I have a quite inspirational copy) was just released. As I've noted here before, Steffen's optimistic view of the future is one I largely share, despite much evidence that our present world has some very serious troubles, now and ahead of us.
On what I believe is a private discussion site I was asked a number of questions about the climate problem. I'm copying my answers here (with some minor corrections of typos and for context) as they may be found helpful for others... or at least as a reminder to myself of what I know.
Q. 1 "I look forward to any insight you can provide into the real verifiable evidence of the human footprint."
I'm not quite sure what you mean by "verifiable evidence". You acknowledge climate seems to be changing. There are two distinct pieces of knowledge that go into "blaming" it on us humans, each of which has been substantiated from multiple observations and physical understanding. These are:
(1) Humans have caused atmospheric CO2 levels to increase considerably over the past century. This youtube video shows the wide range of observations of that increase in considerable detail, also showing how it compares with past changes:
Ray Pierrehumbert's recent brief but excellent exposition of radiative transfer theory in Physics Today and scienceofdoom's continuing effort to clearly explain atmospheric radiation and the "Greenhouse" effect inspired me to do a little playing around of my own with the underlying theory and equations, to get a better feel for some of the expected behavior, and perhaps illuminate another aspect of the problem to a public audience.
I have happily used Google Reader in recent years to collect RSS feeds from news sources and blogs around the web, to provide me with a pretty complete up-to-date view of what's going on in science, technology and general world news. The average day has two to three hundred news items, the bulk of them on topics or people I'm interested in. It's an investment of effort to keep up, but I do at least give a brief glance to most of the items that come through the reader.
One of my regular sources has been New Scientist, a UK-based news organization. I've found them a useful source of up-to-date science reporting, despite a tendency to over-hype things. But apparently they've started including non-fact-checked blogs in their news stream - either that, or their editorial process has developed some very lax standards. Because, a few days ago, I was startled to run across this piece by Fred Pearce, reporting on a so-called "reconciliation" conference on climate, held in Lisbon.
The final 2010 Goddard Institute for Space Studies (GISS) global land+ocean temperature numbers are out and just as I predicted, this year was the hottest in their record. Once again my prediction (really mostly a guess) was within just a few hundredths of a degree of the final number for the year:
|Year||Arthur's Feb 2008 prediction||GISS - January 2011||Difference|
I've long been interested in issues of trust and meaning, particularly in regard to scientific information. The importance of context, the "who, when, where, why" of any piece of information, is critical in determining first whether we even learn of that information, and second the degree to which we accept it as part of our base of knowledge about the world.
Historian and philosopher Francis Fukuyama wrote a book on the subject (titled Trust). Ironically, while I felt some interest in it, I haven't read it because of my reaction to an earlier book of his (The End of History) - which I also didn't read. But anybody who could write a book with that title and the apparent thesis that all the interesting debates and conflicts regarding forms of government were somehow in the past was, I decided, not really worth my time. Thanks to just that cue, my level of trust in his ideas fell essentially to zero, and I haven't read what might otherwise have been very interesting to me. Or perhaps not if my judgment was justified.
Trust is fragile, hard to gain and easily lost. Which was why I found a recent post on science and journalism by Scientific American blogger Bora Zivkovic (who I've followed for a long time as @BoraZ on twitter) a little annoying.
APS Staff were recently asked about our thoughts on the future, to help with a planning exercise for coming years. The following are somewhat frank comments I submitted in response to two of the questions, on biggest challenges and opportunities for the future. I doubt they represent the average views of APS staff right now, but they do capture a number of my concerns and ideas at the present so I thought I'd share a bit more widely... I'd certainly be interested in others' thoughts on these and other ideas for what the relatively near future may hold.
Five biggest (but perhaps not most likely) challenges:
1. Retaining the trust of the physics community as a filter and enabler of physics communication (journals, meetings, new media). Trust is fragile; mistakes that drain that trust could come from any front; openness and honesty in all dealings with the community and society at large are paramount.
There exists a widely quoted story about [18th century philosopher/mathematicians] [Denis] Diderot and [Leonhard] Euler according to which Euler, in a public debate in St. Petersburg, succeeded in embarrassing the freethinking Diderot by claiming to possess an algebraic demonstration of the existence of God: "Sir, (a+b^n)/n = x; hence God exists, answer please!"
This story turns out to be (at least in detail) false, but it was likely invented and resonated because it embodies an underlying truth almost any of us in the sciences have seen: once a mathematical equation comes out, it tends to blind the naive, and even the experienced will often skip over the equations on a first reading of any complex argument. A minor error in a mathematical expression (a forgotten minus-sign being the most common example!) can completely change its meaning, and reasoning about such things requires detailed understanding, it's something that's intellectually demanding, requiring time and mental effort. Sometimes we are willing to put that time in, but more often than not we just don't have the time, or the requisite background, and just skip over the math, hoping that it makes sense to somebody else.
Of course, there is an equation that's proof of amazingly beautiful self-consistency in mathematics, that some have taken as evidence for God:
ei π + 1 = 0
but the beauty of that expression isn't something I intend to get into right now.
What brought to my mind the apocryphal story about Euler and Diderot was a pair of recent posts by Dr. Judith Curry, who I've criticized here before. The first post seemed in some ways to finally be a response to my earlier queries about the no-feedbacks question - about which more below. But in the second she oddly chose to highlight 3 comments which claimed the whole thing was ill-defined, with one of them chock-full of equations that seems to have blinded her and others to the fact it made no more sense than Euler's apocryphal equation, ending with a claim that it's all nonsense:
... it is impossible to evaluate these 2 integrals because they necessitate the knowledge of the surface temperature field which is precisely the unknown we want to identify.
The parameter dTa/dFa is a nonsense
which is the sort of language that should remind my few regular readers of our friends Gerlich and Tscheuschner...
Ever since I can remember I've enjoyed putting together jigsaw puzzles. Even as an adult it's a fun diversion for me; of course there have been lots of opportunities to do simple ones with the kids over the years. Every once in a while, since we've been married, Shelly and I would get out one of the tougher ones and do it together - ones with 3000 pieces, or unusual shapes, or other challenges. Each is different, to some degree unique: dominant colors may greatly help find the right piece with one puzzle, while textures, element size and focus help with another, or sometimes you just have to go by piece shape.
Joe Romm has an excellent perspective on the last year, since "Climategate" - focusing on the developments in the science of climate that make our situation only that much more alarming. The real story of "Climategate" is not the frank discussions between climate scientists revealed in stolen emails, and at least so far not the Watergate-like computer break-in whose perpetrators and sponsors have still not been revealed (though I am sure one day that will prove a very interesting story). As Romm emphasizes, the real tragedy of "Climategate" is the media circus that chased this shiny new conflict-driven nothing of a story when there were far, far more momentous issues regarding the reality of climate at hand. If even one of the 9 scientific claims of the past year reviewed by Romm holds up under further research - and in my judgment very likely at least 4 or 5 of these, possibly 7 or 8, are real - the future for my children will be a far less happy place than I had anticipated even just a year ago.
Andy Revkin's coverage of the climate email hack at the NY Times, for example this early Dot Earth post, was an unfortunate example of the herd mentality among journalists on the subject - I've gone back and forth myself on whether Revkin was to some extent responsible for leading the herd. It was around that time I decided his "Dot Earth" blog, which largely launched my interest in climate science, was just not worth my time any more. But even the usually science-friendly George Monbiot thought what was revealed by the emails was serious. Other than the possibly illegal freedom-of-information suppression request by a flustered Phil Jones (who I'd never heard of before), it was not, as Monbiot later confessed.
The strongest lingering widespread meme raised by "Climategate" seems to be along the line of climate scientists being cliquish and "mean", saying nasty things about their critics. But all of science is like that "under the covers" - science is a relentlessly tough intellectual endeavor, and scientists don't waste their time being polite to people who they see as wrong. I work for research journals and see communications between scientists criticizing one another on their science day after day; a lot of this seems very harsh, some hardly the dispassionate image we have of the objective scientist. I looked through a random sample of such commentary recently, selecting a few relatively generic comments (i.e. leaving out the criticisms that were very specific to a particular piece of scientific work) and have posted them below - if the climategate emails seem overly harsh, well, we get just as bad day in, day out, around here!
It's hard to believe that Professor Judith Curry can spend so much time writing blog posts and not seem to have the time to make sense. I've not bothered to follow the drama in any detail, my earlier interaction with her proved rather pointless - she appeared to learn nothing from it, even repeating essentially the same provably false claims about the bare no-feedbacks response in this Scientific American profile.
Anyway, this is intended as a very brief post just to highlight some of the people who've tried to understand Dr. Curry in recent weeks, and found her claims completely without foundation, as I did in the no-feedbacks case. I strongly recommend Coby Beck's latest post getting to the essence of her conspiracy-theory mindset:
there is another plausible explanation for the formation of the IPCC, the rise in funding of climate science and the emergence of the very strong consensus that climate change is happening, human caused and going to get worse. That explanation is this: science revealed a potential problem for human society, society used its institutions to watch for and investigate this problem, honest research has found strong evidence that the problem is real and serious, and virtually all experts, using their best and sincere judgment, have advised the world that the problem is deadly serious.
No conspiracies, no alterior motives, no malfeasonce, just geeks doing science. I know it is not Hollywood material, but sometimes reality is just that dull.
Hal Lewis, emeritus physics professor at UCSB, has just published an open letter to the American Physical Society announcing his resignation, presumably as both a member and Fellow of the society. Lewis' complaint regards the way the society has treated the issue of climate change; he was the second signatory on this open letter published in Nature last year, so has certainly been known to have strong opinions on the matter.
Of course, I've written a bit here before on the genesis of the 2009 APS Council discussion and my thoughts on the "commentary" that was proposed as a way to satisfy some of the complaints.
On May 6th, 2010, climate skeptic Christopher Monckton testified before the US House Select Committee on Energy Independence and Global Warming. The hearing was supposed to be on The Foundations of Climate Science. Democrats on the committee invited 4 leading scientists from major US scientific institutions to testify; Monckton was the only witness on the Republican side. Commitee membership is listed online and includes James Sensenbrenner of Wisconsin as the ranking member on the Republican side, who presumably was responsible for selecting Monckton. It's hard to believe the Republicans were even taking the hearing seriously with that choice. Nevertheless, many climate scientists and other observers were quite disturbed by the misinformation provided as testimony by Monckton to the hearing. A comprehensive rebuttal of Monckton's claims was recently put together by leading climate scientists, with sample comments from them including "very misleading", "profoundly wrong", "simply false", "chemical nonsense", and "cannot be supported by climate physics".
Unfortunately, this is far from the first time congressional Republicans have perpetrated this sort of stunt. An example with far worse implications is the story of the "Wegman Report", supposedly an analysis of the science underlying scientist Michael Mann's early work on reconstruction of historical temperatures, the so-called "hockey stick" (to the right), which showed that temperatures now are warmer than they have been for many centuries, and getting hotter very fast. Mann's results have been repeatedly reproduced with differing methods by himself and other researchers. A 2006 review by the prestigious National Academy of Sciences determined that, according to data and methods available at that time:
- It can be said with a high level of confidence that global mean surface temperature was higher during the last few decades of the 20th century than during any comparable period during the preceding four centuries. This statement is justified by the consistency of the evidence from a wide variety of geographically diverse proxies.
- Less confidence can be placed in large-scale surface temperature reconstructions for the period from A.D. 900 to 1600. Presently available proxy evidence indicates that temperatures at many, but not all, individual locations were higher during the past 25 years than during any period of comparable length since A.D. 900. The uncertainties associated with reconstructing hemispheric mean or global mean temperatures from these data increase substantially backward in time through this period and are not yet fully quantified.
- Very little confidence can be assigned to statements concerning the hemispheric mean or global mean surface temperature prior to about A.D. 900 because of sparse data coverage and because the uncertainties associated with proxy data and the methods used to analyze and combine them are larger than during more recent time periods.
This NAS report, chaired by Gerald North of Texas A&M University, was actually requested by a congressional Republican - Sherwood Boehlert of NY, who was at the time chair of the House Science Committee. He has since retired - one of the last sensible Republicans in congress.
But other congressional Republicans were not interested in what field scientists had to say, and came up with an alternative report on the "hockey stick". Representatives Joe Barton and Ed Whitfield requested a separate report from statistician Edward Wegman, and had Wegman and colleagues testify to congress about the results. The Wegman report seemed to raise a lot of questions about the "hockey stick" and climate science in general. People who have examined the report in isolation may have been quite impressed by some of its claims - just as those lacking expertise might be impressed by Monckton's song and dance. Now, 4 years after its release, computer scientist John Mashey has done an in-depth study of the report and found a large number of indicators of shockingly low academic quality, and further indications that the report was actually tailored as part of a public relations campaign orchestrated by the usual anti-global-warming suspects (conservative and libertarian think tanks, sponsored by fossil fuel concerns).
As I noted back in December last year, way back in February 2008 when the whole world (at least of climate "skeptics") seemed to be touting a new global cooling trend, I had made some slightly educated guesses about the global average temperature through the end of that year, and for good measure for 2009, 2010, 2011 and 2012 too. My numbers were calibrated to the Goddard Institute global land and ocean temperature index as were the others on the thread - here are mine:
I'm still reading Michael Polanyi's "Personal Knowledge" - it's a deep book, with lots of interesting digressions. The latest that caught my attention was an off-hand remark he makes in his chapter on "Intellectual Passions" in the section on "The Tacit Component":
But there is, unfortunately, no rule by which to avoid the risk of occasionally disregarding [...] true evidence which conflicts (or seems to conflict) with the current teachings of science. During the eighteenth century the French Academy of Sciences stubbornly denied the evidence for the fall of meteorites, which seemed massively obvious to everybody else. Their opposition to the superstitious beliefs which a popular tradition attached to such heavenly intervention blinded them to the facts in question.
with a further footnote:
"Scientists in other countries were anxious not to be considered as backward compared with their famous colleagues in Paris", writes F. Paneth ("Science and Miracles", Durham University Journal, vol. 10 (1948-9), p. 49). "... many public museums threw away whatever they possessed of these precious meteorites; it happened in Germany, Denmark, Switzerland, Italy and Austria."
Dr. Judith Curry is chair of the School of Earth and Atmospheric Sciences at Georgia Tech, and has an extensive background in studying Earth's climate, particularly regarding changes in storms, hurricanes, and the like under changing climate conditions. She recently coauthored what seems a very interesting paper on the growth of Antarctic sea ice - apparently the effect of a moderate degree of warming such as we've seen so far is to actually increase sea ice extent in the southern ocean, thanks to increased precipitation in the form of snow. Higher sea temperatures mean more evaporation of water (mostly closer to the equator) which in turn leads to higher levels of precipitation (mostly further south), and if it's cold enough to snow, then paradoxically the result is actually more ice on the water surface, not less.
Keith Kloor is a free-lance writer who reportedly now teaches journalism at NYU; during 2008-2009 he was on some sort of fellowship in Colorado. He has been blogging for a couple of years on climate issues at Collide-A-Scape, generally on meta-level issues concerning the image of particular individuals and their claims in discussions of climate, rather than any technical science questions. Some of his stuff has been mildly interesting. His best stuff has been interviews with bloggers and scientists who have had differing stances in discussions.
[The following is in regard to models of the high temperature of the surface of Venus which ascribe that high temperature essentially to the high atmospheric pressure on that planet, without properly recognizing the role of infrared absorption by greenhouse gases. In particular, Leonard Weinstein, in previous discussions there, had essentially claimed that even if all solar radiation were absorbed by a thin high layer in Venus' atmosphere at a relatively cool temperature, the surface temperature would still be very high. The following is why I disagree.]