Tuesday, 8 December 2009

no decline to 'hide'

The big kerfuffle over Professor Keith Briffa's remark in the stolen emails that he used a 'trick' to 'hide the decline' has set tongues wagging and 'threatens to derail Copenhagen.' I'm up at 3 am to post this because I'm so disgusted with how this is all unfolding.
Let's get a couple of things straight right at the start:
* The only place he says he 'hid' a 'decline' is in that specific graph
* The 'decline' is in a small number of tree-ring proxy indicators
* What he uses to 'hide' this is the 'real temps' - from tens of thousands of thermometers
* There is no decline to 'hide' in the 'real temps' over the past 50 years; these show a sharp increase
* The real temps are far, far more reliable data than the small number of tree ring proxies
* The proxies are indirect indicators, subject to confounding factors like wet vs. dry, recent air pollution and acid rain
* That problem with the tree rings has not been 'hidden' from the public; it is covered extensively by scientists as the 'divergence problem'
* That problem is a single, small wrinkle against an enormous, huge mass of other data showing warming, using direct measurement with thermometers at over 10,000 sites worldwide that show very clear and unprecedented warming in the last 50 years.
* When we want to look at the past 1000 years, we need to use the indirect proxy data from tree rings (and other proxies like corals, stalactites, boreholes, etc.)
* To compare these two types of data on one graph, the scientists found the best alignment in the period where they overlap (since about 1850)
* In the most recent 50 years, the tree ring series diverge from all the others, and this is the only thing that Prof. Briffa chose to 'hide' in combining the graphs.

To sum up, the 'real temps' for the past 50 years don't have any 'decline' to 'hide'; it's simply outrageous that the data thieves are free to spin a worldwide conspiracy from this one unfortunate combination of words in one email, as if 'trick' + 'hide' = 'everything in the IPCC is a fraud!'?

Now once again we're being treated to 'balance as bias' on CNN as Campbell Brown runs a week-long series 'Global Warming: Trick or Truth?' They're putting anti-science politicos from American Enterprise Institute up against top scientists as if they were comparable. Marc Morano, Stephen McIntrye and their ilk are getting national TV time for their scurrilous, slanderous insinuations that one spinnable email means we can just toss decades of research drawing on tens of thousands of data sources.

I looked on the CNN website and they allowed comments on 'Trick or Truth' but the comments are closed already. The real-time user comments that ran live at the bottom of the screen were really weak; I'll have to see if I can post something better as the show continues.

When I look at Marc Morano on national TV, all I can say is: the world is freakin' crazy. The one thing that looks hopeful right now is that the Copenhagen meetings actual sound like they have some momentum toward a deal, and that the Saudi delegation may be isolated in their oil-soaked protests that they want a total do-over of the past 20 years of climate research based on two phrases in the stolen CRU emails.


Broadlands said...

I watched it too. After an introductory comment that the evidence for global warming from mankind's greenhouse gas emissions is overwhelming Campbell Brown asked Michael Oppenheimer "What is the most persuasive piece of evidence..." He did not answer this question. It is undeniable that anthropogenic CO2 has been rising as global population rises. It seems clear (from CRU's charts) that "rapid" warming has taken place (e.g. 1910-1940, 0.5°C, ~30 ppm CO2, although it then leveled off for 40 years to around 1980 ). So, what IS the answer to Campbell's question? I cannot find it anywhere. What is most persuasive?

Unknown said...

Hi Broadlands.
Thanks for visiting and sorry I've been to tied up to respond. I agree Dr. Oppenheimer didn't have a single simple response. I don't know that I could have done better in his shoes. There are a wide range of different lines of evidence. They all tie in together to make the case. Which one should I pick out as "most persuasive?" Robins in the Arctic? The fact that 95% of glaciers are retreating? The tight correlation of CO2 and proxy temperature, up and down, over and over, throughout the 800,000 year ice core record. The ice core record is the most *striking* data source; we're incredibly lucky to have access to these, and to have had people like Lonnie Thompson work out how to draw so much data from them.
In fact, I wonder if that's really the right question? Why should we have to pick one piece of evidence out of a whole array? It's like asking which soldier won the battle - answer: all of them together.

Broadlands said...

Birds in the Arctic? Glaciers melting? None of this type of answer connects the man-made rise in CO2 with temperature. These observations infer the connection, as was done in reverse in the 70s. Dr. Oppenheimer answered: "The geographic pattern of warming over the past 150 years matches computer simulations of what the warming should have been, given the buildup of greenhouse gases." What all this really boils down to are simulations based on some numbers (now suspect?) "massaged" with terms called homogeneity adjustments and elimination of outliers, plus disputed climate sensitivity parameters, to produce the "most likely" result. Yet, about 33.5 Myr ago pCO2 was between 450 and 1500 ppmv and ice-sheets were not only present but forming. See: Nature 461, 1110-1113 (22 October 2009). Excerpts: "Geological and geochemical evidence indicates that the Antarctic ice sheet formed during the Eocene–Oligocene transition, 33.5–34.0 million years ago. During maximum ice-sheet growth pCO2 (atm) was between 450 and 1,500 p.p.m.v., with a central estimate of 760 p.p.m.v." No anthropogenic CO2 was involved. During the so-called medieval warm period "...two centuries of warm conditions had caused significant sea level rises." An extended sea level rise is a global phenomenon. It rises elsewhere, not just northern Europe, and the rise accompanies ice-cap melting. Again, no anthropogenic CO2 involved. Bottom line question: Do we really want to micromanage the Earth's climate (at great cost) based on what even the IPCC says (p. 40) is just "very likely" but which they admit is based on a few model simulations with limitations and gaps and a limited number of system analyses? Thankfully, we didn't do that back in the early 70s. "Very likely" based on computer models doesn't cut it.