Robert Brown's comment
Quote:Robert Brown says:
March 4, 2012 at 6:09 pm
And yes, that’s true. But who does? I’m not hearing. What’s the number?
Here’s what GISS says:
“For the global mean, the most trusted models produce a value of roughly 14°C, i.e. 57.2°F, but it may easily be anywhere between 56 and 58°F and regionally, let alone locally, the situation is even worse.”
Well, that’s a number. But it doesn’t sound like a claim of 0.05K accuracy.
OK, so I’ll address this one thing again, even though it was part of a really detailed reply with lots of stuff that got turned into randomness by Ifni a big earlier.
Look at the first graph.
Look at the right hand side of the first graph.
Look at the error bar (in green) at the right hand side of the first graph.
Note its magnitude — 0.05 K.
Now look at the first graph again.
Look at the left hand side of the first graph.
Look around 1885, where there is another green error bar.
Note its magnitude — 0.1 K.
Note the website. These are the public graphs for GISS for global average temperature, and this is just such a graph, is it not? If I were John Q. Public I might never read through all of the details of just how this graph were computed — I would just look at it, look at those teensy error bars, and go “Gosh damn, CAGW is real. Look, the world has warmed 0.6K in just thirty year! We’ll all bake to death by 2100, especially if this rate of increase gets even bigger because of all of the enormous feedbacks they tell me are completely true, proven, settled science!”
Consider: In 1885, perhaps a dozen people with a scientific education had actually landed on the entire continent of Antarctica. The Pacific Ocean was mostly Aqua Incognita, visited occasionally by whalers, with a handful of missionaries and plantation owners on a few of its islands. Siberia, China, Mongolia, Tibet were nearly devoid of thermometers, certainly compared to today. The Amazon and much of central Africa was dense jungle, and Burton was still being lionized for having actually having made it to the headwaters of the Nile. Australia and the Western US were still largely a frontier. Many of the ships that plied the waters of the world still did so under sail. Thermometers of the era were generally no more accurate than 1 K, and were sampled enormously erratically compared to 1985. Yet the precision acknowledged in the temperature estimate for 1885 is only twice that for 1985!
Pardon me, it takes me a minute or two to stop laughing. I mean seriously, do they take us all for idiots?
So when you assert that 0.05 is not indeed the precision that GISS claims for its contemporary global average temperatures, that turns out not to be the case. It is indeed the precision they so claim. 0.1 is the precision implied on the Wikipedia page for the Earth, which lists its temperature as 287.2 K — we do try to teach our students not to put that decimal down unless you mean it, but of course nobody listens. GISS claims a precision of 0.1 for its global average temperature estimates from 130 year ago! It also claims, by virtue of putting these temperature estimates on a single curve, that these are apples to apples numbers, that the numbers derived from 1880 data mean exactly the same thing as those derived from 2012 data, that the temperatures in question aren’t just precise in a defensible way given certain presumptions about the data but that they are accurate in similar ways across that entire range.
Excuse me, I have to wipe my eyes again. Oh, my aching sides.
What amazes me is that no one actually calls them on this. In my opinion without having the slightest regard for their methodology their error estimates for 1885 are absurd. I don’t care, in other words, how the number is derived. The precision claimed fails the mere test of common sense — it isn’t true unless an entire textbook worth of assumptions are all true, none of them directly verifiable, all of them begging the question concerning the very phenomenon that is being tested against the numbers.
As I said — and it appears that we might even agree — the correct ballpark for the accuracy of GISS would be 0.5-1 K for its contemporary numbers, and I’d personally guestimate at least 2-3 times that for number out of the nineteenth century, wouldn’t you? As for precision — if there isn’t at least an order of magnitude worse precision for global temperature estimates from the nineteenth century, there is something seriously wrong, quite independent of what you think the sources of the errors might be at the two ends of the scale.
After all, in contemporary weather measurement, we use high precision, precisely calibrated thermometers that typically record temperature with a very high temporal granularity throughout the day and night, in carefully selected locations that still demonstrably suck as Anthony himself and many others have faithfully documented. In the 1880′s the instruments in common use were one to two orders of magnitude less precise, were even more indifferently located, and we have no idea how most of them were sampled by the bored civil servants that took and recorded their temperatures.
I was not attacking GISS per se, mind you, only pointing out that its claimed precision is, in my opinion, absurd on the face of it, independent of methodology. Nor is its accuracy defensible. Nor is its generality across the range of temperatures at hand, not really. Missing Antarctica? We don’t even do that well with Antarctica today, not really.
An honest presentation of errors in GISS would make its error bars far, far larger for the far end of its curves, don’t you think, if you just apply a bit of common sense?
No, now I’ll attack GISS , and indicate why satellite data is so important. Consider the UAH lower troposphere temperature. It is known, both accurately and precisely, apples to apples, from roughly 1979 to the present. It shows almost no statistically significant increase in temperature over that entire period. The temperature anomaly in 1980 was around -0.1 K. The temperature anomaly last month was around -0.1K. Sure, that cherrypicks end points and a linear fit is probably closer to 0.3 K, but the R value of that fit — (without computing it, and assuming point errors on the order of the variance in the data) is going to suck, because the linear trend isn’t very strong compared to no trend at all, noting that the current anomaly on a 31 year average is negative.
That last fact says it all, compared to a purported ~0.6 K increase in GISS, supposedly precise to 0.05 K.
Now if I had to bet on one of the two producing the correct relative anomaly, which one would I choose? In other words, if I imagine that there is such a thing as a global average temperature — in and of itself a bit dubious — and that the changes in GISS or UAH temperatures are an accurate measure of the changes in the global average temperature, we have this pesky factor of two to deal with. That’s a pretty serious thing. It’s the difference between Catastrophe and “Ho, hum.” 0.2 K/decade is in no way comparable to 0.1 K/decade, maybe, if not a lot less.
Personally, I think there is little doubt that the UAH satellite derived lower troposphere temperature is the more reliable number and the more accurate measure of the global mean temperature. For one thing, it is unbiased by things like the UHI effect and sparse sampling that make the GISS result questionable at best anyway! For another, there simply aren’t as many adjustments one can make for things like instrumentation, and one has a variety of controls (e.g. soundings) that are similarly uncorrupted by UHI effects in ground-level air. Simple pictures are the best — there are too many opportunities in GISS to bias the result intentionally or otherwise.
I suspect that this is one of the reasons that the climate science community is “suddenly” becoming a lot more open to the possibility that CAGW is just plain wrong. GISS and UAH LTT are diverging, and of the two GISS is almost certainly the one that is wrong. Wrong by a rather lot. Which makes one look at the graphs a bit more critically, note (perhaps for the first time) how tiny the error is that they are claiming for nineteenth century global average temperatures and say “bullshit“.
This is clearly wrong. If this is clearly wrong, is the entire curve wrong? What’s going on, here?
For some, this comes as a bit of a revelation. They feel betrayed. How could they have ever been so stupid as to believe that we know the global average temperature in 1885 to 0.1 K on the same basis that we now know it to 0.05K? How could they actually be fooled into thinking that we know the global average temperature at all within a half degree now, let alone to within a few hundredths of a degree? They get quite angry and do things like publicly repudiate the IPCC and AR5, because they can’t get anyone to put the right (or at least reasonable) damn error estimates into the data that the public gets to see, lest the public look at them and go “We’re spending a trillion dollars because that is what passes for ‘settled science’ proving Catastrophic Anthropogenic Global Warming?”
It’s enough to make the peasants reach for their torches and their pitchforks, isn’t it?
Once they pick themselves up off the floor and stop laughing.
Not that there is anything terribly amusing about tens of billions of dollars (racing towards hundreds) swindled out of the public by doing the moral equivalent of yelling “fire” in a theater, where the Earth is one big damn theater with no way out.
It is our attitude toward free thought and free expression that will determine our fate. There must be no limit on the range of temperate discussion, no limits on thought. No subject must be taboo. No censor must preside at our assemblies.
–William O. Douglas, U.S. Supreme Court Justice, 1952