Vinkeljernet

Diverse — Drokles on March 13, 2013 at 7:46 pm

Der er en ny graf i byen. Det er en graf der skal overbevise befolkningen om det snarlige klimakollaps. Og alle er glade for den

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Fra National Journal

Back in 1999 Penn State climate scientist Michael Mann released the climate change movement’s most potent symbol: The “hockey stick,” a line graph of global temperature over the last 1,500 years that shows an unmistakable, massive uptick in the twentieth century when humans began to dump large amounts of greenhouse gases into the atmosphere. It’s among the most compelling bits of proof out there that human beings are behind global warming, and as such has become a target on Mann’s back for climate denialists looking to draw a bead on scientists.

Now it’s gotten a makeover: A study published in Science reconstructs global temperatures further back than ever before — a full 11,300 years. The new analysis finds that the only problem with Mann’s hockey stick was that its handle was about 9,000 years too short.

To be clear, the study finds that temperatures in about a fifth of this historical period were higher than they are today. But the key, said lead author Shaun Marcott of Oregon State University, is that temperatures are shooting through the roof faster than we’ve ever seen.

Shaun Marcott fra Oregon State University - der betragter skeptikere som en “fully-mobilized troll army” (takker) - blev derefter overhalet indenom af Joe Romm, der var hurtig til at sexe grafen lidt op til, hvad man vel kan kalde vinkeljernsgrafen

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Marcott uddyber

Today’s study should help debunk the common climate change denial argument that recent warming is simply part of a long-term natural trend. Indeed, Marcott says, the earth should be nearing the bottom of a several-thousand year cool-off (the end-point of the rainbow arc in (B) above), if natural factors like solar variability were the sole driving factors. Instead, temperatures are rising rapidly.

At denne graf vækker opsigt er naturligt, men at den tages for gode varer er - eller burde være - mere besynderligt for den strider imod det fineste i denne post videnskabelige tid, nemlig det gængse konsensus. Men fordi den strider imod gængs konsensus ved at overdrive de allerede overdrevne fremtidsscenarier tages den for gode varer.

Professor Phil Jones, der producerer temperaturkurver for FN, fortalte i 2009 i et interview med BBC at der været tre varmeperioder på 20-30 års varighed adskildt af mindre fald i temperaturen på ca. 30 år. Og kun den sidste er skabt af menneskets udledning af CO2 (hvilket man jo aldrig ville have gættet af at se på tallene alene)

A - Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?

An initial point to make is that in the responses to these questions I’ve assumed that when you talk about the global temperature record, you mean the record that combines the estimates from land regions with those from the marine regions of the world. CRU produces the land component, with the Met Office Hadley Centre producing the marine component.

Temperature data for the period 1860-1880 are more uncertain, because of sparser coverage, than for later periods in the 20th Century. The 1860-1880 period is also only 21 years in length. As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different (see numbers below).

I have also included the trend over the period 1975 to 2009, which has a very similar trend to the period 1975-1998.

So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other.

Here are the trends and significances for each period:

skc3a6rmbillede-2013-03-12-kl-194526

Jones fortalte også at opvarmningen ‘holdt en pause’

B - Do you agree that from 1995 to the present there has been no statistically-significant global warming

Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.

Intet drama andet end hvad teorien fortæller uanfægtet af virkeligheden. Judith Curry er da heller ikke imponeret og det nye vinkeljern af en graf.

There doesn’t seem to be anything really new here in terms of our understanding of the Holocene.  Mike’s Nature trick seems to be now a standard practice in paleo reconstructions.  I personally don’t see how this analysis says anything convincing about climate variability on the time scale of a century.

Rud Istvan skriver for Judith Curry

While the MWP did not completely disappear in this new paper, it turned into a <0.1°C blip colder than 1961- 1990. This is quite curious. The MWP was not a blip for the entire northern hemisphere, as illustrated by this figure adapted from a 2010 paper by Ljungvist.

Evaluate a 300-year MWP using methods lacking 300 year resolution and voila! The MWP turns into a blip diminished by the colder periods on each side.

Ljungqvist 2010

A reference list compiled by CO2Science shows that there are at least 96 proxy studies of Europe, North America, South America, Asia, and Aus/NZ with quantitative estimates of MWP temperatures, plus 109 more with qualitative estimates, and an additional 116 providing evidence that it was a significant, centuries long event that came and went fairly suddenly.

How has the MWP almost disappeared again, just in time to perhaps go missing in IPCC AR5? Science’ supplemental information says the average resolution of the 73 paleoclimate series is 160 years, and the median is 120. The proxy selection was deliberately weighted toward ‘low frequency’ resolution, since the entire Holocene was being assessed. Figure S18c  (below) shows there is no statistically valid resolution to the combined proxy set for anything less than 300-year periods.  [“Gain” was defined as the ratio of output variance to input white noise in simulations ‘stressing’ combined proxy statistical reliability. In other words, for periods less than three hundred years, white noise in is white noise out (no matter whether the Monte Carlo sampling interval is 20 or 120 years) while for periods over 2000 years the output is about 90% ‘valid’ signal.] The paper itself said, “…our temperature stack does not fully resolve variability at periods shorter than 2000 years…”

Marcott resolution S18(c)

Evaluate a 300-year MWP using methods lacking 300 year resolution and voila! The MWP turns into a blip diminished by the colder periods on each side.

Suyts Space’s Hank spørger “why are alarmists so excited?”

Remember “Mike’s Nature Trick?” Marcott has a trick of his own. Take a look at this:

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The above was excerpted from Marcott’s study. Note that he’s calling attention to the break in the Y-axis at 25. You can see it as a white vertical line in the lower left legend. Notice also that Marcott is attributing the break to the Mann et al. dataset.

This new 73 proxy study has alarmists convinced that this is an independent verification and vindication of Mann’s hockey stick. It isn’t. The hockey stick blade at the end of the reconstruction is resulting from an adjustment of the proxy data to agree with Mann’s treemometer study. That, or it is an outright splice of Mann’s data directly.

Don Easterbrook aner også uråd.

Eighty percent of the source data sites were marine, so temperatures from 80% of the data set used in this paper record ocean water temperatures, not atmospheric temperatures. Thus, they may reflect temperature changes from ocean upwelling, changes in ocean currents, or any one of a number of ocean variations not related to atmospheric climates. This in itself means that the Marcott et al. temperatures are not a reliable measure of changing atmospheric climate.

The paper consists entirely of complicated computer manipulations of data (definitely not light reading for anyone but computer modelers) and conclusions. As Andy Revkin (Dot Earth) points out, This work is complicated, involving lots of statistical methods in extrapolating from scattered sites to a global picture, which means that there’s abundant uncertainty.”

Without any original data to assess, how can we evaluate the validity of the conclusions? The only way is to check the conclusions against well-established data from other sources. As Richard Feynman eloquently described the scientific method, once hypotheses (conclusions) are set out, their consequences can be checked against experiments or observations. If a hypothesis (conclusion) disagrees with observations or experiments, it is wrong. It doesn’t make any difference how beautiful the hypothesis (conclusion) is, how smart the author is, or what the author’s name is, if it disagrees with data, experiments, or observations, it is wrong. Period. So let us apply this method to the conclusions of this paper and test them to see if they are right or wrong.

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Det esoteriske anstrøg ved klimakonsortiet behager heller ikke en anden af videnskabens veteraner, Dr. Fred Singer i American Thinker

The original hockey stick, first published in 1998, explained carefully that the modern instrumental (thermometer) record had been grafted onto a centuries-long proxy (non-thermometer) record; the OSU paper neglects to inform the reader about this important fact.

As a reviewer of IPCC reports, I well remember efforts to hide the mixing of proxy and thermometer data: IPCC’s 3rd Assessment report (2001) showed the proxy temperature record with a black line and the 20th century temperatures with a blue line.  I complained that these were very hard to distinguish — especially in a black-and-white Xerox copy.  Since then, the IPCC and everyone else have used a distinctive red color for the instrumental data.  That kind of distinction, however, is missing in the present OSU-Harvard paper.

To use a current analogy: it’s like putting horsemeat into Swedish meatballs that advertise beef.  In the case of the meatballs, the DNA evidence betrayed the addition of horsemeat.  Here it is the fact that one sees sharp temperature changes at the end of the record — despite the authors’ statement that they have used a 100-year smoothing of the raw data.  With long smoothing times like a century, one cannot expect to see temperature spikes that may only be a decade long.

So what did they really do?  I suspect that the paper is a rehash of Marcott’s doctor’s thesis.  He too is a newly minted PhD (in 2011), lucky enough to get Hockeystick #2 not only published, but internationally promoted — It’s all based on analyses of 73 samples of deep-ocean sediments, corals, shells, etc.  Nothing really new here: In 1996 Lloyd Keigwin (of the Woods Hole Oceanographic Institution) published such an analysis in Science.  He found that it was warmer 1000 years ago (during the Medieval Warm Period) - and much warmer 3000 years ago and earlier.

Christopher Booker morer sig i Telegraph over en anden graf, som gør op med de dramatiske temperaturkurver, som vi ellers bombarderes med.

These have the effect of greatly exaggerating those changes, by narrowly focusing just on what are called temperature “anomalies”, showing how they have risen and fallen round their average level in the past 30-odd years.

What the graphs do not show is the actual level of global temperature, as it is measured above freezing point. In other words, they leave out by far the greater part of the total picture. So the respected Canadian environmental writer, Lawrence Solomon, recently had the bright idea of publishing in his Financial Post newspaper column a graph showing the temperature changes of the past 15 years in proper perspective, using figures from the most prestigious of all official temperature records, compiled by the UK Met Office and its Hadley Centre.

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Ved at vise de seneste 15 års globale temperaturudvikling i forhold til frysepunktet giver han et billede af, hvorledes vi som mennsker, sammen med dyr og planter oplever den globale opvarmning, nemlig at den oplever vi ikke.

2 Kommentarer »

  1. Mince je comptais justement rédiger un poste similaire à
    celui-ci

    Comment by gode chaude — May 14, 2014 @ 12:06 pm
  2. Post vraiment attrayant !

    Comment by sodomisatrice — June 10, 2014 @ 12:56 pm

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