Archive for the ‘climate change’ Category

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Time to recognize approaching Southern Hemisphere disaster

December 26, 2013

I warned the world before, and they ignored me, but the evidence continues to mount. The Southern Hemisphere, and maybe the entire world, is headed for a frozen doom.

All day long polar orbiting satellites fly over the Antarctic and the surrounding ocean and measure the extent of the sea ice.  The amount of ice waxes and wanes with the seasons, ranging from about 2 to 16 million square kilometers between southern summer and winter.

Thirty years of this satellite data have made it possible to calculate the average ice extent for any given day of the year.  The deviation from this average is called the “anomaly.”  It is this anomaly data that reveals the impending drastic changes in the Southern Hemisphere.

Here is the anomaly data for the last three years from the University of Illinois’ Polar Research Group…

advance rate

The anomaly is increasing by half a million extra square kilometers every year!!! To put this in perspective, the Earth has a surface area of about 500 million square kilometers. Roughly speaking, an additional 1/1000th of the Earth’s surface is covered by ice each year. Consider that the Southern Hemisphere sea ice maxes out at about 16 million square kilometers each year, then 32 years of the current increase rate would double this amount.

By 2050, a mere 36 years from now, the ice encased Tierra Del Fuego on the southern tip of South America will replace Greenland as the most ironically named place on Earth.  By 2100 the dairy farms surrounding the town of Gore in the Southern Plains of the South Island of New Zealand will be a frozen mockery to the same-named purveyor of global warming alarmism.

Here is what is in store for the Southern Hemisphere…

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You can’t deny this.  This is science!  My conclusion is based on the proven analysis techniques of NASA climate scientist Jay Zwally.

Has the 21st century brought us to a tipping point?

All the best data indicates that a tipping point has already occurred.  Think about this: according to NOAA data (see here and here) 8 out of 10 years with greatest Southern Hemisphere sea ice extent have occurred since 2000!  Here they are in order…

  1. 9/14/13
  2. 9/24/12
  3. 9/24/06
  4. 9/24/09
  5. 9/29/05
  6. 9/28/00
  7. 9/8/04
  8. 9/29/07

We also now know that the all time low temperature for the Antarctic was reached in 2010.  Satellite data shows that on August 10th, 2010, the Antarctic temperature descended to 136 ºF (minus 93 ºC).  This shattered the previous record of minus 128.6 ºF (minus 89.2 ºC), set in 1983.

That is a drop in the minimum recorded temperature of 7.4 ºF in a mere 27 years.  If that continues, as indicated by Jay Zwally type analysis, then the low temperature by 2100 could be minus 159 ºF (minus 106 ºC)!!!

The effects are already being felt

It is now the warm season in the Southern Hemisphere.  Sea ice is making its seasonal retreat, yet the Russian cruise ship, Akademik Shokalskiy, is trapped in the sea ice with “52 tourists, scientists and explorers” and a crew of 22.  You would think the combined brains of all those scientists on board would have kept them out of the zone of freezing water.  While the ship’s brochure points out that “Views are excellent from the large, open decks and the Navigation Bridge'” maybe they couldn’t see the ice coming from the vantage point of the “Lounge and bar, open late afternoon and evening with a wide selection of wines and spirits” (an essential feature of all scientific research vessels).  Our prayers go out to the scientists and others on this harrowing adventure as ice breakers race to free them the frozen grip of the sea.  I hope the sauna stays warm and the booze holds out until they get there.

Why the great silence?

Where are the voices of leading scientists and environmentalists?  Why haven’t you seen anything about this impeding hemispheric disaster on the front pages of the news papers or on prime-time news reports?  A subsequent post will soon answer those questions and break this issue wide open.  

Stay tuned…

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Michael Mann’s delusional fever

November 29, 2013
Michael Mann's fevered dream

Michael Mann’s fevered dream

Ever read the New York Times?  Wadda ya think, does it veer persistantly to the left?  Is the Pope Catholic?

Well, Michael Mann has been huffing and puffing at the Huffington Post that the New York Times has strayed from his approved dogmatism concerning global warming.  They dared to run an opinion piece by Richard Muller.

Richard Muller lives happily on the alarmist side of the road, but on occasion he lets his toes cross the dividing line, so that he can claim some credit for being open-minded.

In a recent op-ed he must have touched one of Mann’s extremely frayed nerves when he said…

“I worried that the famous “hockey stick” graph plotted by three American climatologists in the late 1990s portrayed the global warming curve with too much certainty and inappropriate simplicity.”

Ouch.  This was simply Muller’s demure way of stating the obvious. Of course, the main “American climatologist” who made this graph of “inappropriate simplicity” is none other than Michael Mann.  Muller’s soft punch of a statement seems to have left a big bruise on Mann’s sensitive ego.

Mann thinks The New York Times never should have let Muller engage in this attack on his crowning achievement.  But then the Times went even further and let the apostate spread even more heresy in a second op-ed about tornadoes.  Muller wrote

Despite the recent spate of deadly twisters, including those that tore through the Midwest over the weekend, the scientific evidence shows that strong to violent tornadoes have actually been decreasing for the past 58 years, and it is possible that the explanation lies with global warming…

I am not talking about global warming per se, which I am convinced is real and caused by man-made emissions of greenhouse gases. But not everything attributed to global warming has a scientific basis…

So let’s consider only the most violent tornadoes, the ones in categories EF3 to EF5…

NOAA… shows that the number of these storms has been significantly decreasing over the past 58 years, from over 50 per year in the first half to under 40 per year in the second. The statistical significance of this decrease is extremely high: well above 99 percent confidence.

How dare Muller display such an attitude!

Mann is especially incensed that Muller quoted from an earlier HuffPost article which said…

Michael Mann, a climatologist who directs the Earth System Science Center at Pennsylvania State University, agreed that it’s too early to tell.  “If one factor is likely to be favorable and the other is a wild card, it’s still more likely that the product of the two factors will be favorable,” said Mann. “Thus, if you’re a betting person — or the insurance or reinsurance industry, for that matter — you’d probably go with a prediction of greater frequency and intensity of tornadoes as a result of human-caused climate change.”

But Muller wrote

Michael E. Mann, a prominent climatologist, was only slightly more cautious. He said, “If you’re a betting person — or the insurance or reinsurance industry, for that matter — you’d probably go with a prediction of greater frequency and intensity of tornadoes as a result of human-caused climate change.”

Mann called this innocent contraction “sleight of hand.”  Touchy, touchy.

Mann uses his mighty reasoning powers to discern a conspiracy.  You can’t be too careful when even your friends are out to get you.  He warns us that this is ultimately the work of the Koch brothers, just like every other vile conspiracy against the goodness and light of global warming alarmism and the left in general.  (It used to be Dick Cheney and Halliburton, but I guess they must have passed the world control levers over to the Koch brothers.)  You see, Richard Muller now controls the New York Times, and the Koch brothers control Richard Muller.

Mann wraps his tin foil a little tighter and lectures…

The New York Times does a disservice to its readers when it buys into the contrived narrative of the “honest broker”–Muller as the self-styled white knight who must ride in to rescue scientific truth from a corrupt and misguided community of scientists. Especially when that white knight is in fact sitting atop a Trojan Horse–a vehicle for the delivery of disinformation, denial, and systematic downplaying of what might very well be the greatest threat we have yet faced as a civilization, the threat of human-caused climate change.

Shame on you New York Times. You owe us better than this.

You can get the full temperature of Mann’s paranoid delusional fever at his Huffington Post’s article, Something Is Rotten at the New York Times.

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James Delingpole, please correct this mistake

November 23, 2013

The only thing that bugs me more than when climate alarmists get things wrong is when skeptics get it wrong.

A case in point is the assertion by James Delingpole that a recent volcano in Iceland put more CO2 into the atmosphere that all of human activity since 1950.

Delingpole is a vocal supporter of the skeptic community, and the fact the he has a widely viewed blog , writes for several publications and authored several books, all give his words wide dissemination.  The problem is that when a fence-sitter who is trying to make up his mind about the global warming issue realizes that somebody like Delingpole is asserting and defending an indefensible claim, well, that fence-sitter is likely to fall off the fence to the side of the alarmists.  This will happen even if Delingpole is correct on other points.  Fence-sitters don’t necessarily have the time or inclination to sort out and weigh all the arguments, and something like this can easily tip their judgement scales one way or the other.

Delingpole appeared as a guest on the Mike Rosen Show on Denver’s AM station KOA.  This is a 50,000 Watt station and tens of thousands of people probably heard this exchange.  Rosen is a pretty smart guy and usually nobody’s fool, but he let this bogus assertion slide by…

Audio version: Rosen/Delingpole 11/20/13 MP3

Rosen: 713-8585 our telephone number in Castle Rock. Cliff, you’re on 850 KOA. James Delingpole our guest. Hi Cliff.

Cliff: Mike and James, good morning.

Rosen: Morning

Delingpole: Hi Cliff.

Cliff: Hey, I finally think I have somebody who can actually answer this question.

Rosen: Alright.

Cliff: Ah, you know we’ve got, the greenies are all against cars and the exhaust, and you know, all this pollution that we put in the air. Ah, whats the equivalency of a volcano that’s erupting and spewing stuff into the air thirty miles high.

Delingpole: That’s a good question. You remember that volcano that erupted in Iceland a couple of years ago?

Cliff: Yep, that’s the one that made me start thinking about it

Delingpole: Yeah, I think that, I think that that – that volcano produced more CO2 than I think humans have produced in the last, in the last fifty years.

Cliff: Watta we gonna do about that? (…unintelligible…)

Delingpole: We should ban volcanoes.

You  can hear the entire interview (Wednesday, 10AM, 11/20/13) on KOA’s podcast

What are the facts?

The facts are well know, easily accessible, and have been presented to Delingpole before now.  Here it is summed up by the USGS…

Do the Earth’s volcanoes emit more CO2 than human activities? Research findings indicate that the answer to this frequently asked question is a clear and unequivocal, “No.” Human activities, responsible for a projected 35 billion metric tons (gigatons) of CO2 emissions in 2010 (Friedlingstein et al., 2010), release an amount of CO2 that dwarfs the annual CO2 emissions of all the world’s degassing subaerial and submarine volcanoes (Gerlach, 2011).

The published estimates of the global CO2 emission rate for all degassing subaerial (on land) and submarine volcanoes lie in a range from 0.13 gigaton to 0.44 gigaton per year (Gerlach, 1991; Varekamp et al., 1992; Allard, 1992; Sano and Williams, 1996; Marty and Tolstikhin, 1998). The preferred global estimates of the authors of these studies range from about 0.15 to 0.26 gigaton per year. The 35-gigaton projected anthropogenic CO2 emission for 2010 is about 80 to 270 times larger than the respective maximum and minimum annual global volcanic CO2 emission estimates. It is 135 times larger than the highest preferred global volcanic CO2 estimate of 0.26 gigaton per year (Marty and Tolstikhin, 1998). 

It is an embarrassment to me, as a skeptic, that the alarmist site “Skeptical Science” gets it right while Delingpole, a well know mouthpiece for skepticism, gets it wildly wrong.  This meme has been around for years and was long ago thoroughly debunked.  

I would forgive an acquaintance at a coffee shop or around the water cooler for making this mistake.  Then I would gently try to set him straight with the facts  But if you are going to put yourself forth as some kind of expert, then you need to get your facts straight.  This type of mistake may win converts to your side in the short run, but when people realize how wrong you have were, then they will not believe you even when you are right.  Worse yet, they will also be less inclined to believe other skeptics when they are right.

So, James, please fess up on this issue.  Admitting this mistake will only improve your credibility in the long run.

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By the way, this reminds me of another misinformed claim:that underwater volcanoes in the Gakkel ridge were causing reduced sea ice in the Arctic.

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The Search for Acceleration, part 9, the Baltic Sea

October 23, 2013

magnifying glass 145This is part 9 of a series of posts in which I am searching for a large acceleration in sea level rise rate in the latter part of the 20th century.  Such a rise rate acceleration is needed  to reconcile the 1.8 mm per year average rise rate for the century attributed to tide gauge data and the approximately 3 mm per year rise rate for the tail end of the century attributed to the satellite data.

The Baltic Sea

There are 22 tide gauge stations in the Baltic Sea area that are at least 90% data complete from 1960 to 2005.  Eighteen of those are 90% complete all the way back to 1930 and ten are 90% complete back to 1900.  The weighting (using a 200 km threshold) is nearly constant for the entire 20th century (see weighting graph below).  I will use the usual technique of detrending, weighting, averaging and derivatives, as shown in the following slide show.  (Note that you can pause or increment the slide show forward or backward by using the buttons that appear when your cursor is placed over the image.)

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Conclusion

The following graph makes clear that the Baltic Sea tide gauge data DOES reconcile the sea level rise rate from the tide gauge data with the higher late century rise rate from the satellite data.

Baltic Sea Detrended Acceleration annotated 2
On the other hand, the tide gauge sea level rise rate immediately before the era of satellite data is higher than rise rate after….

Baltic Sea Detrended Acceleration annotated 3

See an index of the Search for Acceleration series here.

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Sources

20th century rise rate average of 1.8 mm/year

1. Church and White Global Mean Sea Level Reconstruction

2. Links to Church and White sea level data

Satellite data (about 3 mm/year): CU Sea Level Research Group

RLR tide gauge data: Permanent Service For Mean Sea Level

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Rahmstorf (2011): Robust or Just Busted (Part 6): Holgate’s sea level data

November 11, 2012

This is part 6 of a multi-part series about “Testing the robustness of semi-empirical sea level projections,” Rahmstorf, et. al., Climate Dynamics, 2011. You can see an index of all parts here. I frequently refer to this paper as R2011.

Recall figure 1 from R2011[1]…

Figure 1 from "Testing the robustness of semi-empirical sea level projections" (Rahmstorf, et. al., Climate Dynamics, 2011)

One of the primary points of this graphic is the quadratic fit of one data set (CW06) overlaid on all the other data sets.  The message that you are to receive is that these various sets of sea level data all tell the same essential story.  The falseness of this claim was discussed in “Quadratic fits of laughter.”

But let’s take Rahmstorf at his word.  Let’s agree with him that these sea level data sets all tell essentially the same story.  R2011’s big point is that the Rahmstorf model is “robust” given a variety of different historical data sources.  So it seems a tad bit strange that after going to all the trouble to point out these various sea level data sources and their similarities, he only gives the projection results of his model for three of them (CW06[2], CW11[3], and JE08[4]).

Of those three input sea level data sets, only two of them give similar sea level projections for the 21st century.  The outlier which results from CW11 shows significantly lower sea level projections.  Because of this, the outlier must be rejected (according to R2011), even though Church and White, the authors of both CW06 and CW11, clearly think the CW11 data is an improvement over their Cw06 data.

What about some of the other sea level rise data sets shown in R2011’s figure 1?  What type of 21st century sea level projections do they yield when inserted into Rahmstorf’s model?

Holgate’s sea level data

Let’s consider the sea level rise data of Simon Holgate.    The above image shows Holgate’s 2004 data[5], labeled HW04.  As I have previously pointed out, R2011 oddly includes Holgate’s 2004 data but ignores his 2007 data[6], H07.  I will consider both.  In my previous post I showed the results of Rahmstorf’s model when either CW06 and CW11 are input with six different combinations of reservoir storage and ground water depletion inputs.  The following two graphs show the results in the same format using HW04 and H07 (instead of CWo6 and CW11) with the same combination of reservoir storage and ground water depletion inputs.  I have kept the horizontal axis scaling the same as in the previous post to highlight the different results when Church and White data is used and when Holgate data is used.  Data files with all the specifics of this data are at the bottom of the post.

FIGURE 2. Sea level rise projections for the 21st century based on my implementation of Rahmstorf’s model under the RCP45 emissions scenario (Moss, 2010)[7] for Holgate sea level data coupled with various combinations of reservoir storage and groundwater depletion data inputs.
FIGURE 3. Sea level rise projections for the 21st century based on my implementation of Rahmstorf’s model under the RCP85 emissions scenario (Moss, 2010)[7] for Holgate sea level data coupled with various combinations of reservoir storage and groundwater depletion data inputs.

For comparison, here are the previously posted results using Church and White sea level data…

 RCP45

 RCP85

Hmmm…

Didn’t R2011 imply that those various sea level data sets shown if figure 1, above, told the same essential story?  Yes, I believe he did!  That is why they overlaid the same quadratic fit onto all of them.

And didn’t R2011 say that their model was “robust?”  Yes, I am quite certain that they did!  In fact the word “robust” was in the title of their paper, and they said…

“We determine the parameters of the semiempirical link between global temperature and global sea level in a wide variety of ways…We then compare projections of all these different model versions (over 30) for a moderate global warming scenario for the period 2000–2100. We find the projections are robust

and

“we will systematically explore how robust semi-empirical sea level projections are with respect  to the choice of data sets”

So, they claim to use “a wide variety of ways” to look at “all these different model versions (over 30).”  They show plots of seven different sea level data sets and imply their similarity.  But they only show projections based on three of them.  Then they reject the projections based on one of the three, even though it is arguably the best sea level data of the bunch.

What do they say about their model’s projections based on the “wide variety” other sea level data sets that look so good overlaid with the same quadratic fit…?

Cricket. Cricket.

How would R2011 reject the projections based on the Holgate data?

How would R2011 reject the projections based on the Holgate data that I have shown above in figures 2 and 3?  Well they would undoubtedly point out that the fit parameter, To (the so called baseline temperature, is way too low.  Recall, R2011 finds To to be on the order of -0.4 °C (below the 1950 to 1980 global average).  When Holgate’s sea level data is used, To is on the order of -4.0 °C.  Hey Rahmstorf, don’t blame me, its your model!

Maybe one of these days I will write a justification for a large negative To.  It is really quite simple.  But I am going to conclude for today.

Which of the many projections do I endorse?

Which projections are better – the ones based on CW06, CW11, JE08, HW04, or H07?  None of them.  As I have pointed out over and over, the Rahmstorf model is bogus, bogus, bogus.  I have now shown, again, that it is also not robust.  It is only marginally better than a random number generator.  HIgher temperatures would likely lead to higher sea levels, but Rahmstorf’s model is useless in determining how much.

Data files with specifics of of my implementation of Rahmstorf’s model using Holgate sea level data

Sea level data: Holgate and Woodworth 2004
Reservoir storage: Chao 2oo8
Ground water depletion: none
Result files…
Summary: vr-summary-121110-165152.doc
Inputs: vr-input-image-121110-165152.png
Fit: vr-fit-image-121110-165152.png
Projections: vr-projections-image-121110-165152.png

Sea level data: Holgate and Woodworth 2004
Reservoir storage: Chao 2oo8
Ground water depletion: Wada 2010 extrapolated to 1880
Result files…
Summary: vr-summary-121029-132349.doc
Inputs: vr-input-image-121029-132349.png
Fit: vr-fit-image-121029-132349.png
Projections: vr-projections-image-121029-132349.png

Sea level data: Holgate and Woodworth 2004
Reservoir storage: Chao 2oo8
Ground water depletion: Wada 2010
Result files…
Summary: vr-summary-121029-132148.doc
Inputs: vr-input-image-121029-132148.png
Fit: vr-fit-image-121029-132148.png
Projections: vr-projections-image-121029-132148.png

Sea level data: Holgate and Woodworth 2004
Reservoir storage: Chao 2oo8
Ground water depletion: Wada 2012
Result files…
Summary: vr-summary-121105-230616.doc
Inputs: vr-input-image-121105-230616.png
Fit: vr-fit-image-121105-230616.png
Projections: vr-projections-image-121105-230616.png

Sea level data: Holgate and Woodworth 2004
Reservoir storage: Pokhrel 2012 extrapolated back to 1900
Ground water depletion: Pokhrel 2012 extrapolated back to 1900
Result files…
Summary: vr-summary-121029-133403.doc
Inputs: vr-input-image-121029-133403.png
Fit: vr-fit-image-121029-133403.png
Projections: vr-projections-image-121029-133403.png

Sea level data: Holgate and Woodworth 2004
Reservoir storage: Pokhrel 2012
Ground water depletion: Pokhrel 2012
Result files…
Summary: vr-summary-121029-132906.doc
Inputs: vr-input-image-121029-132906.png
Fit: vr-fit-image-121029-132906.png
Projections: vr-projections-image-121029-132906.png

Sea level data: Holgate 2007
Reservoir storage: Chao 2008
Ground water depletion: none
Result files…
Summary: vr-summary-121029-133753.doc
Inputs: vr-input-image-121029-133753.png
Fit: vr-fit-image-121029-133753.png
Projections: vr-projections-image-121029-133753.png

Sea level data: Holgate 2007
Reservoir storage: Chao 2008
Ground water depletion: Wada 2010 extrapolated to 1880
Result files…
Summary: vr-summary-121029-135519.doc
Inputs: vr-input-image-121029-135519.png
Fit: vr-fit-image-121029-135519.png
Projections: vr-projections-image-121029-135519.png

Sea level data: Holgate 2007
Reservoir storage: Chao 2008
Ground water depletion: Wada 2010
Result files…
Summary: vr-summary-121029-134334.doc
Inputs: vr-input-image-121029-134334.png
Fit: vr-fit-image-1209121029-134334.png
Projections: vr-projections-image-121029-134334.png

Sea level data: Holgate 2007
Reservoir storage: Chao 2008
Ground water depletion: Wada 2012
Result files…
Summary: vr-summary-121029-135834.doc
Inputs: vr-input-image-121029-135834.png
Fit: vr-fit-image-121029-135834.png
Projections: vr-projections-image-121029-135834.png

Sea level data: Holgate 2007
Reservoir storage: Pokhrel 2012 extrapolated to 1900
Ground water depletion: Pokhrel 2012 extrapolated to 1900
Result files…
Summary: vr-summary-121029-175833.doc
Inputs: vr-input-image-121029-175833.png
Fit: vr-fit-image-121029-175833.png
Projections: vr-projections-image-121029-175833.png

Sea level data: Holgate 2007
Reservoir storage: Pokhrel 2012
Ground water depletion: Pokhrel 2012
Result files…
Summary: vr-summary-121029-140159.doc
Inputs: vr-input-image-121029-140159.png
Fit: vr-fit-image-121029-140159.png
Projections: vr-projections-image-121029-140159.png

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[1]  Rahmstorf, S., et. al., “Testing the robustness of semi-empirical sea level projections” Climate Dynamics, 2011

[2] Church, J. A., and N. J. White, “A 20th century acceleration in global sea-level rise“,  Geophys. Res. Lett., 33, 2006

[3] Church, J. A. and N.J. White, “Sea-level rise from the late 19th to  the early 21st Century“, Surveys in Geophysics, 2011

[4] Jevrejeva, S., et. al. “Recent global sea level acceleration started over 200 years ago? ,”  Geophys. Res. Lett., 35, 2008

[5] Holgate, S. J. and Woodworth, P.L., “Evidence for enhanced coastal sea level rise during the 1990s,” Geophys. Res. Lett., 31, 2004

[6] Holgate, S.J., “On the decadal rates of sea level change during the twentieth century,” Geophys. Res. Lett., 34, 2007

[7] Moss, et. al., “The next generation of scenarios for climate change research and assessment,” Nature, 463, 2010

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Library of data for testing “robustness” of Rahmstorf models

September 5, 2012

This is part 3.5 of a multi-part series about “Testing the robustness of semi-empirical sea level projections,” Rahmstorf, et. al., Climate Dynamics, 2011. You can see an index of all parts here. I frequently refer to this paper as R2011.

I have finally published my small library of temperature, sea-level and sea-level modifier (reservoir storage, groundwater depletion, etc.)  data from various sources.

All of these data files have a consistent format which can be read by my code that calculates fit parameters for the Rahmstorf model relating sea level to temperature.  However, not all of the time series are long enough to be useful in that model.

You can see the data files here.

I am open to suggestions for additions to this list.  If you have any criticisms of the files, such as accuracy of the data, format, selection, anything – please leave a comment.  I will give due attention to any legitimate criticism that is aimed at improving the data.

Coming soon…

I am a slow worker, but I try to be thorough.

The first output from my code, using Rahmstorf’s preferred inputs (GISS temperature, Church and White 2006 sea level data, and the Chao reservoir correction) will be presented soon.  The goal of that presentation will be two-fold: to verify that of my model implementation are consistent with Rahmstorfs; to have a simple format for presenting those result.  That format can then be applied to the results of other input data.

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Rahmstorf (2011): Robust or Just Busted (Part 2) – Quadratic Fits of Laughter

July 6, 2012

This is part 2 of a multi-part series about “Testing the robustness of semi-empirical sea level projections,” Rahmstorf, et. al., Climate Dynamics, 2011. You can see an index of all parts here. I frequently refer to this paper as R2011.

I will refer to Stefan Rahmstorf’s “Testing the robustness of semi-empirical sea level projections”  as R2011 [1].

This post is all about fitting sea level data to a quadratic.

There is only one reason to fit sea level vs. time data to a quadratic: to highlight an acceleration trend.  It only makes sense to do so if you think that the trend is more or less uniform over time.  I have warned against reading too much into a quadratic fit, and especially against using a quadratic fit to imply a future trend in sea level.

I have seen something in R2011 that I have never seen before.  The use of a quadratic fit as a kind of “optical delusion.”

Consider the image at the right.  Do you see the triangle?  Sure you do.  Of course, it is not really there.  But what would you say if I insisted that the triangle really was there and said “The circles are shown merely to help the eye find the triangle?”

R2011 has done much the same thing with a quadratic data fit in their figure 1.   I would think what they have done was just a joke, if it weren’t such an obvious attempt to convince readers that the data says something that it does not say.  Take a look…

Figure 1 from "Testing the robustness of semi-empirical sea level projections" (Rahmstorf, et. al., Climate Dynamics, 2011)

Note the dashed grey lines through each data set.  As R2011 explains in their caption, these dashed  grey lines which pass through all the data sets, are actually the quadratic fit to just one of the data sets (CW06)[2].  They say

“The dashed grey line is a quadratic fit to the CW06 data, shown here merely to help the eye in the comparison of the data sets.”

The point the R2011 wants to make, of course, is that all of these data sets have the same acceleration trend as R2011’s preferred sea level data, CW06.

But that is not true.  In fact, if you fit any of the other data sets to a quadratic you will see that every single one of them has a lower trend than CW06 when projected through the 21st century. Every single one of them.

The following figure shows proper quadratic fits to all the sea level data sets used by R2011 in their figure 1.  The legend shows the sea level rise that would result for the period 2000 to 2100 if these quadratics were extrapolated to 2100.

Quadratic fits for all sea level data sets used by R2011 in their figure 1. The legend shows the sea level rise that would result for the period 2000 to 2100 if these quadratics were extrapolated to 2100
Quadratic fits for all sea level data sets used by R2011 in their figure 1. The legend shows the sea level rise that would result for the period 2000 to 2100 if these quadratics were extrapolated to 2100

Updated Holgate data

Science is about constant refinement of theories and data.  When Rahmstorf is faced with old data and new data from the same authors, he has a special method for deciding which data set is better.  The version that points to higher sea level rise in the 21st century is always considered to be better.  Thus his insistence that the 2006 Chuch and White sea level data is  better than the 2009 or 2011 Church and White data that incorporated Church’s and White’s data reduction improvements.

The same is true for Holgate’s sea level data.  Look at HW04 [3] plots in the above graphs.  This Holgate sea level data covers the mid-1950s to the mid-1990s.  It is a curious thing (not really curious if you understand Rahmstorf’s modus operandi) that R2011 chose this data over Holgate’s updated data from 2007 [4], which covers the entire 20th century.  What would happen if we replaced the HW04 data with the 2007 Holgate data (H07)?  Take a look…

Holgate data from 2004 has been replaces with Holgates updated data from 2007.
Holgate data from 2004 has been replaces with Holgates updated data from 2007.

Let me stress again, I do not recommend extrapolating sea level data with quadratic fit, and I am not endorsing any of the extrapolations shown above.  I am simply guffawing at Rahmstorf’s chuzpa in his figure 1.

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1.  Rahmstorf, S., Perrette, M., and Vermeer, M., “Testing the robustness of semi-empirical sea level projections” Climate Dynamics, 2011

2. Church, J. A.,, and White,  N. J., “A 20th century acceleration in global sea-level rise,” Geophysical Research Letters, 33, 2006

3. Holgate, S. J., Woodworth, P.L., “Evidence for enhanced coastal sea level rise during the 1990s,” Geophysical Research Letters, 31, 2004

4. Holgate S., “On the decadal rates of sea level change during the twentieth century,” Geophysical Research Letters, 34, 2007
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