Uh, Oh! Karl, et. al., is bad news for Stefan Rahmstorf’s sea level rise rate.

Conclusion first

When the 20th century GISS temperature is modified according to Tom Karl, et.al., it causes the 21st century sea level predictions of Vermeer’s and Rahmstorf’s semi-empirical model to go down!

Details

I have written extensively about “Global sea level linked to global temperature,” by Vermeer and Rahmstorf (which I will refer to as VR2009).

VR2009 was a widely cited claim of using historical 20th century sea level and temperature data to calculate parameters that could be used to build a model to predict 21st century sea level rise for various 21st century temperature scenarios.  I reproduced the VR2009 model based on their description.  My code was verified by reproducing the VR2009 results using the same inputs that they used.

I spent a lot of time pointing out some of the bizarre results of their model that surely disqualified it form being taken seriously, some of which can be seen here, here, and here.

I also spent a lot of time pointing out that the VR2009 choices of 20th century sea level data sources left much to be desired.  For example, they used the 2006 Church and White sea level data that was already outdated.  If they had used the revised Church and White data, then their resulting sea level rise predictions for the 21st century would have been much lower.

They happily modified Church’s and White’s outdated sea level data by subtracting a reservoir correction (Chao, et. al.), which made their 21st century predictions for sea level rise go up. But they made no attempt to estimate a groundwater depletion correction. It turns out, unsurprisingly, that the groundwater depletion is of the same magnitude as the reservoir correction (Wada, et. al.), and including it would have made their 21st century predictions go down.

Nevertheless, Rahmstorf would later claim that his modeling approach was “robust!”  That is, it would give essentially the same result for the 21st century given different sources of 20th century sea level data.

So, I also implemented the VR2009 technique using several different sources of sea level data, which should have given similar results, according to Rahmstorf’s claim of robustness.  In fact, they gave widely varying results, and every combination of sea level data, reservoir data, and groundwater depletion data that I tried gave lower results than VR2009’s chosen combination.

New Temperature Data!

The widely reported nearly two decade long pause in global warming was causing suicidal ideation among hard-core global warming alarmists.  Something had to be done to stop them from slitting their wrists with shards of glass from their shattered thermometers.

Just in the nick of time – revised temperature data!   Like all proper revisions of temperature data, this revision caused the reported temperature change of the 20th century to go up.

This was a result of a paper by Tom Karl, et. al. (Nature) based on very thin reasoning (see for example) that argued for such revision.  The folks at GISS (who provided VR2009’s temperature data) glommed onto Karl’s logic and subsequently revised their temperature data accordingly.  Other temperature data source like UAH and RSS did not.

Which means we must ask ourselves, what happens to 21st century sea level rise predictions based on the VR2009 model using the now modified GISS data?

VR2009 applied their model to six families of temperature scenarios for the 21st century form the IPCC’s 4th Assessment Report.  Let’s see what happens to each of those scenarios when we update the 20th century GISS temperature data.

The IPCC temperature scenarios that VR2009 used for prediction of 21st century sea level rise.

Case 1.

Sea level inputs are identical to what VR2009 used: Church’s and White’s sea level with the Chao reservoir correction.  The old GISS temperature data is replaced with the new GISS temperature data.  The table below shows that the new GISS data yields 21st century sea level rises that are about 17% less than when the old GISS data is used.

It is a shame that after Tom Karl went to all the trouble to increase the temperature rise of the 20th century it just makes VR2009’s model predict LOWER sea levels for the 21st century.  This must be a great disappointment to Vermeer and Rahmstorf, so you can be pretty sure they will never tell you this result. But I just did.

Case 2

As I pointed out previously, VR2009 chose to use outdated 2006 Church and White sea level data, instead of Church’s 2009 data.  They also neglected a groundwater depletion correction.  When these improvements are included the VR2009 model yields 21st century sea level rises that are only about 55% of VR2009.  When the new GISS temperature data is included in the mix this drops to about 45%.

Case 3.

Lest Vermeer or Rahmstorf argue that their large sea level rise rates are saved by another update of the Church and White data in 2011, I have include these results also.  The difference between 2009 and 2011 Church and White sea level data was small.  Here is how the 2011 Church and White sea level data version plays out in the VR2009 model. The resulting 21st century sea level rise predictions are only about 43% of the VR2009 predictions.

The trend continues.

It seems that no matter what combination of inputs that are used in the VR2009 model, the predicted sea level rise for the 21st century is always smaller than with VR2009’s choice of inputs.  I wonder what that implies?

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Barack Obama: Glaciologist

The avid outdoors-man and eminent scientist, Barack Obama, has been trekking through Alaska lately.  He is lamenting the demise of the great glaciers of the North.  He is surely grieving over the harm that man is inflicting on the planet by spewing his toxic CO2.  The Washington Post reports…

Standing near the foot of the Exit Glacier, which has receded 1.25 miles since 1815 and 187 feet last year alone, Obama said “this is as good of a signpost of what we’re dealing with it comes to climate change as just about anything.”

The man certainly has a way with words – a true poet.

I guess we are supposed to be alarmed because 187 feet per year is a lot faster than 1.25 miles per 200 years.  After all, 1.25 miles in 200 years averages out to only 33 feet per year.  The message we are supposed to get is that the Exit Glacier is receding about 6 times faster now than its average over the last 200 years.  This, of course, is due to the CO2 that vile humans use to poison the atmosphere and it means endless and escalating disaster unless we socialize the economy of the world.

But what does the National Park service say about the retreat rate of Exit Glacier? The following table of retreat distances and rates comes from the National Park Service’s “The Retreat of Exit Glacier.” Annotation in red was added by me.

So, this data confirms Obama’s assertion that the Exit Glacier has retreated 1.25 miles in the last 200 years.  But it also makes it quite clear that it was retreating as fast, or faster, 100 years ago.

If CO2 is the culprit today, what was the culprit 100 years ago?  The following graph shows the amount of anthropogenic CO2 in the atmosphere as a function of time going back to 1750.  The data comes from Oak Ridge National Laboratory.  I made the plot and added the annotation. It’s kind of hard to explain why the retreat rate was so much greater in the past when there was less than 10% of the anthropogenic atmospheric CO2 than there is today.  Perhaps Professor Obama will elucidate.

My wife and I were up in Alaska a few years ago, and we also visited some some of those receding glaciers.  At Glacier Bay National Park, which is several hundred miles southeast of Exit Glacier, I happened to pick up a park pamphlet that had the following series of illustrations showing the glacier extents in the park going back to 1680.

The first thing that jumps out at you is the rapid ice advance between 1680 and 1750 and the subsequent retreat between 1750 and 1880.  The pamphlet said

“The Little Ice Age came and went quickly by geologic measures.  By 1750 the glacier reached its maximum, jutting into Icy Strait.  But when Capt. George Vancouver sailed here 45 years later, the glacier had melted back five miles into Glacier Bay – which it had gouged out.”

As an aside, a co-worker once told me that the Little Ice Age was not a global phenomenon, but rather, local to Europe.  He cited the Union of Concerned Scientists as the source of this insight.  But there it is, in Alaska!

It is hard to argue with the Union of Concerned Scientists because they’re, well, scientists.  Not just anybody can be a Concerned Scientist.  You have to send a check first.  My wife used to send a check years ago, but it was from our joint account so I figure I was only half a Concerned Scientist then.  Now I guess I am just a wholly unconcerned scientist.

Anyway, Obama was getting excited about 1.25 miles of glacier recession since 1815, and a whopping 187 feet in the last year.  That pamphlet that I mentioned also had a large map of the Glacier Bay area marking the location of the various glaciers back to 1760. It’s easy to string the locations together and calculate the recession rate of these glaciers.  The image at the left  shows the map as I marked it out for Grand Pacific Glacier. (Click to enlarge.)

I have plotted the distance as a function of time for three glacier routes using this crude method.   As you can see below, these glaciers have receded at a much faster rate than Exit Glacier.  But Exit Glacier and the Glacier Bay National Park glaciers have one thing common:  they all retreated at their maximum rate back when anthropogenic atmospheric CO2 levels were very low compared to today.

Let’s take a closer look at the Grand Pacific Glacier.  John J. Clague and S. G. Evans (J. of Glaciology)  used various data sources to plot the retreat of the Grand Pacific Glacier.  I have converted their data to miles and overlaid it with my coarser data from the map. The Clague data and the map data agree nicely, but the Clague data fills in some of the gaps.  The most interesting point is that like Exit Glacier, the retreat rate for the Grand Pacific Glacier was greatest around the last part of the 19th century. In fact, the Clague data may indicate that the Grand Pacific Glacier was slightly progressing, not retreating, during most of the 20th century.

It is pretty clear that the Grand Pacific Glacier was retreating fastest around 1860.  Where is that on the anthropogenic atmospheric CO2 timeline?  The graph below shows that the anthropogenic atmospheric CO2 level was only about 2% of today’s level when the Grand Pacific Glacier was retreating at its fastest by far!

How is that possible???????  I thought it was high CO2 levels that caused the glaciers to recede.

Definition: Barber Event

A monumental climatic event is unfolding before our eyes this year.  The ramifications will affect entire human race, nay, the entire community of Gaia dwelling souls.

 David Barber, 21st Century Arctic Explorer, has been warning us for years, but too many of us have been blinded by our greed for oil and money.  The Arctic will go completely ice free this summer.  This will no doubt force polar bears into extinction and set off a globe spreading chain reaction of extinction and desolation.

This extraordinary occasion deserves its own geological name.  I propose we call it the “Barber Event.”

Here is what will happen to Arctic sea ice…

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