Archive for the ‘rise’ Category

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Salmon and Sea-Level

August 8, 2009

I recently wrote about  the alarmist claim that sea level rise in British Columbia is going to have a serious negative impact on their Salmon population.  An environmental activist playing at journalist wrote for the Victoria Times Colonist:

“The spectre of rising sea levels and ecological change from climate disruption show land-use plans for Vancouver Island and the B.C. coast will need to be revisited and recalibrated to account for rapid and unabated climate change.”

“‘Once set in motion, sea-level rise is impossible to stop. The only chance we have to limit sea-level rise to manageable levels is to reduce emissions very quickly, early in this century. Later it will be too late to do much,’ says senior NASA scientist Stefan Rahmstorf in a recent article for the United Nations Office for the Co-ordination of Humanitarian Affairs.”

There may be a lot of man made obstacles to Salmon survival, such as dams, over-fishing, etc., but sea-level rise is not one of them. 

Let’s get right down to the nitty-gritty.

Salmon have been around for about 500,000 to 1,000,000 years, give or take a few hundred thousand.  This is not a praticularly long time, nevertheless, Pacific Salmon diversified into multiple species, including Cherry Salmon, Sockeye Salmon, Chinook Salmon, Pink Salmon, Chum Salmon, and Coho Salmon.  There are also Atlantic Salmon and even land-locked Salmon.

Will the sea level  rise of the 21st century end the salmon’s success?  Not likely.  Take a look at these sea-level rise rates from Alaska, one of the Salmon’s primary habitats:

Yes, that right, the sea level is dropping at almost all locations where it is measured in Alaska.  So, it doesn’t look like sea level rise is likely to be much of a threat to the salmon in Alaska or British Columbia

But let’s pretend for a moment that the seas will rise dramatically over the next century, or longer.  Would the Salmon survive this dire situation?   If the past is any indication, the Salmon should pull through.  Take a good look at the graph of Holocene sea-level in the graph below. 

Image created by Robert A. Rohde / Global Warming Art.  Go to http://www.globalwarmingart.com/wiki/Image:Post-Glacial_Sea_Level_png

Image created by Robert A. Rohde / Global Warming Art. Go to http://www.globalwarmingart.com/wiki/Image:Post-Glacial_Sea_Level_png

Notice that from about 12,000 14,000 years ago until about 8,000 years ago the sea rose about 120 100 meters.  So, the sea level rose about 2 meters per century for 40 60 straight centuries in the recent (geologically speaking) past!  But the Salmon somehow survived.

What effect did this sea-level rise have on the Salmon’s habitat?  The movie below shows Beringia, consisting of the eastern part of Siberia and Alaska from 21,000 years ago to the present.  Look what happens from 12,000 years ago to 8,000 years ago.  I would judge that as a pretty dramatic change of the Salmon habitat.  Yet they seem to have thrived.  I think they will survive sea-level rise this century.

Barengia 21,000 years ago to present. (NOAA)

Barengia 21,000 years ago to present. (NOAA)

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Vancouver Underwater?

July 23, 2009

First Boston, now Vancouver.  According to the Times Colonist in Victoria, Canada, the folks in Vancouver and on Vancouver Island are in dire danger of sea level rise catastrophe.  They report:

“The spectre of rising sea levels and ecological change from climate disruption show land-use plans for Vancouver Island and the B.C. coast will need to be revisited and recalibrated to account for rapid and unabated climate change.”

“‘Once set in motion, sea-level rise is impossible to stop. The only chance we have to limit sea-level rise to manageable levels is to reduce emissions very quickly, early in this century. Later it will be too late to do much,’ says senior NASA scientist Stefan Rahmstorf in a recent article for the United Nations Office for the Co-ordination of Humanitarian Affairs.”

Really?  Here is 100 years worth of sea level rise data from the B.C. capital, Victoria, on Vancouver Island (Click on graphs to see full graph in its original context):

The sea level rise rate has not changed in Victoria in the last 100 years, even though CO2 levels have gone from about 290 ppm to about 380 ppm today.  Most of that CO2 increase occurred in the last 50 years.  You can see the danger that Victoria is in – I guess we better change the economy of the world in order to save them.  At the current rise rate the sea will rise 8cm (about 3 inches) in the next 100 years. 

If things are too scary in Victoria, then the folks living there might consider emigrating to the city of Vancouver, on the mainland about 50 miles north of Victoria.  They might feel better with the sea level rise rate there…

At the city of Vancouver the sea level has risen a whopping 3.7 (1.5 inches) cm in the last 100 years, and it doesn’t seem to be accelerating. 

But some of the folks in Victoria may not want to move to the mainland, preferring to stay on Vancouver Island.  If so, they could stay on the Island and move about 100 miles northwest to Tofino where they might finally feel safe from the terror of rising seas…

Alas, in Tofino the good people of Vancouver Island might have to contend with a dropping sea level.  At a rate of minus 1.59 mm per year, the ocean would drop 15.9 cm (about 6 inches) in the next 100 years. This dropping sea level might even be worse than a rising sea level, drying out estuaries and wetlands. Everybody knows the only safe sea level is a static sea level.

But seriously folks…

The rate of sea level rise varies form place to place and depends on a lot of factors.  Changes in ice inventories, currents, and geological effects, such as glacial isostatic adjustment all contribute and are worthy of study and measurement.  But they should no be used to foster panic for political ends.

Any serious discussion of the effect of sea level rise in Vancouver Island or the British Columbia sea coast would have to include  the data I have shown above.  So why isn’t this data even mentioned in the Times Colonist article?  You would think a journalist who is seeking the truth, wherever it may lead, would manage to find this data.  But it turns out that the author of the article is not a journalist, but rather Chris Genovali, the executive director of Raincoast Conservation.  Chris Genovali is probably a fine person, and Raincoast Conservation may be a fine organization – I don’t know.  But Genovali is not an objective person when it comes to the issue of sea-level rise in British Columbia or Vancouver Island.

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My experience with Rahmstorf’s non-linear trend line

July 20, 2009

One of the original impetuses for me to start blogging was my experience with Stefan Rahmstorf concerning his 2007 paper “A Semi-Empirical Approach to Projecting Future Sea-Level Rise” (Science, 315, 2007).  I posted a several part critique on my old blogspot site, which I later ported over to this wordpress site. 

But this was only part of the story.  I  have decided to tell the rest of the story after reading “The Secret of the Rahmstorf ‘Non-Linear Trend Line’” at Steve McIntyre’s Climate Audit

Rahmstorf’s sea-level rise paper was based on plotting 120 years worth of sea -level rise rates vs each year’s corresponding global temperature.  Since both of these sets of data are quite noisy, Rahmstorf said ” Both temperature and sea-level curves were smoothed by computing nonlinear trend lines with an embedding period of 15 years.”

Rahmstorf referenced “New Tools for Analyzing Time Series Relationships and Trends” by Moore, et. al. (Eos, 86, 2005) for his nonlinear trend line smoothing technique.  This short paper refers to a variety of techniques for handling time series, including varieties of wavelet analysis and spectrum analysis.  The Moore paper invested several paragraphs on the use of Monte Carlo Single Spectrum Analysis for finding nonlinear trends in sea level and sea temperature, with the reader referred to a variety of  other papers to get the details. 

I waded hip deep into these papers  to get a handle on this new “nonlinear trend line” technique that led Rahmstorf to his startling projection of a huge sea level rise over this century.  I shouldn’t have wasted my time.  I found that I could essentially reproduce his results in an Excel spreadsheet by simply smoothing the original sea-level and temperature data with a 15 year FWHM Gaussian filter. 

Here is Rahmstorf’s sea-level rise rate vs. temperature after his nonlinear trend line smoothing and 5 year binning, followed by my sea-level rise rate vs. temperature after my 15 year FWHM Gaussian smoothing and 5 year binning, and finally, my version of the data without binning.

Rahmstorf's sea level rise vs T

Moriarty's sea level rise vs T binned

Moriarty's sea level rise vs T not binned

Rahmstorf binned his 120 data points into 24 bins containing 5 points each.   The binning was not needed to  remove noise that obfuscated his salient point – the data had already been smoothed through his non-linear trend line technique.     The binning could not be justified by claiming that it somehow made the plot of sea level rise rate vs temperature easier to read.  It actually reduced the amount of information to the reader by removing obvious real structure in the data.

I believe that Rahmstorf deliberately presented his data in a way calculated to deceive.  These are harsh words, and I say them with regret.

The only plausible reason that I can come up with for binning the 120 data points into 24 bins is because the resulting 24 points looked like they could conceivably be fit to a line without failing the laugh test.  Seeing the original 120 smoothed data points made it perfectly clear that there was not a linear relationship between the sea-level rise rate  and the temperature.  The full set of 120 data points also make it clear that when the temperature remains constant the sea level rise rate drops, in direct contradiction of one of Rahmstorf’s own working assumptions.

It turned out that Rahmstorf’s startling conclusion about extreme sea-level rise had nothing to do with any new sophisticated data analysis techniques for deriving nonlinear trend lines.  I got the same results as him using a simple spreadsheet.  Rather, his startling results came from his bogus interpretation.  Specifically, here are the three problems I identified:

1) The assumption that the time required to arrive at the new equilibrium is “on the order or millennia” is not borne out by the data. More…

2) Sea level rise rate vs. temperature is displayed in a way that erroneously implies that it is well fit to a line.  More…

3) Rahmstorf extrapolates out more than five times the measured temperature domain. More…

Rahmstorf’s code and peer review

In the midst of my wandering through a mathematical labyrinth to reproduce Rahmstorf’s results, before my simple excel spreadsheet approach, I asked Rahmstorf several questions via email.  Amazingly, he offered to send me his code, to which I happily accepted.  Here is what he said when he sent it (emphasis added by me):

From: Stefan Rahmstorf [mailto:rahmstorf@xxxxxxxxxxxx.xx]
Sent: Monday, August 20, 2007 13:20
To: Moriarty, Tom
Subject: Science paper

Dear Tom, see attached. Please report any issues you encounter, you are the first outside person to test this code.

Cheers, Stefan


Stefan Rahmstorf
http://www.ozean-klima.de
www.realclimate.org

So, the punchline is that although his data and results had been published a half a year before in the journal Science,  the highly regarded, unassailable, peer reviewed pinnacle of scientific research , I was “the first outside person to test his code.”

Again, I offer this harsh criticsm with regret, because Rahmstorf was, after all, kind enough to send me his code.