Fact Checking the Third Assessment Report from the CA Climate Change Center, Part II
08/11/2012 Leave a comment
In part II of this fact checking and analysis let’s take a look the section titled Coasts: Faster Rising Seas, which implies that sea levels are rising faster than they have historically. Really! In the introduction paragraph they authors state:
Coastal counties in California are home to about 32 million people, generating billions in revenues from industry, shipping, tourism and other economic activities that support millions of jobs. Every California coastal community will experience the impacts of sea-level rise in the decades ahead, and some are already feeling the effects.
Then in the next paragraph:
Sea level along California’s coastline has risen about seven inches in the last century. This rate is expected to accelerate considerably in the future. Assuming that sea-level changes along the California coast continue to track global trends, sea level along the state’s coastline in 2050 could be 10-18 inches higher than in 2000, and 31-55 inches higher by the end of this century. This represents a four- to eightfold increase in the rate of sea-level rise over that observed in the last century. [Note color emphasis added]
All of this is accompanied by this graphic:
Let’s examine each one of the above statements high lighted in color (blue and red) and this graphic. The graphic appears to show a historical rising sea levels, and does not reflect reality. Below is a NOAA chart of sea level change in the San Francisco Bay. An eyeball analysis indicates sea levels in the Bay are declining.
Now to the high lighted text in blue: Sea level along California’s coastline has risen about seven inches in the last century. This rate is expected to accelerate considerably in the future.
According to NOAA the sea level rise over the past century was 7.92 inches, almost eight inches. However, it is not accelerating as shown in this NOAA chart.
A.A. Boretti recently published a paper in Coastal Engineering and found the rate of sea level rise has greatly decelerated over the past 10 years, which “is clearly the opposite of what is being predicted by the models,” and that “the [sea level rise] reduction is even more pronounced during the last 5 years.”
Here is a graphic representation:
The Boretti Paper, Short term comparison of climate model predictions and satellite altimeter measurements of sea levels, can be found HERE.
Boretti (2012) begins his work by noting that in its report of 2007, the IPCC projected that global sea level was likely to rise somewhere between 18 and 59 cm by 2100; but he says that certain “model-based analyses performed recently have predicted much higher sea level rise [SLR] for the twenty-first century,” even “exceeding 100 cm if greenhouse gas emissions continue to escalate,” citing most pointedly in this regard the studies of Rahmstorf (2007, 2010). However, he notes that studies reaching just the opposite conclusion have also been published, referencing those of Holgate (2007), Wunsch et al. (2007), Wenzel and Schroter (2010) and Houston and Dean (2011).
Working with what he calls “the best source of global sea level data,” which he identifies as the TOPEX and Jason series of satellite radar altimeter data, Boretti applies simple statistics to the two decades of information they contain to “better understand if the SLR is accelerating, stable or decelerating.” So what did he find?
The Australian scientist reports that the average rate of SLR over the almost 20-year period of satellite radar altimeter observations is 3.1640 mm/year, which if held steady over a century would yield a mean global SLR of 31.64 cm, which is just a little above the low-end projection of the IPCC for the year 2100. However, he also finds that the rate of SLR is reducing over the measurement period at a rate of -0.11637 mm/year2, and that this deceleration is also “reducing” at a rate of -0.078792 mm/year3.
Now back to our analysis, The Third Assessment Report report states “Assuming that sea-level changes along the California coast continue to track global trends.”
The trend is not acceleration, in fact the records show deceleration, even in San Francisco Bay.
In summary, sea levels started declining about 2006, outside of the model projections. In the past five years sea level rise has decelerated. The assumptions in the report are wrong and are inconsistent with the facts. As a result California policy makers will be making decisions based on flawed information. They will be preparing for a very low probability event, building sea walls, relocating critical resources all at a huge cost to the tax payers. At the current rate, by 2100 sea levels might only rise about 1 foot, not the scary 31-55 inches outlined in the report.
Why do we let these people get away with this distortion of the facts? Where are our elected leaders demanding answers?