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Wednesday, June 6, 2012

North Carolina Scientists Cull the Chaff from the Data, Keep the Chaff and Find that the Sea Levels Rise......


What if North Carolina scientists produced a scientific study that winnowed 12,000 years of data down to roughly 35 years of data within  eight charts, then proceeded winnow those eight charts of data down to one? And what if the data retained in each of the cullings was the most extreme? Would you say that they kept the chaff and threw out the grain?

Would the result be an abuse of science?

Since the last Ice Age or glaciation sea levels have been rising and  for planning and development reasons the state of North Carolina needs to know the likelihood and magnitude of sea level change as it applies to the North Carolina coast.  To that end a report on the magnitude of sea level change  along the North Carolina coast was prepared in 2010 by the N.C. Coastal Resources Commission’s Science Panel on Coastal Hazards.

Here is that North Carolina Sea-Level Rise Assessment Report.

Colbert recently did an entertaining, if uneducated, report referencing the findings of the N.C. Coastal Resources Commission’s Science Panel on Coastal Hazards:

Let's take a closer look at the report that predicts a 39" rise in sea level over the next 100 years along the coast of North Carolina.

Fortunately the report's 19 contributors belies its brevity, a brief  eight pages including charts, thus very little patience is required for the following background.

The objective according to the report:

The intent of this report is to provide North Carolina’s planners and policy makers with a scientific assessment of the amount of SLR likely to occur in this century.

The report references but does not use all the  data from four studies covering different periods of time:

  • 12000 years ago to the present - Horton et al. (2009) which found that the (RSL)  relative sea level rose roughly 19"/century from 12000 years ago to 3500 years ago then dropped to 4"/century from 3500 years ago until today.
  • 2000 years ago to the present - Kemp (2009 thesis) which found that  (RSL) relative sea level rise was 4"/century except during the Medieval Warm Period during which the sea level rose at a rate of 6.7"/century  and except for the 20th century during which time the relative sea level rose at 12.6"/century.
  • 500 years ago to the present - Kemp et al. (2009) which found a 20th century rise in (RSL) relative sea level  of 13"/century.
  • 35-75 years ago to the present - Zervas (2004) which found a variety of rates of change in MSL ranging from 8"/century to 16.8"/century through data charts 

As can be seen above the Science Panel had at its disposal 12000 years of data.  The first culling of that data occured when the Science Panel chose the Zarvas (2004) data while excluding the other data sets.  According to the Science Panel:

The Science Panel has chosen to use the tide gauge data for projections because the tide gauge data represent a more direct indicator of sea level. 

That choice allowed the Science Panel to effectively ignore 11,965 years of the 12,000 years of data or 99.7% of their data and focus on the most extreme rates of change in sea level.  Also note that the choice to focus exclusively on tide gauge data resulted in measuring MSL rather than relative sea level (RSL). Or stated another way, the data the Science Panel chose represents changes in sea level without regard to geographical or  geological changes that may have resulted in the appearance of a changing sea level.   MSL as defined by the Science Panel "is simply a measure of the increase in the volume of water in the oceans, expressed as a change in the height of the oceans."  

Below is the data that remains after the Science Panel completed its first culling of their data:

Note that the rate of sea level  change  in some locations along the North Carolina coast is much greater than in other areas.  That may seem odd but  such variation could be explained local geology and by geological processes if not for the fact that such processes were not taken into account in this data.   

The second culling of the data occurred when the Science Panel chose to ignore 7 of 8 tide table charts or nearly 90% of the data that remained from the first culling.  One would think the Science Panel may have chosen the median, Beaufort or Atlantic Beach, for example. Or, perhaps, one would have thought that if the Science Panel were truly interested in producing a chart from which the whole of  the North Carolina coast may derive utility it would have taken an average of all the available tide table data.  But, no.  The Science Panel chose the fringe readings within the tide gauge charts produced by the Duck NC tide gauge.  

So, to recap.  The Science Panel first reduced their data by 99.7% .  Then of the .3% of data that remained  another 90% was simply ignored.  Not only did the Science Panel dispense with most of their data, but in each culling event the most extreme data was retained from which to project the amount of sea level rise (SLR) that was likely to occur during the next 100 years off the coast of North Carolina.

Below are the results from the above abuse of science and data  -- what is laughably called a "minimum trend line" (in green) derived from the most extreme data that the Science Panel had available and  from which the same panel could project  a  rate of sea level rise of 39"/century via highly questionable IPCC modeling.  

It is no wonder the NC legislature may consider a bill to guard NC from such fantasy science being produced by the state itself. It's a waste and a distraction.


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