Guest Post by Willis Eschenbach
A recent post by Anthony Watts highlighted a curious fact. This is that records of some two and a half million oceanic pH samples existed, but weren’t used in testimony before Congress about ocean pH. The post was accompanied by a graph which purported to show a historical variation in ocean pH.
I was unimpressed by the graph in that post, which seemed simplistic and, well, in a word, wrong. But on the other hand, I certainly found it bizarre and most interesting that someone would throw out that huge amount of scientific data. That was the reason I forwarded it to Anthony, in the hope of unraveling the actual truth of the matter.
So … as is my wont, I’ve now taken a look at the data myself, albeit at the moment a very preliminary look. The data was conveniently provided by a WUWT commenter in .csv format here, my compliments to him for the collation. He also has a good explanation of the process, along with R code. Note that there has been no quality control on the data. About 2% of the surface pH values are well outside the range of oceanic pH, and I removed them before looking further at the data.
Now, the first question I asked was, where were the samples taken? The problem with the graph in the recent post linked to above is that it lumps together samples taken in various parts of the planet. And unless the sampling is uniform in time and space, this is a Very Bad Idea™.
So I made a map that shows where each surface sample was taken. For simplicity, and because this was my first cut, I restricted myself to those samples with a depth of 0 (right at the surface), which are a bit less than a tenth of the total samples. Here are two different views of the same location data.
Figures 1a and 1b. Two views of the location of the surface samples of the global pH dataset, centered on the Pacific and the Atlantic. In some regions you can see the tracks of the oceanographic expedition vessels quite clearly.
Now, I must confess that this was a surprise to me. I hadn’t expected the concentration of samples around Japan, it appears the Japanese oceanographers mush have been quite busy. And I also hadn’t expected the high sample density in the Baltic Sea and the other enclosed seas (the Black Sea between Turkey and Russia, and the Caspian Sea to its right).
Finally, here are the average pH values by gridcell, for the entire period of record
Now, you can see from these maps that we cannot simply put all of that data into a single box and extract a timeline from it.
So … was there “pHraud” in not utilizing this data? I say no, there was no fraud. I say this in part because it’s so difficult to infer intent. Because I have been falsely accused of having bad intent a number of times, I’m sensitive on the subject. I dislike accusations without evidence, and I see no evidence of fraud in this case.
However, it is a huge scientific resource, two million plus pH samples taken by oceanographers over decades, and not using it without some solid scientific reason for ignoring it just doesn’t work for me. What I suspect has happened is that the mass and complexity of the data was too overwhelming, and so the investigators simply put it into the “Too Hard” pile. But that’s just speculation, the real reason may be entirely different. Regardless of the reason, I do think that the authors should have explained their omission.
In any case, that’s the story so far. It certainly appears to me that there is plenty of data there for meaningful time series extractions in some areas. There are, for example, about 400 1°x1° gridcells that have more than a hundred observations per gridcell, and groups of nearby gridcell cells combined have much more data. The North Atlantic and the oceanic area off of Japan seem like they would have more than adequate data for time series extraction.
I may or may not do any followup on this dataset, but I invite readers to use the data for their own analyses.
Regards to all,
ADDENDUM: As usual, I request that if you disagree with someone, please have the courtesy to QUOTE THEIR EXACT WORDS THAT YOU DISAGREE WITH, so that we can all understand the exact nature of your objections.