Guest Post by Willis Eschenbach
Over at Climate Audit, Steve McIntyre is doing his usual superb job deconstructing bad science. In this case he is discussing the recent publication of the long-delayed “Pages2K” two-thousand-year multi-proxy study of ocean temperatures. The paper is called, “Robust global ocean cooling trend for the pre-industrial Common Era,” Helen McGregor, Michael Evans, et al., and it was published August 17, 2015 in the journal Nature Geoscience.
Steve has provided the R code for reconstructing their bizarre method of binning the data in 200-year bins, and then converting the values from degrees C to standard deviations. After going through all of that strange process to get their results, the second author opined in their press release:
Today, the Earth is warming about 20 times faster than it cooled during the past 1,800 years,” said Michael Evans, second author of the study and an associate professor in the University of Maryland’s Department of Geology and Earth System Science Interdisciplinary Center (ESSIC). “This study truly highlights the profound effects we are having on our climate today.”
And here is their money graph, the one that is supposed to show those results.
Figure 1. From the Pages2K study, showing their binned ocean temperature results in units of standard deviations.
It shows the data in 200-year bins, centered in the middle of each bin, so the first bin is from 0-200 AD and the last bin is from 1800-2000 AD. I saw that graph and I said “Huh?” The change from 1700 to 1900 is not anywhere near 20 times as steep as the drop from the start of the study to the present, as Michael Evans claims. That is simply not true.
However, his statement is clear evidence that they are desperately looking to find a “hockeystick” shape, and are trying any method to find a way to present their results so that they appear to support their alarmist claims.
In any case, I thought I’d take a bit of a different tack from that of the authors, and show their results by ocean, in the original units of degrees C. We won’t be needing any math at all, as I prefer to start my investigations by just using the Mark I Eyeball. Before we can begin to discuss how we might average or combine these records, we need to first see just exactly what each individual record looks like. Let me start by showing the Indian Ocean:
Warming 20 times faster than it cooled? According to the proxies, the Indian Ocean didn’t cool much if at all, and it didn’t warm much if at all. Those findings certainly do not agree with the author’s claims.
Next, here’s the Southern Ocean, the waters that encircle Antarctica.
This graph to me perfectly exemplifies the problem with their method of averaging proxies to discern past temperatures. You can see that two proxies start out within a half-degree of each other at 14.5°C-15°C … and one cools steadily for the entire record, while the other doesn’t cool at all. Obviously, both are unlikely to be correct … but which one (if either) is correct?
Then we have the bizarre trace down near Antarctica where the water is cold … it says that the temperatures warmed by about 7°C from the year zero to the year 900 … and then cooled down by 7°C from there to 1900 or so. Unlikely.
Does anyone really believe that if we just average these proxy records in some form that we will actually have an accurate measure of the temperature variation in the Southern Ocean? Because for me, that’s all “garbage in”, and no matter how you might standardize it or anomalize it or average it, you’ll still get “garbage out” for your purported Southern Ocean temperature.
In any case, moving on, we have the Mediterranean …
This is getting ridiculous. In their unending quest to claim recent anthropogenic warming, they’ve included a short segment that shows strong warming from 1700 to almost 2000 … but the rest of the Med disagrees. One proxy goes level, one has a slight rise since about 1700, and one falls pretty steadily from 400 to 2000. Again, garbage in …
We have two proxies from the Arctic Ocean, viz:
Hilarious. One shows recent warming, and one shows recent cooling, both starting about 1700. People take this seriously? Go figure.
The Pacific is next.
I cannot object in strong enough terms to professionals passing this nonsense off as science. They’ve included several short segments that show the Pacific warming very rapidly, along with another short segment showing it warming and then cooling, and a final short segment that shows it not changing at all since the year 1300… how can anyone mistake this foolishness for actual scientific findings?
I do love the purple line at the bottom, though, showing the Pacific Ocean warming by about two degrees from the year 0 to the year 1380 … righty-o ….
And to round out the madness, here’re the Atlantic proxies …
These include a proxy that claims, in all seriousness, that an area of the Atlantic which had a temperature of 15°C in both the year 0 and the year 1800 had fallen by a whacking 5°C, and was down to 10°C, by 1920 … I’m sorry, but that’s simply not credible. Had it happened, we would have seen it in the observational record.
And strangely, almost all of the cooler Atlantic proxies (less than 22°C) show steady cooling from beginning to end … who knows why.
I’m sorry, but their study is just scientific onanism. There is no way that we can combine these 57 proxies, regardless of what technique we might use, and come out with a meaningful value for global ocean temperature changes.
But that’s just what they claim that they’ve done. They’re claiming that it’s simple, all they have to do take those crazy results from those six oceans, standardize them, take a weighted average based on the area of the ocean in question, and presto, they come up with the global ocean temperature history for the last 2,000 years …
I say that’s dumb as a bag of ball bearings.
Finally, I defy anyone to show me an anthropogenic effect anywhere in these results. Most of the proxies that cover the period 1900-2000 show cooling temperatures, not warming temperatures as the authors claim.
Steve McIntyre continues to parse the study, and I’m sure will have further interesting results. I can’t recommend his site highly enough.
My best wishes to everyone, we now return you to my regularly scheduled holiday … at this moment the railroad train is coming by our tent, and the whistle is loud enough to make your eyes water.
PS—Is there valuable information in these 57 proxies? I would say yes, very likely so … but they will never find it using those methods. Instead, each proxy needs to be considered on its own merits, and whatever value it might have needs to be considered and determined without reference to the others.
AS USUAL: If you disagree with someone, please have the courtesy to quote the exact words you object to. That way, we can all understand both who and what you are replying to.
DATA AND CODE: Available at Steve McIntyre’s site, linked to above.