The modern Argo sea temperature data was "matched" (no supporting details available - see this) with the 1870's data.
“The significance of the study is not only that we see a temperature difference that indicates warming on a global scale, but that the magnitude of the temperature change since the 1870s is twice that observed over the past 50 years,” said Roemmich, co-chairman of the International Argo Steering Team. “This implies that the time scale for the warming of the ocean is not just the last 50 years but at least the last 100 years.”
Not surprisingly there has been a steady increase in temperature since the 1870's (details here).
I suppose well before man started destroying the planet with CO2.
More than likely, though, it all may be meaningless for a number of interesting reasons...
First of all the set of data from the 1870's is just that - one set of data. Probably not as precise (for example, the measurements where taken with the Challenger moving so the thermometers were dragging behind the boat at an angle rather than at a precise depth) as you would find today (see this).
So no one knows how accurate the thermometers were back then... Interesting.
I would have imagined that with all the "historical climate research" I hear about (like the Challenger data) someone would have gone to the trouble of doing some serious research into the historical accuracy of temperature measurement.
Yet magically we can extrapolate significant results from this?
Another interesting point in reading all this is that as the ocean heats up it expands.
This means that the ocean level rises - without a single glacier melting - because a warmer ocean occupies more volume (and a colder ocean less).
So how is it possible to sort out how much of the ocean is rising from "melting glaciers" versus simple expansion due to basic physics. We learned this in third grade. The nuns had a small tub that they put on a stove. We took a flask, a stopper and a tube and set it up so that water partially filled the flask and was present in the glass tube (extending from above the stopper down into the water in the flask.
We tied a string around the position of the water in the tube. Then we heated the tub. The water in the flask expanded and it rose in the tube (we tied a red thread around the tube to indicate this). We then cooled the tub by putting ice into it and the water level on the tube dropped (we tied a blue thread there).
Apparently they no longer teach third grade physics so no one knows what's going on nor do they account for it in these kinds of things.
Then we have the satellite data and quantum noise. I wrote about this a while back.
All of which conflict with the ocean temperature data and the conclusions drawn previously.
More than I ever I have to say that none of this seems like real science anymore.
All kinds of money, effort and time put into something which is really not knowable in the first place because its not a closed system - meaning that there are other influences in play which we cannot know, measure or account for (for example, what impact do solar flares have on global climate...?)
In college in the 1970's one of the things I learned was that there was a difference about studying something objectively and subjectively. Subjective study meant that you were just "conjuring up" something without concrete objective data to back it up.
It was easy, at least for me, to be fooled by this sort of thing.
I remember writing a paper and the TA saying "this isn't research" because what I wrote about I acquired from some book (Peter Tomkin's "The Secret of the Great Pyraminds" I think). The book had a lot of mumbo jumbo about pyramids - but nothing to back it up. Certainly the book was interesting to a 16-year-old mind but it wasn't science.
Over the years I have learned that while lots of things "seem cool" that does not mean they are facts or evidence of anything.
(One thing the "pyramid" nonsense of the time claimed was that you could place a dull razor blade (remember those?) inside a pyramid and it would resharpen... I was unable to reproduce this "scientific aspect" of the Pyramid book - which ultimately led me down the road of doubt.)
And further, that the harder you look at something the less you know - almost to the point where you see that simply matching data to equations (as does physics) tells you nothing about why something is so.
Yet it is easy to confuse the equations with the why. And even if we think we know the why at a small scale, say as in the search for the Higgs boson, we again see that knowledge at one scale (quantum reality) does not work at a larger scale (macro reality).
If science were really the "answer" to everything this sort of thing would not be a problem.
Of course, adding "soft science" to all this just makes the objectivity even less clear.
Maybe the Great Pyramids are just yesteryear's idea of "Global Warming."