Sometimes, you just have to laugh at the sheer desperation of claims being made. Such is the case of the agitprop known as “Climate Central” which is privately funded to produce slick graphics and scare stories about climate change. Case in point, their recent graph that purports to show why the atmosphere hasn’t warmed as expected:
h/t to Frank Strzalkowski on Facebook for bringing it to my attention. He writes:
According to this graph, the oceans have warmed up over 10 times more than the air. It’s the latest excuse as to why the air temperatures have been flat for almost 20 years. “The Oceans Ate It Up”.
This is one of those graphs that really try and deceive as there is no -y- axis scale. So who knows what the difference is between 1970 and 2015. Could be 10C or .1C
Climate Central captions the graphic with this:
Where’s the global heat? Check the oceans
You can watch the video here: https://www.facebook.com/climatecentral/videos/10159605183015024/
First, let me point out (as Frank does) that the graph is unitless on the Y axis, it’s only listed as a percentage, with no reference to a baseline for comparison, though it could be assumed that they mean since 1970.They claim they Y axis (which has no tickmarks) is in “zettajoules”, which if you look it up, says this:
Gosh, 10 to the 21st power of joules! That seems huuuge, but then there’s this for comparison:
Wow, 5.5 x10 to the 24th power joules strikes the surface of the Earth each [year] as energy from the sun, that’s roughly 3 orders of magnitude larger than the claimed heat increase in the oceans since 1970. In other words, in the scheme of things, not a lot of heat energy by comparison to Earth’s yearly heat budget from the sun.
They reference chapter 3 of the 2013 IPCC AR5 report “Climate Change 2013 The Physical Science Basis, Chapter 3” as the source for the graph data. You can download it direct from the IPCC here: https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_SummaryVolume_FINAL.pdf
There also doesn’t appear to be any Ocean Heat Content figure like Climate Central Claims in that report, however, there is a figure like it in the AR5 IPCC Synthesis Report: http://ar5-syr.ipcc.ch/ipcc/ipcc/resources/pdf/IPCC_SynthesisReport.pdf
Looking at that graph, the idea that increasing CO2 heated the oceans 10x more than the land or atmosphere is just preposterous. Try warming a pot of water by making the room temperature a degree warmer.
What’s even more preposterous is the claimed precision in being able to define this heat content gain, which has it’s basis in sea surface and at depth temperature measurements. Willis Eschenbach has already dealt with this before in a WUWT post: Ocean Temperature And Heat Content
Anthony has an interesting post up discussing the latest findings regarding the heat content of the upper ocean. Here’s one of the figures from that post.
Figure 1. Upper ocean heat content anomaly (OHCA), 0-700 metres, in zeta-joules (10^21 joules). Errors are not specified but are presumably one sigma. SOURCE
He notes that there has been no significant change in the OHCA in the last decade. It’s a significant piece of information. I still have a problem with the graph, however, which is that the units are meaningless to me. What does a change of 10 zeta-joules mean? So following my usual practice, I converted the graph to a more familiar units, degrees C. Let me explain how I went about that.
To start with, I digitized the data from the graph. Often this is far, far quicker than tracking down the initial dataset, particularly if the graph contains the errors. I work on the Mac, so I use a program called GraphClick, I’m sure the same or better is available on the PC. I measured three series: the data, the plus error, and the minus error. I then put this data into an Excel spreadsheet, available here.
Then all that remained was to convert the change in zeta-joules to the corresponding change in degrees C. The first number I need is the volume of the top 700 metres of the ocean. I have a spreadsheet for this. Interpolated, it says 237,029,703 cubic kilometres. I multiply that by 62/60 to adjust for the density of salt vs. fresh water, and multiply by 10^9 to convert to tonnes. I multiply that by 4.186 mega-joules per tonne per degree C. That tells me that it takes about a thousand zeta-joules to raise the upper ocean temperature by 1°C.
Dividing all of the numbers in their chart by that conversion factor gives us their chart, in units of degrees C. Calculations are shown on the spreadsheet.
So, in reality, that OHC increase depicted by Climate Central is actually a tiny temperature increase of a few hundredths of a degree C, and one that is likely below the resolution and the precision of the thermometers measuring water temperature to resolve.
As Willis states in that post:
I find the claim that we know the average temperature of the upper ocean with an error of only one hundredth of a degree to be very unlikely … the ocean is huge beyond belief. This claimed ocean error is on the order of the size of the claimed error in the land temperature records, which have many more stations, taking daily records, over a much smaller area, at only one level. Doubtful.
So since the temperature increase is tiny and probably within the error band of measurements, it’s no wonder Climate Central resorts to scary looking heat graphs with what looks like huge numbers.
In reality, it’s the proverbial mountain from a molehill, but isn’t that what most climate claims are anyway?