“Be kind, for everyone you meet is fighting a hard battle” - Often attributed to Plato but likely from Ian McLaren (pseudonym of Reverend John Watson)

Saturday, July 12, 2014

Feigning literacy, nothin' up my sleeve

Image courtesy of Chris Butler, Big Chris Gallery
I look at various climate related sites, both those who are skeptical of what I'll call climate disruption caused by the products of mankind's burning of fossil fuels and those who accept the theory (using "theory" here as a scientist would use it, analogous to, say, Newton's theory of gravitation). One of the most frustrating things I find is writers who present a veneer of scientific literacy but, upon even cursory investigation by anyone with a reasonable yet far short of specialist knowledge (e.g., myself) are easily revealed to be nonsense. Yet the scientific veneer ("look! charts! equals signs!") can lead people with almost no scientific or mathematical literacy to place credence in this nonsense. And, sadly, that latter group is a very large one.

A good example is to be found here. Those who follow the ebb and flow of the so-called debate around climate disruption will likely have heard of the "hiatus" in warming, that is, a slowing down of the rate of increase of global temperature. Given the demonstrable increase in energy retained by the earth/ocean/atmosphere system (for what is, in my opinion, a silly if not counterproductive "measurement" of this heat, see here) because of our greenhouse gas emissions, scientists have advanced theories for the so-called "missing heat." As best I can determine, the leading theory is that the oceans are heating and doing so to greater depth than had been anticipated.


But Anthony Cox is having none of it. He reproduces the graphic graphic at left. It charts a time series of "Change in Total Heat Content" data from 1955 through (apparently) 2014. As an aside, my pedantry requires that I mention that "heat content," though widely used and accepted, is poor terminology. Heat is an interaction between a system and its surroundings resulting in a change in internal energy of the system. Temperature, in turn, can be (loosely) considered to be a measure of one specific component of average internal energy.

In any case, Mr. Cox objects, and provides charts showing a calculated equivalent temperature rise in degrees celsius. I'm not sure why he bothered to calculate. The source of such data, NOAA's National Oceanographic Data Center, provides a chart with degrees celsius as the ordinate in the same set of charts as that from which the "heat content" chard is reproduced. Such a chart is here and, in fact, the charts showing heat content are computed from temperature measurements.

But what's the difference? Why does one chart show the data in joules and the other in degrees celsius? The joule is a unit of energy. One joule is an extremely small amount of energy in comparison to everyday experience; the heat energy available in a single piece of plain M&M candy is more than 14,000 joules. A gallon of gasoline releases about 125,000,000 joules when completely oxidized. That's why the heat content chart has such huge numbers. What you see on the vertical axis is measured (actually, computed from temperature measurements in the ocean vertical profile) heat content with a reference number subtracted. Accordingly, this is an "anomaly," and each "tick" on the vertical axis represents a 1022 (1 followed by 22 zeros) joules from the reference period. It does not represent the "total heat content" of the oceans. It represents gains and losses in comparison to the reference period.


To the left is the data showing temperature (again, as an anomaly) over the period. Note that this was taken straight from the the NODC web site, no need for the calculations performed by Lucia at the "The Blackboard."

Mr. Cox contends that the heat content anomaly in joules is used because the big numbers look more scary then the same data presented as temperature anomaly in degrees celsius.

This is simply untrue. The amount of energy that will heat a cubic meter of water by 1 degree celsius will heat about 3,100 cubic meters of air (at sea level pressure) by that same degree celsius. This is due in small part to the higher specific heat of water but mostly to water being about 1,000 times as dense as air (again, at sea level pressure). Looked at another way, the amount of energy required to heat the upper 700 meters of ocean worldwide by 1 degree celsius would heat the ENTIRE atmosphere some 170 degrees celsius (assuming that the specific heat of air is constant as temperature changes, which it is not).

Now, is the interaction between incoming solar energy, outgoing long wave radiation, ocean circulation, heat transfer, etc. as simple as this calculation? Of course not. That's why scientists study these things, measure the relevant parameters, seek hypotheses that explain the measurements, etc. Are there significant questions to be answered with respect to the data presented and how it's measured? Yes. Are scientists trying to answer these questions? Yes. That's what science is.

But the conclusion is that energy (referred to by NOAA as "Heat Content" and tracked as an anomaly) is an entirely appropriate way to picture one component of the effect of greenhouse gases on our ocean/atmosphere system. It is NOT a nefarious way to be able to insert scary large numbers into a chart. And, to reemphasize for yet the third time, the same set of NOAA charts that shows the energy anomaly in joules shows its effect in degrees celsius as well. So who really has deception as their goal?

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