Comments on: Climate measurement can mislead http://www.crispinhull.com.au/2008/09/13/climate-measurement-can-mislead/ Journalism and other writing Thu, 02 Feb 2012 03:23:26 +0000 hourly 1 http://wordpress.org/?v=3.0 By: Canberra Times letter writers http://www.crispinhull.com.au/2008/09/13/climate-measurement-can-mislead/comment-page-1/#comment-890 Canberra Times letter writers Fri, 18 Nov 2011 23:24:26 +0000 http://www.crispinhull.com.au/?p=81#comment-890 Hull's rising heat Three citizens have become hot and bothered about Crispin Hull's seemingly unremarkable assertion that a rise in average Earth temperature from 15 degrees to 17 amounts to (about) 13per cent (Letters, September 15). D. Zivkovic says that, in coming to this conclusion, Hull has committed a logical error that any Year 9 student would not make. God help the education system if he is right about that. There are no logical errors in Hull's article. Contrary to Zivkovic's misinterpretation, the article is all to do withgeneral misunderstandings about measurement scales and percentages derived therefrom. Aert Driessen says Hull should have gone on to assert that the 2 per cent increase in degrees Fahrenheit equates to ''an increase of atmospheric CO2 content from 0.00038 per cent to 0.0004 per cent (380ppm to 400ppm)''. He had the science wrong here: substitute 450/480 for 400. But his point is well made and, apparently unrecognised by him, is a good example of the thrust of Hull's article. Annette Barbetti moves the goal posts right down into the nether world and starts the temperature scale at Kelvin's absolute zero: whence the rise is 0.694 per cent. The irony is that all three, in criticising Hull, are victims of the errors he was concerned about. Jack Lonergan, Isaacs Degrees of ridicule After Jack Lonergan ridiculed me and other letter writers for failing to get the point of Crispin Hull's ''Two degrees of separating wheat from chaff on warming'' (September 13, pB9), I re- read Hull's article again several times, wondering if Lonergan was right and the rest of us so wrong. Nope, I still don't know what Lonergan was going on about. I might be too thick to get what Hull meant to say, but I can read, and this is what he did say: ''We should stop measuring climate projections in degrees Celsius. We should start using percentages.'' He implied, erroneously, that it made sense to measure temperature changes in percentage terms. By cherry-picking the Celsius scale because it makes global warming seem bad, and deriding the Fahrenheit scale simply because it makes it seem like a ''trifle'', Hull was guilty of intellectual dishonesty. Specious analogies with car speedometers didn't help. His closing paragraph ''Two degrees. No worries. Thirteen per cent. Ouch'' was a perfect way for him to conclude his article because it summed up indeed admitted that dishonesty. If my letter had been published in its entirety (minus the errors introduced by the sub-editor) it would perhaps have been clear that I was mocking the notion that 13 per cent (Celsius) was any more meaningful than 6 per cent (Fahrenheit), or 1 per cent (Kelvin). There are legitimate ways of explaining to the public that two degrees of warming might really be something to worry about. Expressing it as a percentage of some arbitrary number is not one of them. D.Zivkovic, Aranda I am delighted at Jack Lonergan's response (Letters, September 17) to my letter of September 15 because it gives me the opportunity to talk science instead of politics. Lonergan believes that I should have factored in a CO2 increase as high as 480ppm instead of the 400ppm in my example. It really doesn't matter, even if he wanted me to take it up to 1000ppm. He obviously thinks that the relationship between rising CO2 and warming is linear. But it is not. It is logarithmic. Warming caused by an increase of CO2 from, say, 10ppm to 20ppm (about 1.5 centigrade degrees, not 1.5 degrees C) is more than 10 times greater than the warming effect reflecting an increase of CO2 from 100ppm to 200ppm, and much greater still for warming caused by CO2 increases from say 500ppm to 1000ppm. By way of visualising this, if changes in temperature are plotted on a vertical axis (from zero to 1.6 C degrees) and CO2 concentration is plotted on a horizontal axis (from zero to 480ppm) then the graph line depicting the relationship between these two variables looks like a ski jump. It starts top left at 1.5 C degrees when CO2 concentration is 20ppm and drops very quickly to 0.2 C degrees when the CO2 content is about 80ppm. At 200ppm CO2 the line is practically horizontal, meaning that even very large increases in CO2 (running the line further to the right), even to 1000ppm, would hardly register on the vertical axis and so indicate only a negligible warming effect. Strange how nature works. Aert Driessen, McKellar Hull is not even right to a degree, let alone two of them By The Canberra Times Crispin Hull (Two degrees of separating wheat from chaff on warming, pB9, September 13) made a basic error of logic that a Year 9 science student should be able to spot. According to him, if we assume that the average world temperature is 15 degrees, then a warming of two degrees represents 13 per cent, which sounds like a lot. Ignoring the important question of whether ''average world temperature'' is even a meaningful concept, the problem is that five degrees measured from an arbitrary zero point, the freezing point of water. The fact that Hull knew enough to ask the crucial question, ''Upon what do you base your percentage change?'' made his article look like a propaganda piece rather than simple ignorance. The freezing point of water has no special cosmic significance. The Fahrenheit scale puts it at 32F, therefore a rise of 3.6F (2C) from 59F is 6 per cent, which doesn't sound nearly as bad as 13 per cent. Hull implied that the Fahrenheit scale is somehow ''worse'' than Celsius (apparently only because it makes global warming seem smaller), but both are just arbitrary ways of measuring temperature. The bottom line is, 2 per cent, 6 per cent and 13 per cent are pretty meaningless: two degrees is two degrees. D.Zivkovic, Aranda 20 parts per million If Crispin Hull wants to further sensationalise global warming reporting by saying warming has increased 13 per cent instead of two degrees Celsius if average global temperature (whatever that means) rises from 15C to 17C, he should also say that what this fuss is all about is an increase of atmospheric CO2 content from 0.00038 per cent to 0.0004 per cent (380 ppm to 400 ppm). Aert Driessen, Mackellar Absolute zero marks Crispin Hull thinks that a 2C increase in temperature would mean a 13 per cent hotter world. He is mistaken. He should have measured the temperature from absolute zero (zero degrees K, or minus 273.15 degrees C). The temperature would rise from 288.15K to 290.15K, or 0.694 per cent. Annette Barbetti, Kaleen Hull’s rising heat
Three citizens have become hot and bothered about Crispin Hull’s seemingly unremarkable assertion that a rise in average Earth temperature from 15 degrees to 17 amounts to (about) 13per cent (Letters, September 15). D. Zivkovic says that, in coming to this conclusion, Hull has committed a logical error that any Year 9 student would not make. God help the education system if he is right about that. There are no logical errors in Hull’s article. Contrary to Zivkovic’s misinterpretation, the article is all to do withgeneral misunderstandings about measurement scales and percentages derived therefrom. Aert Driessen says Hull should have gone on to assert that the 2 per cent increase in degrees Fahrenheit equates to ”an increase of atmospheric CO2 content from 0.00038 per cent to 0.0004 per cent (380ppm to 400ppm)”. He had the science wrong here: substitute 450/480 for 400. But his point is well made and, apparently unrecognised by him, is a good example of the thrust of Hull’s article. Annette Barbetti moves the goal posts right down into the nether world and starts the temperature scale at Kelvin’s absolute zero: whence the rise is 0.694 per cent. The irony is that all three, in criticising Hull, are victims of the errors he was concerned about.
Jack Lonergan, Isaacs
Degrees of ridicule
After Jack Lonergan ridiculed me and other letter writers for failing to get the point of Crispin Hull’s ”Two degrees of separating wheat from chaff on warming” (September 13, pB9), I re- read Hull’s article again several times, wondering if Lonergan was right and the rest of us so wrong. Nope, I still don’t know what Lonergan was going on about. I might be too thick to get what Hull meant to say, but I can read, and this is what he did say: ”We should stop measuring climate projections in degrees Celsius. We should start using percentages.” He implied, erroneously, that it made sense to measure temperature changes in percentage terms. By cherry-picking the Celsius scale because it makes global warming seem bad, and deriding the Fahrenheit scale simply because it makes it seem like a ”trifle”, Hull was guilty of intellectual dishonesty. Specious analogies with car speedometers didn’t help. His closing paragraph ”Two degrees. No worries. Thirteen per cent. Ouch” was a perfect way for him to conclude his article because it summed up indeed admitted that dishonesty. If my letter had been published in its entirety (minus the errors introduced by the sub-editor) it would perhaps
have been clear that I was mocking the notion that 13 per cent (Celsius) was any more meaningful than 6 per cent (Fahrenheit), or 1 per cent (Kelvin). There are legitimate ways of explaining to the public that two degrees of warming might really be something to worry about. Expressing it as a percentage of some arbitrary number is not one of them. D.Zivkovic, Aranda
I am delighted at Jack Lonergan’s response (Letters, September 17) to my letter of September 15 because it gives me the opportunity to talk science instead of politics. Lonergan believes that I should have factored in a CO2 increase as high as 480ppm instead of the 400ppm in my example. It really doesn’t matter, even if he wanted me to take it up to 1000ppm. He obviously thinks that the relationship between rising CO2 and warming is linear. But it is not. It is logarithmic. Warming caused by an increase of CO2 from, say, 10ppm to 20ppm (about 1.5 centigrade degrees, not 1.5 degrees C) is more than 10 times greater than the warming effect reflecting an increase of CO2 from 100ppm to 200ppm, and much greater still for warming caused by CO2 increases from say 500ppm to 1000ppm. By way of visualising this, if changes in temperature are plotted on a vertical axis (from zero to 1.6 C degrees) and CO2 concentration is plotted on a horizontal axis (from zero to 480ppm) then the graph line depicting the relationship between these two variables looks like a ski jump. It starts top left at 1.5 C degrees when CO2 concentration is 20ppm and drops very quickly to 0.2 C degrees when the CO2 content is about 80ppm. At 200ppm CO2 the line is practically horizontal, meaning that even very large increases in CO2 (running the line further to the right), even to 1000ppm, would hardly register on the vertical axis and so indicate only a negligible warming effect. Strange how nature works.
Aert Driessen, McKellar
Hull is not even right to a degree, let alone two of them
By The Canberra Times

Crispin Hull (Two degrees of separating wheat from chaff on warming, pB9, September 13) made a basic error of logic that a Year 9 science student should be able to spot. According to him, if we assume that the average world temperature is 15 degrees, then a warming of two degrees represents 13 per cent, which sounds like a lot. Ignoring the important question of whether ”average world temperature” is even a meaningful concept, the problem is that five degrees measured from an arbitrary zero point, the freezing point of water. The fact that Hull knew enough to ask the crucial question, ”Upon what do you base your percentage change?” made his article look like a propaganda piece rather than simple ignorance. The freezing point of water has no special cosmic significance. The Fahrenheit scale puts it at 32F, therefore a rise of 3.6F (2C) from 59F is 6 per cent, which doesn’t sound nearly as
bad as 13 per cent. Hull implied that the Fahrenheit scale is somehow ”worse” than Celsius (apparently only because it makes global warming seem smaller), but both are just arbitrary ways of measuring temperature. The bottom line is, 2 per cent, 6 per cent and 13 per cent are pretty meaningless: two degrees is two degrees.
D.Zivkovic, Aranda
20 parts per million
If Crispin Hull wants to further sensationalise global warming reporting by saying warming has increased 13 per cent instead of two degrees Celsius if average global temperature (whatever that means) rises from 15C to 17C, he should also say that what this fuss is all about is an increase of atmospheric CO2 content from 0.00038 per cent to 0.0004 per cent (380 ppm to 400 ppm).
Aert Driessen, Mackellar
Absolute zero marks
Crispin Hull thinks that a 2C increase in temperature would mean a 13 per cent hotter world. He is mistaken. He should have measured the temperature from absolute zero (zero degrees K, or minus 273.15 degrees C). The temperature would rise from 288.15K to 290.15K, or 0.694 per cent. Annette Barbetti, Kaleen

]]> By: Professor Greg Jackson, Kambah http://www.crispinhull.com.au/2008/09/13/climate-measurement-can-mislead/comment-page-1/#comment-23 Professor Greg Jackson, Kambah Fri, 06 Feb 2009 01:11:41 +0000 http://www.crispinhull.com.au/?p=81#comment-23 What's your speed? I believe Mark Wilson (Letters, January 7) does Robert Miles (Letters, January 5) an injustice in regards to speedometer readings, and myself on technologically controlled speed limitations (Letters, July 13), but does make some good points. While Miles refers to a brilliant suggestion of a year or two ago, there have been recent letters too. Crispin Hull made the key point about perceptions, using speedometer readings as one of several examples (Opinion, September 13, p9). Several letter writers completely misunderstood Hull's article, except perhaps Jack Lonergan (Letters, September 17) and myself (unpublished). Speedos commonly read from 0 to 240-odd km/h. So, in Australia, you are certainly speeding when the needle is only halfway around the dial. Hull's idea was to change the dial to read, say 0-130km/h so that your perception of speeding would be more apparent when the needle was nearly fully wrapped clockwise around. Miles understood this, but used the 0-110km/h range as an example. Wilson is up in arms on this, but Miles did say, for example, 110km/h. So make the top speedo number, say, 130km/h. This covers all of Wilson's points, while not unduly compromising Hull's original idea. As for my suggestion on technologically imposed car speeds, 20km/h over seems reasonable. Professor Greg Jackson, Kambah What’s your speed?

I believe Mark Wilson (Letters, January 7) does Robert Miles (Letters, January 5) an injustice in regards to speedometer readings, and myself on technologically controlled speed limitations (Letters, July 13), but does make some good points.

While Miles refers to a brilliant suggestion of a year or two ago, there have been recent letters too.

Crispin Hull made the key point about perceptions, using speedometer readings as one of several examples (Opinion, September 13, p9).

Several letter writers completely misunderstood Hull’s article, except perhaps Jack Lonergan (Letters, September 17) and myself (unpublished).

Speedos commonly read from 0 to 240-odd km/h. So, in Australia, you are certainly speeding when the needle is only halfway around the dial.

Hull’s idea was to change the dial to read, say 0-130km/h so that your perception of speeding would be more apparent when the needle was nearly fully wrapped clockwise around. Miles understood this, but used the 0-110km/h range as an example.

Wilson is up in arms on this, but Miles did say, for example, 110km/h. So make the top speedo number, say, 130km/h. This covers all of Wilson’s points, while not unduly compromising Hull’s original idea.

As for my suggestion on technologically imposed car speeds, 20km/h over seems reasonable.

Professor Greg Jackson, Kambah

]]>