I can’t tell the bottom from the top

homer.jpgA couple of weeks ago I blogged about NIWA’s climate summary for 2008, but inexplicably missed a most excellent response to the figures from the NZ Climate “Science” Coalition’s energy expert Bryan Leyland. He must have been digging through some dusty tomes in the library, because he arrived at the astonishing conclusion that New Zealand was warmer 141 years ago:

New Zealand’s national average temperature of 12.9 degrees C during 2008, described by NIWA as ‘milder than normal” was in fact cooler than it was 141 years ago, this, and worldwide drop in temperatures since 1998, demonstrate that claims of man-made global warming have lost touch with reality.

Oh really?

Mr Leyland said it is important that all New Zealanders, but especially politicians, understand the significance of the two sets of temperature readings.

Quite so, Bryan, quite so. Let’s see if I can help out a little…

Here’s the big picture (click for a larger version):nztempsNIWA0801edit.png

This chart shows the full data series for NZ annual average temperature, stretching back to 1853. But what’s this? It looks like 1867 was cooler than 2008. What’s going on? Surely Bryan would have taken care to ensure that he was choosing comparable figures, but it appears he didn’t:

The 1867 temperature readings are contained in the Transactions and Proceedings of the Royal Society of New Zealand 1868-1961, which contain tables, described as forming “the most reliable data for judging of the climate of New Zealand, extracted from the reports of the Inspector of Meteorological Stations, for 1867.”

I wonder when this list was compiled? At least 48 years ago, it appears. And it would have been based on a different methodology to the NIWA data. In other words, Bryan is comparing apples to oranges, and ending up with a fruit salad. If we look at the NIWA data, 1867 was certainly a bit warmer than the years either side, but the period from the 1860s to 1920s was markedly cooler on average than today, and 2008 was significantly warmer than 1867.

Look again at the NIWA data, and we can see that Bryan missed a really big cherry. 1861 was a very warm year — warmer than 2008. If you want to compare two years out of 150, he would have done better to pick those two Pacific Roses. It wouldn’t have proved anything about global warming, of course, because NZ’s average temperature is not a proxy for global temperature, and you can’t determine a trend just by drawing a line between the start and end points on a graph. In this instance, a quick eyeball of the data shows the obvious — lots of cold years in Victorian times, lots of warm years recently.

There’s another problem with using 1861, however. The NZ temperature record is generally said to begin in 1867 because that was the year that met stations around the country standardised on using Stevenson screens around their thermometers. Earlier temperature records are therefore subject to more potential error. But I don’t suppose that would have worried Bryan, who continues his analysis with an explanation of why we need to compare the two years:

“Firstly, they are 141 years apart which is a more accurate period for changes in climate with its natural cycles of warming and cooling. To put this difference of 0.2 degrees C into perspective it should be compared to the fourth assessment report by IPCC in 2007 that the world warmed by 0.6 degrees C in the previous 100 years. Temperature variations of this tiny extent are meaningless and certainly do not justify the extreme mitigation measures currently being discussed.

As we’ve seen, the difference is greater than Bryan’s cherry-picked data suggests, and if you look back over the last 100 years, NZ has actually warmed by 0.7ºC — more than the globe as a whole. Now there’s an inconvenient truth for Leyland to chew on. However, undaunted by reason, he continues:

“Secondly, this gives the lie to the myth about carbon dioxide as a cause of so-called global warming. We know from Siple ice cores that the level of CO2 in the atmosphere was 290 ppm, and we know from the American readings at Mauna Loa that the level today is almost a third higher at 385 ppm. CO2 increased but warming didn’t,” Mr Leyland concluded.

The world and NZ did warm, so we have prima facie evidence that carbon dioxide might have played a role. Correlation does not prove causation, but we have clinching evidence — the radiation physics of the atmosphere, which tells us that greenhouse gases warm the planet. So more gas, more warming.

That’s something I hope our politicians will remember. Bryan might think he can fool some of the people some of the time, but if this is the best he can do he might as well give up now.

(Original chart supplied by Jim Renwick, additional comments by Jim Salinger, arrows etc by me. My thanks to the Jims for their prompt assistance.)

[The Hollies]

10 thoughts on “I can’t tell the bottom from the top”

  1. Question — has the accuracy of thermometers been taken into consideration here? 1860 was not a good year for thermometers, nor many of the intervening years up to about 1950. A well researched project on the usage and accuracy of “thermometers” may cause some concern!


  2. Dude. Science is old. Thermometers are reaaaally old tech. Just check the wikipedia page on Thermometer – by the mid-1600’s they had scales and everything.

    But you’re right … the vintage of a thermometer should be taken into account. Maybe head around the country on a thermometer trail, investigating the body and nose of the locally produced thermometers. Remember to spit out the mercury!

  3. I think JCS has a valid point, in that the error bars around the older temperature averages will be larger, not least because of non-standard siting. However, it’s also worth remembering that averages of lots of readings are generally more accurate than single readings, as errors tend to cancel.

  4. [Note: Theon joins many current and former NASA scientists in dissenting from man-made climate fears. A small sampling includes: Aerospace engineer and physicist Dr. Michael Griffin, the former top administrator of NASA, Atmospheric Scientist Dr. Joanne Simpson, the first woman in the world to receive a PhD in meteorology and is formerly of NASA, Geophysicist Dr. Phil Chapman, an astronautical engineer and former NASA astronaut, Award-Winning NASA Astronaut/Geologist and Moonwalker Jack Schmitt, Chemist and Nuclear Engineer Robert DeFayette was formerly with NASA’s Plum Brook Reactor, Hungarian Ferenc Miskolczi, an atmospheric physicist with 30 years of experience and a former researcher with NASA’s Ames Research Center, Climatologist Dr. John Christy, Climatologist Dr. Roy W. Spencer, Atmospheric Scientist Ross Hays of NASA’s Columbia Scientific Balloon Facility]

  5. Hi all —
    In another of our Series discussions on this venue I presented a reference as follows:
    (1) EARTH’S CHANGING CLIMATE. Lecture Series by Dr. Richard Wolfson, the Benjamin F. Wissler Professor of Physics at Middlebury College. This is a six hour video lecture series (12 segments of 30 minutes each) on two DVDs produced by The Teaching Company of Chantilly VA 20151-1232.
    This series covers in-depth detail of the science and methodology of climate change. It is not an advocacy program. Interestingly, Dr. Wolfson does not even mention Methane-Clatherate in this lecture series — knowledge on that subject is almost too new to have been included. These is a substantive amount of time devoted to the history of temperature methodology and “thermometers” that I believe you would find useful in your studies and contemplations on early attempts at science methodology.

    In addition — Consider the breakneck speed in learning that is occurring today. Methane-hydrate was first discovered, if memory serves, by NASA about 1980 in the Rings of Saturn. At that time we did not know that it existed on Earth. Today, on earth, we have discovered so much-methane hydrate that we KNOW that we no longer have an energy crisis, per se, and that there is a sufficient quantity of CH4 stored within the ice lattus, to supply clean natural gas for the next 1000 years.

    JCSpilman, P.E.

  6. Last year a Japanese drilling company drilled a Natural Gas well in NorthWest Canada that delivered “commercial quantities” of natural gas from a methane-hydrate source. As a result the Japanese and the USA have signed a mutual testing/research agreement to drill experimental wells close off-shore on the Japanese homeland.

    The methodology of the experiment in Canada involved placing an inline turbo pump in the drill stem below the water level and forcing water DOWN into the hydrate strata — at the same time the turbo pump forced air (and gas) from above the insertion point ( and a section of perforated casing) UP the drill stem to the collecting apparatus. This seems counter-intuitave but evidently the pressure changes and gas release worked as a viable scheme and resulted in the “commercial quantities” of gas for more than a week.

    JCSpilman, P.E. (ret.)

  7. Thanks JCS, very interesting. I know that the stability of the deposits is a concern when drilling. There are also concerns that warming of the sea floor may destabilise shallow clathrate deposits, as this report at Nature Reports: climate change demonstrates.

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