David Stockwell and Anthony Cox reply to Lewandowsky and His Lies, Dam Lies and Statistics
COGNITIVE science is about the action and process of knowing, that is about intelligence and rational and non-rational intellectual processes. Professor Stephan Lewandowsky is a professor of Psychology specialising in cognitive process. He thinks the cognitive processes of Anthropogenic Global Warming (AGW) sceptics is deficient and on the same level as “truthers” and other “conspiracy theorists”. Furthermore, he is not backward in telling anyone who will listen that sceptics are “damn liars”.
Lewandowsky’s fulminations against sceptics continues a sinister trend in the AGW debate with a number of prominent AGW supporters casting aspersions about the moral legitimacy of scepticism and calling for sceptics to be jailed or prosecuted or at the very least banned as Senator Bob Brown advocates for leading sceptic Andrew Bolt. However, Lewandowsky’s diatribes go beyond legal and political action and calls into doubt the sanity of the sceptical position.
This is serious, for merely questioning the ‘science’ of AGW one now faces the opprobrium of having one’s mental ability questioned.
Lewandowsky has been very active, having several articles published at the ABC’s Unleashed. His most recent one is cunning. Apparently realising that the old stand-by of arguing from authority is not having any success in converting an increasingly cynical public, Lewandowsky has attempted to directly involve the public in the scientific process of validating the evidence for AGW. This process is described in his latest ABC article:
Because Lewandowsky is an award winning statistician and uses statistics in this latest paper another award winning statistician, Dr David Stockwell, thought having his sanity queried was worth the risk of highlighting the egregious statistical errors of Lewandowsky’s article.
While prepared to publish Lewandowsky’s offensive opinion, the ABC refused to publish the following rebuttal:
Lewandowsky and the Statistics of Global Warming
Professor Lewandowsky says: “Statistics, when done properly, provide a robust and revealing tool to understand reality.”
He is right; statistics can help us understand the why and how of our physical world; good statistics can even help us prepare for our future. Have the statistics of anthropogenic global warming [AGW] helped us understand our physical world and helped us prepare for our future?
Lewandowsky warns us that “Single events carry little information” and to use single events to prove AGW is untrue is “cherry-picking”. In Lewandowsky’s opinion, one cold British winter [actually there have been three] does not a summer make. Rather it is the long-term changes which prove AGW, the reduction in the Arctic ice-cap, the rising seas and the increasing temperature.
This is true. The Intergovernmental Panel for Climate Change [IPCC] says that a minimum of 30 years have to be taken into account before any conclusions about changes in the physical reality of climate can be made. But the Arctic ice-cap was smaller in the 1930’s, and warmer, according to researcher Professor Petr Chylek. Sea levels have been rising for the last 10 thousand years, since the current interglacial or warm period began, at rates of increase much more rapid than the rates of today. And temperature has been increasing in the modern era since 1850, well before AGW is supposed to have begun.
This is the point about statistics; they are only as good as the information or data: the raw numbers. “Cherry picking” a section of data is not the only way of corrupting a statistical analysis; omitting or changing the data can do it as well. For instance Lewandowsky says “the Arctic icecap has shrunk by an area roughly equivalent to the size of Western Australia since 1980”. It sounds bad doesn’t it? It must be AGW. But this is the statistical technique of omission. What the Professor has not mentioned is that the Antarctic has increased in size since 1980 by an area roughly equivalent to two Western Australias. So, overall ice levels have increased.
Lewandowsky used two graphs to prove that the full range of data will reveal the truth and allow people to so readily see the trend that they can predict the future. The two graphs show identical data but with different headings; one an imaginary share price and the other the official temperature record of the IPCC, NASA GISS.
Even if we accept the NASA GISS temperature record as accurate the important issue is whether CO2 caused the trend. CO2 alone can’t have. CO2 has been increasing during the 20th Century at a constant rate but the temperature anomalies show many periods with cooling. Is it “cherry-picking” to focus on these cool periods?
No. And for two reasons. Firstly, some of the cooler periods are longer than 30 years and so represent a climate period. It is legitimate to regard a cooler period as a contradiction to AGW and that some other factor is affecting the climate.
Secondly, Lewandowsky has not considered that there may be a better statistical explanation for the temperature record; choosing an inferior explanation is hard to justify. In fact there is a better explanation than CO2.
The better explanation is the Sun. One measure of the Sun’s influence on the Earth’s climate is called the Total Solar Irradiance [TSI]. TSI is a measure of the absolute intensity of solar radiation, integrated over the entire solar irradiance spectrum incident on the Earth’s atmosphere, that is, the sunlight reaching the atmosphere. Proxies of TSI such as sunspots go as far back as 1600. Figure 6.5 of the last IPCC report, AR4, shows the derived variations in TSI over this period according to a number of studies.
How can a comparison of whether TSI is a better explanation than AGW for the temperature anomalies of NASA GISS be done?
It can be done through statistics. Dr Jeffrey Glassman has compared the correlation between TSI and the temperature record over the 20th Century and found a 90% correlation. By comparison meteorologist Joseph D’Aleo calculates a statistical correlation between CO2 and temperature of only 42%.
Both the science of the Sun and AGW are supposedly well established yet the amount of money being invested in AGW is vastly greater than that being spent researching the Sun with less than half the statistical justification. This may be good business but it is not good science.
Lewandowsky says that for statistics to be effective one should use “All the data, for the entire globe, and for all available years.”
But Lewandowsky has not met his own criteria of “All the data”. The NASA GISS record is NOT the complete temperature record of AGW. The complete record is much longer.
Take Michael Mann’s hockey-stick. The hockey-stick is a 2000 year temperature record based on dendro-climatic or tree-ring data. The hockey-stick purports to show an even temperature until the 20th Century when temperature increases at the same time as CO2.
We have already seen that TSI is a better statistical explanation for the 20th Century but what is the best explanation the rest of the 2000 years?
The best explanation is not CO2. A new paper which was published with the honour of occupying the entire edition of a major research journal, The Annals of Applied Statistics, shows this. The paper is by two expert statisticians, Blakeley McShane and Abraham Wyner, who show the hockey-stick is based on flawed statistics and the Medieval Warm Period [MWP] was as warm and probably warmer than today.
In the spirit of Lewandowsky’s study we showed his graphs to David Stockwell’s school-age daughters who also thought the trend would be up. However, when the girls were shown a 2000 year temperature record consistent with McShane and Wyner’s analysis, they extended the graph downwards. The conclusion? Perception of trend direction depends on the duration examined.
More importantly, when asked if this was a good way to predict the future global temperature of the planet they said “Of course not!” Smart girls.
McShane and Wyner’s study is a major contradiction to AGW. Real data, and a variety of statistical methods, including those relied on by AGW proponents, fail to show anything unusual about the present temperature; and that includes Lewandowsky’s record extremes which the IPCC has shown to have occurred nine times over the last 1000 years.
With the past and the present statistically defeated for AGW what can AGW do? As Lewandowsky shows, like any fortune teller, it looks to the future where, statistically, anything is possible.
Predictions are the stock in trade of AGW. All the AGW experts have used statistics to tell us what the future climate will be. The results have been statistically improbable in that they have been wrong at both the short term and the long term. For instance, in the short term the MET, England’s national weather service, has predicted mild winters from 2008; the winters have been some of the coldest in the last century. In 2005 the MET predicted a cold winter; it was mild.
In Australia, the Bureau of Meteorology [BoM] and CSIRO have predicted on the basis of climate model projections that the severity and intensity of droughts will double by 2050. David Stockwell has published a peer-reviewed statistical comparison of their models with the observations, which shows droughts decreasing over the last century, while the models showed droughts increasing last century. The claim of an increasing drought trend in Australia was based on invalid model simulations. This is a classic case of the statistical method of garbage in, garbage out.
In 2007, CSIRO and BoM scientists Power and Smith published a paper claiming that due to increasing greenhouse gasses the Southern Oscillation Index [SOI] has shifted to a permanently lower level. This echoed a claim by NASA scientist Jim Hansen that one of the consequences of AGW might be permanent El Niño (hot, dry) conditions, leading to persistent droughts in Australia. However in a 2008 paper Professor Neville Nicholls showed that the change in the SOI was not statistically significant and the apparent decrease was largely due to a run of El Niño events during the late part of the 20th Century.
The recent strong La Niña (cool, wet) and high SOI conditions contributing to flooding in Australia has shown Nicholls’ statistical analysis is correct. Despite comments by prominent AGW scientists like David Karoly, Ian Lowe and Tim Flannery these are entirely natural conditions; the flood records for Queensland show that in the past, before AGW began, there were bigger and regular floods. As Professor Stewart Franks notes natural variability is creating the weather not AGW.
Lewandowsky in his study has gone to the public, for vindication. One can only hope his study instructions were not as forthcoming as the condemnation in his article of the “damn liars” who “deny climate science”.
The general public is the ultimate arbiter and that is as it should be in a democracy. Science and statistics are the handmaidens of public decision making and they should be transparent and honest, “crystal clear” as Lewandowsky says. If they aren’t then the numbers will not stack up.
The numbers of AGW don’t stack up and Lewandowsky’s test subjects will be left to decide whether lies, damned lies OR statistics best describes AGW.