MITCHELL: The meaningless concept of an ‘average’ temperature of the Earth

Students take part in a global protest for climate change in Cambridge city centre, England, Friday March 15, 2019. Angry students mobilized by word of mouth and social media skipped class Friday to protest what they believe are their governments' failure to take though action against global warming. (Stefan Rousseau/PA via AP)

In the last article in this series on Anthropogenic Global Warming (“AGW”), I made the statement that “the concept of an average temperature of the earth is a figment of the climate scientist’s imagination.” Since that article was published, I have had numerous requests from readers to explain my reason for disputing the concept of calculating the earth’s average temperature in climate science analyses, since it forms the very basis for the AGW hypothesis.

First, I think that a review of basic mathematical concepts is in order. Mathematics is the language of science; however, it is important that scientists who employ mathematics not seek to mislead or deceive. A calculation in mathematics can be accurate without being valid. Let me illustrate this point with a simple example.


Suppose that during the coronavirus pandemic, a principal in a school asked a teacher to report on the health of the 15 students in his classroom. The teacher decided to measure the body temperature of each student as a proxy for their health condition. Seven of the students had a body temperature of 97.6. F; five had a temperature of 97.1 F; and three had a temperature of 103 F, because they had recently contracted the coronavirus. The average temperature of the fifteen students was calculated to be 98.5 F, well within the average range for a “normal” body temperature. The teacher reported to the principal that the average health of the students was normal. The calculation was accurate, but the conclusion was invalid.

Let’s examine the methodology that climate scientists use to calculate the average land-surface temperature, so we can illustrate the illegitimacy of the methodology employed to calculate the earth’s average temperature. Land-surface temperature measurements at different locations throughout the world are obtained daily by volunteers who record the high and low temperatures at meteorological surface air temperature stations (“MSATS”). Those readings are then “adjusted” for homogeneity and time of observation. 

The homogeneity adjustment is conducted if the readings are outside an established range of nearby MSATS; they are “adjusted” to agree with surrounding readings. The readings are further “adjusted” for the time of day that they were taken. If the volunteer read the thermometer at 12 p.m. instead of 2 p.m. to obtain the daily high temperature, the temperature reading may be arbitrarily increased by a climate scientist processing the data under the assumption that the temperature would have been higher at 2 p.m. instead of 12 p.m. 

My calculations, using published data on the homogenization and time of observation adjustments to MSATS temperature readings during the period 1980-2010, demonstrate that the combined adjustments have added 0.45 C (0.81F)/decade to the average MSATS readings. They added a significant warming bias to the data.

At this point, the methodology used to calculate the land-surface average temperature is rendered scientifically invalid. In legitimate scientific investigations, one does not “adjust” the data obtained in an experiment or investigation. To maintain the integrity of an investigation, the actual results (data) must be recorded. If the data is obtained in an inaccurate manner, the methodology must be changed. The data can not be changed to account for an inaccurate methodology. Let’s look at a famous example in history to illustrate the proper way to conduct a scientific investigation.

In May, 1919, Arthur Eddington, a physicist and professor of astronomy at Cambridge, traveled to the West African Island of Principe to photograph a total solar eclipse in an effort to conduct an observational test of the field equations involved in Einstein’s General Theory of Relativity. Einstein had predicted that starlight passing nearby the Sun would be deflected by about 1.75 arc-seconds by the effect of the Sun’s gravitational field on space, twice what Newton had predicted based on his linear theory of gravitation. As it turns out, the measurements that Eddington conducted on the astrographic lenses he used to photograph the eclipse proved Einstein right. Although Eddington had read Einstein’s work and believed him to be correct, it would have been unthinkable for Eddington to “adjust” his measurements to fit Einstein’s predictions. Subsequently, he sent 10 copies of the plates to colleagues around the world to independently verify his measurements.

The average temperature of the earth is calculated by climate scientists by averaging adjusted temperature data for the earth’s land mass, oceans and atmosphere for the day, month and year, adding it all together and then calculating an average of the adjusted averages. The result is meaningless and is the figment of the climate scientists’ imagination. 

This article is the seventh in a continuing series by Guy K. Mitchell, Jr. Mr. Mitchell is the founder and Chairman of Mitchell Industries, a diversified manufacturing company based in Birmingham, Alabama. Mr. Mitchell is writing a book on man-made global warming.