Guest “put in context” by David Middleton
Our friends from the CO2 coalition published another excellent report.
This white paper by Richard Lindzen and John Christy examines the global record for mean temperature anomalies. Your focus isn’t on whether it’s right or wrong; It is due to its importance in relation to natural variability and its inherently low signal-to-noise ratio. Here is the summary:
STUDIES AND RESOURCES, WHITE PAPERS AND OTHER PUBLICATIONS
4th December 2020
The Global Mean Temperature Anomaly Record
How it works and why it is misleading
by Richard S. Lindzen and John R. Christy
The Coalition of CO2 is honored to present this Climate Issues in Depth Paper by two of America’s most respected and productive atmospheric physicists, MIT professor emeritus Richard Lindzen, longstanding member of the coalition, and Professor John Christy of the University of Alabama in Huntsville to introduce.
Professor Lindzen has published over 200 scientific articles and books in his five-year career. He has held professorships at the University of Chicago, Harvard University and MIT. He is a fellow and awardee of the American Meteorological Society and the American Geophysical Union. He is also a member of the National Academy of Science and was the lead author of the scientific volume of the third United Nations IPCC Assessment Report. His research has highlighted the scientific uncertainties about the effects of carbon dioxide emissions on temperature and climate in general.
Professor Christy, the director of the Earth System Science Center at the University of Alabama in Huntsville, began studying global climate problems in 1987. He has been Alabama’s state climatologist since 2000 and a member of the American Meteorological Society since 2002. He and CO2 Coalition member Dr. Roy W. Spencer developed and maintained one of the most important global temperature data sets on which scientists and government agencies relied, and used microwave data observed by satellites in the troposphere since 1979. For this achievement, they were awarded the NASA Medal for Outstanding Achievement in Scientific Achievement.
The purpose of this paper is to explain how the data set referred to by policymakers and the media as the global surface temperature record is actually being preserved and where it fits into the popular narrative associated with climate alarm.
At the center of most discussions about global warming is the recording of the global mean surface temperature anomaly – often misleadingly referred to as the global mean temperature record. This paper deals with two aspects of this data set. First, we note that this record is just one link in a rather long chain of inference that leads to the alleged need to reduce CO2 emissions worldwide. Second, we examine the implications of the way the dataset is created and presented, and show why the dataset is misleading.
This is because the record is often treated as a kind of single direct instrumental measurement. However, as the late Stan Grotch of Laurence Livermore Laboratory pointed out 30 years ago, it is actually the average of widely dispersed station data, with actual data points almost evenly spaced between large positive and negative values.
The average is simply the small difference between these positive and negative excursions, with the usual problem associated with small differences in large numbers: at least so far, the one degree Celsius increase in the global mean since 1900 has been inundated by the normal fluctuations at individual stations , and therefore has little relation to what is actually going on at a particular station.
The changes at the stations are distributed over the global average increase of one degree. Even if a single station had registered this increase itself, this would assume a typical annual temperature range of, say, -10 to 40 degrees in 1900 and replace it today with a range of -9 to 41. People, plants and the weather at this station would find it hard to tell this difference.
However, the increase appears to be significant in the charts used in almost all presentations as they omit the range of the original data points and expand the scale to make the mean change appear large.
While the record shows certain consistent trends, it is also quite noisy, and fluctuations of a tenth or two degrees are unlikely to be significant. In the public discourse little attention is paid to the greats; Rather, the focus is on whether this anomaly is increasing or decreasing. Given the noise and sampling errors, it is quite easy to adjust such averaging and even change the sign of a trend from positive to negative.
The usual presentations often suppress the noise by using moving averages over periods of 5 to 11 years. However, such processing can also suppress significant features such as the large variations that always occur at individual stations. Finally, we show the big natural temperature changes that Americans face each year in 14 major cities. For example, the average difference between the coldest and warmest moments each year is between about 25 degrees Celsius in Miami (a change of 45 degrees Fahrenheit) to 55 degrees in Denver (a change of 99 degrees Fahrenheit). We contrast this with the easily manageable rise in the global average temperature anomaly of 1.2 degrees Celsius over the past 120 years, which has caused so much alarm in the media and in political circles.
The full paper can be found here: Global Mean Temperature Anomaly Record 12.20
This is evident from their concluding remarks:
In fact, the alarming global temperature change of 1.2 degrees Celsius over the last 120 years, shown in Figure 7, corresponds only to the thickness of the “Average” line in Figure 9. As the figure shows, the difference corresponds to the average temperature compared to January to July in these large cities ranges from just under ten degrees in Los Angeles to nearly 30 degrees in Chicago. And the average difference between the coldest and warmest moments each year ranges from about 25 degrees in Miami (a change of 45 degrees Fahrenheit) to 55 degrees in Denver (a change of 99 degrees Fahrenheit).
Global Mean Temperature Anomaly Record 12.20
Here is Figure 7:
Here is Figure 9:
I think an even better way to put the global mean surface temperature anomaly record in proper context is to display it on the same scale as a traditional household thermometer.
Anomaly against the thermometer. Oh where, oh where did my little HadCRUT4 go?
In the representation above 0 ° C on HadCRUT4, the approximate average surface temperature on earth is plotted at 15 ° C on the thermometer. Both have a range of 80 ° C.