“Just the facts, ma’am.”
“Politics is a battle of ideas; in the course of a healthy debate, we’ll prioritize different goals, and the different means of reaching them. But without some common baseline of facts; without a willingness to admit new information, and concede that your opponent is making a fair point, and that science and reason matter, we’ll keep talking past each other, making common ground and compromise impossible.”
– President Obama (Jan. 10, 2017)
Simple Definition of fact
- : something that truly exists or happens : something that has actual existence
- : a true piece of information
Source: Merriam-Webster's Learner's Dictionary
“Just the facts, ma’am.” #1
Some simple words are often used imprecisely. In discussions related to climate science, the simple word “fact” is a case in point. For example, a temperature measurement taken by an observer from a particular instrument, in a particular enclosure, at a particular location and at a particular time is frequently referred to as a “fact”. However, it is only a “fact”, as defined above, in those particular circumstances. It is not necessarily and not even likely “a true piece of information”, in the broader sense, since it is affected by those circumstances.
Temperature measurements taken “near-surface” are “selected” for inclusion in the temperature record; and, are then “adjusted” to account for the particular instrument, enclosure, location and time of observation. These “adjusted” measurements are not “something that truly exists or happens”, but rather an estimate of something that might “truly exist or happen”.
An “ideal” near-surface temperature measurement site is identified as follows: Climate Reference Network (CRN) Site Information Handbook
Class 1– Flat and horizontal ground surrounded by a clear surface with a slope below 1/3 (<19º). Grass/low vegetation ground cover <10 centimeters high. Sensors located at least 100 meters from artificial heating or reflecting surfaces, such as buildings, concrete surfaces, and parking lots. Far from large bodies of water, except if it is representative of the area, and then located at least 100 meters away. No shading when the sun elevation >3 degrees.
Such a site is estimated to be able to produce a near-surface temperature measurement with an error of less than 1oC, assuming proper instrument selection and calibration, proper enclosure and timely reading. Such a measurement is a “fact”, subject to those limitations.
Climate science deals with these errors of “fact” regarding near-surface temperature measurements by using temperature anomalies, or the differences between temperature measurements taken at a particular site. These anomalies are “facts” only if there have been no changes in any of the circumstances which affect the measurements; and, they cease to be facts if the measurements are “adjusted”, rendering them merely estimates.
“Just the facts, ma’am.” #2
Above I discussed the limitations on “facts”; and, the difference between facts and estimates related to individual temperature measurements, whether analyzed as discrete temperatures or temperature anomalies.
Once near-surface temperature measurements have been recorded, selected and “adjusted”, the next step in the process is to combine these selected, “adjusted” temperature estimates, expressed as anomalies from previous selected, “adjusted” temperature estimates, into an estimated global average near-surface temperature anomaly. While it might be argued that errors in the recorded temperature measurements might be random, it cannot be argued that the selection of the temperature measurements to be included in the global average calculation or the “adjustments” made to these temperature measurements are random. There could be no rational explanation for making random “adjustments” to measurements.
The estimated global average surface temperature anomaly is reported to two decimal place “precision”; and, used to calculate decadal rates of temperature increase to three decimal place “precision”. This level of “precision” is highly questionable, bordering on ridiculous, considering the inaccuracy of the underlying temperature measurements. The underlying temperature measurements are estimated to be in absolute error by an average of more than 2oC in the US, where they have been surveyed and their siting compared to the US CRN1 siting requirements. The expected inaccuracy of the remaining global temperature measuring stations is assumed to be similar, though they have not been surveyed and their siting compared to the US CRN1 siting requirements.
Finally, the estimated “adjusted” global average temperature is reported to two decimal place “precision”. This estimate is reported as a “fact”, though the particular circumstances under which the estimate might have been a “fact” are ignored.
“Just the facts, ma’am.” #3
“Just the facts, ma’am.” (1 & 2) discussed “facts” in the context of individual near-surface temperature measurements and global average temperature anomaly calculations. The final step in the climate change analysis process is the creation of future climate change scenarios using climate models.
There are numerous climate models, none of which have been verified. Therefore, it cannot be said that there is a climate model which is a “fact”, in the sense that it accurately models “something that truly exists or happens”, rather than hypothesizes something which might happen if the model were accurate.
The climate models are run using a range of inputs for climate sensitivity and climate forcings, because there are no specific, verified values for the various sensitivities and forcings. Therefore, not only are the climate models not “facts” (“something that truly exists or happens”), the inputs which feed the models are not “facts” either, in the sense that they are “a true piece of information”. It is not even a “fact” that the actual climate sensitivity or actual climate forcings are within the ranges of the values used as inputs to the models.
Therefore, the modeled scenarios of future climate change (temperature change) are not “facts”, or arguably even based on facts. Rather, they are estimates, based on estimates, of the potential change in current estimates over some future period.
Based on the “facts”, as discussed in these commentaries, there is only a tenuous basis for concern about catastrophic anthropogenic climate change.
That’s “Just the facts, ma’am.” (HT: Sgt. Joe Friday, LAPD)