Skepticism About Lower Atmosphere Temperature Data
Posted on 8 January 2012 by dana1981
Note: This article was submitted to Forbes as a correction to the op-ed by James Taylor in question, but Forbes declined to publish it, so instead we're posting it here.
Forbes recently published an op-ed written by James Taylor of the Heartland Institute on the subject of the University of Alabama at Huntsville (UAH) atmospheric temperature measurements on the record's 33rd anniversary. Unfortunately, the article contained a litany of errors which completely undermine its conclusions, and exhibited a distinct lack of true skepticism.
The main subject of the article was the fact that according to climate models, the Earth's lower atmosphere should warm approximately 20% faster than the surface, whereas UAH estimates place the lower atmosphere warming at about 20% less than surface temperature measurements. A true skeptic would acknowledge that there are three possible explanations for this discrepancy:
- The models are incorrect and the lower atmosphere should not warm faster than the surface.
- The surface temperature estimates are biased high, showing more warming than is actually occurring.
- The UAH lower atmosphere temperature estimates are biased low, showing less warming than is actually occurring.
Because the climate model expectation of greater lower atmosphere warming is based on solid fundamental atmospheric physics, and the accuracy of the surface temperature record was recently independently confirmed by Richard Muller and the Berkeley Earth Surface Temperature (BEST) project, the third possible explanation appears to be the most likely. This possibility is further supported by the fact that other groups have estimated greater atmospheric warming than UAH, and measurements by radiosondes (instruments on weather balloons) also show greater atmospheric warming than UAH.
It is certainly a possiblity that is worth considering, and yet it was notably absent from the three possible explanations for the model-data discrepancy provided by James Taylor in his article. In fact, every one of the three possible explanations offered by Taylor involved the man-made global warming theory being either exaggerated or incorrect. Refusing to consider a possibility which is inconvenient for one's pre-conceived notions and/or biases reveals a distinct lack of true skepticism.
Taylor's article contained a litany of additional errors. For example, he reported that the UAH temperature data "seem to show warming closer to 0.3 degrees over the 33 year period, or 0.09 degrees Celsius per decade," as opposed to the UAH-reported 0.14°C per decade warming. This is false. John Christy reported that if the influences of volcanic eruptions (which have a temporary cooling effect by releasing particulates into the atmosphere which block sunlight) are filtered out of the UAH record, the warming trend is reduced to 0.09°C per decade. However, in order to make an apples-to-apples comparison, the volcanic influence must also be removed from the climate models, which neither Christy nor Taylor did.
Additionally, a recent study by Foster and Rahmstorf filtered out the effects of not just volcanic eruptions, but also the El Niño Southern Oscillation (ENSO) and solar activity, which can also have significant short-term impacts on global temperatures. They confirmed Christy's finding that removing volcanic effects decreases the warming trend over the past three decades, but additionally removing ENSO and solar influences increases the trend over that same period. In other words, by only removing the influence of volcanoes, Christy and Taylor cherrypicked the effect which would minimize the observed warming trend. This again exhibits a distinct lack of true skepticism.
Taylor also implied that unlike surface temperature measurements, the UAH satellite data do not "require guesswork corrections." In reality, the UAH record requires a great number of corrections, because the satellite instruments do not even directly measure atmospheric temperatures. Rather, they measure the intensity of microwave radiation given off by oxygen molecules in the atmosphere, from which the scientists estimate the temperature. The satellites sensors face down toward the Earth and radiation therefore reaches the satellites having travelled upwards through a warming lower atmosphere and cooling upper atmosphere. This influences any warming signal received by the satellites, and because the lower atmosphere is what is being measured. creates a cooling bias that has to be accounted for. But it doesn't end there; bias also exists between the various instrument sensors on each satellite, and the satellite orbits decay over time. These and a number of other obstacles mean a lot of careful and painstaking analysis is required. As a result of all this complexity and data correction, there's much that can go wrong.
Considering these challenges, it's not a surprise that there have been a number of major corrections to the satellite temperature data over the years. Groups outside of UAH identified two major errors in the UAH analysis, both of which had caused Spencer and Christy to significantly underestimate the atmospheric warming. Despite the difficulties in the available data, and the numerous adjustments made to their analysis, Spencer and Christy have all along insisted that their data set is correct, and they (and James Taylor) continue with this overconfidence today. However, the most likely explanation for UAH showing less warming than models and atmospheric physics predict is that UAH is biased low.
Taylor's error-riddled article demonstrates that when it comes to climate science, we should listen to climate scientists, who are true skeptics, rather than a law and policy expert from a fossil fuel-funded think tank.
Rather than correct the errors by publishing this article, Forbes compounded the problem by publishing a very similarly erroneous post from serial misinformer Patrick Michaels (who admits that like Taylor, he is also heavily fossil fuel-funded). Ironically, Forbes recently published Peter Gleick's 2011 Climate B.S.* of the Year Awards. If Forbes continue with this trend of publishing and compounding misinformation while ignoring corrections, perhaps they will make a run for the 2012 award!