The subtitle of this post should be “much ado (by warmists) about very little (temperature change)”. What I have to say here will come as no surprise to a reader who is familiar with and impervious to global-warming hysteria. But the subject has been on my mind during these hot months of summer in Texas, which always stimulate a righteous sermon about global warming by our local weather Nazi.
I have downloaded two databases of global temperature estimates: the “official” GISS set (here) and the University of Alabama at Huntsville (UAH) set for the lower troposphere (here and here).
The GISS set comprises surface thermometer records going back to January 1880. It takes a lot a massaging to construct a monthly time series of “global” temperatures that spans 137 years, with spotty coverage of Earth’s surface (even now), and wide variability in site conditions, among other problems that can occur in a not-truly-global or systematically controlled network of thermometers over the span of 137 years. There’s the further issue of data manipulation, the most recent example of which was the erasure of the pause that had lasted for almost 19 years.
The UAH database goes back to December 1978, and consists of readings obtained by a system of satellites. A satellite-based system has obvious advantages over a surface-based system, if one’s objective is to obtain accurate and consistent estimates of Earth’s atmospheric temperature.
There are other databases, including those produced by RSS (satellite-based) and HadCRUT (surface-based). But the point of this post is to compare GISS records with those a satellite-based system, and I have chosen the GISS and UAH systems for that purpose.
In this graph you will see that despite efforts to hide the decline — a cooling trend from about 1940 to the late 1970s — GISS could only muster a long pause in the rise of its global temperature estimates.
(I used December 1978 as the “zero” point for ease of comparison with the next graph.)
Now look at UAH vs. GISS for the span covered by UAH, namely, December 1978 to the present:
The pause, according to RSS, extended from February 1997 to November 2015. This agrees with the UAH data for that period, which show a flat trend; whereas, the GISS data for that period show a rising trend. Taking the UAH slope as the correct one, it seems that GISS overstates the slope of the pause by 0.0011 degree C per month. Subtracting that overstatement from the GISS coefficient for the entire period gives a new GISS slope of 0.0007 degree C per month, which is close to the UAH slope of 0.001 degree C per month. It is also the same as the GISS slope for 1880-1937 (see first graph).
I therefore conclude the following: GISS has been doctored not only to hide the decline from about 1940 to the late 1970s and the pause from 1997 to 2015, but also to exaggerate the rise from the late 1970s to the present.
What is really going on? The recent rise in temperature has been ripped out of context. This is from a post by Dr. Tim Ball, the second item in “related reading”:
Recent discussion about record weather events, such as the warmest year on record, is a totally misleading and scientifically useless exercise. This is especially true when restricted to the instrumental record that covers about 25% of the globe for at most 120 years. The age of the Earth is approximately 4.54 billion years, so the sample size is 0.000002643172%. Discussing the significance of anything in a 120-year record plays directly into the hands of those trying to say that the last 120-years climate is abnormal and all due to human activity. It is done purely for political propaganda, to narrow people’s attention and to generate fear.
The misdirection is based on the false assumption that only a few variables and mechanisms are important in climate change, and they remain constant over the 4.54 billion years. It began with the assumption of the solar constant from the Sun that astronomers define as a medium-sized variable star. The AGW proponents successfully got the world focused on CO2 [emphasis added], which is just 0.04% of the total atmospheric gases and varies considerably spatially and temporally…. [I]t is like determining the character, structure, and behavior of a human by measuring one wart on the left arm. In fact, they are only looking at one cell of that wart….
Two major themes of the AGW claims are that temperature change is greater and more rapid than at any time in the past. This is false, as a cursory look at any longer record demonstrates…. The Antarctic and Greenland ice core records both illustrate the extent of temperature change in short time periods. Figure 1 shows a modified Antarctic ice core record.
Figure 1 (Original Source SPPI.org no longer available)
The total temperature range is approximately 12°C (-9°C to +3°C). The variability is dramatic even though a 70–year smoothing average was applied. The diagram compares the peak temperatures in the current interglacial with those of the four previous interglacials. The horizontal scale on the x-axis is too small to identify even the length of the instrumental record.
Steve Goreham shows how small a portion it is in this diagram of the last 10,000 years (Figure 2).
Another graph shows the same period, the Holocene Optimum, in a different form (Figure 3).
(Read the whole thing.)
The null hypothesis about “climate change” is that recent warming, whatever its true extent, is of a piece with natural variations in Earth’s temperature. I have yet to read anything that refutes the null hypothesis. A lot of what has been written seems, at first glance, to do so. But it does not do so. It assumes, or aims to prove, a causal connection between the steady rise in atmospheric CO2 that has accompanied the industrialization and mechanization of the world and the coincidental — and halting — rise in the temperature record since Earth began to emerge from the Little Ice Age. Thus the inability of simplistic climate models, which are heavy on CO2 effects, to accurately “hindcast” actual temperature changes, that is, to replicate them from the vantage point of the present.
But most of the public “knows” only the scare story told by the red line in my first graph. There’s no context. The explanation (“CO2 bad”) is superficial and misleading. But it sells the story that pseudo-scientists and politicians like James Hansen, Gavin Schmidt, Michael Mann, and Al Gore. want to sell. And which is sold with the eager assistance of the pro-big-government media outlets in the U.S. (i.e., most of them). It sells the story that leftists want to sell because it supports their need to control the lives of others through the agency of government.
Related reading (listed chronologically):
Ron Clutz, “Temperatures According to Climate Models“, Science Matters, March 24, 2015
Dr. Tim Ball, “Long-Term Climate Change: What Is a Reasonable Sample Size?“, Watts Up With That?, February 7, 2016
The Global Warming Policy Foundation, Climate Science: Assumptions, Policy Implications, and the Scientific Method, 2017
John Mauer, “Through the Looking Glass with NASA GISS“, Watts Up With That?, February 22, 2017
George White, “A Consensus of Convenience“, Watts Up With That?, August 20, 2017
Jennifer Marohasy, “Most of the Recent Warming Could be Natural“, Jennifer Marohasy, August 21, 2017
AGW: The Death Knell (with many links to related reading and earlier posts)
Not-So-Random Thoughts (XIV) (second item)
AGW in Austin?
Understanding Probability: Pascal’s Wager and Catastrophic Global Warming
The Precautionary Principle and Pascal’s Wager
AGW in Austin? (II) (with more links to related reading)
Four Kinds of “Liberals”
The Vast Left-Wing Conspiracy
Leftism As Crypto-Fascism: The Google Paradigm