By Glenn Spitzer (November 4, 2023)
Who are these “climate change deniers” we hear so much about? Does anyone really doubt the climate changes?
Well, yes. There are climate change deniers—a lot of them. They live right under our noses, and they are celebrated. Here’s a quote from one of the most famous climate change deniers:
“Our civilization has never experienced any environmental shift remotely similar to this. Today’s climate pattern has existed throughout the entire history of human civilization.”
That was Al Gore in 2007. According to Gore, the climate was “shiftless” for thousands of years—a paradigm of stability.
Gore’s quote was a restatement of Michael Mann’s 1998 “hockey stick theory.” Mann argued that the Earth’s climate held steady for all of human history (the hockey stick handle) until suddenly in the 1900s the temperatures increased, representing the upturned blade of the hockey stick.
Mann’s theory is the basis of the modern CO2-focused “global warming” movement, which ironically morphed into the “climate change” movement. Mann’s theory informs the positions taken by the Intergovernmental Panel on Climate Change (IPCC), the agency dictating policy to your local, state, and federal governments.
The most important assumption in Mann’s theory is that there was no climate change prior to the 20th century. But this assumption is false. It is climate change denial; it is the sacrifice of truth for a desired outcome.
Mann’s 1998 study intentionally ignored several thousand scientific publications showing other periods of climate change throughout human history, such as the Medieval Warm Period (about 900 AD to 1300 AD), the Little Ice Age (about 1300 AD to 1915 AD), and the Roman Warm Period (about 1 AD to 500 AD). Despite claims of perpetual stability, it turns out the climate is always changing.
Scientists estimate that, during the Medieval Warm Period, for example, the temperatures in parts of Europe were 1.0-1.4° Celsius (1.8 – 2.5° Fahrenheit) warmer than they are now. (Oliver, 1973; Fagan, 2000; Fagan, 2007; and Singer and Avery, 2007). Oxygen isotope studies in China, Germany, Greenland, Ireland, New Zealand, Switzerland, and Tibet, as well as tree-ring data from many sites throughout the world, confirm the Medieval Warm Period. The studies are so numerous (several thousand published papers confirming this warming), that it raises the obvious question: “Why do climate activists deny that the climate is always changing?”
There are two important reasons why activists deny climate change. First, the acceptance of prior warming periods undermines the argument that a modern warming is an existential threat; and second, prior warming periods undermine the idea that anthropogenic (manmade) CO2 is the primary cause of climate change.
The Medieval Warm Period is a particularly inconvenient truth for the modern climate activists because it shows warming has beneficial effects on humanity. As the European region became warmer, agriculture spread and generated food surpluses. The European population doubled. In short, the Medieval Warm Period underscores the reality that, while humans struggle in colder weather, we generally thrive in warmer weather. In other words: no crisis justifying extraordinary intervention.
But more importantly, what does a constantly changing climate say about the effects of anthropogenic CO2?
The fact that the climate has been changing significantly for thousands of years (actually millions) begs the question: what causes climate change? This is a messy question. Activists seek to foreclose options by addressing causation through simple correlation. If climate change is only a recent phenomenon, one that began coincidentally with the rise in anthropogenic CO2, then causation is simple.
However, if this fact pattern is a fiction, then the correlation argument falls apart. When we understand the climate is always changing, and was changing well before the rise of anthropogenic CO2, then we are confronted with the reality that other factors are at play. Anthropogenic CO2 is placed in proper context as a potential factor of uncertain significance. Importantly, when simple correlation no longer drives our analysis, we are freed to assess other causal factors more seriously.
When people acknowledge that anthropogenic CO2 could not possibly cause climate change throughout human history, they are forced to question their religion. When guided by truth instead of ideology, the following questions become more interesting:
- How is it that the last six great ice ages started with far more CO2 in the atmosphere than we have now?
- Is it true, as many experts note, that temperatures drive CO2 levels, and not the other way around?
- How does anthropogenic CO2 drive climate when it makes up less than 5% of total CO2 (with most coming from the oceans, volcanoes, decaying vegetation, and forest fires)?
- Isn’t the sun the most important cause of climate, and what effects follow from sun spots and solar flares?
- If greenhouse gases (GHGs) are the most significant drivers of climate change, then why do we focus on CO2, when water vapor (i.e., clouds) is a far more impactful GHG? (In fact, there have been a flurry of recent published studies on the effects of clouds.)
For many in science, self-preservation and status remain subordinate to truth and courage. Many have sacrificed research funding and reputation to criticize Mann’s theories, including IPCC lead authors John Christy (former NASA climatologist) and Richard Lindzen (former MIT professor). In fact, numerous climate experts upended their professional lives by pointing out that Mann’s theory is more activism than fact (including Professors Tim Ball, Ian Clark, Ian Plimer, Nir Shaviv, Piers Corbyn, Steven Koonin, Judith Curry, and William Happer—to name a few).
Experts Steve McIntyre and Ross McKitrick presented a detailed analysis of the flaws of Mann’s 1998 theory in a series of studies in 2003 and 2005, detailing the numerous technical flaws with Mann’s analysis. They found Mann’s theory was invalid “due to collation errors, unjustifiable truncation or extrapolation of source data, obsolete data, geographical location errors, incorrect calculation of principal components and other quality control defects.”
In a 2014 paper, McKitrick summarized the theory’s most significant problem as an issue of unreliable proxy data. Namely, Mann relied on a small and controversial subset of tree-ring records of bristlecone pine cores from high and arid mountains in the US Southwest. The scientists who published the tree-ring data on which Mann relied (published by Graybill and Idso in 1993) specifically warned that the data should not be used for temperature reconstruction and that the 20th century data had regional anomalies.
The overarching takeaway here is that we cannot cede the power of thought to the “experts.” Experts serve an important role in that they assist us in analyzing matters beyond our common understanding. But experts are mere fallible humans. When they are controlled by their biases, flawed in their analysis, or misguided by incorrect data, then we must reject their conclusions.
By Glenn Spitzer
About Glenn Spitzer
Glenn Spitzer is an environmental litigator who practices in California. He predominantly represents governmental agencies.
