Climate change deniers are individuals who refute the existence of climate change, and they are quite numerous. One prominent figure who has denied climate change is Al Gore, who made a statement to that effect in 2007. His denial echoed the "hockey stick" theory presented by Michael Mann in 1998. Mann's theory proposed that the Earth's climate remained stable until the 1900s, when temperatures suddenly rose. This theory forms the basis of the contemporary "global warming" movement, which has now become the "climate change" movement. The positions held by the Intergovernmental Panel on Climate Change (IPCC), which greatly influence government policies, are built upon Mann's theory.
However, it is important to note that Mann's theory is based on a false premise - that there was no climate change before the 20th century. By rejecting scientific evidence for the sake of desired outcomes, this amounts to denying climate change altogether. Mann's study deliberately disregarded numerous scientific publications that demonstrate various periods of climate change throughout human history. Examples of such periods include the Medieval Warm Period, the Little Ice Age, and the Roman Warm Period. These instances clearly indicate that the climate is constantly changing.
During the Medieval Warm Period, for instance, temperatures in parts of Europe were estimated to be 1.0–1.4°C (1.8–2.5°F) warmer than current temperatures. Multiple studies involving oxygen isotope measurements and tree ring data from different locations in the world have confirmed the existence of this warming period. Despite the abundance of published research supporting this warming phase, it raises a pertinent question: why do climate activists persist in denying that the climate is always changing?
There are two significant reasons why activists deny climate change. Firstly, acknowledging previous warming periods undermines the argument that current warming is an existential threat. Secondly, past instances of warming challenge the notion that human-generated CO2 is solely responsible for climate change. These factors contribute to the denial of climate change among certain individuals.The Medieval Warm Period presents a challenge for modern climate activists as it demonstrates the positive impacts of warming on society. During this period, agriculture and food surplus saw an increase in Europe, ultimately leading to population growth. These findings highlight the idea that warmer weather generally benefits humans instead of causing a crisis that requires significant intervention. Moreover, the prolonged history of climate change raises questions about its causes. Activists often simplify the issue by correlating climate change with the rise of human-induced CO2 emissions. However, considering that climate change has occurred throughout history, even before the increase in human-induced CO2, it becomes necessary to explore other factors. This helps put the significance of anthropogenic CO2 into perspective, encouraging a more open-minded approach to understanding the causes of climate change.
Challenging the notion of anthropogenic CO2 as the sole cause of climate change throughout history forces people to question their beliefs. This realization prompts individuals to consider alternative causal factors. In their pursuit of accurate scientific analysis, many scientists have taken the risk of criticizing theories that prioritize activism over facts. The flaws in Michael Mann's theory, as highlighted by experts like Steve McIntyre and Ross McKitrick, include collation errors, outdated or incorrect data, and reliance on unreliable proxy data. These shortcomings underscore the importance of not blindly accepting the expertise of individuals but rather actively examining their biases, flawed analysis, and incorrect data. Only through critical evaluation can we ensure accurate and reliable information to inform effective climate activism.