Climate skeptics’ arguments generally fall within the following five main categories according to Washington and Cook (2011). An understanding of these categories of skeptics’ arguments can help you evaluate arguments not only related to climate change, but to a variety of issues.

Conspiracy Theories

Skeptics may suggest that there is a vast conspiracy among scientists to deceive the public. For example, in 2009, a few highly reputable climate scientists’ emails were stolen from the servers at the University of East Anglia in Britain. A few quotes were misinterpreted and used to claim that global warming was a conspiracy. This incidence is referred to as “Climategate.” A series of international investigations were conducted, and the scientists were all cleared of any scientific malpractice.

Fake Experts

Skeptics may question whether there is a scientific consensus on the cause of climate change. When reports, such as the Petition Project, published by the Oregon Institute of Science and Medicine in 2008, lists over 31,000 people who claim to be scientists and reject human-caused climate change; people may doubt whether there is a scientific consensus. It is important to examine who the experts are. In this case, the experts included mostly people with a bachelor’s in any field of science and engineering and not climate scientists. In a comprehensive survey of 3,146 earth scientists, who actively research climate change,97.5% answered that human activity is a significant contributing factor in changing mean globaltemperature (Doran and Zimmerman, 2009).

The Expectation of Certainty

People want 100% certainty; yet science focuses on establishing probability rather than certainty. Through the use of consensus-building activities––challenging others’ ideas, reexamining and retesting data, critiquing others’ work through the peer-review process––scientists have been able to accumulate knowledge about which we can be reasonably confident. There are, however, scientific mysteries that are not yet well understood, and conclusions about these are likely to have a much lower probability of accuracy.

Climate models are important tools that help scientists understand the past, present, and future climate. These models are based on mathematical equations that represent the basic laws of physics that govern the interactions within the climate system. Climate models are tested against observations so that scientists can see if the models correctly simulate what happened. These models can then predict future trends. Even though skeptics often question the uncertainties of climate models, these models have evolved to the point where they can successfully predict long-term trends and are developing the ability to predict shorter-term, more chaotic changes.

Cherry-Picking Evidence

Climate skeptics often cherry-pick the evidence they use to support their claims and ignore other evidence. For example, skeptics may select data from a shorter a span of time––a year or a decade––to show a particular trend, such as cooling temperatures or a decrease in the melting rate of Arctic sea ice. However, it is necessary to look at data over a longer time period—at least 30 or more years—to analyze climate trends.

Science Misrepresentations

A common claim of skeptics is that climate has changed naturally in the past, so recent changes in climate must also be natural. According to Washington and Cook (2011), this argument reveals a lack understanding of climate sensitivity––a measure of how responsive the temperature of the climate system is to a change in energy balance. It is easy to accept misrepresentations if you do not have a thorough understanding of Earth’s energy balance and role of the natural greenhouse effect. There are many other misrepresentations related to a lack of scientific understanding. You will explore several of these “misrepresentations” when you develop a scientific argument.

See Skeptical Science and Washington and Cook, 2011 for more information and examples of these types of climate arguments.