Debunking the deniers: the 5 pillars of science behind human-caused climate change  

If you’re a scientist, science communicator or the lone climate change advocate at your dining-table discussion, you’ve probably debated a climate change denier or two. So how can we bust the myths and misinformation and deliver the facts about climate science?

A group of scientists and science communicators, including Stephan Lewandowsky and John Cook, have updated their handbook on debunking climate deniers. But before launching into a discussion about climate change, it is important to understand a few common tactics used by climate change deniers.

#1: Cherry-picking data

Climate change deniers may select a small aspect of climate change that gives an incomplete or distorted picture to argue their point.

#2: Exaggerating uncertainties

They may fixate on gaps in knowledge to argue that ‘we know nothing’. While there is still research to be done to fully understand the impacts and responses to climate change, climate scientists are very confident about a lot of things, such as that our climate is changing and that recent changes are mainly caused by human activities.

#3: Claiming obscure alternative causes of climate change

They may argue that changes in the Sun, volcanoes, the ozone hole, natural variability, or anything except carbon dioxide emissions from human activities is responsible for climate change.

#4: Pointing out errors

They may heavily criticise any incorrect statement that reaches the media or fixate on past data discrepancies.

#5: Discrediting scientists

They may play the person rather than the ball, saying that scientists are corrupt or are exaggerating to get more funding.

Decoding tactics and arguments used by climate change deniers allows us to understand their viewpoints, and how best to debunk their misinformation and incorrect arguments. But to do so, we need to ensure our own science communication about climate change science is effective. Understanding the 5 pillars of science behind human-caused climate change helps us do this.

Pillar 1: Theory

Climate change science is based on a physical understanding of the climate system, the basics of which have been known since the 1800s. The primary drivers of climate – sunlight, cloud cover, greenhouse gases, ocean heat uptake, atmospheric and ocean circulation, and ice and snow – have been well understood for years. Detailed climate models run on sophisticated supercomputers can now simulate future climate in ways that can help make decisions.

Pillar 2: Carbon dioxide trend

Atmospheric carbon dioxide concentrations are higher now (417 parts per million) than at any time in the past 2 million years. Evidence of the rapid rise in carbon dioxide due to human activities comes from many independent observations and studies across the globe. The chemical signature of atmospheric carbon dioxide confirms its origin to be from burning fossil fuels.

Pillar 3: Observed climate change

Observed changes in many different components of the climate system are consistent with theoretical and modelled expectations of human-caused climate change.

Pillar 4: Missing alternative theory

No other causes can explain the climatic changes that have been observed over the past 200 years. Scientists have examined the variations of sunlight, volcanic eruptions, natural climate vulnerability and other factors and shown that recent warming can only be explained due to human activities increasing greenhouse gases in the atmosphere.

Pillar 5: Impact

Recent climate change is just the start of what may come. Compared with the past 2,000 years of natural climate variability, the next 100 years will see rapid and unprecedented temperature rises if no efforts are made to reduce global emissions.

So, we know the tactics of deniers, and we know the science behind human-caused climate change. But what is the best way to debunk misinformation about climate change?

The Debunking Handbook 2020 outlines the best process for refuting misleading or incorrect scientific information. It recommends that you:

1. lead with the facts (the correct information) in a simple, clear and pithy way
2. follow this with a warning that the myth or misleading information is incorrect
3. explain how the myth or misinformation is incorrect using logical and clear arguments based on facts
4. finish by reiterating the fact (repeating it multiple times, if possible) to reinforce the correct information.

Using the 5 pillars of science behind human-caused climate change, refuting misleading information or myths clearly and repeatedly, and communicating in a factual, succinct and calm way are the best ways to make a scientific case so compelling that even the most decided climate change deniers will have to listen. Good luck!

Access the debunking Handbook 2020 for more insights into how to refute scientific misinformation: www.climatechangecommunication.org/wp-content/uploads/2020/10/DebunkingHandbook2020.pdf