Often, when I raise the issue of climate change with strangers, they jump immediately to the matter of doubt – any and every reason we might have for doubting that climate change is a real and serious problem. They point to the uncertainties associated with computer models, and to past instances where problems do not seem to have been as bad as we once feared they could be.
Critical thinking is a good and necessary thing. At the same time, I don’t think focusing on the doubts is the appropriate response to what we now know about the climate. The world’s scientists have reached a consensus that human activities warm the planet. Most importantly, there is a lot of agreement and evidence that doubling the amount of CO2 in the atmosphere warms the planet by about 3°C, and that warming of more than 2°C is dangerous. We also know that there is more than enough coal, oil, and gas on Earth to double the amount of CO2 in the atmosphere several times. As a consequence, we know that burning all the world’s fossil fuels would be dangerous.
To me, this collection of beliefs seems like it ought to motivate considerable action to move to alternative forms of energy. It’s like a group of doctors telling a patient that they probably have cancer. It would be unwise for the patient to delay taking any action until they could be 100% sure of the diagnosis – especially if the patient would only be satisfied with an extreme form of proof. After all, the only way to know for sure that you have a potentially fatal illness is to wait until it kills you. Similarly, the only way to prove for certain that climate change threatens human civilization is to let it continue unchecked until that outcome is achieved.
We should certainly maintain a realistic sense of what we know about the climate, what is uncertain, and what remains deeply mysterious. At the same time, we should not put off action just because we don’t know absolutely everything. That is especially true given the nature of the choice confronting us. We would need to stop using fossil fuels anyhow, since they would run out if we didn’t stop using them voluntarily. Furthermore, we know that fossil fuel production and use causes all sorts of harm to human health and welfare. By moving to a zero-carbon global economy, we will reduce the amount of risk climate change creates for humanity. At the same time, we will shift the energy basis of society to a renewable one that can be relied upon forever, and which does not involve the same toxic emissions and other forms of ecosystem destruction linked to fossil fuels.