Whatever your position on climate change policy, this question is a good one to ask. It drives you to do two important things: consider what it would take to change your mind, and consider the risks associated with making the wrong choice.
I would change my position on what action we should take in response to climate change if any of the following was adequately demonstrated:
- The Earth’s climate is not changing.
- Greenhouse gas emissions are not the cause of warming.
- Warming will not be dangerous.
Exactly what level of evidence would be required is difficult to pre-judge, but the definitive rebuttal of any of those positions would be sufficient to prompt a major change in the policies I would advocate.
On the question of risks, there are two major kinds of error we could make: over- and under-reacting. If we over-react to climate change, we would sacrifice wealth and other opportunities in order to cut out emissions, achieving no good purpose. At the very worst, we would seriously damage the global economy for an indefinite span of time, and delay the emergence of many people from extreme poverty. If we under-react, the very worst outcome would be the undermining of the capability of the planet to support human life. This is clearly a much worse outcome, though it is not an easy task to determine how probable it is, relative to the ‘overreact and go broke’ possibility. Clearly, I think that the risks of climate change as it is now understood justify much more action than we have taken to date.
Another thing to bear in mind is that there are co-benefits to shifting the energy basis of our society from fossil fuels to zero-carbon and renewable options. In his response to the Munk Debate, Tyler Hamilton lays out a few: “I mean, even in the unlikely event that climate change science shows us we overreacted, is it such a bad thing that we also acted to reduce air pollution, mercury emissions, the use of water in thermal power plants, and the other environmental footprints caused by our addiction to fossil fuels. That’s a pretty nice consolation prize.” In a situation where we took aggressive action, we would also be better protected from the distinct but related challenge of peak oil. Fossil fuels are inevitably going to run out anyhow, so the real cost here is of making the transition away from them earlier than we otherwise would. Climate change or not, a fossil fuel based economy simply cannot keep going forever.
Ultimately, the choice we make on climate change policies is a matter of risk management. Being able to hedge against a potentially catastrophic risk, and secure co-benefits, while simultaneously running some risk of overreacting seems much more prudent and sensible than doing the opposite.