numbers, not adjectives — D. J. C. MacKay

12  Alice, Bob and the Climate

Carl Edward Rasmussen, July 4, 2024

[ comment: Alice and Bob are fictional characters commonly used as placeholders in discussions. As I explain in my piece on degree person days, Bob's experience doesn't literally correspond to that of a specific person. But units of degree person days summarise the effects of incremental emissions to global climate change in a relatable personal way, which adds up to identical consequences. One decomposition isn't more real than another, but intuitive, relatable measures are essential to our understanding. ]

Alice and Bob don't know each other personally, but they both know that the other exists somewhere in the world. Alice is considering taking an action which will release 2 tons of CO₂ into the atmosphere, which Alice and Bob share. For the purposes of this fable, it doesn't matter much what the action is, let's say it's a long haul flight. Bob will experience the extra heating caused by the CO₂ released by Alice's activity. If Alice goes ahead with her plan, Bob will experience 1000 days of 1°C hotter environment, than if Alice choses not to. That's because, 2 tons of CO₂ is equivalent to 1000 degree person days.

In the following, we imagine what reasoning Alice may use to decide whether or not to take her action, possibly considering the plight of both herself and Bob. But in our thought experiment, Alice and Bob can't directly discuss the problem with each other, because they don't know each other's identities. What might Alice do?

• Alice thinks that it's unlikely that there will be a good outcome to the climate crises, and thinking about it makes her depressed, so she avoids that.
• Alice thinks that there are more urgent issues than climate change. The characteristic time for climate change is decades, so it is unlikely to ever reach top priority.
• Alice reasons, that since many other people are in the same situation as Bob, for example Charlie, Dave and millions of others, it doesn't on the whole, matter much what happens to Bob.
• Alice thinks climate change is unavoidable anyway, and is happy to contribute.
• Alice is a member of a frequent flyer program, and will lose her status if she reduces her flying.
• Alice thinks, that since she doesn't know Bob personally, it's not her problem. If Bob had been family, or a friend, colleague or neighbour, it would be different.
• Alice thinks it only makes sense to avoid her action if millions of other people will do the same, otherwise her individual contribution feels insignificant.
• Alice thinks it's silly to think of the impact of her action on a single person, and dismisses the idea.
• Alice is concerned about Bob, but since it is either expensive, inconvenient or downright impossible to do what Alice wants to do without releasing the CO₂, she will do it anyway.
• Alice thinks, that we've got the Paris Agreement, and the annual COP meetings, surely the climate will be sorted out by someone else.
• Alice would like not to undertake the action, but because of pressures of her employer, social group or family, she feels she has to conform. Society is to blame. Alice is vaguely aware that society is made up of individuals like herself, but she's never been much of a trail blazer.
• Alice thinks in principle it is wrong to take her action, but since so many other people do it too, this legitimises it.
• Alice thinks that climate change is a hoax.
• Alice has children, and it's important to her to give them the best prospects for the future.
• Alice was never that good at science. Surely climate change can't really be happening?
• Alice works for the fossil fuel industry. She knows that climate change is having disastrous consequences now and in the future, but she has to make a living.
• Alice thinks that Bob's problem is none of her concern, thinking about him would interfere with her personal freedom.
• Alice thinks of herself as a moral and ethical person. But she has a busy life to get on with, and really doesn't have time to think about Bob.
• Alice has empathy for Bob although she doesn't know him personally, and decides not to take her action.
• Alice realises that although she is Alice and Bob is Bob, it could have been reverse. If she had been Bob she would have wished that Alice would be altruistic, and therefore she reasons that she should avoid her action.

Which Alice are you?

To be successful in limiting climate change, we have to understand Alice's reasoning.