Sunk costs are investment choices (not necessarily monetary) that limit alternative choices, in this case climate-friendly choices. Four species of this have been identified:
- Financial investments: If someone invests in a car, for instance, she or he is then less likely to bicycle for environmental reasons. This monetary choice scales all the way to up to making important investments in fossil fuel stocks.
- Behavioral momentum: Habits are difficult to change, and many of our habits are not climate-positive. For example, eating habits and transportation habits can have strong negative effects on the climate and environment.
- Conflicting goals and aspirations: This is an especially difficult dragon. We all have multiple goals, often quite worthy in themselves, and those other goals and aspirations often conflict with the goal of not harming the environment.
- Lack of place attachment: Those who love the place in which they live are more likely to take care of it. Conversely, those with less attachment to the place where they live are also less likely to act in pro-environmental ways.