The first idea amounts to an error theory. Some of the rhetorical appeal of the economic realist position rests on a misdiagnosis. The essential rationale for the current generation’s continuing with relatively high levels of emissions in the near term is one of self-defense, rather than self-interest more generally. Given the tightening emissions budget, and strong evidence of severe risks to the future, the initial default answer to the trajectory question is that we should cease emitting. At first glance, the only even vaguely adequate reason for not doing so is that such a demand is unreasonable, in the sense of violating fundamental entitlements that are protected by a right to self-defense.
To see the appeal of this view, imagine that our generation faced a different intergenerational issue. Suppose the normal food supply became contaminated with a pesticide that has only intergenerational effects. Specifically, the pesticide caused increasingly severe and painful deformities three generations hence and then for ten more generations, in direct proportion to the amount used by us. What could justify our continuing to employ it?
The obvious answer is “very little.” Among the more dubious possibilities would be claims such as “food produced this way is cheaper than organic,” or “the future will be richer if we keep using the pesticide,” or “the future should pay us to stop using the pesticide.” More promising answers would include “we will starve,” or “our families will fall into poverty,” or “given the structure of our economy, our community will collapse.” These all involve severe consequences for the agent, and so appeal to something like a right to self-defense.
Still, the self-defense framing does not leave everything as it was. On the one hand, such a right would come with sharp limits. Consider some examples. First, one is normally required to use other, nonharmful means of escaping the threat if possible (e.g., in the pesticide case, if you can afford organic food without sacrificing something even vaguely comparable to what is inflicted on future generations, buy it). Second, if no nonharmful means is immediately available but the threat is ongoing, one may harm, but there remains a strong obligation to find a nonharmful way out as quickly as possible, even if this involves costs to oneself. (For example, if an immediate pesticide ban will cause mass unemployment and collapse in some communities, work hard to phase it out quickly, or to find new jobs or even new communities for the displaced.) Third, even when harm is permitted, one is allowed only to use the minimum force necessary (e.g., the minimum amount of pesticide that is absolutely necessary, or the amount that minimizes total exposure for future people). Fourth, one must provide compensation for the unavoided harm (e.g., invest in research to find a cure, medical infrastructure to care for victims, etc.).
On the other hand, the right to self-defense is not necessarily universally applicable, or even welcomed. First, according to some, the right does not apply if one is deemed the aggressor (e.g., an extortionist). Second, some believe that self-defense is impermissible if the victim is innocent. Third, and perhaps most interestingly, as self-defense is a right rather than a duty or obligation, some may choose not to invoke it, at least not as strenuously as is permissible. For instance, they may choose to take on extra burdens themselves rather than pass them on to their children or grandchildren; or they may simply prefer, as a moral matter, not to inflict extra burdens on others, even if they have a right to do so. In my view, these are important but underappreciated elements of climate ethics.
The self-defense approach helps to explain the appeal of some versions of economic realism. Specifically, it can account for the thoughts that self-interest suggests some kind of constraint on what can legitimately be asked of people, and that nevertheless we need to phase out emissions quickly. It does so without suggesting that ethics is irrelevant or counterproductive, and without endorsing extortion. Nevertheless, it involves stringent restrictions, with profound implications for climate policy.