 One critical responsibility is to limit the emission of greenhouse gases. Many hold that, at the moment, some greenhouse gases can nonetheless be permissibly emitted. There is, then, a question about how the use of the remaining “greenhouse gas budget” can be distributed and among whom. As we have seen the size of the budget depends in part on what temperature target is selected and how risk averse we think we should be. To illustrate: the Fifth Assessment Report of the IPCC reported that if we want to have a probability of at least 67% of avoiding a more than 1.5°C increase in global mean temperatures then there is a budget of approximately 420 GtCO2 (Rogelj, Shindell, &amp; Jiang 2019: 108). (If we operate with a less ambitious target then the budget is quite different. See table 2.2 in Rogelj, Shindell, &amp; Jiang [2019: 108].)