How much do people care about future generations? More philosophers say we should ascribe value to people who have not been born yet, but it's not clear that non-specialists agree. Humanity’s thus-far inadequate efforts to address climate change, for example, could be taken as proof that people are indifferent to the future quality and quantity of human lives. Based on surveys and survey experiments with representative samples of respondents in four countries—Sweden, Spain, China, and South Korea—we find that, in fact, most people say they do care about future generations, and would even be willing to reduce their standard of living so that people can lead better lives in the future. Many are unenthusiastic, though, about two kinds of actions that governments could take for the benefit of future generations: enacting policies to reduce either global warming or the national debt. We show that low support for these actions is due to people’s scepticism about their effectiveness as much as it is due to the discounting of future lives per se. At least some of what looks like indifference to future generations, then, is instead disbelief, or distrust, in the governmental actions and their benefits. Many people are pessimistic about the functioning of major social institutions, and so they see sacrifices for the future as futile. Conversely, people who are optimistic, and who expect human living standards to rise in the future, are more willing to make sacrifices for the benefit of (richer) future generations.