Space colonization doesn’t solve extinction.

In the other direction, among the downward paths, questions about space loom even larger. As the four horsemen of the anthropogenic apocalypse and other perils, natural and human-made, have come into view, the expectation that space can play a uniquely and decisively positive role in either fixing Earth problems or escaping from them has become an unquestioned article of faith, endlessly repeated by space advocates as well as most analysts of catastrophic and existential threats. If “all humanity’s eggs are in the one vulnerable and fraying basket” of the Earth, as widely proclaimed, then spreading human settlements into the cosmos seems a straightforward path to human survival. And if asteroids colliding with the Earth are a threat to civilization and the species, then a space program to detect and divert them becomes vitally necessary. The overwhelmingly dominant view is that space activities have an entirely positive role to play in addressing perils to human survival. In contrast to many technologies that promise both perils and benefits and that must, somehow, be partly restrained, the question is not whether space efforts are desirable but rather how soon they can be made feasible. Despite the breadth and sophistication of their visionary thinking, neither space expansionists nor analysts of catastrophes give much consideration to possible ways in which space activities might exacerbate or trigger existing threats or create new ones.11 In futurist thinking about technogenic threats, large-scale space expansion enjoys a special status, a space exceptionalism, which in turn is supported by and supports a space exemptionalism, a free pass from a serious consideration of its possible downsides.

Is this strongly optimistic view of space and macrodisasters well founded? In opening this question and weighing space ventures as sources of such threats as well as solutions to and escapes from them, this analysis raises the possibility that many significant space activities should be restrained or relinquished on the same grounds that many now believe them to be an unalloyed good, and that human survival may actually hinge on the ability of governance to avoid rather than undertake major space expansions. It is certain that the Earth will become uninhabitable over the very long term of hundreds of millions and billions of years into the future, and that humanity can survive only by leaving the Earth and migrating elsewhere in the cosmos. But these threats are so temporally distant that they can have absolutely no relevance to current human choices and activities. Many of the threats imminent within the next centuries are significantly of human origin, and space expansionists rarely consider the possibility that the patterns of human activity producing these threats might be carried into space along with the spread of humans. Nor do they consider whether regimes to restrain threatening technologies, if established on Earth, can persist if human polities spread across the solar system.