Strong longtermism maintains that how we should act morally is determined almost entirely by the expected effects on the welfare of our descendants existing thousands if not millions of years into the future, who might include both other humans and any artificial agents with a comparable or higher moral status that we end up creating. It is based on three key assumptions: (i) that our descendants will have a moral status that is at least as high as ours and therefore (...) should not have their welfare discounted by us; (ii) that there is a good chance that these individuals will vastly outnumber us; and (iii) that we can do things here and now that can be expected to positively shape the long-term trajectory of humanity. The aim of this contribution is to suggest that authors such as Will MacAskill and Hilary Greaves have been too optimistic about all these assumptions as a result of having ignored evidence that the populations of postindustrial countries are becoming less intelligent due mostly to the negative relationship that has emerged within these societies between intelligence and fertility and to the proclivity of intelligent people to delay parenthood. (shrink)

Highlights: -/- • -/- Proposes forward-looking approach to studying climate collapse risks. • -/- Suggests diminishing returns on climate adaptation as a collapse mechanism. • -/- Suggests strategies for sustainable adaptation pathways in face of climate change. • -/- Illustrates analysis with examples of small island states and global food security. -/- Abstract: -/- This article proposes a forward-looking approach to studying societal collapse risks related to climate change. Such an approach should indicate how to study emerging collapse risks and (...) suggest strategies for adapting to them. Our approach is based on three postulates that facilitate a forward-looking approach: (1) collapse, if it occurred, would be a lengthy process rather than an abrupt event; (2) significant collapse risks already exist in some places; and (3) diminishing returns on adaptation to intensifying climate impacts are a key driver of collapse risks. The first two postulates suggests that collapse risks can be studied in process, while the third points to strategies for adaptation pathways that avoid unsustainable diminishing returns. Applying diminishing returns to climate change adaptation, rather than sociopolitical complexity or resource extraction, is also a novel theoretical contribution to collapse literature. [Open access]. (shrink)