Predictions of doom and disaster are becoming depressingly common, even among scientists and academics. It’s tempting to dismiss such doom-mongering as mere sensationalism. After all, scientists have made similarly gloomy predictions in the past and they have been wrong. In his 1968 book, The Population Bomb, for example, the demographer Paul Ehrlich predicted that in the 1970s and 1980s hundreds of millions of people would starve to death because population growth would outstrip the increase in food production. In fact, world food production grew much faster than global population. There were famines, but not on the scale predicted by Ehrlich, and their roots lay in politics.

So when yet another scientist paints an apocalyptic picture, it’s easy to get “warning-fatigue” and dismiss him altogether. Yet this would be a terrible mistake with Thomas Homer-Dixon, one of the best-informed and most brilliant writers today. Recently, his research has focused on threats to global security in the 21st century and on how societies adapt to complex economic, ecological and technological change. The Upside of Down is his most ambitious book yet and argues that life is going to get very much harder for everyone.

The reasons for this pessimistic outlook include several of the usual suspects — population growth, climate change and the increasing scarcity of high-quality energy sources such as oil. But it also includes some less obvious threats that tend to exacerbate

the effects of the more familiar ones, such as the rising connectivity of our technological and transport networks, which increases the risk that a failure in one part of a system will cascade further and faster to other parts of the system.

The most sensible strategy is to be prepared. Yet, as Homer-Dixon points out, the idea of making our technological and social systems more resilient, so they can deal more successfully with future disasters, is hardly addressed by governments. He is not quite so clear about what all the various “tectonic stresses” he identifies will eventually lead to. But he is very clear that, whatever the exact nature of the coming catastrophe, it will be very nasty. And come it will.