In his recent book Collapse, Jared Diamond has looked at the fates of many previous human societies. Many societies have failed in the past because of environmental problems, but some have survived for long periods by being cognisant of, and responding to, environmental constraints. Whatever we face as a result of our unprecedented interconnection with the natural world, complacency is not a good strategy under the present circumstances. Diamond catalogues the reasons for failure:

1. Failure to anticipate the impending environmental collapse because of surprise, an incorrect sense of place or other unexpected ecological interactions,

2. Failure to perceive imminent changes because of slow or imperceptible change, or a lack of evidence, or a disagreement about what constituted evidence (there is a lesson here about climate change),

3. The application of apparently rational behaviour, often arising from the ‘tragedy of the commons’,

4. Irrational behaviour, greed, poor decisions and denial,

5. The application of unsuccessful solutions.

Many of these we have discussed here; the reasons for the past collapses of human societies are still with us. We are the first generation to realise the true nature and magnitude of regional and global constraints. The present nexus of increasing population, energy and resource demands, climate change and biodiversity loss, together with changing network architectures, increases the risks. Ecological surprise, hysteresis effects, uncertainty and debates about evidence are characteristic of the complex, non-linear world in which we live.