Why does the world stay green? Book

A groundbreaking book that is even more relevant today than when it was written.

It was widely criticised at the time and is now often written-off as having been 'widely discredited' - obviously only by people who haven't read the book. As they say many, many times, it is not a prediction - nor could it ever be - but rather an attempt to investigate the "behavior modes" of a connected system of exponential growth and positive feedback loops with finite resources.

No-one can model the future of the entire complex global system with any kind of definitive predictive accuracy, but they can still provide very useful insights into the potential behaviour of a system. No transition can be pinpointed to one time or one place, but a message of caution is still relevant.

Their message was simply this: As the pace of growth increases exponentially, delays in system feedbacks could prove catastrophic as the response time can be too slow to avoid overshoot and an inability to maintain levels of food production, industrial output and capital, and therefore population. No matter how they modified resource levels and technological growth, unchecked growth always ended up with overshoot and collapse.

So far we have managed to avoid all of the limits we've faced collectively, but as the world gets faster and faster, every limit passed simply exposes us to a new one. I compare it to the speed of cars. We have surpassed many of the limits to vehicles in modern times, each capable of higher performance, but yet we have still had speed limits which haven't changed for decades. That is because we recognise that no matter how good the vehicles become, the reaction time and abilities of the driver stay the same. The faster we go, the lower the tolerance for error, and the bigger the mess if anything goes wrong.

It is a sobering read, but it was also a positive one, in that it presented options for how to avoid overshoot. The only problem is that that was 40 years ago. In more recent runs of the model they can no longer find a plausible set of input parameters that avoid overshoot. So let's hope the next limits we encounter are enough of a close call to wake us up to realising that we can't grow materially forever, but not so bad as to be catastrophic.