I’ve just finished reading Limits to Growth The 30 year update, while one of my favourite jokes is “How do you make God laugh? Tell him your plans for the future”, the authors of this book use system dynamics to model the planet and chart our future development in terms of population, industrial production, food production, pollution, resources and human welfare.
A common belief today is we are able to produce more with less, todays cars contain less metals than lasts years cars, you get more kilometres to the litre and they are less polluting, this may be true but if we are producing 2% more cars per year. As the number of cars is increasing exponentially it is impossible for our technological improvements to reduce the overall environmental damage caused by the motor car. It can be hard to recognise exponential growth as we can be easily fooled into thinking it is linear growth. Try folding a piece of paper in half, the width grows exponentially and before long it’s impossible to fold in half any more.
But it gets worse, when extracting resources, we are naturally lazy and extract the easiest one’s first, so for example all the tin ore in Cornwall at the surface is gone. The Cornish tin miners then dug mines, pumped water from the mines, exhausting first the high grade ore then switching production to slightly lower grades of ore. Each of these steps required more capital and energy than before. The lower grade ores require more pre-processing therefore more energy than before to create the finished product. This pattern can be seen throughout the world, BP in the 1970’s brought ashore oil from the North sea, what at the time was considered a harsh environment. In 2010 BP can prospected for oil in waters 1,500m deep in the Gulf of Mexico, with near fatal consequences for the company.
In summary the world requires natural resources to produce stuff which we need, with a population growing exponentially we require more natural resources. The world is finite we first exhaust the easy to get at resources then we have to increasingly spend more money and resources to extract what we require to produce stuff.
When these relationships are modelled more formally you can three results from your model steady state, oscillation and overshoot and collapse. The authors of Limits to Growth assert that it is very likely we are in overshoot, but not in collapse. Collapse they believe is not 100% certain, there is hope, the Human race came very close to destroying the ozone layer, but took action thanks to better understanding of the science involved, international cooperation and understanding by the public of issue.
Signs of overshoot can be seen in Tropical forestation and global fisheries. Non sustainable agricultural practices are widely practiced.
No one likes a prophet of doom but if you wish to disagree with their conclusions these are the points to contest:
1) Growth of population and economy when it does occur tends to be exponential.
2) There are limits to the source of materials and energy need to sustain the population and economy,
3) The growing population and economy receive distorted signals that limits are approaching and delay responding to them.
4) The limits are not only finite but erodible.
In summary a book well worth reading, and should give you plenty to think about.