Simple population model
Here is an exercise for GSCE/A level Geography students I developed for RIS (Researchers in Schools)
I like it because it speaks directly to students' futures.
The UK is overpopulated in the sense that its current ecological footprint is significantly larger than its ecological capacity. This means that its population is consuming more environmental resources than are actually available to it.
So are we all doomed? Let's find out.
Looking at the Data
The UK's current population represents a high water mark, and is due to go into steep decline as its rapidly ageing population dies off leaving diminishing numbers of younger people with low birth rates in its wake. Germany and Japan are already beginning this decline. The US, Canada and Australia are only staving it off by mass immigration. Much of the developing world is just one generation behind. This is a natural transition that happens as countries "modernise". Coupled with it is a pretty rapid reduction in environmental impact per unit of GDP production that’s been going on since the 1960's - at least in the developed world.
Model & Validation
Students construct a simple stepwise forecast model of the UK's population, GDP per capita and total ecological footprint on a spreadsheet, where people are born, have babies at 30 and die when they are 80. Birth rates vary with GDP per capita, modified by the GINI coefficient. This effects future population, GDP and ecological impact. In the model, immigration of people in their 20′s is included, a proportion of whom settle permanently and have children too. All assumptions can be changed to investigate their impact and the model is validated against data from 1900 to the present.
Results & Conclusions
Provided there is
- imminent reduction in income disparity (down to current Scandinavian levels) to boost GDP and birth rates
- the rapid convergence on today’s environmental state-of-the-art (also Scandinavian) continues
- adequate short-term immigration
the model trends suggest something like this:
So by about 2100, the UK could end up ecologically sustainable with a stable population of about 40 million pretty well off people. Much depends on their decisions.
An exciting time to be starting out!
