Leading on neatly from Tom’s post about sustainable population growth is another New Scientist piece, which posits that Europe’s predicted decline in population will actually bring a whole raft of economic and infrastructural problems with it:

… look a little deeper, and the picture becomes more complicated. Decreasing population does not necessarily promise environmental benefits. The cost per head of population for infrastructure such as sewage systems or electricity supply increases when population numbers go down, making clean water and non-polluting energy even more expensive than they are today.

So can Europe overcome its demographic and ecological challenges at the same time? The solution might be found in a rarely discussed concept: demographic sustainability.

High population growth, such as that now taking place in many African countries, is not sustainable. But very low fertility rates are unsustainable too. It will be hard for countries with persistently low fertility to remain competitive, creative and wealthy enough to keep ahead of their country’s environmental challenges. What is needed is a middle ground.

A demographically sustainable Europe needs to have a stable or slowly shrinking population as the existing infrastructure operates most efficiently when the number of inhabitants remains fairly constant. What would it take to achieve this? At present, the average fertility rate in Europe is 1.5 children per woman, and in countries below this line there is an urgent need for family policies to encourage women to have more children. Countries with fertility rates above 1.8, including France, the UK and Sweden, do not need further pro-birth policies as immigration will fill the demographic gap.

I’m not going to contest the maths, but I think pro-birth policies will probably be unnecessary. Climate change is going to produce a whole lot of environmental refugees in the next few decades, and those countries with a declining birth rate could open their borders to them – two birds with one stone, if you will.

However, if those countries also happen to be the ones most paranoid about being “overrun” by immigrants, I guess it’s back to the government-sponsored Have More Kids campaigns… [awesome CGI population density map image by Arenamontanus]

[ For the record, I think that it behoves us as a sentient species to limit our population so as to best protect and sustain the environment that keeps us alive (and hence protect and sustain ourselves). However, sentience and sense have never directly proportional, and show little sign of becoming so any time soon… so I guess mitigating the fallout is the best plan in the meantime. ]