Talking about population gets you into trouble. Mention it and you're 'anti-human', an 'extreme Green', 'racist', 'anti-immigrant', or dictating to developing countries how they should behave. You're told the real issue isn't over-population, but lack of equity in distribution of resources.
It's hard not to sound misanthropic when discussing population. Conservatives accuse you of favouring abortion, contraception, fertility control and sterilisation in developing countries, and progressives say you're a cultural imperialist diverting attention from social justice.
Discussion of population lost respectability in the mid-1980s following the sterilisation policies of Congress Party governments in India and the one child policy in China. In contrast Thailand, Indonesia and Bangladesh have run successful population programs without draconian measures.
There are also powerful vested interests maintaining high rates of immigration in Western countries which have reached zero population growth. Business wants to maintain consumers for goods and services, regardless of the pressure this puts on local environments. In market-oriented thinking new immigrants add to the pool of consumers rather than impacting a fragile environment.
The result: politicians avoid population issues like the plague (except when, like Kevin Rudd and Finance Minister Lindsay Tanner, they're beating the drum for an even 'bigger Australia').
The consequence is our country has a higher per capita growth rate from immigration (2.1 per cent for the year ending June 2009) than Indonesia. This will have a very large impact on Australia's attempt to cut greenhouse gas emissions because so many of these people are coming from countries with a lower standard of living and a much lower contribution to global warming.
These kinds of disconnects in policy formulation occur because immigration and population have become taboo topics among bureaucrats and politicians who fail to see, or are unwilling to tackle, the mutual contradictions involved. Global warming is lost between the discontinuities.
The great religious traditions have only the most rudimentary views on the morality of population limitation. Because the religious traditions have been largely absent from this debate, it has been mainly carried on in secular and economic terms by biologists, demographers and economists.
The reason why religious people have avoided this issue is simple: it is a theological and moral minefield. Embedded in it are a whole range of acute ethical issues and challenges to ingrained attitudes.
A basic moral conundrum concerns the ethical issues involved in inter-generational rights: if we consume