Specifically, at the moment we support children of “poor”[1] parents in a variety of ways through the social welfare system, and directly though agencies like the Police and fostering system. We also educate all children regardless of their parent’s wishes and supply medical care etc regardless of ability to pay. If those measures are left in place, the market pressures are quite limited.

Human rights are an important driver of that: we don’t consider it reasonable to punish children because their parents are poor.

At another level, it’s well established that poor people commit more of the important crimes[2] so society has an interest in reducing the factors that cause poverty. So using poverty to reduce the birth rate might also increase the death rate amongst the non-poor. from an environmental perspective that doesn’t have to be bad, but it’s likely to produce negative environmental secondary effects as those who can afford to defend themselves.

So, how do we “fix” that to allow market pressures to act?

[1] just how far up the income scale does “Working for Families” go, anyway?
[2] important as determined by policing and jail sentences. For example, robbing a bank by deliberately fooling the bank manager gets you little to no prison time in the unlikely event you’re even prosecuted, doing so by pointing a gun at said manager gets you lots of jail time.

Over-consumed is indeed a sticky term, however I don’t think it is too essential for the point he is making. I think the primary point is that if we believe that there is scarcity of resources, then the price signal will reflect that – as a result there is no need to “limit” the population.

Now, rauparaha appears to be saying that EVEN IF over-consumption is the problem (so without it we wouldn’t need population control for sure – but even if we have it) market prices will take account of this – we don’t need arbitrary population management to do that.

Now if the market price does not reflect that there must be a reason – and he says that it is better to deal to that reason directly to the market failure than to arbitrary control the population. This also makes sense.