“With regard to ‘filling the earth and subduing it’, do you think that Christians also have a responsibility to the earth and its strained resources? I.e. is it possible for Christians to have ‘too many’ kids? (Is the earth overpopulated and strained; how much should we consider this?)”
The answer to this question is ‘yes’ and ‘no’!
Yes, Christians certainly have a responsibility to the earth and its resources. In the context of Genesis chapters 1 and 2, where this phrase is found, ‘subduing’ the earth implies a responsibility towards the good world that God has given us – our job is to be the ‘image of God’ in the world, servant rulers over the creation. So we must take our responsibilities seriously, caring for the earth as God cares for it.
However – and this is where the question is heading – does the second part of God’s command negate the first? That is, have we come to a point where there are simply too many people in the world, and where any more ‘filling’ will mean that we aren’t properly taking care of the world? Or to ask it in perhaps a more biblically faithful way, have we already completed our obedience to God’s command to ‘fill’ the earth – i.e. is the earth now full and we can stop procreating?
The answer to these questions is a resounding “no” (at the very least not yet) – and let me explain why. Overpopulation, at least by itself, is not causing the strain on the earth’s resources. What is causing this strain is a much more basic problem, a problem which Francis Schaeffer identified way back in the sixties, a problem which the Bible talks about again and again – human greed (e.g. Exodus 20:17, Romans 1:29, James 4:2-3). It’s not that there are too many people, it’s that each person, on average (especially in the West), is unsatiably using more and more resources. Think of Australians: in general, on average, we are gobbling up oil to get ourselves around more conveniently, we are gobbling up land because the average household size has dropped so that fewer and fewer people are now living in bigger and bigger houses – not to mention the extra cost in electricity for heating and lighting, etc. The strain on the earth’s resources would be stopped overnight if we all became content with what we had and happy to live with larger families under one roof.
Or take food resources, for example. To quote a statistic I heard only recently (see this news article): there are now more obese and overweight people in the world than there are malnourished people in the world (that includes countries such as China). That statistic means that there is far more than enough food for everybody, many times over. It’s just that it’s not being distributed properly – because of corruption and greed. The technology that we have at our disposal means that we are able to distribute the world’s resources. At least in the area of food, the statistics show that we are far from overpopulated.
In my experience, when I have met couples who refuse to have children because they don’t want to contribute to “overpopulation”, it’s far more likely that this is not the real reason. The real reason is much more likely to be that they don’t want their comfortable lifestyle, and their desire to be “upwardly mobile” (i.e. covetous) to be affected. In fact, a far better thing for them to do for the world’s resources would be for them to have children and to teach them, by word and example, to be less greedy, more content to live with each other in the same household and use less petrol and electricity, etc.
Of course, the best thing we can do for our world is to speak and live out the the gospel, to our neighbours and our children, which will bring change in people’s lives, teach us contentment, and enable us to put greed and covetousness to death.