There's merit on both sides of this argument. But rather than labelling views that differ from our own, we should lay out the pros and cons of both larger and smaller population sizes.
Like -
1. Who and what benefits the most from increasing the size of our population?
2. Are the environmental impacts caused by urban growth justified by the claims of economic growth?
3. If the answer to Q2 is yes, then what can be done to offset the environmental damage, and will the expense negate any benefits gained with people growth?
4. Who is disadvantaged the most by population growth?
5. Who will be disadvantaged the most by a static or a reduction in population size?
It would be interesting to see if we can focus our arguments in categorised responses rather than the haphazard manner in which the subject is sprayed around by all of us, including the media and both extremes of our politicians.
