A recent study suggests that condoms can help us combat anthropogenic climate change (see Condoms save the Planet). I guess it’s obvious really. Fewer people, fewer problems.
But I think this illustrates that many of the solutions to humanity’s problems come down to human rights issues. In particular the rights of women in many countries. If women in these societies got the human rights they deserve, including reproductive choice, we would probably see a decline in excess population growth, terrorism and civil wars. Religious and cultural intolerance, which victimise many women, could be reduced. We could tackle problems of disease, water quality and standards of living with more chance of success. And the proliferation of human rights would no doubt improve the economies of these countries.
Nobel prize winner Murray Gell-Mann made these points in his excellent book, The Quark and the Jaguar: Adventures in the Simple and the Complex. Perhaps I am showing my own bias here (after all I am not a woman) by drawing attention to another aspect of human rights Gell-Mann discussed. This is the rights of the aged. Particularly the provision of social security for the aged.
Social provision for income for the aged would take that responsibility away from their children. This would be another factor restricting the need for large families.
Download the report (pdf): Reducing Future Carbon Emission by Investing in Family Planning.