The worlds population is growing and is overpopulating. This is negatively affecting the worlds biodiversity.
The correct answer in this case is liberalism.
Socialism is the opposite as it entails (Among other things) the idea of fast changes, if need be with revolution. Neither does utilitarianism talk about social progress through reform.
Libertarians talk exactly about what the question is about; one of the main tennets of liberalism is that they prefer and would like to witness social change through reforms.
Reggin land, Reggin world, Reggin Sahara.
