I remember back when I was in Grade school in the early 90's that we were supposed to have over 12 Billion people by now, and experiencing exponential growth.
I remember back in the early 90's that according to the 'experts' we wouldn't be able to walk around outside in daylight without head to toe clothing and sun screen because mere moments of exposure to sunlight would cause horrible UV burns because we wouldn't have any Ozone layer left.
In the 70's, it was predicted that by the 90's we would be facing mass starvation because of population growth and regions like India and Africa should be 'sacrificed' and not sent any food to conserve valuable resources.
In the 70's, it was scientific FACT that by the year 2000 Los Angeles would be covered in Glaciers and the earth would be in the grip of another Ice Age.
In the 1950's, it was predicted that the world supplies of crude oil would be exhausted by the year 2000.
In the 1950's it was supposed that earth would be a radioactive cinder due to nuclear technologies by now, not bombs per-se.
The point I'm making is that Experts have always been predicting imminent doom for mankind, and yet the imminent doom never seems to materialize. Too often the people who proclaim that the world will be facing 'terrible consequences' tend to merely see humans as consumers and takers from the planet, they never attribute the innovation and capabilities of the human mind in overcoming problems and dealing with problems. Invention, imagination and intellect are things that are never taken into account. We speak of 'over-population' but such over-population never seems to bear out on the level that is predicted. Decreasing resources is always seen as the overwhelming end of all things, and yet it's never realized that humanity has this amazing capacity to adapt and overcome challenges that stand before it.
Limiting the numbers of children in societies, enacting euthanasia for surplus population, we find ourselves looking at a society that simply does not place value on human life. If we step to the point where we simply say a human is a number, and that number must be reduced to reach an 'optimal' number, we sacrifice humanity itself. We reach that point where we simply decide to give up innovation in exchange for an arbitrary number, we will give up the thing we're trying to save, the human race. So what if we survive, what kind of survival would we find if human lives are culled to serve a greater good?
Innovation, intellect and scientific development is what is needed, faith in the most intrinsic of human attributes, not in the sacrifice of human life to maintain the status quo.