AGW: a bigger issue than overpopulation? [View all]

[GliderGuider]

It's not considered good form in activist circles to say, "Oh, don't worry about overpopulation - that was last century's problem. Climate change will fix that before we can even intervene." Still, this is a position I adopted in the last year as I began to realize just how soon AGW could take a bite out of the world's fresh water and food supplies - and how big that bite could be.

To demonstrate my reasoning visually I created the graph below. It shows two lower UN world population scenarios, called the Medium and Low Fertility Variants. The world is currently on the Medium Fertility curve, and most population activists would call it a win if we could get moved over onto the Low Fertility curve.

Branching off from each of the UN variants I show a second path that incorporates a gradually increasing downward pressure on population growth, caused by climate change, beginning in 2025. In each case the pressure starts at 0.0% and reaches -1.0% by 2050.

As you can see, this degree of climate change pressure inflects the Medium Fertility scenario down over time until it comes close to matching the Low Fertility scenario by 2050. The same degree of pressure applied to the Low Fertility scenario causes the world's population to begin falling quite rapidly beginning in 2030 - culminating in a drop of half a billion in the final six years.



Is pressure like this within the realm of possibility? It doesn't take much imagination to see the impact of long-term droughts in Russia, Australia, the USA and China on the world's wheat and rice supplies, and glacier-fed rivers are already running dry here and there. It seems quite possible that concerns about overpopulation will be seen as quaint relics within a few decades.