"System change is now inevitable. Either because we do something about it, or because we will be hit by climate change. '...

"We need to develop economic models that are fit for purpose. The current economic frameworks, the ones that dominate our governments, these frameworks... the current economic frameworks, the neoclassical, the market frameworks, can deal with small changes. It can tell you the difference, if a sock company puts up the price of socks, what the demand for socks will be. It cannot tell you about the sorts of system level changes we are talking about here. We would not use an understanding of laminar flow in fluid dynamics to understand turbulent flow. So why is it we are using marginal economics, small incremental change economics, to understand system level changes?"

Wednesday, October 24, 2007

How Many People Can the Earth Support?

That is the title of an excellent book by demographer Joel Cohen. Though it's over a decade old, I still highly recommend it for getting the big picture.

Apparently there is a quasi-official UN estimate in answer to this question. The relevant web page explicitly forbids hotlinking or reproduction, so please just go have a look. Apparently the sustainable population at western consumption levels is under 2 billion, and at under 6 billion at "medium" consumption levels. The demographers' consensus prospect that the population will settle at perhaps less than 10 billion over this century is therefore not really all that reassuring.

There are some source documents listed in text embedded in the graphic. It would be interesting to see how they arrived at these numbers.


AK said...

United Nations Department of Economic and Social Affairs population Division Homepage

Which includes:

World Population Prospects: The 2004 Revision, volume III: Analytical Report which appears to contain the detailed data.

An updated version with an on-line calculator is here.

The Global Footprint network home page contains a Results Page (hectare version). I haven't actually run the numbers, but they look like they fit.

Dano said...

EO Wilson said at Japanese or American consumption levels, the earth's population could support ~ 200 M.

"Ecological overshoot" is a good term for our quandary.