by steam_cannon » Sat 01 Dec 2007, 04:30:48
$this->bbcode_second_pass_quote('Lighthouse', 'H')ow do your sources calculate the carrying capacity. Can you give me a sample calculation and show me what they put in consideration in their calculations to arrive at this figures? Can you post this please here on this board?
Maybe check their bibliographies... Or google for a bit more of their work and read more to answer that question. The full details of many studies are often in journals which charge for the article. Also you might be able to find some of these authors in the Journal indexes of your most local large city library, you may be able to find their full research.
It is a difficult question, here's why...These "Equations" often are complex computer simulations which entail volumes of data describing resources all around the world. If you didn't find an easy equation in a study on this subject, this may be why. I really don't feel like looking up equations tonight, so I'll give you a few hints where to look. And maybe Monte can help too...
Google: "calculating the earth's carrying capacity"
A greatly simplified example that came up...$this->bbcode_second_pass_quote('', '
')"The Vancouver-Lower Fraser Valley Region of British Columbia, Canada, serves as an example. For simplicity's sake consider the region's ecological use of forested and arable land for domestic food, forest products, and fossil energy consumption alone: assuming an average Canadian diet and current management practices, 1.1 ha of land per capita is required for food production, 0.5 ha for forest products, and 3.5 ha would be required to produce the biomass energy (ethanol) equivalent of current per capita fossil energy consumption. (Alternatively, a comparable area of temperate forest is required exclusively to assimilate current per capita C02 emissions (see 'Calculating the Ecological Footprint'). Thus, to support just their food and fossil fuel consumption, the region's 1.7 million people require, conservatively, 8.7 million ha of land in continuous production. The valley, however, is only about 400,000 ha. Our regional population therefore 'imports' the productive capacity of at least 22 times as much land to support its consumer lifestyles as it actually occupies (see Figure 20.3). At about 425 people/km2 the population density of the valley is comparable to that of the Netherlands (442 people/km2)" [p.p. 369-371]
http://dieoff.org/page13.htm
Their "summary" on calculations is a few pages.