ENVE3503 – Environmental Engineering Population Growth

1. ENVE3503 – Environmental Engineering Population Growth The Sorcerer’s Apprentice

2. 1048576 524288 262144 131072 65536 32768 16384 8192 4096 2048 1024 512 256 128 64 32 16 8 4 2 1 Exponential Growth

3. Exponential Growth 1048576 524288 262144 131072 65536 32768 16384 8192 4096 2048 1024 512 256 128 64 32 16 8 4 2 1 exponential growth model, with X0 = 1 = 0.69 d-1

4. The Death Term another intrinsic characteristic of the organism.

5. Limits to Exponential Growth (non-renewable and renewable resources) non-renewable resources http://wildgoosechasing.blogspot.com/2007/12/experts-world-population-will-explode.html

6. Logistic Growth (limitation by non-renewable resources) carrying capacity, K While some organisms may reach a population size that is limited by non-renewable resources, higher organisms would be expect to encounter limitation by renewable resources first.

7. Limits to Exponential Growth (non-renewable and renewable resources) renewable resources http://www.cbc.ca/gfx/images/news/photos/2008/06/27/f-un-food-distribution-584.jpg

8. The Monod Model (limitation by renewable resources) Half-saturation constant: substrate level at which the growth rate is at one-half it’s maximum. Growth Rate Substrate Concentration

9. The Monod Model (limitation by renewable resources) Should that population grow beyond its equilibrium size or if it were to experience an interruption in food supply, e.g. a famine, the population would decline and ultimately disappear. A population in equilibrium with its food supply is maintained at a constant level.

10. The Yield Coefficient (linking substrate depletion and growth Biomass, Substrate Time

11. Life at carrying capacity … • Carrying capacity holds populations in check through density-driven phenomena such as, • lack of space • increased incidence of disease • increased susceptibility to predation Consider the differences in life at carrying capacity for non-human and human populations.

12. A catastrophe of Malthusian proportion … The 18th Century British economist recognized that populations grew exponentially, checked only by “misery or vice”, by which he meant . He asserted that because the “means of subsistence” increased in a linear fashion, demand would eventually outstrip supply with catastrophic results. How may humans experience “misery and vice” in a catastrophe of Malthusian proportions?

13. Soiling the global nest … carrying capacity, K Paul Chefurka, a Canadian photojournalist and computer scientist, has suggested that as we pile environmental insult upon environmental insult, we diminish the carrying capacity of our global ecosystem. In this sense, we are not moving toward the crisis, the crisis is moving toward us! What is the role of the environmental engineer in restoring the Earth’s carrying capacity? Can you think of an example where this has been accomplished?

14. IPAT: the elephant in the global living room technology population affluence impact

15. IPAT and the environmental engineer the technological solution technology population affluence impact

16. IPAT and us the social solution technology population affluence impact

17. Farmer Bean and Her Pigs Drawings by Bill Sproule