population and resources

malthusian catastrophe

point where population outstrips food soupply, forcing a sharp corrective decline in population

preventive checks

those that lower birth rate

positive checks

those that raise death rate

malthus believed that positive checks would

correct the imbalance of weak preventive checks, thus causing the catastrophe

malthus's ceiling has been repeatedly relaxed by

technological advances

normal idea of carrying capacity doesn't work for humans because

we can innovate and importe

ecological deficit

when human population's load exceeds habitat's productive capacity

overshoot

population exceeds available carrying capacity

potential human population limit

between 10 and 20 billion depending on consumption level

demographic equation

R = (b - d) + (i - e)

crude birth and death rates (CBR/CDR)

annual number of live births/deaths per 1000

total fertility rate (TFR)

average number of kids a woman would likely have during childbearing years

replacement fertility rate

number of kids a couple must have to replace themselves, around 2.1 for stability

infant mortality rate (IMR)

deahts less than 1 year old per 1000 live births

life expectancy at birth

average years a newborn can expect to live

rate of natural increase =

CBR - CDR

rule of 70

doubling time = 70/r

IPAT equation

impact = population • affluence • technologya

affluence measured in

consumption or income per person

technology measured in

environmental impact per consumption unit

a smaller but wealthier population can outweigh one that is

larger and poorer e.g. Canada GHG emissions

affluence leads to environmental damage because

more productivity leads to greater throughput of energy and materials, as well as greater individual consumption

demographic trap

stuck in stage two (high CBR and low CDR) because of need for family labor

population momentum

tendency for population to keep growing or shrinking even after fertility rate reaches replacment level

commoner's mechanism seen in

kerala; no fertility mandate, was voluntary due to less infant mortality, eduction, and female employment

3 ways to adjust carrying capacity

make pie bigger, put fewer forks on the table, or teach better table manners

make pie bigger

increase capacity

fewer forks

reduce population

better manners

decrease demand/consumption