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from the On-a-Pale-Horse-vs-Being-a-Green-Mother dept.
The world population is growing because the birth rate exceeds the death rate, so to stabilize the world population either the birth rate needs to drop, or the death rate needs to increase. The most cited reference for population studies is the projections of future population (PDF) made by the Population Division of the United Nations. The UN report projects the world population to eventually stabilize as a result of countries settling in to a birth rate that falls around the replacement level.
A commentary by Stephen Warren in the open access journal Earth's Future takes the UN report to task for focusing on birth rate. He notes that all species generate offspring in numbers well above the replacement level of two, but you don't see historically the kind of population growth like you do with humans. He argues that despite all the negative feedback mechanisms on population (such as war and pestilence), it seems that Malthus (PDF) was correct that food supply is the driving factor, and wonders whether it is even possible to stabilize the world population until food production levels off.
[Editor's Comment: Original Submission]
(Score: 4, Interesting) by WillAdams on Tuesday May 26 2015, @05:10PM
Leveling off food production won't be a choice, but a consequence of physics and chemistry. Some cold, hard facts:
- we're using 2.5 earths worth of renewable resources each year (the extra 1.5 comes from non-renewable sources such as petro-chemicals)
- current food production techniques burn 10 calories of petro-chemical energy (or convert it into fertilizer) to grow 1 calorie of food energy
- a lot of fertilizer and a fair number of chemicals wash out to the seas due to modern industrial farming practices
- the limiting element for converting the earth's crust into biomass is potassium --- look up where the reserves are, how large they are, and note which country has stopped exporting, but is instead importing all that it can
- a lot of land is becoming contaminated with salt by being irrigated w/ not-quite desalinated water
On the bright side, apparently at $200/bbl of oil, it becomes economically feasible to use solar power to make long chain hydrocarbons from warm moist air using fuel-air liquefaction techniques (assuming someone solves the catalyst problem).
(Score: 2, Informative) by Anonymous Coward on Tuesday May 26 2015, @09:45PM
are you sure it's potassium not phosphorus?
for the rest, spot on ..
(Score: 2, Informative) by Anonymous Coward on Wednesday May 27 2015, @01:10AM
It is both actually http://wikipedia.org/wiki/Potash [wikipedia.org] and http://wikipedia.org/wiki/Phosphorus#Fertiliser [wikipedia.org]
(Score: 1) by WillAdams on Wednesday May 27 2015, @03:19PM
Yes, conflated potassium w/ phosphorous. Thank you for pointing that out. My thanks to the AC for noting that the two are inter-related to a degree.
(Score: 0) by Anonymous Coward on Monday June 01 2015, @10:36AM
It's whichever that runs low/out first...
Sustainable growth is an oxymoron on a finite planet.
(Score: 0) by Anonymous Coward on Monday June 01 2015, @10:33AM
Whichever's the lowest. That's how it works.
If you think "organic" produce is expensive, just imagine if much of the world had to go back to eating "organic food".