Thoughts on Earth Hour and the population of the world

So I’m reading comments on the web about Earth Hour – the annual international event to raise awareness of climate change.   Sponsored by the WWF, the organization asks that everyone in the world to turn off their lights for one hour, beginning at 8:30 p.m. local time on Saturday the 28th of March, 2009.  Today.

I followed a series of responses to a blog at the Christian Science Monitor, here:

and here:

Really, most of the response posts were heavily opinionated, sarcastic, and denigrating.  The posts were from both liberal and conservative points of view — most were pretty bad, basically reverting to calling each other names.   I love the level of intelligent discourse on the web…

So I took a side-track, and followed some posts about the population of the world. Why not?

Response post #1: “What good will this do? The reason we are so messed up is overpopulation …”

Later response post: “… you need to do some research. The world is not overpopulated. There is plenty of room left for everybody on this planet. In actuality, population is declining so we need more people on this planet if we are to survive as a species.”

And a later post: “Population is declining? Not according to this:

Now we’re getting somewhere: A reference to some facts.  There are some interesting points about the population from that posted reference:
 – the population is not declining, but the rate of growth is decreasing.
 – The annual growth rate peaked at 2.19% in 1963; now, it’s down to 1.15%. 
 – The UN predicts that growth rate will continue to decline, down to an effective zero growth rate, and that the world population will stabilize at or near 10 Billion by the year 2200. 
 – Today (2009) the world population is in the neighborhood of 6.8 billion.

So, let’s evaluate the assertion from the first post: “The reason we are so messed up is overpopulation.”  Specifically, I wondered if we’d even have enough land to feed all those people.  The details I found are below — but the bottom line answer is:
 – We’ve got plenty of land now to feed 6.8 Billion people.
 – We’ll have to economize a bit to feed 10 Billion. 
So it’s not lack of food for the population that is making us “messed up”.  Distributing the food is, I think, a problem. Some people have plenty, some have way not enough. Also, the amount of heat and pollution that we currently create, per person – I think that’s a problem, too.

Seems to me that the results of Earth Hour, when we all turn off the lights, is actually a good start.  A good next step would be for everyone to turn off their lights more often. 

Oh, yeah: and stop calling each other “stupid”.

Regarding my assertions about feeding the population, here’s my supporting research,  These facts are from single-page Google searches – I didn’t really look too hard!

1. 10 Billion people is an interesting figure, considering this statement: “The earth currently produces 2,264 million metric tons of cereals, which is the staple food of the world. If each person consumes 2,000 calories per day, 2,264 million metric tons of cereal will support a little bit over 10 billion people. Currently, around half of all arable land in the world is producing crops.”

2. How much land do we have? “Land covers 29.22 percent of the Earth’s surface. This is about 57.5 million square miles (149 x 106 square kilometers).”

3. How much land can we grow food on? “About three-quarters of the earth’s surface is covered by water. Of the 57 million or so square miles of land, half are covered by mountains, deserts, or polar ice caps.

That leaves only one-eighth of the earth’s surface for man’s use in farming. And up to the 20th century, about half of that available land has been lost to erosion.

So of the earth’s 200 million square miles, only about one-sixteenth, or less than 15 million square miles, is suitable for farmland!”

4. By my math, if the needs of 10 Billion people must be supplied by 15 Million square miles, then 667 people must be supported by each square mile.  And a square mile is 640 Acres (  So each person would be supplied by .96 acres.  (Today, with only 6.8 Billion people, each person has 1.4 acres available for food supply.) This is my math, and these are only simple averages. For a reality check, I would suggest that folks in Kansas, say, actually have more useful acres available for food production than folks in, say, the Sahara desert.

5. How much land does it take to feed one person?  “The minimum amount of agricultural land necessary for sustainable food security, with a diversified diet similar to those of North America and Western Europe (hence including meat), is 0.5 of a hectare per person … It is realistic to suppose that the absolute minimum of arable land to support one person is a mere 0.07 of a hectare–and this assumes a largely vegetarian diet, no land degradation or water shortages, virtually no post-harvest waste, and farmers who know precisely when and how to plant, fertilize, irrigate, etc. [FAO, 1993]”

6. My calculations and conclusions: First, that’s an interesting range of estimates — from 0.07 to 0.5 hectares – they differ by a factor of 7.  The lower estimate must be really subsistence level (with the upper estimate being fairly upscale!)  Back to Google: 1 Acre = .405 Hectares.  So that translates to: we need between 0.17 and 1.2 acres per person. For the current population of 6.8 billion, we have more than enough for everyone to eat at the upscale level: we’ve currently got 1.4 acres per person.  For the projected stabilized population of 10 Billion, when each person would have (on average) .96 acres available for food, we’ll have to cut back on our lifestyle, but we won’t be near the really-subsistence level of .17 acres per person.

Well, that’s my story and I’m stickin’ to it.


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