Shaken And Stirred, 007?

We are 007 -- that is, Oh! Oh! Seven billion! According to the UN, the world population has reached 7 billion. That's a lot of people.

To put this in historical context: In 1350, estimated total world population, following a number of years of famines and the Bubonic plague, was down to 370 million. A mere 661 years later, it is 2011, and we have almost 20 times that number of people.

(Interesting aside: 661 years is about 30 generations. The folks living in 1350 were my 28th-great-grandparents. Since the number of my ancestors doubles with each generation, then I have slots for over 1 billion 28th-great-grandparents. Each of the the 370 million people on the earth in 1350 would appear in an average of three slots on my family tree -- and that's true of each of the 7 billion of us alive today.)

In 1804, world population reached 1 billion.
123 years later, 1927, we reached 2 billion.
The next billion took only 33 years to add: in 1960 we reached 3 billion.
And the fourth billion took us only 14 years: 1974: 4 billion.
We reached 5 billion in 1987, and 6 billion in 1999.

We've been adding an additional billion people every dozen years since 1987. The total numbers are going up, but the rate of growth is declining. From 5 billion to 6 billion is a 20 percent increase while 6 billion to 7 billion is a 16.7 percent increase -- yet both the 6th and the 7th billion took 12 years.

In fact, the growth rate peaked in 1963 at 2.2 percent per year. Does 2.2 percent per year seem mild? During the 1960s, Paul Ehrlich's The Population Bomb, attracted a lot of attention, yet 2.2 percent per year might not seem very explosive. If the economy is growing at only 2.2 percent per year, that's regarded as sub-par: average US economic growth was 3.8 percent per year for the first 27 post-war years (1946 - 1973), and has averaged 2.7 percent per year since then (1974 - 2010).

However, it takes only a constant growth rate of 0.45 percent per year to get from 370 million to 7 billion in 661 years.

Here's a breakdown of that 0.45 percent overall Average Growth Per Year (AGPY):
AGPY for the 454 years, 1350 - 1804: 0.22 percent
AGPY for 123 years, 1804 - 1927: 0.57 percent
AGPY for 33 years, 1927 -1960: 1.24 percent
AGPY for 14 years, 1960 - 1974: 2.08 percent
AGPY for 13 years, 1974 - 1987: 1.73 percent
AGPY for 12 years, 1987 - 1999: 1.53 percent
AGPY for 12 years, 1999 - 2011: 1.29 percent

So the population growth rate is slowly coming down from its peak -- but is still higher than the AGPY  between 1927 and 1960 -- or any period before that. In fact, a growth rate of 1.29 percent per year would still produce a population doubling every 54 years. If the AGPY of the last 12 years were to continue, we'd reach 14 billion (twice the current population) by 2065, like so:
2022    8 billion
2031    9 billion
2039    10 billion
2047    11 billion
2054    12 billion
2060    13 billion
2065    14 billion

Fortunately, this is not  likely. The growth rate has been declining since 1963 and is expected to continue to decline. The US Census Bureau projects that we'll reach 8 billion in 2027 (rather than 2022), and 9 billion in 2046 (rather than in 2031). Most of the studies predict the growth rate to reach zero around mid-century. World population would then flatten out around 9 or 10 billion, and may even begin to decline a bit.

Education -- particularly the empowerment of women is a crucial variable. The more we can accelerate empowerment of  women, then the sooner we'll see a variety of positive developments, including faster declines in the population growth rate.

Can the earth support 9 or 10 billion of us? Can it even support, sustainably, the present 7 billion of us? If all 7 billion people consumed resources at the rate of the average US lifestyle, the answer is clearly no. It would take 5.3 earths to supply 7 billion people with what the average US resident gets. 

So. One of  the following must occur:

1 - Sharp population declines. We'd have to get down to less than 1.5 billion if the one earth that we have were to supply us all at a level of the average US citizen; or
2 - Substantial reductions in consumption for the wealthy. Those who consume at or above the US average will need to adopt lifestyles consuming less than a fifth of what we now consume; or
3 - Massive poverty for the majority. We might try continuing to let a few people consume vastly disproportionate shares of the resources by forcing 90 percent or so to live in poverty; or
4 - Some combination of #1, #2, and/or #3; or
5 - We'll run out of earth -- with attendant massive famines, resource wars, etc.

Your assignment, Agent 007 -- the assignment of the oh, oh, seven billion agents on the planet -- is to avoid #5. We also need to avoid #3 as much as possible. The risk of instability, unrest, and violence -- not to mention the moral wrong -- of #3 should be avoided. #1 ain't gonna happen -- unless #5 happens first, thereby causing #1. So that leaves #2 -- or some form of #4 that consists mostly of #2.

That's what we gotta do. It's enough to leave us shaken. But will we be stirred to accept this assignment?

Start by learning more:
Good introduction to the population issue: here
Ian Angus and Simon Butler argue that enviornmental crises come much more from the wealthiest 1 percent than from the rest of the 7 billion: here.
Article about Bill McKibben's take on climate change and population: here.