Friday, July 26, 2013

The Nature of Growth

Ecological economists point out that continued growth must ultimately exceed sustainable levels. Any rate of growth involves repeated doublings, which lead to astronomical levels of production in the long run, beyond what the global environment could conceivably support. This is why ecologists say that growth cannot continue indefinitely on a finite planet.

The effects of growth become noticeable suddenly. We can see how suddenly by doing a thought experiment. Imagine a pond that has only one one-thousandth of its area covered with algae, and imagine that these algae reproduce rapidly enough to double the area that they cover in one day.

In the first three days, the algae grow from the initial 1/1000 to 2/1000, to 4/1000, and then to 8/1000. Even after three days, the area that they cover is less than 1% of the pond, such a small area that we would probably not even notice them.

In the next four days, they grow to 16/1000, then to 32/1000, to 64/1000, and to 128/1000. Now that they cover more than one-tenth of the lake, we notice them, but they still seem to be a relatively small problem that is not urgent.

But in the next three days, they grow to 256/1000, then to 512/1000, and before the end of the tenth day, they cover the entire lake and kill all other life in it. Because the problem seems small during the early and middle stages of growth, we are likely to ignore it until it is close to causing disaster.

Because effects of growth become noticeable suddenly, it is surprising how quickly developing nations will reach America’s current standard of living if their current growth rates continue. To round down a bit, China’s economy has been growing at a rate of about 10% a year in recent decades, which means it doubles every seven years. Seven years ago, its per capita consumption was one-eighth of America’s, and the world was just beginning to see that its demand for resources was a problem. Now, its per capita income is more than one-fourth of America’s, and in just two more doublings, its per capita income will be greater than America’s is now.

When it comes to the effect that economic growth has on the earth’s ability to absorb pollution and supply resources, we are like the people who have just begun to notice that the algae in their lake are a problem and who do not realize that the algae will cover the lake completely in two or three days.


Blogger Jim Moore said...

A very good concise post. It seems to me that the human mind intuitively grasps linear growth, even when there is none, and thinks a trend will continue along a linear path e.g. the form of your sports team or a racehorse, but is unable to fathom exponential growth and its rapid effects without applying science and mathematics. I wonder what behavioural researchers such as Dan Ariely make of this.

7:07 AM  

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