Sunday, December 16, 2007

Petri Dish Planet

How much have you factored population growth into your economic beliefs?

In first year biology one of the items of study was contrasting world population to bacteria population in a petri dish.

The lesson went something like, this is a graph of the world population:

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This is a graph of bacteria in a petri dish:

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The lesson ended by showing how the graph ended. I could not find such a graph, but I found one of E. coli grown in a glucose solution:

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The graph I remember of the petri dish did not have much of a stationary phase, but peaked and went straight to the death phase.

The lesson has always impressed upon me that the Earth is finite in its resources. Human population is still growing, however, we have evidence that our current consumption levels are exceeding our renewable resources. The petri dish was a closed system whereas the Earth is replenished with energy from the sun.

But that doesn't mean that resources are being replenished as fast as we are using them. Take water for instance. My recent readings on water include that ships traveling the Great Lakes have had to reduce loads by 10% to prevent scraping on the bottom of the lake. Some northern lake lost 60% of its water in one year.

My travels to the US and my personal visits to the Mt Shasta region and Hoover Dam dating back to the 70s and recently also to the Grand Canyon gave me a personal view of water issues. I have memories of a commercial for Mt Shasta pop and I remember the strong association of the white caps of Mt Shasta with clean, cold, refreshment.

These are two images I found on the web, both summer pictures of Mt Shasta. There used to be a glacier on Mt Shasta and that contribution to the water supply is pretty much gone now.

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I took pictures of the enormously declining levels of the water reserves, but they seem to have lost. The water supply from Mt. Shasta is important to California.

Lake Mead is also important to California and much of the agriculture. I visited Hoover Dam in 79 and again this year. I don't know how well the picture shows it, but the water level is disturbingly down.

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In that second picture my memory is that the water level was close to the top of the dam in 79.

Information I've seen on Florida indicates that the height of continental Florida is going down because the underground water reserve is declining so drastically. The water reserve was restored due to the swamp land and everglades. Swamp lands have been drained and the everglades have been shrinking. The ability to restore that underground water supply has been cut by more than half.

Everything that we have and know about our economic data is based on a planet that had not yet shown us its limits, however, that is changing. Our food supply has declined since the year 2000. Water and food are pretty damn important. Yes we have ways to make it go further, less resource intensive food choices as in grains compared to meats.

And what of our air quality? Carbon dioxide levels in the world are increasing through a warming period. Historically a warming period, as in after an ice age, has more plant growth that binds the carbon dioxide and it declines. We are living a warming stage that has carbon dioxide levels increasing. We've cut our trees and dramatically increased the release of carbon dioxide by the burning of fossil fuels.

Look at the data and you have to ask, just how good is our economic growth in comparison with the growth in human population? I think the data is telling us that things will be changing and in the process so might our beliefs in economic growth.

Population information.
Bacterial growth.
Bacterial growth data.

5 comments:

Deborah said...

http://www.china.org.cn/english/SO-e/33957.htm

Deborah said...

http://en.ce.cn/National/Local/200608/19/t20060819_8199907.shtml

Deborah said...

http://gristmill.grist.org/story/2008/2/22/13050/7938

gruth said...

Shasta still has numerous glaciers on it -- mostly on the north and east side. The southwest face you showed photos of it has not held glaciers in historic time, to my knowledge.

Agreed about the declining levels in reservoirs along the CO river.

Deborah said...

Gruth, I had the same visual perspective on my trips past it over the 27 year period, the first in 79, then around 1990 and then last year. It was shocking different than my memory of it.