A few weeks ago I finished reading The Best American Science Writing 2001. It’s a marvelous collection of all the “best” essays written on scientific topics from last year. One article, “Running Dry” by Jacques Leslie, really shocked me. It’s all about the depletion of the Earth’s freshwater and the (disastrous) effects damming has had on the planet’s ecosystem. There’s going to be a special on The Discovery Channel tonight about China’s Three Gorges Dam (8pm). The tag-line of the special is:
“The Chinese have a plan to tame the large, muddy and unpredictable Yangtze River with a huge dam that measures two and a half miles wide and 650 feet high. Creating a reservoir 400 miles long, the dam will be the world’s largest concrete structure.”
That sounds amazing, right? After reading the article by Leslie, though, to me it sounds downright scary.
The planet accommodates 40,000 large dams – dams more than four stories high – and some 800,000 small ones. They have shifted so much weight that geophysicists believe they have slightly altered the speed of the earth’s rotation, the tilt of its axis, and the shape of its gravitational field. Together they blot out a terrain bigger than California.
I’m of the opinion that anything mankind does to significantly alter our freaking course around the sun is probably not a good idea. Am I the only one concerned about this?
I think the word SLIGHTLY is key here. Compared to the overall mass of the planet, I just can’t see any way to move that much weight to cause a SERIOUS shift overall. Remember – you can’t create matter, only rearrange it. The planet couldn’t have been perfectly “balanced” in the first place. Us little guys can’t move enough around to make that big a difference. Most of it is ocean anyway.