Earth Day 2007

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April 22 is Earth Day!

earth day

I like Earth Day. It gives one a sense of hope for the future. Unfortunately, the environmental problems we face today are even more daunting than the ones that precipitated the original Earth Day in 1970. The issues at that time mostly centered around point source pollution problems (DDT, dirty smokestacks, polluted rivers, etc). These issues are fairly easy to understand and not very controversial unless you own a chemical company or a power plant.

Environmental problems today are a lot more complex than localized pollution. Of all the big problems (loss of tropical rainforest, access to clean drinking water, widespread fisheries collapse) Global climate change is by far the most frightening. There is a single phrase that keeps me thinking about this issue: *runaway feedback loop*. Any scientist or engineer knows what this means and why it's such a big deal.

Here is a simple example that almost everyone has experienced. A microphone on a stage is set too close to the speakers. Sound from the speakers is fed into the microphone, is amplified through the speakers, then back into the microphone and around and around until you get a very loud and annoying screech. There are two notable characteristics of this example: 1) The incredible noise volume reached before the system reaches a new stable state and 2) The speed at which the system goes from O.K. (quiet) to not O.K. (Eardrum busting screech).

The example as applied to global climate change is heated environment releases more CO2, which heats the environment more, which releases more CO2 (or worse Methane), which heats the environment more, and so on...

Far Fetched? Possibly. I don't think anyone knows for sure if how much of this will happen, but the consequence are potentially catastrophic. That's why this is a big deal.

Some links:
Al Gore's An Inconvenient Truth: