If you’ve ever heard a public-address system screech, you’ve heard a feedback loop in action. The microphone picks up a little noise, the amplifier makes it louder, sends it out through the speaker, whereupon it is picked up by the mike and amplified again until it turns into a primal scream.
Feedback loops are accelerating the impacts of the greenhouse effect on global climate. Increased amounts of carbon dioxide in the atmosphere, acting like the glass in a greenhouse, trap solar radiation near the earth’s surface, raising the temperature. As it gets warmer in the northern reaches where the tundra and taiga are permanently frozen, they start to thaw in summer. When they thaw they release large amounts of carbon dioxide, which increase the greenhouse effect. Feedback loop.
Feedback loops, most of them unforeseen, have accelerated the effects of global warming well beyond the worst-case scenarios of just a few years ago. The Paul Revere of global climate change, James Hansen of NASA’s Goddard Institute, describes in the current edition of Newsweek how badly those scenarios — many of which he wrote himself — have been trampled.
Well, stupidity has feedback loops as well. Continue reading →