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Wednesday, April 25, 2007

Coyne's Crappy Car Metaphor

From CTV:

The Harper Conservatives have stunned the House of Commons by supporting a Bloc Quebecois motion that calls for absolute limits on greenhouse gas emissions.

Andrew Coyne responds that this is a "non-story":

If the Tories had "rejected" absolute limits, how did they expect to get to the 45 to 65% reduction (from 2003 levels) projected in the Clean Air Act (Ambrose version)?

The whole "intensity" vs "absolute" target controversy, as I've written before, is a complete red herring. It's simple arithmetic: before you can get to absolute reductions, you have to reduce the "intensity," in the same way that before you can stop your car, you have to slow down.

Which just shows that Coyne has swallowed the Tory koolaid, but has added his typical frilly nuances to their basic claim.

In fact, intensity reductions do not necessarily ever lead to absolute reductions. If you lower your amount of GHGs emitted per unit of production, and your production increases, so too can your absolute emissions. To follow the logic of Andrew's metaphor accurately, it is as though he is saying that you must slow the rate of acceleration of your car before you can actually slow your car, before you can stop your car. Which is patently false. Its also terribly bad advice to give to a speed junkie: "you must bring the car to a halt, but before you do that feel free to stomp on the gas for awhile, just not as hard as you were planning to stomp on the gas."

I'm away from the PC all day again today. This may be all you see here. Have fun.

(PS. Lord Kitchener explains this much better than me in his comments to Andy's post.)

2 comments:

  1. I'm glad someone's willing to analyse the similes our lazy punditocracy likes to entertain to explain things they can't be bothered to articulate more insightfully. I tend to start tuning out whenever someone (particularly a righty) starts saying "It's like..."

    GHG emissions per unit of production versus reduction in absolute levels is the type of comparison anyone who's graduated high school should be able to understand. We should give Coyne credit for understanding who his audience is.

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  2. Anonymous2:38 PM

    A better anology is to hold a black sheet of paper in front of a light. Notice how you can't see the light now. Put another sheet of black paper on top of the first one. Why haven't you seen the same reduction in light as when you just used 1 sheet? Because the first sheet reached the saturation point for light blockage.

    Same with CO2 concentrations in the atmosphere. The saturation limit was reached thousands/millions of years ago, establishing the greenhouse effect. Once that level is reached, you can increase CO2 levels all you want and there will be hardly any additional 'greenhouse' effect from it. Doubling C02 doesn't double the warming effect.

    However, altering solar intensity DOES change the warming pattern. If we wish to regulate warming on Earth, all we have to do is regulate the Sun.

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