- 1. Acto I: James Hanses critica el sistema
"Because cap and trade is enforced through the selling and trading of permits, it actually perpetuates the pollution it is supposed to eliminate. If every polluter’s emissions fell below the incrementally lowered cap, then the price of pollution credits would collapse and the economic rationale to keep reducing pollution would disappear."
[Noten como Hansen piensa en términos de dualidad, de complementariedad. El razonamiento no es incorrecto, aunque se puede precisar. No se trata nada más de las emisiones de cada polluter, pero de la suma. Al regulador le importa un nivel agregado de emisiones. Si la suma agregada fuera menor al objetivo, entonces la restricción de emisiones no está activa, y el precio sombra de las emisiones (que sería equivalente al precio de los permisos) sería cero. Esto se aclara un poco más en el ejemplo numérico de esta entrada. Ahora, si bien el razonamiento no es incorrecto, no resulta plausible ¿Qué caso tiene un cap redundante?]
Acto II: Krugman recrimina
"What the basic economic analysis says is that an emissions tax of the form Hansen wants and a system of tradable emission permits, aka cap and trade, are essentially equivalent in their effects. "
Sobre la equivalencia del cap and trade y el tax, veáse la discusión de esa misma estrada. El mensaje es que, en efecto, hay situaciones en que ambos esquemas son equivalentes. Pero hay otras en que uno u otro son preferibles.
Luego dice,
"It will truly be a tragedy if people generalize from the financial crisis to block crucially needed environmental policy."
De acuerdo. Continúa:
"Things like this often happen when economists deal with physical scientists; the hard-science guys tend to assume that we’re witch doctors with nothing to tell them, so they can’t be bothered to listen at all to what the economists have to say, and the result is that they end up reinventing old errors in the belief that they’re deep insights."
Y se siente raro que Krugman defienda a la economía.
"James Hansen's op-ed attacking cap-and-trade is not quite as stupid as Krugman makes it out to be (Unhelpful Hansen). Krugman's graph is fine, but doesn't drive the point home. Non-economists who have heard about the polluter-pays-principle can be excused for not understanding that it's the price not the punishment which internalizes the externality. "
...
"As far as I know, the relevant uncertainty case, with uncertainty about both marginal abatement and damage costs, has not been analyzed in the literature"
Bueno, pues como se dijo en la ya multicitada entrada, claro que dicho caso se ha analizado, desde hace mucho. Un comentarista se lo hace saber a Roumasset, quien perfectamente reconoce.
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