"Emissions trading sounds like a compelling idea in principle but the practicalities are much less attractive. [...] it's depoliticized over-consumption (i.e. we are told it no longer matters who causes what harms, provided we all pay the right amount) [...] emissions trading carries a series of practical problems. A weak cap means increased emissions but a tight cap, based on a effective climatic targets would likely lead to regressive social consequences, for instance, privileging a Londoners' stag party over a Polish OAPs' warmth."
- Dr John Broderick in "Should we stop worrying about the environmental impact of flying?", Guardian 31st Jan 2013.
This neatly summarises one of my concerns with emissions trading schemes. The question of the relative social good associated with a particular set of emissions is assumed to be answered through a direct equation with the economic cost of that good. If a stag party for a rich Londoner costs as much as heating the home of an elderly Polish couple, then these social goods are deemed equivalent, despite the fact that one is a luxury while the other may well be a necessity under certain circumstances. In some ways, it is a similar issue to the globalisation of the food market. If there are wealthy people willing to pay for a luxury cash crop on another continent, this is taken as justifying the eradication of local food autonomy in a developing country.
But not all goods are commensurate on a common scale. It is not possible to put a price on everything. The logic of the market is not universally applicable.