I once spent a night in a room above a wine bar in Antwerp. The place was lovely - large bed, view over an art nouveau square, little kitchen area with a bottle of Genever in the fridge - and so was the bar downstairs. Unfortunately I was kept awake all night by the bar next door which was more of a get shitfaced on Trappist beer and dance until you puke kind of place. I mentioned this to the owner of the wine bar the next morning and he apologized, said that it was not the first time this had happened and promised he would speak to the owner of the other establishment. He did and the upshot was that the owner of the noisy bar offered to pay half of my night's accommodation. In some sleep-deprived, masochistic fit of righteousness I refused, saying that it was not right that someone should repeatedly screw their neighbour and then pay their way out of it. A situation rather like this, where some people will respect the rules of civism and get reimbursed by others who don't is what is proposed by the "cap and trade" approach to carbon emissions. Of course the "cap" part of "cap and trade" - the total amount of carbon to be emitted worldwide is fixed at a certain level which will encourage companies to use less so that they can sell their surplus allowance to other companies who can't or won't reduce their emissions - means that the two scenarios are not exactly the same. (So far as I know no such proposal has been made about world noise levels, although a quieter world would presumably be one of the side effects of a low carbon economy.) This "cap" will be progressively lowered so as to insure the price of the carbon credits does not stabilize or fall and hence polluting will stay costly. Unfortunately there is a proposal to alter the bill before the US congress to allow companies to purchase offsets instead/as well as carbon credits. This would mean that there would be no limit at all - the "cap" would become purely theoretical. And regardless of whether the offset amendment is included in the bill or not regional discrepancies will inevitably exist - and indeed may even get worse. While over all pollution might go down, in certain areas it will stay the same or even increase - a victory for the planet but not for the people living near a dirty power station (or a noisy bar). If "cap and trade" is to work both locally as well as globally (and the verdict is still out on both of these points) it will need to be coupled with laws that limit the emissions any one source can produce. In this regard the announcement yesterday by the Environmental Protection Agency that carbon dioxide and five other greenhouse gases pose a danger to human health is extremely good news as it paves the way for the agency to regulate emissions of these gases. One wonders why it took so long to arrive at such a finding (I'm guessing eight years of George W. Bush didn't help) but, as with Obama's belated decision to attend the Copenhagen summit at all, better late than never.