by: Chris Dillow

There’s something about the Copenhagen summit that‘s puzzling me. To see it, approach the issue from the perspective discussed by James Buchanan in The Calculus of Consent.

There are, he said, three broad ways of organizing our affairs, each with costs and benefits; he was writing about individuals, but for our purposes, we can replace individuals with governments. These ways are:
1. Simple individual action. In our context, this means national governments setting their own individual climate change policies.
2. Voluntary contractual agreements.
3. Enforced collective action. In the case of the private individuals Buchanan was discussing, this means government action. In our context though, it means a global government with the ability to coerce national ones into reducing emissions.
Now, here’s my puzzle. Politicians seem to think that climate change is best tackled by (2) - hence the summit. Why?
It’s obvious why (2) is superior to (1) - because stopping climate change is a public good. But why is (2) superior to (3)?
There are some obvious possibilities. Maybe climate change isn’t so catastrophic, so the costs of failing to reach an agreement will be too small to justify losing national sovereignty. Or maybe the costs of reaching an agreement are in fact small, so we are in the world of the Coase theorem, where private agreements can be optimally efficient without government action.
However, much of the rhetoric surrounding the summit seems inconsistent with these possibilities. That editorial says:
Unless we combine to take decisive action, climate change will ravage our planet, and with it our prosperity and security.
And Brown says:
If by the end of next week we have not got an ambitious agreement, it will be an indictment of our generation that our children will not forgive
But if the costs of failure at Copenhagen really are so catastrophic, and are a serious risk, then perhaps  mode (2) is the wrong way of addressing the problem, and we might need global government instead. And yet, AFAIK, none of the summiteers is suggesting this possibility.
Let's contrast this with smoking in pubs. In theory, private contractual arrangements could control this - either by non-smokers paying smokers to desist, or smokers paying non-smokers for the right to do so. But the UK government decided against this, and imposed a ban. It decided that mode (3) is superior to mode (2). But if this is true for smoking, why is it not true for an issue with allegedly vastly greater costs of failing to reach a private agreement? 
So what’s going on? Is their rhetoric just wind? Are governments ignorant of the basic Buchananite principles for deciding where decisions are best taken? Or do they instead care more about preserving their power than saving the planet, and see Copenhagen as merely a legitimation ritual? Could it be that those calling for radical alternatives to the summit do, in fact, have some logic on their side?