Global warming and externalities

How a carbon tax can "solve" global warming

Tim Worstall (yes, when he's not trolling he's quite good) has a piece up at the Telegraph explaining how carbon taxes work, and why they could "solve" global warming:

In economic theory, the problem here is that my actions that create emissions also damage someone else. But I don't have to pay for the damage I've caused. This is called an externality and the economists' solution is something called a Pigou Tax. That is, we add a tax equal to the damage I'm doing, so that I do pay for that damage.

Worstall cites the Stern Review's figure of $80 per tonne of CO2 as a good starting ground for where to set a carbon tax, and explains why it's the most efficient way to deal with climate change:

As a made-up example: my car emits one tonne CO2 when I drive it to buy fresh bread for lunch. That's $80 of damage I cause in the future by doing so. But the benefit to me is trivial: if you paid me 50p (alright, £5 in the rain) I'd cycle instead and not emit the CO2. The value to me of driving is that 50p; the costs to someone else are the $80. Clearly, this is a bad deal for everyone else: they're bearing costs much greater than the benefit to anyone at all. An $80 a tonne tax would get me cycling and that would be a good thing: I've stopped doing something where the benefit is lower than the cost.

However, we've a pregnant woman in pre-eclampsia. She needs to go to hospital in an ambulance which is going to emit that tonne, that $80 worth of CO2. Without it she and the child will be dead; with it they'll be fine. We usually value a statistical life in the £2 – 3 million range. That's what the railways will spend on safety to save a life on average. Or we could use the £50,000 that NICE applies to one year of good-quality life. If your drug treatment costs more than this, then you won't get it on the NHS; less and you might. Different numbers but much the same outcome: burn that fuel and damn the $80 of future damages, because they're much lower than the benefits that are achieved right now from burning that fuel.

This efficiency is why a carbon tax – or the harder to impose, but fairer and economically identical "cap-and-trade" system – really is the best way to deal with global warming. By definition, it deals with "bad" emissions while allowing "good" ones, and it does so far better than a legislature could ever hope to with a sprawling network of tariffs and subsidies.

But Worstall does somewhat overstate the case in one area, when he writes:

The other part [of a reader's question] – what's the point if we're not going to spend the money on green projects? – misunderstands the purpose of the tax. We're not trying to raise money: we're trying to change prices.

Changing prices is only half the effect of a carbon tax – or any Pigou tax. The other half is compensating the "victim" for their loss.

Suppose we live in a little two person economy where every tonne of CO2 you produce causes $80 worth of flooding damage to me. Imposing a carbon tax solves half the problem, in that it stops you polluting if you only get $10 benefit from it. But it doesn't solve what happens if you can make $100 from polluting.

In that case, you pay $80, and make $20 profit. I'm still left with $80 of flooding damage. The proper use of the money raised is to compensate the me for that loss. Otherwise, a tax which merely sorts out externalities becomes a revenue-raising tool of Government. In practice, this means that money raised from a carbon tax should be used on "green projects".

Which would annoy Worstall's fellow Telegraph blogger James Delingpole.

Anti-carbon tax protestors in Australia. Photograph: Getty Images

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

Photo: Getty Images
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The buck doesn't stop with Grant Shapps - and probably shouldn't stop with Lord Feldman, either

The question of "who knew what, and when?" shouldn't stop with the Conservative peer.

If Grant Shapps’ enforced resignation as a minister was intended to draw a line under the Mark Clarke affair, it has had the reverse effect. Attention is now shifting to Lord Feldman, who was joint chair during Shapps’  tenure at the top of CCHQ.  It is not just the allegations of sexual harrassment, bullying, and extortion against Mark Clarke, but the question of who knew what, and when.

Although Shapps’ resignation letter says that “the buck” stops with him, his allies are privately furious at his de facto sacking, and they are pointing the finger at Feldman. They point out that not only was Feldman the senior partner on paper, but when the rewards for the unexpected election victory were handed out, it was Feldman who was held up as the key man, while Shapps was given what they see as a relatively lowly position in the Department for International Development.  Yet Feldman is still in post while Shapps was effectively forced out by David Cameron. Once again, says one, “the PM’s mates are protected, the rest of us shafted”.

As Simon Walters reports in this morning’s Mail on Sunday, the focus is turning onto Feldman, while Paul Goodman, the editor of the influential grassroots website ConservativeHome has piled further pressure on the peer by calling for him to go.

But even Feldman’s resignation is unlikely to be the end of the matter. Although the scope of the allegations against Clarke were unknown to many, questions about his behaviour were widespread, and fears about the conduct of elections in the party’s youth wing are also longstanding. Shortly after the 2010 election, Conservative student activists told me they’d cheered when Sadiq Khan defeated Clarke in Tooting, while a group of Conservative staffers were said to be part of the “Six per cent club” – they wanted a swing big enough for a Tory majority, but too small for Clarke to win his seat. The viciousness of Conservative Future’s internal elections is sufficiently well-known, meanwhile, to be a repeated refrain among defenders of the notoriously opaque democratic process in Labour Students, with supporters of a one member one vote system asked if they would risk elections as vicious as those in their Tory equivalent.

Just as it seems unlikely that Feldman remained ignorant of allegations against Clarke if Shapps knew, it feels untenable to argue that Clarke’s defeat could be cheered by both student Conservatives and Tory staffers and the unpleasantness of the party’s internal election sufficiently well-known by its opponents, without coming across the desk of Conservative politicians above even the chair of CCHQ’s paygrade.

Stephen Bush is editor of the Staggers, the New Statesman’s political blog.