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.

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Will Euroscepticism prove an unbeatable advantage in the Conservative leadership race?

Conservative members who are eager for Brexit are still searching for a heavyweight champion - and they could yet inherit the earth.

Put your money on Liam Fox? The former Defence Secretary has been given a boost by the news that ConservativeHome’s rolling survey of party members preferences for the next Conservative leader. Jeremy Wilson at BusinessInsider and James Millar at the Sunday Post have both tipped Fox for the top job.

Are they right? The expectation among Conservative MPs is that there will be several candidates from the Tory right: Dominic Raab, Priti Patel and potentially Owen Paterson could all be candidates, while Boris Johnson, in the words of one: “rides both horses – is he the candidate of the left, of the right, or both?”

MPs will whittle down the field of candidates to a top two, who will then be voted on by the membership.  (As Graham Brady, chair of the 1922 Committee, notes in his interview with my colleague George Eaton, Conservative MPs could choose to offer a wider field if they so desired, but would be unlikely to surrender more power to party activists.)

The extreme likelihood is that that contest will be between two candidates: George Osborne and not-George Osborne.  “We know that the Chancellor has a bye to the final,” one minister observes, “But once you’re in the final – well, then it’s anyone’s game.”

Could “not-George Osborne” be Liam Fox? Well, the difficulty, as one MP observes, is we don’t really know what the Conservative leadership election is about:

“We don’t even know what the questions are to which the candidates will attempt to present themselves as the answer. Usually, that question would be: who can win us the election? But now that Labour have Corbyn, that question is taken care of.”

So what’s the question that MPs will be asking? We simply don’t know – and it may be that they come to a very different conclusion to their members, just as in 2001, when Ken Clarke won among MPs – before being defeated in a landslide by Conservative activists.

Much depends not only on the outcome of the European referendum, but also on its conduct. If the contest is particularly bruising, it may be that MPs are looking for a candidate who will “heal and settle”, in the words of one. That would disadvantage Fox, who will likely be a combative presence in the European referendum, and could benefit Boris Johnson, who, as one MP put it, “rides both horses” and will be less intimately linked with the referendum and its outcome than Osborne.

But equally, it could be that Euroscepticism proves to be a less powerful card than we currently expect. Ignoring the not inconsiderable organisational hurdles that have to be cleared to beat Theresa May, Boris Johnson, and potentially any or all of the “next generation” of Sajid Javid, Nicky Morgan or Stephen Crabb, we simply don’t know what the reaction of Conservative members to the In-Out referendum will be.

Firstly, there’s a non-trivial possibility that Leave could still win, despite its difficulties at centre-forward. The incentive to “reward” an Outer will be smaller. But if Britain votes to Remain – and if that vote is seen by Conservative members as the result of “dirty tricks” by the Conservative leadership – it could be that many members, far from sticking around for another three to four years to vote in the election, simply decide to leave. The last time that Cameron went against the dearest instincts of many of his party grassroots, the result was victory for the Prime Minister – and an activist base that, as the result of defections to Ukip and cancelled membership fees, is more socially liberal and more sympathetic to Cameron than it was before. Don’t forget that, for all the worry about “entryism” in the Labour leadership, it was “exitism” – of Labour members who supported David Miliband and liked the New Labour years  - that shifted that party towards Jeremy Corbyn.

It could be that if – as Brady predicts in this week’s New Statesman – the final two is an Inner and an Outer, the Eurosceptic candidate finds that the members who might have backed them are simply no longer around.

It comes back to the biggest known unknown in the race to succeed Cameron: Conservative members. For the first time in British political history, a Prime Minister will be chosen, not by MPs with an electoral mandate of their own or by voters at a general election but by an entirelyself-selecting group: party members. And we simply don't know enough about what they feel - yet. 

Stephen Bush is editor of the Staggers, the New Statesman’s political blog. He usually writes about politics.