New Times,
New Thinking.

  1. Business
  2. Economics
8 May 2012updated 12 Oct 2023 10:44am

Global warming and externalities

How a carbon tax can "solve" global warming

By Alex Hern

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.

Select and enter your email address Your weekly guide to the best writing on ideas, politics, books and culture every Saturday. The best way to sign up for The Saturday Read is via saturdayread.substack.com The New Statesman's quick and essential guide to the news and politics of the day. The best way to sign up for Morning Call is via morningcall.substack.com
Visit our privacy Policy for more information about our services, how Progressive Media Investments may use, process and share your personal data, including information on your rights in respect of your personal data and how you can unsubscribe from future marketing communications.
THANK YOU

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.

Content from our partners
The UK’s skills shortfall is undermining growth
<strong>What kind of tax reforms would stimulate growth?</strong>
How to end the poverty premium