How do you price the death of the world?

Climate change is hard to account for.

Grist's David Roberts writes about the distinction between climate change and other environmental problems:

The first difference is that carbon dioxide is not like other pollutants… The typical climate-policy targets that get thrown around — reducing emission rates by 80 percent by 2050, for example — are relatively meaningless. They focus on the rate of flow from the faucet. But that’s not what matters. What matters is the amount in the tub. If the tub fills up enough, global average temperature will rise more than 2 degrees Celsius and we’ll be in trouble. Avoiding that — staying within our “carbon budget” — is the name of the game.

The second difference is that climate change is irreversible.

Roberts cites a 2009 paper from Nature, "among many others":

The climate change that takes place due to increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop. Following cessation of emissions, removal of atmospheric carbon dioxide decreases radiative forcing, but is largely compensated by slower loss of heat to the ocean, so that atmospheric temperatures do not drop significantly for at least 1,000 years.

Climate change is notoriously tricky to deal with in standard economic terms. Part of it is that, to any normal person, something which is irreversible for 1,000 years sounds at least ten times worse than something which is irreversible for 100 years, if not even worse still.

Economically, though, the two are essentially the same. "Present value" is an economic concept dealing with the fact that money in the future is worth less than money now – because you can always invest money now and have more money in the future. Of course, that assumes long-term growth, which, if we're talking about world-changing events like anthropogenic climate change, might not be a safe assumption.

But the end result of the calculations is that nearly any cost beyond a hundred years into the future isn't worth spending money today to avoid. The intuitive conclusion – that it's worth fighting climate change harder if it will last for a millennium than a century – isn't the case. Assuming growth.

But there are even bigger problems for climate change than that. The vast majority of economic responses to it require calculating a "likely cost", and then applying that to the measures proposed to combat it. So, for example, a properly implemented carbon tax requires a calculation of the damage one tonne of CO2 does to the environment, in order to accurately price in the negative externalities.

Unfortunately, conventional ways of pricing risk rather fall over when considering something like climate change, because it carries a non-zero risk of existential threat. That is, there are proposed mechanisms whereby "runaway climate change" could present a civilisation-ending threat.

How do you price the end of civilisation? One option is to look at the value of everything in the world. It would be quite an accounting task, and one faced by the UK government last year when they had to put a price on Stonehenge to fulfil new bookkeeping requirements. The American government puts the value of the entirety of the US at $110trn, so it seems likely that the value of all the world's civilisations is well into 16 figures.

That's high, but it's countable. The real issue comes when you look at an alternative way of measuring the cost of risk, which is the amount you would pay to prevent it. Presumably, there is no sum which would not be worth spending to prevent the end of civilisation. Any cost would be less than the destruction of everything.

By that measure, then, the damage caused by an existential threat is infinite. But the problem with infinite quantities is that they don't work very well in conventional mathematics. Back to the normal risk accounting: you typically multiply the damage you are risking with the chance it will happen. So we are happy to suffer high risk of low damage – like groping for a glass of water at midnight with the lights off – or low risk of high damage – like driving a car – but not high risk of high damage – like driving a car at midnight with the lights off.

But infinity multiplied by anything other than zero is still infinity. Conventional risk assessment simply falls apart when confronted with something the magnitude of the worst possibilities of climate change.

Note too that it doesn't require the risk to be large. I think the risks of climate change are greater than most, but I also think it's extraordinarily unlikely that it actually would result in the end of civilisation. But can we rule it out with certainty?

The best way to look at it is to compare it to our every day lives. Thousands of people are killed crossing the road every day. To do so carries a non-negligible personal existential threat – that is, you might die. Yet I see people dodging traffic to get to work 30 seconds earlier every day, which suggests that, instinctively, we don't treat the risk of death with as much weight as we perhaps should.

But I think theres a different motivator at work. We know death is bad, and that it's worth doing a lot to try and avoid it; but we also know death can come from any corner. And the same is true of fighting existential threats to civilisation. If we could spend ludicrous sums to eliminate them all, it might be worth it; but who's to say we won't prevent climate change, only to die from an asteroid hit? Or cap our future development by not experimenting with nanotech, only for an angry AI to kill us in our sleep?

Climate change could be very, very bad indeed. But making the important choices about the trade-offs we should make to fight it are hard because, not despite, its seriousness.

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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The tale of Battersea power station shows how affordable housing is lost

Initially, the developers promised 636 affordable homes. Now, they have reduced the number to 386. 

It’s the most predictable trick in the big book of property development. A developer signs an agreement with a local council promising to provide a barely acceptable level of barely affordable housing, then slashes these commitments at the first, second and third signs of trouble. It’s happened all over the country, from Hastings to Cumbria. But it happens most often in London, and most recently of all at Battersea power station, the Thames landmark and long-time London ruin which I wrote about in my 2016 book, Up In Smoke: The Failed Dreams of Battersea Power Station. For decades, the power station was one of London’s most popular buildings but now it represents some of the most depressing aspects of the capital’s attempts at regeneration. Almost in shame, the building itself has started to disappear from view behind a curtain of ugly gold-and-glass apartments aimed squarely at the international rich. The Battersea power station development is costing around £9bn. There will be around 4,200 flats, an office for Apple and a new Tube station. But only 386 of the new flats will be considered affordable

What makes the Battersea power station development worse is the developer’s argument for why there are so few affordable homes, which runs something like this. The bottom is falling out of the luxury homes market because too many are being built, which means developers can no longer afford to build the sort of homes that people actually want. It’s yet another sign of the failure of the housing market to provide what is most needed. But it also highlights the delusion of politicians who still seem to believe that property developers are going to provide the answers to one of the most pressing problems in politics.

A Malaysian consortium acquired Battersea power station in 2012. Initially, it promised to build 636 affordable units. This was pretty meagre, but with four developers already having failed to develop the site, it was still enough for Wandsworth council to give planning consent. By the time I wrote Up In Smoke, this had been reduced to 565 units – around 15 per cent of the total number of new flats. Now the developers want to build only 386 affordable homes – around 9 per cent of the final residential offering, which includes expensive flats bought by the likes of Sting and Bear Grylls.

The developers say this is because of escalating costs and the technical challenges of restoring the power station – but it’s also the case that the entire Nine Elms area between Battersea and Vauxhall is experiencing a glut of similar property, which is driving down prices. They want to focus instead on paying for the new Northern Line extension that joins the power station to Kennington. The slashing of affordable housing can be done without need for a new planning application or public consultation by using a “deed of variation”. It also means Mayor Sadiq Khan can’t do much more than write to Wandsworth urging the council to reject the new scheme. There’s little chance of that. Conservative Wandsworth has been committed to a developer-led solution to the power station for three decades and in that time has perfected the art of rolling over, despite several excruciating, and occasionally hilarious, disappointments.

The Battersea power station situation also highlights the sophistry developers will use to excuse any decision. When I interviewed Rob Tincknell, the developer’s chief executive, in 2014, he boasted it was the developer’s commitment to paying for the Northern Line extension (NLE) that was allowing the already limited amount of affordable housing to be built in the first place. Without the NLE, he insisted, they would never be able to build this number of affordable units. “The important point to note is that the NLE project allows the development density in the district of Nine Elms to nearly double,” he said. “Therefore, without the NLE the density at Battersea would be about half and even if there was a higher level of affordable, say 30 per cent, it would be a percentage of a lower figure and therefore the city wouldn’t get any more affordable than they do now.”

Now the argument is reversed. Because the developer has to pay for the transport infrastructure, they can’t afford to build as much affordable housing. Smart hey?

It’s not entirely hopeless. Wandsworth may yet reject the plan, while the developers say they hope to restore the missing 250 units at the end of the build.

But I wouldn’t hold your breath.

This is a version of a blog post which originally appeared here.

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