Climate hazards are unlimited, our resources aren't

How to think about very bad things that may happen very far in the future.

How much tax should they pay for our safety?

Here’s a climate thought experiment.

The year is 1526, and you’re the monarch of some great power. An angel appears and tells you that if you make a painful sacrifice on behalf of your kingdom —say, extracting 20% more in taxes from your already dirt poor subjects — you will be able to prevent some catastrophic evil 500 years in the future. An apocalyptic outbreak of plague, say, forecast for the first half of the 21st century.

You know that, a couple of centuries prior, something like a quarter of the people of Europe died from the plague. So you have every reason to believe this threatened harm would be catastrophic.

Should you make this sacrifice, squeezing the peasants you rule on behalf of the people of the far future?

There are good reasons to think you shouldn’t, even if you believe every word the angel says.

You could say, with some verisimilitude, that the subjects of the far future are not really your responsibility. You could conjecture —correctly, as it turns out— that they’re likely to be far wealthier than the medieval peasants you reign over. You could guess —also correctly— that by the beginning of the 21st century, they will have invented a cure for bubonic plague, making a big sacrifice futile.

Knowing what we know today, I think we can say unambiguously that a 16th century monarch would have been wrong to sacrifice prosperity in his time for such an uncertain benefit so deep in the future.

Shouldn’t some awareness of this dynamic color the way we think about responses to climate catastrophes that, as far as we can tell, may be both very real and potentially quite distant in time?

What if, in relation to the people of the 26th century, we in the 21st are the medieval peasants, ignorant of our own relative poverty and backwardness, scared of threats that won’t look so threatening to the people of the deep future?

I find myself mulling thought experiments like this one now and then, as I think about how we should respond to threatened climate catastrophes. Not because I don’t think climate hazards are real — they’re very real. And not because I think we should do nothing to counter them — I spend my entire working life thinking about what we should do to counter them.

Instead, I dwell on them because I find it frustrating that the element of time is so often elided in questions about existential climate threats.

Because it is absolutely true that we’re flirting with climate tipping points that, were they to play out across a single generation or two, would be absolutely catastrophic.

It’s super easy to scare people telling them AMOC is about to collapse and that will ultimately mean European winters ten degrees colder than what we’ve known.

It’s easy to scare people telling them the West Antarctic Ice Sheet may already be past its tipping point and will ultimately mean sea levels rising as much as 10 meters from where they are now. If you leave out the time dimension, people naturally tend to imagine the full impact happening next year and obviously that’s a catastrophe.

In reality, the damage we would face for setting off these tipping points turns entirely on how long an adaptation period we’ll have. If European winters get, on average, two degrees colder per century over the next five centuries, Europe will adapt. Yes, the Londoners of 2526 will have to deal with the winters Newfoundland has in the 21st century, but then no Londoner in 2526 will have any memory of the old days, and the city will adapt. It will, by almost any reckoning, be a much more affluent London than that of today, and may very well innovate ways of dealing with colder winters as alien to us as the idea of antibiotics were to the monarchs of the 16th century. And sea levels that rise 6 m. per decade are an entirely different type of calamity than they would be at 60 cm. per decade. One puts civilization under enormous strain, the other one mostly just annoys us.

There’s a certain tendency, in catastrophist/accelerationists spaces, to act as though the possibility of catastrophic outcomes in the future were the beginning and the end of the debate about climate change.

People talk about the potential cataclysm that would follow from the thawing of Siberian permafrost as though it was enough to sustain any amount of current spending for prevention. If some potential outcomes carry an essentially infinite cost, this line of argument goes, then the expected value of seeing them come to pass is infinite no matter how small the probability chance we assign to them.

The thinking, transposed to 1526, comes out as “well, we just saw bubonic plague kill half the people alive, no sacrifice is too big to prevent it happening again.”

I think we need to resist this form of thinking. It’s plainly wrong. Worse, it’s unhelpful.

In the real world, decision-makers have no choice to trade off between incommensurable priorities. Children still need educating, roads paving, hospitals staffing and armies still need arming, however hazardous climate hazards may be. If your hazard function contains no limiting principle, if it doesn’t generate a basis for accepting some mitigation efforts but rejecting others, it can’t serve as a guide to action.

Where climate hazards are unlimited, but their timelines are unknown, models are always going to be an uncertain guide to action. The cold, hard reality is that whether we end up spending too much or too little to manage them will only be known ex post.

From today’s vantage point, all we can say for certain is that we ought not to waste the resources we do devote to managing climate hazards. Given the unquestionable political reality that willingness to spend is limited, and hazard exposure is not, the one thing we cannot abide is waste. If you take climate hazards seriously as hazards, then every climate dollar should be ruthlessly scrutinized for how much warming it prevents.

Here, I think we can say unambiguously that our performance has been atrocious. With climate fully subsumed into the nonsense back-and-forth of partisan polarization, the vast bulk of what passes for climate activism is blissfully disconnected from any recognizable version of atmospheric physics. We pour money into symbolically resonant projects in the absence of even a rudimentary cost-benefit analysis, as though the intention to make a difference mattered more than the actual impact achieved.

The preening, virtue-signalling brand of climate politics is exactly as fallow as the callous, vice-signalling antics of the denialist right. That’s not surprising, of course: climate realities are convoluted and confusing, partisan signalling is simple and feels good.

Still, somebody has to be the grown up in this room. Somebody has to point out that our resources remain limited, even if our hazard exposure isn’t, and that being the case, we certainly can’t afford to waste what resources we can devote to this problem. I get it that that’s not a message that will sustain a mass movement, I know it won’t fit on a bumper sticker. But it’s true, damnit, and that ought to count for something.