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Comment by dash2 | Hacker News Reader

Respectfully suggest this is nonsense. No serious climate scientist thinks we are going to fall off a cliff. There will be huge costs, yes. Civilization won't end, no.

What people fail to grasp is that costs can be absolutely enormous but look like a blip compared to the effect of GDP growth in the long run. World War II is an example. The millions of deaths barely show up on a graph of world population. The huge losses barely interrupt the smooth rise of GDP. Similarly, climate change could knock 5% off GDP permanently, this would be "the world's biggest collective action problem" as I think Nick Stern put it, but it wouldn't stop human society getting much richer.

Edit: a bit of backup: https://www.forbes.com/sites/michaelshellenberger/2019/11/25...

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Respectfully suggest that this analysis is more whistling in the dark.

The very idea that human leadership has things under control overlooks multiple events in history - e.g. the Bronze Age Collapse we're still trying to explain - and suggests both amnesia and completely undue hubris. The idea also overlooks the potential for other kinds of simultaneous disaster being heaped on. (CME's for one.) We can anticipate them, but they are beyond our control - and may disable further options.

There was a mass extinction of hundreds of species of megafauna just before our known history begins. Can't agree on the cause - but nonetheless the Moving Hand moved on.

In the past two years, the fear and death created by one little invisible bug, which we declined to prepare for, has badly damaged economic stability. If we continue to overplay our weak hand, who will pay for the damage - and with what?

This seems like a general argument that "unexpected bad things might happen". I agree, sure - but this argument applies equally to, for example, alien invasions or grey goo. The question I'm addressing is whether global warming will cause civilization to collapse or humans to go extinct. I claim no serious climate scientist thinks that.

The mass extinction has been definitively traced to coincidence with the comet strike of 10818 BCE.

Actual proof that each extinction was actually directly caused will be harder to come by. E.g. maybe dire wolves died because their prey went extinct. And, we still don't know why bison survived.

> No serious climate scientist thinks we are going to fall off a cliff. There will be huge costs, yes. Civilization won't end, no.

I've read more than a couple of articles, linked to here on HN, of climate scientists claiming that this is indeed a civilization-ending cliff.

It's been mentioned like this in other media, for example in Cosmos 2. Yes, that's divulgation, but nonetheless, it means the scientists consulted for Cosmos 2 believe this.

edit: just googled Michael Shellenberger. He is not a subject matter expert on climate change, and Wikipedia describes him as "a controversial figure" among environmentalists, which means his position is not mainstream and probably shouldn't be used to state "no serious scientist believes...". Note: I'm not saying he is wrong, he could be right; it's just that his view is not mainstream for now.

I don't think the cliff in the article is referring to the phenomenon of a climate cliff. I think that is taking it too literally. I DO think climate change will be a disaster for humanity if we do nothing. It's not a sudden event by any means. The disaster will take decades of inaction and acceleration before we realize we are in it.

But the analogy, which is that we are headed for a disaster and at this point we must take rapid drastic action to avoid it, I think is correct. Rapid action means making decisions now to commit to decades of repair work. It means immediately stopping new climate bomb projects. On the scale of a society, change that takes decades is akin to swerving a bus. And if we take no action, I think the analogy of crashing in to a canyon is appropriately bad. The only difference is that falling off a cliff happens in an instant, and no harm is done if you stop at the last minute, whereas with climate change the problem is slowly getting worse day by day. So yeah, it is not a perfect analogy, but I don't think we are meant to take the cliff as a direct analogy to climate change occurring all at once or not at all. Doctorow certainly knows that is not physically correct.

Now if you look at human activity on long timescales, the decisions we make this century can drop us off a cliff in to disaster, or change our trajectory to just some bumps and bruises. And I think on this time scale the cliff analogy is more literal. You just can't think on the year by year timescales we normally think.

The Clathrate Gun could be the cliff, though I think he was just using a weak metaphor. There could be enough trapped methane in the Arctic to trigger a major warming event if we break a certain warming threshold. This also may have happened before eons ago.

https://en.m.wikipedia.org/wiki/Clathrate_gun_hypothesis

Also the biggest problem to solve for the climate crisis is to solve for diesel fuel. If you could replace Diesel engines with anything else or curb their emissions that is the biggest contributor to CO2.

Nature did a poll of IPCC authors (https://www.nature.com/articles/d41586-021-02990-w) and 60% of them expect the world to warm >= 3°C.

Science does not work by popular vote.

I was adding context to OP's statement that "No serious climate scientist thinks we are going to fall off a cliff". If 60% of the most influential climate scientists expect the world to warm >= 3°C, and one believes (like I do) that >=3°C of warming constitutes a "cliff", then OP's statement is incorrect.

No, my point isn't about 3 degrees of warming - I agree that's possible. My point is that 3 degrees of warming will not cause civilization to end, still less human life.

> No serious climate scientist thinks we are going to fall off a cliff.

It's not a literal cliff. Doctorow was using a metaphor. And they're never exact fits, they are loosely analogous.

He probably chose a bus in an attempt to make the trolley problem more current and approachable.

Right. I understand that Doctorow was not literally saying that all humans will fall off a cliff, into the sea.

Serious scientists are not allowed to predict it. But it is certainly among the end states. Even likely ones.

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