The costs of global warming: 2% of global GDP | Hacker News Reader

The costs of global warming: 2% of global GDP

marginalrevolution.com

14 pointsBostonian14 comments

By this measure agriculture is around 4% of the global GDP, so losing it entirely should not be an issue.

The latest IPCC AR6 report paints a picture of a barely habitable planet by 2100.

https://www.ipcc.ch/report/ar6/wg1/

https://interactive-atlas.ipcc.ch/

The model they used in the linked paper gives a 20% chance per 1C after 3C for large-scale discontinuity, otherwise economic and non-economic damage is just a quadratic function of the temperature.

Back in reality 3C would be Mad Max, dead oceans and unhabitable land. Meat scalpers instead of graphics card scalpers. We would still prevail if the atmosphere remains viable, but not as a civilization. Certainly not at this level of resource consumption.

The asymmetry is remarkable, too.

A few years ago the argument was "preventing global warming would cost 0.1% of GDP, and that's totally unbearable."

Edit: "a few years ago", hah. That was the late 1990s or thenabouts, when that's all it would have taken.

It seems inevitable at this point that part of the solution is investing in carbon capture technology in the future to offset the damages we're causing today, the question is; are the damages reversible? Asking individuals to consume less is useless at best and hypocrite at worst.

I recently looked into this. The IPCC claims that atmospheric carbon decays at about 2.5% per year. Current growth is about 0.5% per year. I think carbon-capture has a place in hitting net zero emissions. But don't think it ever have a meaningful impact on accelerating CO2 reduction afterwards. The environmental sinks are just too great for it to add meaningful impact.

It will also be interesting to see what happens if atmospheric CO2 levels hit steady state conditions. Will there be interest and political will to unwind them to earlier levels?

Hmm. Covid lockdowns last year decreased global carbon emissions by only 6.9%, but reduced GDP by about 3.5%, according to a quick Google.

Given this, it seems that reducing carbon emissions by 100% would cost a lot more than 2% of global GDP, making us better off just living with global warming.

You have the causality reversed.

In covid, the emissions dropped because economic activity slowed (to the tune of 3.4% gdp). The economy didn’t slow because we reduced emissions.

The causality actually doesn't matter to much for my argument.

Less travel, manufacturing, and general production in 2020 was what caused both gdp and ghg emissions to drop. They are correlated. They both move in the same direction.

They don’t necessarily move in the same direction since climate change has a significant cost to GDP.

Not quite. COVID shut down sectors by infection risk not by carbon intensiveness.

You're assuming that the method of reducing carbon emissions would be lockdowns?

What a broken premise, you must realize that makes no sense?

Same logic: Burning down my kitchen eliminated 1/8 of the ants in my house, therefore the cost of exterminating all the ants would be burning down the whole house.

No.

I'm saying that lower economic activity and lower ghg emissions are correlated; they move in the same direction.

They're conditionally correlated. Some ways you touch one touches the other. Same as the ants and the house.

Yes, you're correct that it's possible to trade some more highly emissive things for less emissive things, such as an ICE car with an electric car, and that won't necessarily lower GDP. But that's not what I'm talking about. Trying to prevent climate change is mostly a massive waste of time, effort, and money if you're only going to knock out a quartile or half of emissions. Even if we get to the point that the world emits 18 billion tons of CO2 per year instead of the 36 billion we do at present, the climate will continue to warm, and so you'll have spent all this time, money, and effort and still be where we are today anyway.

So when we're talking about stopping all greenhouse gases and preventing further warming of the planet, you're going to necessarily cripple economic output, and as far as I can detect, it's going to be by a lot more than 2% of GDP.

> But that's not what I'm talking about.

Okay, but is there a reason you're not talking about that, other than that it is bad for your argument?

> Even if we get to the point that the world emits 18 billion tons of CO2 per year instead of the 36 billion we do at present, the climate will continue to warm, and so you'll have spent all this time, money, and effort and still be where we are today anyway.

Warming isn't binary. Dumping twice as much CO2 into the atmosphere isn't the same thing as half.

> So when we're talking about stopping all greenhouse gases and preventing further warming of the planet, you're going to necessarily cripple economic output

Is this just a feeling? Seems unmotivated by the rest.

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