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Comment by rb808 | Hacker News Reader

> Levels of CO2 in the atmosphere have surged past an important threshold and may not dip below it for "many generations".

Is this at all reversible? I presume not.

The real problem is that lots of people and putting a lot of effort and money into reducing emissions - where if the above is correct seems very very difficult (with a growing developing world) and likely a waste of time.

Surely we should be trying harder to scrub CO2 from the atmosphere and spend less time on reducing emissions?

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> Surely we should be trying harder to scrub CO2 from the atmosphere and spend less time on reducing emissions?

It's simply a matter of cost. While we are continuing to put CO2 into the atmosphere, preventing one gram of CO2 from being emitted is equivalent to scrubbing one gram of CO2 from the atmosphere, and at present the former is far, far cheaper than the latter, and there is a huge amount of low hanging fruit still to be gathered. In fact, a lot of the emissions abatement is profitable - for instance an LED lightbulb might cost $5-10, but saves you 500-750 kWh over its lifetime, which is $50-100 worth of electricity even without pricing in carbon. The hope is if you introduce a carbon price (for instance by cutting other taxes and introducing a revenue neutral carbon tax) that you can further spur investment so that the market will make more of these technological developments towards resolving the problem. That may involve scrubbing carbon, for instance the recent process which has got a lot of publicity, using renewable electricity to turn CO2 into ethanol. But you're looking to resolve things at the lowest cost, and it may be that scrubbing is unnecessarily costly, and you can do everything through other means. We need to just price in the externality and let the market do what it does best.

Sure maybe cutting emissions can be cheaper than scrubbing - but the article says the CO2 levels are already too high. If we magically stop all emissions right we should be scrubbing as well.

So maybe we should be reducing emissions where its easy - and scrub

> Sure maybe cutting emissions can be cheaper than scrubbing - but the article says the CO2 levels are already too high

Ah, I see what you mean. It's a bit like national debt and deficit I suppose. At the moment, debt is high, and the deficit is high. CO2 abatement measures can reduce the deficit, but not the debt. You'd need CO2 scrubbing to actually push the deficit into surplus, and reduce the debt, rather than just stabilize it.

In an ideal world, you're right that we want to be getting the total concentration down, not just stabilizing it by reducing the rate of increase. But I think that stabilization would be such a major challenge for the foreseeable future that we should be looking to that first. Prioritizing more expensive ways of trying to reduce the total concentration in 30-50 years, over cheaper ways of stabilizing the concentration right now would, in my opinion, be making the perfect the enemy of the good.

Also, I'm not sure stabilization at 450 or 500 ppm (equivalent to 2-3C warming) would be that bad, what we're trying to do is avoid the definitively atrocious outcome of warming above the 2-3C range.

We release it because it allows us to produce energy (burn something). To remove it from atmosphere would require to put it some higher energy state so that we can store it and that require again some source of energy. Pumping pure CO2 in some mine will probably not do the job.

In reality, we will try to just reduce temperature without removing CO2, but CO2 causes problems other than tempterature rise. See ocean acidification.

There seems to not be any good solution really.

yeah, but we release it because burning things is an easy way of releasing energy whenever / wherever we need it. Reducing CO2 can be done pretty much anywhere in the world. So if we needed to build a nuclear powerplant somewhere just to power our CO2 scrubbers, so that our cars and planes could burn fuel, that's completely doable.

Plant a hell of a lot of trees?

That is actually the most effective way of scrubbing CO2. The problem is that trees take up a lot of valuable real estate.

Lots of unused land are shrubs, grass and hillsides. The mediterranean coast used to be all trees a little more than two millenia ago[0]. Some semi-arid zones around deserts could also support reforestation.

[0] https://en.wikipedia.org/wiki/Deforestation_during_the_Roman...

Just stop growing is the solution itself.

If we were to "just stop growing", it would pretty much collapse the entire civilization on the spot. Unfortunately, the assumption of growth is the basis of not just the economy, but a lot of things in the society.

Sure, I think we should move away from the growth-based economy. But this needs to be a gradual process.

The path to reducing emissions is much clearer than the path to efficiently scrub CO2 from the atmosphere. Also, scrubbing CO2 from the atmosphere gets harder and harder as CO2 emissions grow. There is some research to sequester CO2, but I don't think we have an ideas that are better than planting trees.

The elephant in the room that people don't talk about is population growth. If we don't get that under control, there really is no chance of us avoiding catastrophic consequences, like melting of the methane clathrates.

The vast majority of the CO2 is produced by only a small part of the population (the rich people in the west), and they aren't the ones whose population is growing.

Actually China is #1, triple the USA. Have they stopped growing?

https://en.wikipedia.org/wiki/List_of_countries_by_carbon_di...

How much of that is by factories producing things for consumers in the west?

Its mostly charcoal cooking fires if I understand right.

China has a birth rate distinctively under the one necessary for a constant population. But as people keep living longer, the total population is going to grow slightly for some years to come. The bigger environmental impact is, that the energy consumed per citizen is still growing as prosperity develops.

Education, prosperity and equality can solve that.

TED talk: https://www.ted.com/talks/hans_rosling_on_global_population_...

Prosperity == higher living standards, which means more resource consumption per capita. So you merely substitute population growth with increased living standards as driving factor for emission increases.

I take issue with Hans Rosling (even though i happen to live in Stockholm). His message is 'dont worry, they will have babies for 50 years, then it will be all ok'. Sub-saharan Africa will have a similar population density to south east Asia. The world will have 10 billion. That's ok. But the truth is we don't know the carrying capacity of the earth. It's deeply unpopular to say this, but the only way i can see us solving this collective action problem is with a world government.

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