Hacker News Reader

Comment by kijin | Hacker News Reader

Could we grow this thing artificially in a suitably stratified sea or lake to cause a meaningful drop in the atmospheric CO2 level?

If growth is only limited by the availability of phosphorus, well, we already know how to supply phosphorus on an industrial scale.

View on HN

I would caution a easy solution as frankly we are but cavemen in the understanding of a complex ecosystem like earths. Attempting what amounts to a terraforming experiment would be a extremely high risk endevour with possibly catastrophic ends.

We're already messing with things in what we think is the opposite direction to what's proposed by kijin.

Besides, how can we ever make progress on planetary improvement if we always just shrug and say that we're cave people? We have to try something.

What we want to be is a feedback controller, which means we can try stuff, but we need to be good at monitoring the changes and reacting to them.

I'm less worried about the monitoring parts, thanks to tireless work of scientist and technologists worldwide. We monitor things on the ground, in the sea, and increasingly also from space.

I'm worried about reaction time, though. Our institutions, especially political ones, absolutely suck at doing the right thing in a timely manner.

Good points. I would also just point out that our institutions suck regarding timing mainly because it's against their interests. If you have some way to improve the planet that isn't against special interests, it might not be fast, but will probably be a lot less slow.

We're already terraforming Earth, and not only with pollution, but also with fire, cities, transportation, dams...

One thing this article suggests is that this event caused mass extinction itself as the climate change probably wiped out those North Pole turtles. I think that is just the point of unexpected consequences I’m trying to raise. Previous attempts to reverse catastrophic changes to ecological environments have been unmitigated disasters. Just ask Australians about the cane toad or rabbits.

Inaction is not a privileged choice.

What's the alternative to deliberately trying to change the environment in order to combat the effects of global warming or even reversing that process entirely?

We've effectively, though inadvertently and not to our benefit, already been modifying our environment for quite some time now. Simply limiting CO2 output might just not be enough to avoid a catastrophic outcome in the future. Even if it were, that 'simply' in 'simply limiting' might not be so simple after all. Even if all relevant political bodies in the world agreed on this - which they currently and unfortunately sometimes emphatically don't - the exact means of how do so in any meaningful way isn't entirely clear. You can't just order industry and traffic to produce less CO2 overnight.

It certainly won't be an easy solution but such approaches need to be discussed and not ruled out entirely beforehand.

> not to our benefit

That remains to be seen, IMHO because it would be very lucky that the current global climate is the optimum for human activities.

For example, with a bit more CO2 in the atmosphere plants grow bigger. Warming might also open more land to agriculture than is lost. Etc.

Yeah, possibly, or more likely it's incredibly dangerous making rapid changes to the chaotic but balanced system that we live within.

The plants might grow bigger - until a voracious pest migrates into the newly available area and destroys them, or wildfires raging in the newly warmed area burn them to the ground.

The current global climate is probably not the optimum for human activities - perhaps that was some time ago, before the extreme weather events that we are ushering in started wreaking havoc. There's no reason to believe that fucking up the planet is somehow leading us towards a better, more optimum situation.

My point is that a warmer climate does not imply a worse climate for human activities overall.

Currently the narrative is change = bad.

What narrative? There are extensive models! More climate chaos = bad!

Using the term "climate chaos" in a discussion about changing climate is indeed pushing a narrative.

CO2 levels have increased by 50% over the past couple of centuries. Are plants growing bigger as a result?

Yes. Although this can be countered by other factors (e.g. less water, excessive heat, etc).

You know this has been studied, right? The conclusion is that it's a big net negative for humanity.

Haven't seen so definitive results...

For example, it is projected that wheat yield would decrease in India. Fine. But how much more wheat would we be able to grow in, e.g., Russia?

You find out! Soil doesn't magically turn productive you know, it takes an ecosystem to make topsoil.

"It should be noted that the overall yield of grain crops in Russia is expected to drop by as much as 17 per cent by 2050. At the same time, in the Central, Volga, and Ural Federal districts the plunge in crop yield is described as ‘catastrophic’ at 14, 30, and 38 per cent by 2050, respectively."

"Without adequate measures to adapt agriculture to climate change, the annual economic loss from a decrease in climate-determined crop yield in Russia is estimated at RUB 108bn (approximately $3.5bn) by 2020 and over RUB 120bn (approximately $3.9bn) by 2050."

Logically this can only come from reduced precipitation, which can be countered.

And of course, more adapted crops can be grown.

There is a lot of potential in Russia to benefit from warmer conditions.

> What’s the alternative

How about just having our cake and not eating it too? Rewind the last 200 years and go back to a preindustrial society. Admit that this level of progress is a candidate for the Great Filter and turn around.

Sounds crazy, but if facing imminent destruction, why rule anything out?

Deliberately going back to a preindustrial society in the end means deciding who is going to live and who isn't (including both currently living human beings and those potentially born in the future). Who is to make that decision and on what grounds?

By the way, intentionally rewinding to a preindustrial society technically is a candidate for the Great Filter, too. While a civilisation that does this will survive it won't be discoverable anymore in order to provide an answer to the question "Where's everyone?".

Back to preindustrial society? What to do with the 80% of humanity this can't feed?

> Simply limiting CO2 output might just not be enough to avoid a catastrophic outcome in the future.

All but one of the IPCC scenarios now require massive CO2 sequestration on the order of half of current yearly emissions starting in 2050.

--> Current emissions are 40 Gt CO2/year, the sequestration is calculated at 20 Gt CO2/year, the optimists of the IPCC give us 4-500 Gt CO2 further leeway of emissions to stay below 1.5°C until 2100 which are about 10 more years at the current rate. (However, the methane deposits in the permafrost are thawing far faster than the models said, so we might have a lot less.)

We should be rioting in the streets, really. The kids have the right idea.

The "sane" alternative is to reduce our CO2 emissions to a point where we can use carbon capture to remove more than we emit. While fertilizing aquatic plants is also a form of carbon capture it's much harder to control and understand compared to our artificial methods.

Whether we have the political will to do this before positive feedback cycles make it impossible remains to be seen.

An interesting thing to explore would be its potential as a biofuel: connect carbon exhausts from factories (cement, etc) to pools/tubes containing Azolla, maybe with solar concentrators to give it even more sunlight.

Pipeline enough of these to generate a continuous (hydro-)carbon output, that can be transported elsewhere, or burnt on-site for electricity generation (and the results backfed to the pools).

The idea here would be to effectively create a giant organic solar panel, with its output in the form of (hydro?-)carbons. Ideally burnt on-site (thus they would act as a battery storage), but it could also be exported.

If we're not going to end our reliance on hydrocarbons today, it better be non-fossils ones, since the only reason CO2 levels climb is that we burn fuel that was sequestrated until recently. Earnings from fuel/electricity sales could be reinvested to fund this at a bigger scale. It wouldn't surprise me if everything could be ran as a completely closed loop, at least for electricity generation.

Of course, the idea isn't new, as a cursory search reveals [1]. I wonder if it could be further enhanced using GMOs such as [2].

[1]: https://www.treehugger.com/corporate-responsibility/15-algae...

[2]: https://arstechnica.com/science/2019/01/re-engineering-photo...

It's the first question that came to my mind, and as it turns out we're obviously not the first to ask it: http://www.climatefoundation.org/azolla.html

Could azolla be farmed and sold for carbon credits? Would it be possible to do so in international waters, tax-free?

Yes, it can be sold for carbon credits if sequestered properly. No, it's a fresh water plant.

I guess the main problem is the fact that it took 800,000 years to sequester 3000 ppm worth of CO2 out of the atmosphere, or roughly 3 ppb per year on average. And that was when there was a lot more CO2 to sequester than now.

We only need to sequester about 140 ppm of CO2 this time. It would still take tens of thousands of years at the natural rate, but we could probably increase the growth rate a hundredfold by carefully selecting high-sequestration cultivars, pumping them full of nutrients, and harvesting them at just the right interval to maintain optimal production. At least it sounds much more promising than the CO2-capturing contraptions I've seen on HN over the years.

Antarctic and Arctic oceans are very nutrient-rich so phosphorus is not the problem. Iron deficiency is the main limiting factor of plankton growth of algae in those areas.

Dumping iron-sulfate into the ocean has tested and it seems to work. https://www.nature.com/news/dumping-iron-at-sea-does-sink-ca...

http://theazollafoundation.org/azollas-uses/as-a-co2-sequest...

Maybe we could revisit the idea of re-flooding Lake Eyre? :)

Reply on news.ycombinator.com