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Comment by beerlord | Hacker News Reader

Can we bio-engineer seaweed which doesn't decompose and can't be eaten?

Its not a joke - these were the circumstances of early Earth, before microbes evolved to digest lignin and cellulose. Trees would fall and not decompose, eventually being compressed into coal.

https://www.nationalgeographic.com/science/phenomena/2016/01...

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It would probably be dangerous to engineer an organism that doesn't break down. Imagine a living, growing plastic. Except not a Dr. Who villain.

Well presumably we could still collect, dry and burn what accumulates on the shore, and the rest would fall to the seabed. If the alternative is a hothouse Earth, with large sections of the planet rendered uninhabitable, geoengineering schemes like this are going to be necessary. We can start with iron fertilisation experiments - Australia has a lot of it, and is near oceans.

You risk creating a locust-like scenario, where it's impossible to fully control areas with specimen outbreaks.

Wouldn’t burning it defeat the carbon sequestration purpose?

That would be a desperate attempt to reverse a runaway process, if it turns out to be too successful.

>>Well presumably we could still collect, dry and burn what accumulates on the shore, and the rest would fall to the seabed.

Immortal plastic organism will eventually evolve to a lot more that 'trap carbon' work. Human's barely live for 60 years, and yet we can transfer all our knowledge generations one after the other. Imagine what an organism that can never die could do.

> the rest would fall to the seabed

And kill a ton of sea life?

What sea life will be left after a few more decades of acidification?

This classic novel explores that scenario.

https://www.goodreads.com/book/show/41094.Greener_Than_You_T...

https://en.wikipedia.org/wiki/Biochar production is one approach to this that is low-tech and doesn't require organism engineering. It's kinda counter intuitive that burning a rich source of carbon would keep it out of the atmosphere, but turning organic material into charcoal stabilises it and renders it inedible and insoluble, and it's really useful as a soil amendment in a lot of places, and it's very likely safe to dump in deep ocean if we ever run short of places to put it.

Farmed seaweed and algae > biochar is a very promising sequestration approach, I think.

Wouldn't this biochar be the charcoal mines of tomorrow?

What I'm saying, is that if it's cheaper than regular coal people will buy this to burn. So you still need an incentive to not burn fossil fuels.

Biochar is unlikely to be cheaper than coal, ever. Optimistic long-term estimates are $100 per ton [1].

[1] http://biomassmagazine.com/articles/4080/beyond--the--hype

There's nothing wrong with burning a renewable resource. You're still at net 0 carbon emissions.

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