There was a project a decade or three ago to fertilise the oceans to encourage plankton growth. The thinking was that massive plankton plumes would soak up massive amounts of the dreaded CO2 and thus save us from whatever the scare du jour was.

When rooly-trooly scientists ran the numbers they realised there wasn't enough fertiliser on the planet to achieve the aims. Still those who made the claims got some publicity and those who debunked them got all sorts of grants to look into it. So all's well... except for the taxpayer who had to fund the merry-go-round.

That history doesn’t actually support the conclusion you’re drawing from it, mhaze.

Ocean fertilisation wasn't abandoned because someone "ran out of fertiliser". It was constrained because the carbon drawdown was limited and transient, ecological side-effects were uncertain, and scaling effects were hard to predict or verify. In other words, because the system didn't behave linearly when tested.

Negative results aren't a failure of science, they're how boundaries get mapped. They're also why claims about new benefits, whether carbon sequestration or rainfall modulation, still have to engage questions of scale, predictability, reversibility, and governance rather than being waved through by analogy or dismissal.

That's the issue under discussion here.

There's a lot of fertiliser here - horseshit.

"Ocean fertilisation wasn't abandoned because someone "ran out of fertiliser". "

Oh good. Lucky I didn't say it did. But standard JD. Make up my views and then tell me how wrong I am to have said something I didn't say. When you have to make these things up, you've already lost.

" It's whether deliberately perturbing coupled ocean–atmosphere systems can be done predictably, reversibly, and with acceptable risk, and who decides that threshold."

But weather systems are chaotic, as are natural fertilisation events. Also, experiments are done on a small scale (unless you are a dumhead Aus government building a wind and solar grid), and as mhaze pointed out, the purpose is not to remove CO2 as that would be world wide and there is not the fertilizer. The purpose would be to observe the effect on marine life over an area of ocean and to monitor for increases on dimethyl sulphide, cloud formation and rainfall.

mhaze,

I didn't attribute a quote to you, I addressed the conclusion you were advancing.

If you disagree with that conclusion, you're welcome to explain why the historical constraints on fertilisation don't still apply here.

That you chose not to and opted to nit-pick instead is... telling.
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Fester,

Saying weather systems are chaotic doesn't remove the issue, it is the issue. If the effects are inherently chaotic, then claims about influencing rainfall in useful ways become weaker, not stronger.

At the same time, shifting the discussion to small-scale observational experiments quietly abandons the original claims about helping farmers or preventing disasters, which depend on effects being scalable, directional, and policy-relevant.

No one is arguing against small, permitted research. The unresolved question is whether observations at limited scale can justify confidence about outcomes when magnitude, duration, or spatial extent change. That's where predictability, reversibility, and governance still matter.

Until that gap is addressed, appeals to "ingenuity", natural analogies, or past funding debates dont resolve the substantive disagreement.