But it feels like we're tinkering with a system we barely understand. Ocean ecosystems are delicate, and messing with nutrient flows or phytoplankton populations could have weird downstream effects (literally and figuratively).

You're not wrong, but I think people also underestimate how out of balance the system already is.

It's not like Earth is this perfectly spinning top that some people want to give a nudge. It's more like it's already crashing about while we keep whacking it harder and harder with billions more barrels of oil injected into the atmosphere every year.

I agree we shouldn't recklessly throw new shit at it, but incremental experiments might be worthwhile.

But humans have already been tinkering (tinkering is not the word to describe large scale disturbances) with delicate systems we barely understand since the industrial revolution. But when it comes to technological solutions like this, somehow people think that's too risky.

We're already tinkering by dumping shitloads of carbon into the atmosphere.