Sorry to hear about the weight struggle. My personal experience is that it's a very habit dependent and hard to conquer thing.

And yes, we can’t possibly convince everyone. We shouldn't try. Long term thinking is really hard. We need top down public policies informed by science. Heavy tax incentives and disincentives.

We should definitively try seeding the oceans, but planet scale engineering is some scary shit. The stakes are as high as can be and calculating all possible outcomes is next to impossible. It's also hard to start small and scale. So, very much needed and terribly dangerous.