This is a very shallow analysis, feels like an undergrad wrote that. You just wouldn't build a bomb that big, if it were a uranium bomb you'd need on the order

This is a very shallow analysis, feels like an undergrad wrote that. You just wouldn't build a bomb that big, if it were a uranium bomb you'd need on the order of 100 tons of highly enriched uranium and one of the problems would be "how do I get that much uranium close enough together to even build a bomb". The damn thing would be the size of a small to medium ship. And the guy is talking about burying it under kilometers of seabed. When it went of it would be (not cause, be) a 8+ scale earthquake.... one could go on but you get the point. It's a silly napkin math idea that someone decided to put on arxiv. If you wanted to blow up the seabed with nukes to sequester carbon practically, you could do it, but it would take a lot of them and there would be a lot of effects to the local ocean.