[adwn]

> a small increase in temperature in the ocean, [...] or an increase in above-surface CO2 levels

Those are permanent, globally occuring, chemical phenomena. A sonic boom is a very temporary, very local, mechanical phenomenon. You cannot draw any conclusions from one to the other.

> tiny sonar noises a few hundred kilometers away

Sonar originates from within water, while sonic booms originate in the air. Most of the boom's acoustic energy will probably be reflected by the transition from one medium to the other.

I think marine life will most likely be a lot less disturbed by sonic booms than by naturally occuring storms.