It is amusing how in their goal to be carbon neutral they're just heating the sea directly, cutting out the atmosphere as a middle-man. I'm not sure what the numbers on it are though. I guess heating the sea will only be once but having CO in the atmosphere will provide recurring heating.
I imagine it's the difference between using the oven in your home and installing insulation. The oven does directly heat your home a bit, and the insulation does not, but the insulation will have a much bigger impact.
