I wonder if these can be considered the next generation of underwater gliders. There was a very interesting program on them recently - either on PBS or Discovery, can't recall exactly.
http://en.wikipedia.org/wiki/Underwater_gliders
"Save the world" is such a broad term. It really depends on what things about the world you find to be most important.
If your primary concerns are safety from hazardous ocean-based weather, security of offshore energy generators and fisheries, and a better understanding of the ocean's effect on climate change, Liquid Robotics' technology would certainly qualify as "saving the world".
What's amazing is how sophisticated this technology is and how underreported it is. They are using fiberglass hulls to evade radar and transmitting their location using state of the art encryption.
"I was told 'find something interesting to do'." -jag
They should have been a wee bit more specific about whose interests they were referring to!