If I could change the world by doing what I love I would be an Oceanic Engineer. Jacques-Yves Cousteau laid vital work that opened the ocean world to us and many since have followed him into the deep. We, as a collective whole, have yet to truely discover and use the oceans to their fullest potentials. It has been said that land is the one thing that we are not making more of. However, what if we made use of the real estate beneath the waters. Sub-aquatic cities have been used many times in science fiction but I believe that with more research we could make it a reality.
This could change the world by adding living space and new exotic travel destinations. Opening up the science for more work in hyberbarric theory and other pressure therapies. Could the cure for cancer lay beneath the waters of this planet? It is a possibility but unfortunately one that will not be realized if we do not explore that avenue.