"In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts, often producing free neutrons and lighter nuclei, which may eventually produce photons (in the form of gamma rays)". The big Elephant in the room with nuclear fusion is radioactive decay. It causes all kinds of nasty problems. The spent enriched uranium is permanently (relatively) a highly toxic devastating pollutant. On the bright side technologies have been developed to reuse the spent uranium, but its still radioactive afterwards. Other problems with Nuclear fission are its weapon applications. Nuclear Reactors are kept in very restricted locale's and are very suspicious in rogue nations. The difference between making a bomb and making a power plant are quite different, but the presence of enriched uranium causes all the more problems.
Over the past two decades large sections of glacier, Many of them dwarfing Rhode Island, have broken off from the Antarctic Glacial Shelf and fallen to the sea.
Switchgrass is one potential biofuel that is closely being explored by experts. It may have a role in the sustainable energy future.