A NASA analysis shows that Pacific Island nations are at great risk from sea level rise over the next three decades. Tuvalu, Kiribati, Fiji, Nauru, and Niue will be surrounded by an "irreversible" extra 6 inches of water by the early 2050s — no matter how much heat-trapping pollution is slowed down from adding to the existing problem in the atmosphere, according to the Jet Propulsion Laboratory.