The Greater United Nations, also known as, the "Greater U.N.", is the government of Earth, formed in A.D. 2065. Unlike its predecessor, the United Nations, this organization united the various factions of Earth into a single governing body. After World War III, an accord was signed between assorted international factions with the stated goal of preserving the human race and protecting Earth's environment.
The Greater U.N. has proposed large-scale space development and emigration projects to help restore Earth's ecosystem, establishing the USTA (Universal Science and Technology Administration) to focus on those issues.
It is unclear as if they are in any way related to the World Republic Federation, or if this governing body still exists after the forming of the Terran Alliance in SD 12.