SEES was funded by NSF in 2023 to provide synchrotron beamlines at several US DOE-funded synchrotrons. However, most of the beamlines operated by SEES have been run by COMPRES and GSECARS for several decades. SEES is a successor to both GSECARS and COMPRES, combining support for all the beamlines that those two organizations supported into a single organization. SEES is also able to add some new support for Earth and Environmental science use at beamlines that were not supported by either COMPRES or GSECARS.
The merger of the GSECARS and COMPRES beamlines into a single entity was a community-led effort that began in 2020. Some information about how this came about is at https://synchrotron-geoscience.uchicago.edu