Use initial capitals for the names of IPCC working groups and reports:
Working Group I IPCC Fourth Assessment Report (AR4)
Use initial capitals for formal terms:
Last Glacial Maximum Last Millennium International Polar Year 2007–2009
Use lower case for generic terms:
Earth system models (ESMs) global climate model [or general circulation model] (GCM)
Reminder. Initial capitals are used only for formal names. Informal and collective (plural) references to the same item do not need capitals. See Capital letters for further information on when to use capitals.
