I have found documented proof that David Spangler served on the Board of Directors at the United Nations as a "Planetary Citizen".
Here is the PDF document which references this:
In the UN archives: http://archives-trim.un.org/webdrawer/rec/423068/view/Items-in-Secretary-Generals%20Statements.PDF
Mirror in case document is removed: https://docs.google.com/open?id=0B6Dmg6MKtIqUMGU5OWU0N2YtMWNiZC00Y2E5LWI0ZWEtMjdkNmEzNTE4OTM2
Search the document for "David Spangler" and you will find his name listed under "BOARD OF DIRECTORS" on a page titled "PLANETARY CITIZENS".
This document is located in the United Nations document archive, and dates back to 1975.
This document is very old and was scanned and uploaded into the UN's archive in 2006. It is no wonder it is hard to come by more information about the "Planetary Initiative" and David Spangler's involvement in it: any documents which have anything to do with it predate the modern computer era, and would need to be manually scanned and uploaded to the internet for the information to be easily found through a web search.
This is DOCUMENTED PROOF of David Spangler's involvement with the United Nations as a Board of Director of the Planetary Initiative, in the official UN archives no less.
Praise the Lord Jesus Christ, Holy Son of the living Father, for helping reveal the truth in this matter.
Revelation 1:17-18 (NASB)
When I saw Him, I fell at His feet like a dead man. And He placed His right hand on me, saying, “Do not be afraid; I am the first and the last, and the living One; and I was dead, and behold, I am alive forevermore, and I have the keys of death and of Hades.