2005 Proposal ITU-R WP 7A from the US
The abandonment of leap seconds?

nc1985wp7a
Proposed Revised Recommendation ITU-R TF.460-6

In 2005 the United States Working Party 7A drafted a new version of the document which defines UTC with the expectation that it would be presented to the ITU in November. This document proposed that leap seconds should be abandoned. The document was subject to public review until October 14.

The result of the Department of State review was that the US delegation did not submit this document. However other national delegations did submit revised versions, and as of 2010 the draft was forwarded to the ITU-R Radiocommuincations Assembly. It is expected that will be presented for a vote in 2012, and if 70% of the nations approve there will be no more leap seconds.

The text of proposals from the US must be publicly circulated prior to submission to the ITU-R. The document here was obtained during that review. Once proposals have been submitted to the ITU-R they are no longer public, so the proposed draft revision as of 2011 is not available.


The MSWord file with a draft proposed revision to ITU-R TF.460 dated 2005-09-19 from USWP-7A was available from the FCC web site. It contains markup indicating changes made by Ron Beard and Wayne Hanson. (It has now been removed from the active section of the FCC web site, but it may reappear in the archives. If any version of it is submitted to the WP7A of the ITU-R for the 2005 November meeting it will appear as one of the contributions.)

The most significant difference between the 2004 proposal (nc1893wp7a) and the 2005 proposal (nc1985wp7a) is that the date of the change to the nature of UTC is not to be 2007-12-21, but December 21 of the year five years after the change is adopted by the ITU-R.

Links to various documents related to the above

Brief summary of arguments against the proposal

Some of the strongest arguments are from Dr. P.K. Seidelmann, formerly of the US Naval Observatory, editor of the Explanatory Supplement to the Astronomical Almanac, and member of USWP7A who wrote a letter indicating that there was no justification for change.

Here is a brief list of some other points


Steve Allen <sla@ucolick.org>
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