Coordinated Universal Time (UTC) to retain “leap second”
New reference time scale to be considered by World Radiocommunication
Conference in 2023
Geneva, 19 November 2015 – The ITU World Radiocommunication
Conference (WRC-15), currently in session in Geneva from 2 to 27 November, has
decided that further studies are required on the impact and application of a
future reference time-scale, including the modification of coordinated universal
time (UTC) and suppressing the so-called “leap second”.
Leap seconds are added periodically to adjust to irregularities in the
earth’s rotation in relation to Coordinated Universal Time (UTC), the current
reference for measuring time, in order to remain close to mean solar time (UT1).
A leap second was added most recently on 30 June 2015 at 23:59:60 UTC. The
proposal to suppress the leap second would have made continuous reference
time-scale available for all modern electronic navigation and computerized
systems to operate while eliminating the need for specialized ad hoc time
The decision by WRC-15 calls for further studies regarding current and
potential future reference time-scales, including their impact and applications.
A report will be considered by the World Radiocommunication Conference in 2023.
Until then, UTC shall continue to be applied as described in
Recommendation ITU‑R TF.460‑6 and as maintained by the
International Bureau of Weights and Measures (BIPM).
WRC-15 also calls for reinforcing the links between ITU and the International
Bureau of Weights and Measures (BIPM). ITU would continue to be responsible for
the dissemination of time signals via radiocommunication and BIPM for
establishing and maintaining the second of the International System of Units
(SI) and its dissemination through the reference time scale.
Studies will be coordinated by ITU along with international organizations
such as the International Maritime Organization (IMO), the International Civil
Aviation Organization (ICAO), the General Conference on Weights and Measures
(CGPM), the International Committee for Weights and Measures (CIPM), the
International Bureau of Weights and Measures (BIPM), the International Earth
Rotation and Reference Systems Service (IERS), the International Union of
Geodesy and Geophysics (IUGG), the International Union of Radio Science (URSI),
the International Organization for Standardization (ISO), the World
Meteorological Organization (WMO), and the International Astronomical Union
“Modern society is increasingly dependent on accurate timekeeping,” said ITU
Secretary-General Houlin Zhao. “ITU is responsible for disseminating time signals by both
wired communications and by different radiocommunication services, both space
and terrestrial, which are critical for all areas of human activity.”
“The worldwide coordination of time signals is critical for the functioning
and reliability of systems that depend on time,” said François Rancy, Director
of the ITU Radiocommunication Bureau. “ITU will continue to work with
international organizations, industry and user groups towards providing coherent
advice on current and potential future reference time-scales.”
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is in session, 2-27 November at the International Convention Centre Geneva
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