[LEAPSECS] "China move could call time on GMT"

Rob Seaman seaman at noao.edu
Fri Jan 6 13:27:19 EST 2012

There were various messages on this topic over the years but I don't have time to search them out now.

In addition to Tony's very cogent point (and note that only a small fraction of the world implements DST to permit hiding the adjustment), and ignoring the fact that there is no actual proposal on the table to attempt to implement leap hours as timezone shifts, the real point is that this would be a decadal shift of timezone offsets. Arizona is UTC-7 now and would be UTC-8 later. (Quick! Or is it UTC-6?!?) And then UTC-9, UTC-10, etc., decade after decade.

Those of us who work for organizations that collaborate with partners in the southern hemisphere will also understand that even if both sites do DST, the adjustments are seasonally in opposite directions, playing bloody hell with telecon schedules, etc. And this would introduce at least a six month period of confusion into each decade's transition even if the various governments and agencies and corporations did a perfect job of cooperating.

Either this TZ notion makes sense, in which case it should be straightforward to address these issues and others in a concise white paper - or it makes no sense and we should stop treating it like an established fact. At any rate it is the responsibility of the proponents of "Draft Revision to ITU-R Recommendation TF.460-6" to make this case before action is taken.

On Jan 6, 2012, at 11:07 AM, Tony Finch wrote:

> Ian Batten <igb at batten.eu.org> wrote:

>> On 5 Jan 2012, at 23:49, Rob Seaman wrote:


>>> And I have reckoned the exact opposite. A leap hour or timezone shift

>>> per decade is way too frequent for people to put up with.


>> Why not? They handle DST shifts every six months. What's the

>> difference for 99% of the population?


> DST shifts are predictable, whereas one-off changes cause all sorts of

> pain. The most recent serious example was the North American change in

> 2007. One of the problems it exposed is that a lot of calendaring software

> is not robust in the face of changes to timezones.


> I said TZ changes are "easy to cope with if your timezone system is

> already handling random political fluctuations" which is currently the

> case in some parts of the world, but the rich world seems to be

> rigidifying - for instance, changing the rules in Europe requires more

> than two dozen countries to agree, so it's much less vulnerable to

> interference from under-employed politicians. So I don't think the

> timezone fudge will be as easy to implement in 600 years' time as recent

> history suggests.


> Tony.

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