[LEAPSECS] Comments on predictions for this century

[Dennis Ferguson]

On 17 Jan, 2015, at 14:43 , Steve Allen <sla at ucolick.org> wrote:
>> perhaps you could add a prominent note indicating that they are all
>> wrong about the near future - and that one reasonable analysis
>> predicts that the effect would be < 1 minute by 2100.
> 
> There is another reasonable analysis by two other folks who worked at
> USNO.  McCarthy and Klepczynski wrote the article that was published
> in GPS World (1999) v10, #11, pp50-57 where we read
>    The difference between UT1 and UTC would near one minute in 2050,
>    if no further leap seconds were inserted in UTC.
> and
>    By the end of the twenty-first century, we see that UTC would be
>    expected to differ from UT1 by more than two minutes.

But the paper also predicts that between when it was written in 1999
and now we would accumulate 16 or 17 additional leap seconds when we've
only had 3.  Our present LoD is significantly shorter than they then thought
it would be. I think the argument is that the best predictor of the future
is not a 1999 prediction of the LoD we would have now extrapolated forward by
the historical rate of LoD increase, but the LoD we actually have now
extrapolated forward by the historical rate of increase.

Dennis Ferguson