> These are the people for whom adjudicating upon such matters as France’s attempted move to the decimal system and the International Atomic Agency’s periodic decision to add nuclear seconds to the world time system are the bread and butter that they grapple with at work every day.

I believe the author is referring to leap seconds? International Atomic Agency is I think jumbling up the International Atomic Energy Agency and International Atomic Time. The agency responsible for leap seconds is the International Earth Rotation and Reference Systems Service (IERS); the IAEA is not involved in timekeeping standards as far as I know.