Time would be much less of a problem if Terrestrial Time was used internally everywhere. That is: if TT (realized as TAI) were used as the fundamental definitio

Time would be much less of a problem if Terrestrial Time was used internally everywhere. That is: if TT (realized as TAI) were used as the fundamental definition of time, rather than UTC; and UTC were treated as just another timezone. Then, there would be only three problems, which decompose nicely: 1. Trying to keep the system time accurate, and accounting for the possibility it isn't. 2. Having up-to-date time zone information 3. Converting TT to/from a date/time in some particular format in a particular timezone. (1) is fundamentally unavoidable. (3) is complicated but well-defined. (2) should be handled by the system. All that's left is calculations on time values, which if they're in TT (i.e. actual time) are very well behaved. Ultimately this is the fault of the standards bodies. POSIX defines time in terms of UTC. NTP tries to keep the system clock synced with UTC. Postgres "timestamp with timezone" stores UTC. Zone files state offsets in terms of UTC, and even worse, transition times are stated with reference to a timezone (see tzfile(5) and RFC 8536), which is completely insane. This could change. Existing standards can't but new standards could be introduced to succeed the old ones and exist side-by-side. Maybe, instead of proposing changing UTC because they find leap seconds inconvenient, an organization like Facebook could actually do something useful and push for them.