Quasar ‘clocks’ show universe was five times slower soon after the Big Bang - https://www.zmescience.com/science/news-science/quasar-clocks-time-slows-down-early-universe/

Melting polar ice is changing Earth’s rotation and slowing down time. Here’s how this will affect the leap second - https://www.zmescience.com/space/melting-polar-ice-timekeeping/