When one considers time travel, it is wise to become aware of a set of agencies and policies that are responsible for keeping our clocks on time, and of the consequences of their policies for surfing the chronoscape. A small policy change can cause all sorts of problems.
The current system that ensures that clocks run on time involves coordination between the International Earth Rotation and Reference Systems Service (IERS), the International Bureau of Weights and Measures (BIPM), and the Radiocommuncation Sector of the International Telecommunications Union (ITU-R). The IERS charts the Earth’s movements, the BIPM takes signals from atomic clocks distributed around the globe in order to define a precise clock time, and the ITU-R sets policies and standards. Right now these institutions are engaged in the debate over the future of the leap second.