Various proposals have been made to replace the system of time zones based on offsets from Coordinated Universal Time (UTC) with UTC+00:00 as a local time globally.

For most of history, the position of the sun was used for timekeeping. During the 19th century, most towns kept their own local time. The standardization of time zones started in 1884 in the US.

The time-zone map is a hodgepodge — a jigsaw puzzle by Dalí.

Arthur C. Clarke proposed the use of a single time zone in 1976. Attempts to abolish time zones date back half a century and include the Swatch Internet Time. Economics professor Steve Hanke and astrophysics professor Dick Henry at Johns Hopkins University have been proponents of the concept and have integrated it in their Hanke–Henry Permanent Calendar.

UTC+00:00 as a universal time zone is already used by airline operators around the world and other international settings where time coordination is especially critical. This includes military operations, the US National Oceanic and Atmospheric Administration and the International Space Station. Within the United States, some have cited effective international use of UTC in certain industries as evidence that a permanent national time zone would work within the United States, a change the Secretary of Transportation would have the authority to make.

For example, at 08:00 (8 AM), with UTC±0 as a worldwide standard, the sky in the Eastern United States would look how it normally does at 03:00 (3 AM), and in China would look how it does at 16:00 (4 PM). However, in the United Kingdom, the sky would look the exact same as it normally does at 08:00 (8 AM).