Holocene calendar

Overview

Cesare Emiliani's proposal for a calendar reform sought to solve a number of alleged problems with the current Anno Domini era, also called the Common Era, which numbers the years of the commonly accepted world calendar. These issues include:

• The Anno Domini era has no year "zero", with 1 BC followed immediately by AD 1, making calculation of time spans difficult.
• The years BC/BCE are counted down when moving from past to future, complicating the calculation of timespans further.
• The birth date of Jesus is a less universally relevant epoch event than the approximate beginning of the Holocene.
• The Anno Domini era is based on the erroneous or contentious estimates of the birth year of Jesus of Nazareth. The era places Jesus's birth year in AD 1, but modern scholars have determined that it is more likely that he was born in or before 4 BC. Emiliani argued that replacing the contested date with the approximate beginning of the Holocene makes more sense.

Instead, HE uses the "beginning of human era" as its epoch, arbitrarily defined as 10,000 BC and denoted year 1 HE, so that AD 1 matches 10,001 HE. This is a rough approximation of the start of the current geologic epoch, the Holocene (the name means entirely recent). The motivation for this is that human civilization (e.g. the first settlements, agriculture, etc.) is believed to have arisen within this time. Emiliani later proposed that the start of the Holocene should be fixed at the same date as the beginning of his proposed era.

Accuracy

When Emiliani discussed the calendar in a follow-up article in 1994, he mentioned that there was no agreement on the date of the start of the Holocene epoch, with estimates at the time ranging between 12,700 and 10,970 years BP. Since then, scientists have improved their understanding of the Holocene on the evidence of ice cores and can now more accurately date its beginning. A consensus view was formally adopted by the IUGS in 2013, placing its start at 11,700 years before 2000 (9701 BC), about 300 years more recent than the epoch of the Holocene calendar.

Equivalent proposals

In 1924 Gabriel Deville proposed the use of Calendrier nouveau de chronologie ancienne (CNCA), which would start 10,000 years before AD 1, which is identical to Emiliani's much later proposal.

Since 1929, Dievturība adherents use Latviskā ēra (the Latvian Era) which begins at the same point; this coincides with the first inhabitants’ influx to the territory of present Latvia (10500–10047 BCE). According to the Latvian Era, 12026 is written for 2026 CE. Detailed explanation of Latvian Era by Ernests Brastiņš was first published in 1934.

In 1963 E.R. Hope proposed the use of Anterior Epoch (AE), which also begins at the same point.