The Holocene calendar, also known as the Holocene Era or Human Era (HE), is a year numbering system that adds exactly 10,000 years to the currently dominant (AD/BC or CE/BCE) numbering scheme, placing its first year near the beginning of the Holocene geological epoch and the Neolithic Revolution, when humans shifted from a hunter-gatherer lifestyle to agriculture and fixed settlements. The current year by the Gregorian calendar, AD 2021, is 12021 HE in the Holocene calendar. The HE scheme was first proposed by Cesare Emiliani in 1993 (11993 HE).
Cesare Emiliani's proposal for a calendar reform sought to solve a number of alleged problems with the current Anno Domini era, which number the years of the commonly accepted world calendar. These issues include:
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.
Human Era proponents claim that it makes for easier geological, archaeological, dendrochronological, anthropological and historical dating, as well as that it bases its epoch on an event more universally relevant than the birth of Jesus. All key dates in human history can then be listed using a simple increasing date scale with smaller dates always occurring before larger dates. Another gain is that the Holocene Era starts before the other calendar eras, so it could be useful for the comparison and conversion of dates from different calendars.
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.
In 1963 E.R. Hope proposed the use of Anterior Epoch (AE), which also begins at the same point.
Conversion from Julian or Gregorian calendar years to the Human Era can be achieved by adding 10,000 to the AD/CE year. The present year, 2021, can be transformed into a Holocene year by adding the digit "1" before it, making it 12,021 HE. Years BC/BCE are converted by subtracting the BC/BCE year number from 10,001.
|10001 BC||-10000[a]||0 HE||Beginning of the Holocene Era|
|9701 BC||-9700||300 HE||End of the Pleistocene and beginning of the Holocene epoch|
|4714 BC||-4713||5287 HE||Epoch of the Julian day system: Julian day 0 starts at Greenwich noon on January 1, 4713 BC of the proleptic Julian calendar, which is November 24, 4714 BC in the proleptic Gregorian calendar|
|3761 BC||-3760||6240 HE||Beginning of the Anno Mundi calendar era in the Hebrew calendar|
|3102 BC||-3101||6899 HE||Beginning of the Kali Yuga in Hindu cosmology|
|2250 BC||-2249||7751 HE||Beginning of the Meghalayan age, the current and latest of the three stages in the Holocene era.|
|45 BC||-0044||9956 HE||Introduction of the Julian calendar|
|1 BC||+0000||10000 HE||Year zero at ISO 8601|
|AD 1||+0001||10001 HE||Beginning of the Common Era and Anno Domini, from the estimate by Dionysius of the Incarnation of Jesus|
|622, 1 AH||+0622||10622 HE||Migration of Muhammad from Mecca to Medina (Hegira), starting the Islamic calendar|
|1582||+1582||11582 HE||Introduction of the Gregorian calendar|
|1912||+1912||11912 HE||Epoch of the Juche and Minguo calendars|
|1950||+1950||11950 HE||Epoch of the Before Present dating scheme|
|1960||+1960||11960 HE||UTC Epoch|
|1970||+1970||11970 HE||Unix Epoch|
|1993||+1993||11993 HE||Publication of the Holocene calendar|
|2021||+2021||12021 HE||Current year|
Setting the beginning of the human era at 10,000 BC would date [...] the birth of Christ at [25 December] 10,000.