Holocene calendar

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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 Gregorian calendar (AD or CE) numbering scheme, placing its first year near the beginning of the Holocene geological epoch and the Neolithic Revolution, when humans transitioned from a hunter-gatherer lifestyle to agriculture and fixed settlements. The current year in the Holocene calendar is 12,018 HE. The HE scheme was first proposed by scientist Cesare Emiliani in 1993.[1]


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:

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

Instead, HE uses the "beginning of human era" as its epoch, arbitrarily defined as 10,000 BC denoted year 1 HE, so that AD 1 matches 10,001 HE.[1] 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 would later propose that the start of the Holocene be fixed at the same date as the beginning of his proposed era.[2]


Human Era proponents claim that it makes for easier geological, archaeological, dendrochronological 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 1994 he mentioned that there was no agreement on the date of the start of the Holocene era, with contemporary estimates ranging between 12,700 and 10,970 years BP.[2] Since then, scientists have improved their understanding of and can now more accurately date the beginning of the Holocene. A consensus viewpoint has solidified and was formally adopted by the IUGS in 2013. Current estimates place its start at 9701 BC, about 300 years more recent than the epoch of the Holocene calendar.[3]


Conversion from Julian or Gregorian AD years to the Human Era can be achieved by adding 10,000 to the AD year. The current year of AD 2018 can be transformed into a Holocene year by adding the digit "1" before it, making it 12,018 HE. BC years are converted by subtracting the BC year from 10,001. A useful validity check is that the last single digits of BC and HE equivalent pairs must add up to 1 or 11.

Comparison of some historic dates in the Gregorian and the Holocene calendar
Gregorian year ISO 8601 Holocene year Event
10001 BC −10000 0 HE Beginning of the Holocene Era
10000 BC −9999 1 HE
9701 BC −9700 300 HE End of the Pleistocene and beginning of the Holocene epoch[3]
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 era in the Hebrew calendar
3102 BC −3101 6899 HE Beginning of the Kali Yuga era in Hindu cosmology
2698 BC −2697 7303 HE Reign of the mythical Yellow Emperor, epoch of the traditional Chinese calendar
753 BC −0752 9248 HE Legendary Founding of Rome, starting the ab urbe condita era
544 BC −0543 9457 HE Legendary death of Siddhartha Gautama, epoch of the Buddhist calendar
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 (Anno Domini), from an incorrect estimate of the Incarnation of Jesus
AD 622 +0622 10622 HE Migration of Muhammad from Mecca to Medina (Hegira), starting the Islamic calendar
AD 1582 +1582 11582 HE Introduction of the Gregorian calendar
AD 1912 +1912 11912 HE Epoch of the Juche and Minguo calendars
AD 1950 +1950 11950 HE Epoch of the Before Present dating scheme
AD 1970 +1970 11970 HE Unix Epoch
AD 1993 +1993 11993 HE Publication of the Holocene calendar
AD 2018 +2018 12018 HE Current year
AD 10000 +10000 20000 HE

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  1. ^ a b Emiliani, Cesare (1993). "Correspondence – Calendar Reform". Nature. 366 (6457): 716. Bibcode:1993Natur.366..716E. doi:10.1038/366716b0. Setting the beginning of the human era at 10,000 BC would date […] the birth of Christ at [25 December] 10,000 
  2. ^ a b Emiliani, Cesare (1994). "Calendar reform for the year 2000". Eos. 75 (19): 218. Bibcode:1994EOSTr..75..218E. doi:10.1029/94EO00895. 
  3. ^ a b Walker, Mike; Jonsen, Sigfus; Rasmussen, Sune Olander; Popp, Trevor; Steffensen, Jørgen-Peder; Gibbard, Phil; Hoek, Wim; Lowe, John; Andrews, John; Björck, Svante; Cwynar, Les C.; Hughen, Konrad; Kershaw, Peter; Kromer, Bernd; Litt, Thomas; Lowe, David J.; Nakagawa, Takeshi; Newnham, Rewi; Schwander, Jacob (2009). "Formal definition and dating of the GSSP (Global Stratotype Section and Point) for the base of the Holocene using the Greenland NGRIP ice core, and selected auxiliary records" (PDF). Journal of Quaternary Science. 24 (1): 3–17. Bibcode:2009JQS....24....3W. doi:10.1002/jqs.1227. Archived (PDF) from the original on 2013-11-04. 

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