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Holocene calendar facts for kids

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The Holocene calendar, also called the Holocene Era Human era or (HE), is a year numbering system that adds 10,000 years to the currently used Anno Domini (AD) or Common Era (CE) system. It places the first year near the beginning of the Holocene epoch and the Neolithic revolution. People who like the Human Era system say that it makes for easier geological, archaeological, dendrochronological and historical dating. They say that it is based on an event more important than the birth of Jesus. The current year of 2020 AD can be made into a Holocene year by adding the number "1" before it, making it 12020 HE. The Human Era was first thought of by the scientist Cesare Emiliani in 1993 (11993 HE).

Cesare Emiliani's reasons for wanting a new calendar include:

  • In the Anno Domini system the birth of Jesus represents the year 1. People now think Jesus was born four years later.
  • The years BC are counted down when moving from past to future, making calculation of lengths of time difficult.
  • The Anno Domini system has no year zero, with 1 BC followed by AD 1. It is important to not forget this when calculating lengths of time.

Instead, HE places its epoch to 10,000 BC. This is a rough approximation of the start of the current geologic epoch, the Holocene (the name means entirely recent). The reason for this is that human civilization (e.g., the first settlements, agriculture, etc.) is believed to have started within this time. All important dates in human history can then be listed using a simple increasing date scale with smaller dates always before larger dates.


Conversion to the Human Era from Julian or Gregorian AD years can be achieved by adding 10,000. BC years are converted by subtracting the BC year from 10,001.

A useful check is that the last single number of BC and HE equivalent pairs must add up to 1 or 11.

Gregorian years ISO 8601 Human Era
Holocene Epoch
30001 BC −30000 20000 BHE
10001 BC −10000 0 HE
10000 BC −9999 1 HE
9001 BC −9000 1000 HE
1000 BC −0999 9001 HE
100 BC −0099 9901 HE
2 BC −0001 9999 HE
1 BC +0000 10000 HE
1 AD +0001 10001 HE
2 AD +0002 10002 HE
2020 AD +2020 12020 HE
10000 AD +10000 20000 HE

Related pages

  • Common Era
  • Julian date (JD) – the interval of time in days and fractions of a day since January 1, 4713 BCE, Greenwich noon, Julian proleptic calendar.
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