Climate stage· The columns of time

Holocene

11.7 ka → Today

The Holocene is the current geological epoch, opened 11,700 years ago, whose stable climate stands out against the hundred thousand years before it.

Current geological epoch, opened 11,700 years ago and characterised by climatic stability unusual in comparison with the preceding hundred thousand years. Agriculture, cities and state organisations fall entirely within it.

What the evidence shows

The lower limit is fixed by a global golden spike, designated by the acronym GSSP and commonly called a golden spike. The procedure is worth making explicit: geologists do not define a limit by a number of years, which would vary with each new measurement, but by a unique physical point in a reference section chosen and voted upon, a determined depth in a core or a determined layer in an outcrop. The limit is that point; the age expressed in years is only its current estimate, and other regions of the world do not date the limit but refer themselves to it. The point retained here lies in a Greenland ice core, at 11,700 years before the year 2000, where the chemical composition records the end of the Younger Dryas cooling. In 2018, the International Union of Geological Sciences divided the epoch into three ages, each with its own reference point, represented by the three narrow bands below. What is remarkable about the Holocene is the regularity of its climate rather than its temperature, a regularity to which the adoption of agriculture is generally referred.

Bounds and conventions

This limit is among the few on the timeline resulting from a formal decision, written and ratified. It does not for all that constitute a natural threshold: the warming it marks was spread over several decades and did not have the same expression in the two hemispheres. It constitutes a conventional limit, which is the condition of a shared chronology.

Base at the GSSP of the NGRIP2 core, 11,700 years b2k.