Early Eocene Climatic Optimum (Q509)

Subject, term, tag: Early Eocene Climatic Optimum

Early Eocene Climatic Optimum (EECO)

Language	Label	Description	Also known as
English	Early Eocene Climatic Optimum	Subject, term, tag: Early Eocene Climatic Optimum	Early Eocene Climatic Optimum (EECO)

Statements

Instance of

Category

source version

IPCC Glossary v1.5

1 reference

Source

https://apps.ipcc.ch/glossary/

date accessed

27 May 2026

Part of

Working Group I: Climate Change 2021 – The Physical Science Basis

0 references

Definition

The EECO is a period of geological time that occurred about 53 to 49 million years ago, during the Eocene Epoch. Continental positions at this time were somewhat different to present due to tectonic plate movements. Geological data indicate that the EECO was a period of relatively high atmospheric CO2 concentrations (about 1150–2500 ppmv) and relative warmth (global mean surface temperature was about 10–18 °C above the 1850–1900 reference), and polar ice sheets were absent. (English)