Greenland Ice Core

Greenland Ice Core at American Museum of Natural History, New York (image cropped)

Source Image  Eden, Janine & Jim | CC BY 2.0


The farther backward you can look,
the farther forward you are likely to see.

~ Winston Churchill


Human civilization emerged about 12,000 years ago, and home sapiens appeared in 'our' present form about 200,000 years ago.  The study of past CO2 levels and past climates helps us undersand the condition in which human societies developed.  This 'paleoclimate' information offers important lessons for understanding sustainability and the range of climatic conditions that human societies are known to be suited for.

To understand past climates, ice cores provide a high-resolution record of key climate variables that span the period in which homo sapiens appeared and human civilization developed.  Aside from the high-precision CO2 measurements that Charles David Keeling started at the South Pole in 1957 and the Mauna Loa Observatory in 1958, ice cores are the best source of atmospheric CO2 data for the prior 1 million years.

Scientists have been drilling ice sheets and analyzing the ice cores since the 1950s, particularly in Antarctica and Greenland.  Areas with accumulating snow turn to ice with air bubbles that preserve samples of the atmosphere from world atmospheres of the past.  Scientists are able to analyze the cores to learn about past changes in the concentration of atmospheric gases and the glacial-interglacial cycles for the past million years. 

Here, use the CO2 data and graphs to explore changes in the past, from a thousand to a million years before present.


Ice Core Research


NOAA NCEI  Ice core data

NOAA NCEI  NOAA paleoclimatology ice core datasets

NSIDC  Antarctic Glaciological Data Center

EGU 2013  Finding a 1.5 million-year record of earth's climate




NASA 2005  Paleoclimatology: The Ice Core Record

SkS  We've been through climate changes before



CO2 Past.  CO2 Present.  CO2 Future.