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

Homo sapiens appeared in our present form about 200,000 years ago.  Human civilization emerged about 12,000 years ago.  The study of past CO2 levels and climates helps us undersand the conditions 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

Articles

NASA 2005  Paleoclimatology: The Ice Core Record

SkS  We've been through climate changes before

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

 

Homo sapiens appeared in our present form about 200,000 years ago.  Human civilization emerged about 12,000 years ago.  The study of past CO2 levels and climates helps us undersand the conditions 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

 

Articles

 

NASA 2005  Paleoclimatology: The Ice Core Record

SkS  We've been through climate changes before

 

 

1 KYr

1,000 Years CO₂ Data (papers: 1989-1997)

 

Three ice cores drilled at Law Dome, East Antarctica from 1987 to 1993 resulted in atmospheric CO₂ records from 1006 A.D. to 1978 A.D. 

The records extend into recent decades for which instrument measurements of atmospheric CO₂ levels occured.  This was enabled because of the high rate of snow accumulation at the Law Dome drill sites. Scientists reported that the air enclosed in the three ice cores have unparralleled age resolution.

Uncertainty in the data is 1.2 parts per million (ppm).   Pre-industrial CO₂ levels range from 275 to 284 ppm.  Lower levels occured between 1550 and 1800 A.D.  These ice cores show major growth in atmospheric CO₂ levels in the industrial period except 1935-1945 A.D. when levels stabilized or decreased slightly.

Source Graph  Etheridge et al. (via CDIAC)

 

 

Link

 

CDIAC  Historical CO₂ records from Law Dome ice cores

CDIAC  Data | Etheridget et al. (1998)

CDIAC  Graphics

NOAA-NCDC  Composite Data | 0 - 800 KYr [Excel]

 

Reference

 

D.M. Etheridge, L.P. Steele, R.L. Langenfelds, R.J. Francey, J.-M. Barnola and V.I. Morgan. 1998. Historical CO₂ records from the Law Dome DE08, DE08-2, and DSS ice cores. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.

 

 

400 KYr

400,000 Years CO₂ Data (papers: 1999 to 2005)

 

 

 Atmospheric CO₂ History |  400,000 Years Before Present

 Source Graphic  SkS CC BY SA 3.0 [Large JPEG]

Alternate Graphic  CDIAC | CO₂ Record from the Vostok Ice Core (2.3 KYr - 417 KYr B.P.)

 

Data

 

CDIAC  Vostok | 2.3 KYr - 417 KYr

NOAA-NCDC  Composite Data | 0 - 800 KYr [Excel]

 

0 - 22 KYr | Dome C, Antarctica

 

Science 2001  Monnin et al. | Atmospheric CO2 concentrations over the Last Glacial Termination [abstract]

 

22 - 393 KYr | Vostok, Antarctica

 

J. Geophysical Res. 2001   Pépin et al . | Hemispheric climate forcings deduced from Vostok cores & LLN-2D [.pdf]

Nature 1999  Petit et al. | Climate and atmospheric history, 420,000 years from Vostok ice core [abstract]

Nature 2005  Raynaud et al. | Palaeoclimatology: The record for marine isotopic stage 11 [abstract]

 

393 - 416 KYr | Dome C, Antarctica

 

Science 2005  Siegenthaler et al. | Stable C Cycle & Climate Relationship in Late Pleistocene [.pdf]

 

 

Source Graphic   Climate Central [2015 article] [image downloads]

 

References

 

Monnin, E., Indermühle, A., Dällenbach, A., Flückiger, J., Stauffer, B., Stocker, T. F., . . . Barnola, J.-M. (2001). Atmospheric CO2 concentrations over the Last Glacial Termination. Science, 291(5501), 112-114. doi:10.1126/science.291.5501.112

Pépin, L., Raynaud, D., Barnola, J. M., & Loutre, M. F. (2001). Hemispheric roles of climate forcings during glacial-interglacial transitions as deduced from the Vostok record and LLN-2D model experiments. Journal of Geophysical Research, 106(D23), 31885–31892. doi:10.1029/2001JD900117

Petit, J. R., Jouzel, J., Raynaud, D., Barkov, N. I., Barnola, J. M., Basile, I., . . . Stievenard, M. (1999). Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature, 399(6735), 429-436. doi:10.1038/20859

Raynaud, D., Barnola, J.-M., Souchez, R., Lorrain, R., Petit, J.-R., Duval, P., & Lipenkov, V. Y. (2005). Palaeoclimatology: The record for marine isotopic stage 11. Nature, 436(7047), 39-40. doi:10.1038/43639b

Siegenthaler, U., Stocker, T. F., Monnin, E., Lüthi, D., Schwander, J., Stauffer, B., . . . Jouzel, J. (2005). Stable carbon cycle-climate relationship during the Late Pleistocene. Science, 310(5752), 1313-1317. doi:10.1126/science.1120130

 

 

650 KYr

650,000 Years CO₂ Data (paper: 2005)

 

Source Graphic  IPCC AR4 2007  [Hi-Rez Image]

 

Data

 

NOAA-NCDC  Composite Data | 0 - 800 KYr [Excel]

 

416 - 664 KYr | Dome C, Antarctica

 

Science 2005  Siegenthaler et al. | Stable C Cycle & Climate Relationship in Late Pleistocene [.pdf]

 

Reference

 

Siegenthaler, U., Stocker, T. F., Monnin, E., Lüthi, D., Schwander, J., Stauffer, B., . . . Jouzel, J. (2005). Stable carbon cycle-climate relationship during the Late Pleistocene. Science, 310(5752), 1313-1317. doi:10.1126/science.1120130

 

 

800 KYr

800,000 Years CO₂ Data (paper: 2008)

In 2008, Dieter Lüthi and other scientists pubished a paper in Nature that extended the ice core record of atmospheric CO₂ concentrations from 650,000 years before present to 800,000 years before present.  To do this, they analyzed the lowest 200 metres of the ice core drilled at EPICA Dome C in Antarctica.  The work added two glacial cycles to the CO₂ record.  Scientists found that atmospheric concentrations correlated strongly with Antarctic temperature throughout the eight glacial cycles in the 800,000 year ice core record.  They report a reading of 172 parts per million (ppm) CO₂ as the lowest CO₂ concentration ever recorded in an ice core--about 10 ppm lower than the previous lowest reading.

 

Source Graphic  Lüthi et al, 2008

 

 

Links

 

Nature-2008  Lüthi et al | High resolution CO₂ record 650-800 KYr [Abstract]

Nature-2008  Lüthi et al | High resolution CO₂ record 650-800 KYr [Open PDF]

NOAA-NCDC  Lüthi et al | High resolution CO2 record 650-800 KYr [Data: Excel*]

NOAA-NCDC  Lüthi et al | High resolution CO2 record 650-800 KYr [Data: Text*]

CDIAC   800 KYr ice core records of atmospheric CO2

* The data includes a composite for atmospheric CO2 data that spans 800,000 years.

 

Reference

 

Luthi, D., Le Floch, M., Bereiter, B., Blunier, T., Barnola, J.-M., Siegenthaler, U., . . . Stocker, T. F. (2008). High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature, 453(7193), 379-382. doi:10.1038/nature06949

 

Related

 

Climate of the Past-2007  Chronology for the EPICA Dome C ice core [PDF]

 

 

1 My

1 Million Years CO₂ Data (2015 Paper)

 

In 2015, John Higgins of Prince University and colleagues extended the ice core to approximately 1 million years (990,000) with ice core records from shallow blue ice that may "contain the oldest easily accessible ice on the planet" (p. 6887).  Between 800 KYr and 1 MYr before present, researchers found that the concentration of CO₂ in the atmosphere ranged between 221 and 277 parts per million. They are comparable to cycles between 450 and 800 KYr ago, although slightly higher.  The study also shows that the coupling of Antarctic temperature and atmospheric CO₂ extended into the mid-Pleistocene that ended almost a million years ago.

 

Links

 

Princeton | Higgins Lab  Atmospheric compositon 1 million years ago [2015 PNAS paper]

ResearchGate  Atmospheric composition 1 million years ago

PNAS  Atmospheric composition 1 million years ago [abstract]

 

Media

 

Phys.org 2015  Ice cores store atmospheric bubbles from 1 M years ago

 

Reference

 

Higgins, J. A., Kurbatov, A. V., Spaulding, N. E., Brook, E., Introne, D. S., Chimiak, L. M., . . . Bender, M. L. (2015). Atmospheric composition 1 million years ago from blue ice in the Allan Hills, Antarctica. Proceedings of the National Academy of Sciences, 112(22), 6887-6891. doi:10.1073/pnas.1420232112

 

2 My

 

2 Million Years CO₂ Data (2019 Abstract)

Over the past eight hundred thousand years, glacial–interglacial cycles oscillated with a period of one hundred thousand years (‘100k world’1). Ice core and ocean sediment data have shown that atmospheric carbon dioxide, Antarctic temperature, deep ocean temperature, and global ice volume correlated strongly with each other in the 100k world2,3,4,5,6. Between about 2.8 and 1.2 million years ago, glacial cycles were smaller in magnitude and shorter in duration (‘40k world’7). Proxy data from deep-sea sediments suggest that the variability of atmospheric carbon dioxide in the 40k world was also lower than in the 100k world8,9,10, but we do not have direct observations of atmospheric greenhouse gases from this period. Here we report the recovery of stratigraphically discontinuous ice more than two million years old from the Allan Hills Blue Ice Area, East Antarctica. Concentrations of carbon dioxide and methane in ice core samples older than two million years have been altered by respiration, but some younger samples are pristine. The recovered ice cores extend direct observations of atmospheric carbon dioxide, methane, and Antarctic temperature (based on the deuterium/hydrogen isotope ratio δDice, a proxy for regional temperature) into the 40k world. All climate properties before eight hundred thousand years ago fall within the envelope of observations from continuous deep Antarctic ice cores that characterize the 100k world. However, the lowest measured carbon dioxide and methane concentrations and Antarctic temperature in the 40k world are well above glacial values from the past eight hundred thousand years. Our results confirm that the amplitudes of glacial–interglacial variations in atmospheric greenhouse gases and Antarctic climate were reduced in the 40k world, and that the transition from the 40k to the 100k world was accompanied by a decline in minimum carbon dioxide concentrations during glacial maxima.

Links

Nature | Abstract:  Two-million-year-old snapshots of atmospheric gases from Antarctic ice

Media

Science Daily 2019 Two million-year-old ice provides snapshot of Earth's greenhouse gas history

Reference

Yan, Y., Bender, M.L., Brook, E.J. et al. Two-million-year-old snapshots of atmospheric gases from Antarctic ice. Nature 574, 663–666 (2019) doi: https://doi.org/10.1038/s41586-019-1692-3

 

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*** Related

 

CO2.Earth   Annual CO2 Data | 1958 to Present