The 1993 GRIP ice core results were stunning: European (GRIP, 1990-1992) and American (GISP2, 1988-1993) teams drilled through over a mile and a half of Greenland ice to bedrock, with GISP2 reaching 3,053 meters deep and 1.55 meters into bedrock on July 1, 1993 after five years of drilling. Using oxygen isotope ratios as temperature proxies, they found climate shifted from glacial to interglacial conditions in just 3-5 years — not millennia — twice over 15,000 years. During the Eemian substage 5e, Greenland had only two ice domes with unglaciated land between them.
Greenland ice cores reveal climate shifted from glacial to interglacial in just 3-5 years, twice
Key facts
- GRIP ice core results published in 1993 after 5 years of drilling through the Greenland ice sheet to bedrock
- American and European teams both drilled to bedrock during coordinated expeditions
- Oxygen isotope ratios (O16 vs O18) used as temperature proxy in ice layers
- Approximately 80-100 year lag for snow to convert to glacial ice under pressure
- Greenland ice sheet is over a mile and a half thick
- Eemian substage 5e: sea levels were 20-25 ft higher; Greenland had only two ice domes with unglaciated land between
- Published in Nature: based on annual ice layer thickness over 15,000 years, climate twice shifted from glacial to interglacial in just 3-5 years
- Meltwater pulse 1A dated to approximately 14,500 years ago; Younger Dryas and Bølling-Allerød periods interrupted post-glacial warming
Sources
Paleo Data Search | Studyncei.noaa.gov
Greenland Ice Core Project (GRIP) 1993. Climate instability during the last interglacial period recorded in the GRIP ice core. Nature, 364, 203–207.
Climate instability during the last interglacial period ...nature.com
Isotope and chemical analyses of the GRIP ice core from Summit, central Greenland, reveal that climate in Greenland during the last ...
Greenland ice core projecten.wikipedia.org
The project ran from 1989 to 1995, with drilling seasons from 1990 to 1992. As a result, ice cores capable of continuous flow analysis have been acquired even ...
GISP2icecores.org
On 1 July 1993, after five years of drilling, GISP2 penetrated through the ice sheet and 1.55 meters into bedrock, recovering an ice core to 3053.44 meters ...
Climate instability during the last interglacial period recorded ...nora.nerc.ac.uk
Greenland Ice-core Project Members. 1993 Climate instability during the last interglacial period recorded in the GRIP ice core. Nature, 364 ...
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