Fact Check: "Greenland was nearly ice-free multiple times during the Pleistocene."
What We Know
Recent studies have provided substantial evidence supporting the claim that Greenland was nearly ice-free during multiple periods of the Pleistocene epoch, which lasted from approximately 2.6 million to 11,700 years ago. Research published in Nature indicates that Greenland experienced extended deglaciation, with periods where the ice sheet was reduced to less than 10% of its current volume (Schaefer et al., 2016). This study utilized measurements of isotopes in bedrock cores to establish that Greenland's ice sheet could have been absent for over 280,000 years at a time, suggesting that the ice sheet's history is more complex than previously believed (Schaefer et al., 2016).
Furthermore, a more recent study highlighted that the center of Greenland's ice sheet melted, revealing a tundra landscape that existed within the last million years. This study confirmed the presence of plant and insect remains, indicating that the region was indeed ice-free during warmer climatic periods (Hidy et al., 2024).
Analysis
The evidence supporting the claim comes from multiple peer-reviewed studies, which have been conducted by reputable institutions. The 2016 study by Schaefer et al. is particularly significant as it challenges the long-held belief that Greenland's ice sheet has been stable for millions of years. The use of isotopic dating provides a robust method for determining the age of the sediment and the historical presence of ice (Schaefer et al., 2016).
The reliability of these sources is bolstered by their publication in high-impact journals such as Nature and the Proceedings of the National Academy of Sciences, both of which have rigorous peer-review processes. The studies also involve collaboration among various research institutions, including the Lawrence Livermore National Laboratory and Columbia University, enhancing their credibility (Hidy et al., 2024).
Critically, while some earlier models suggested a continuous existence of the ice sheet throughout the Pleistocene, the findings from these studies indicate that such models may be overly simplistic. The evidence of ice-free periods aligns with broader climatic patterns observed during interglacial periods, further supporting the claim (Hidy et al., 2024).
Conclusion
The claim that "Greenland was nearly ice-free multiple times during the Pleistocene" is True. Multiple peer-reviewed studies provide substantial evidence that supports this assertion, demonstrating that Greenland's ice sheet has not been a permanent fixture throughout its geological history. The findings indicate significant periods of deglaciation, which have implications for understanding current climate change and sea-level rise.
Sources
- Greenland was nearly ice-free for extended periods during the Pleistocene
- Greenland ice sheet melted in recent past
- Greenland was nearly ice-free for extended periods during the Pleistocene (PDF)
- Northwest Greenland During Two Pleistocene Ice-Free Intervals
- New study reveals evidence of ice-free times at the center of Greenland
- Greenland was nearly ice-free for extended periods during the Pleistocene
- Greenland wasn’t always covered in ice, scientists say
