Secrets of Earth's climate in six-million-year-old ice

Secrets of Earth's climate in six-million-year-old ice

Author: PNAS January 12, 2026 Duration: 9:39

Air quality and pet health

Science Sessions are brief conversations with cutting-edge researchers, National Academy members, and policymakers as they discuss topics relevant to today's scientific community. Learn the behind-the-scenes story of work published in the Proceedings of the National Academy of Sciences (PNAS), plus a broad range of scientific news about discoveries that affect the world around us.

In this episode, Sarah Shackleton shares climate lessons learned from 6 million-year-old ice.

In this episode, we cover:
•[00:00] Introduction
•[01:02] Paleoclimate and ice scientist Sarah Shackleton introduces the information researchers can glean from ice cores.
•[02:02] She recounts the age extent of previous ice cores.
•[03:03] Shackleton describes the Allan Hills Ice Area.
•[04:35] She describes the method for ascertaining the age of air in an ice core.
•[05:49] She explains the results of the study and the insights into the climate in Antarctica over the last 6 million years.
•[06:32] Shackleton talks about the ice at the base of the core, and the research implications of the study.
•[08:13] Caveats and limitations of the study.
•[09:11] Conclusion.

About Our Guest:

Sarah Shackleton
Assistant scientist
Woods Hole Oceanographic Institution

View related content here: https://www.pnas.org/doi/abs/10.1073/pnas.2502681122

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Tune into PNAS Science Sessions for a direct line to the people shaping modern science. Produced by PNAS, this podcast offers more than just summaries of published research; it’s where you hear the candid, often personal stories behind the headlines. Each episode features concise conversations with the researchers themselves-from emerging voices to established Academy members-alongside the policymakers whose decisions are informed by this work. You’ll get a genuine sense of the questions that drive these experts, the unexpected hurdles they face in their labs and field studies, and why their findings matter right now. The scope is deliberately wide, reflecting the interdisciplinary nature of science itself, covering discoveries that range from microscopic processes to planetary-scale phenomena. This isn't about dry lectures, but about capturing the human endeavor of investigation. For anyone curious about how science actually unfolds and wants to understand the context of breakthroughs as they happen, this podcast serves as an essential, engaging resource. It connects the dots between a published paper in a prestigious journal and the real-world implications that ripple out from it.
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