What's Really Under Antarctica's Ice?

Key Concepts:

• Antarctica's subglacial environment: Mountain ranges, valleys, island chains, rivers, and lakes hidden beneath the ice sheet.
• West Antarctic Ice Sheet (WAIS): Its potential collapse and contribution to sea-level rise.
• Volcanic activity in West Antarctica: Over 100 volcanoes under the ice and their potential impact on ice sheet stability.
• Subglacial lakes: Nearly 700 lakes beneath the ice sheet and the microbial life they harbor.
• Ice sheet lubrication: The role of liquid water in accelerating glacier flow into the ocean.
• Volcano-ice interaction: The feedback loop between volcanic eruptions and ice melt.
• Snowball Earth: Past periods of near-total ice cover and the role of volcanism in deglaciation.
• Octopus DNA: Evidence of past WAIS collapse during the last interglacial period.

1. Unveiling Antarctica's Hidden Landscape

• The British Antarctic Survey has created the most detailed map of Antarctica's subglacial environment.
• Beneath the ice lies a landscape of mountain ranges, valleys, island chains, rivers, and lakes.
• The ice sheet is on average over 2 kilometers thick, representing 34 million years of accumulated snowfall.
• Melting of the entire ice sheet could raise global sea levels by 190 feet.

2. The Imminent Threat to the West Antarctic Ice Sheet

• Accelerated ocean warming has already locked in drastic melting of the WAIS.
• Total collapse of the WAIS might be more imminent than previously thought.
• The WAIS holds enough water to cause 5 meters of sea level rise.
• Warm ocean water seeps underneath the ice shelves, melting them from the bottom and lubricating the base of glaciers.

3. Antarctica's Volcanic Activity

• West Antarctica is possibly the largest volcanic region on Earth, with over 100 volcanoes identified.
• Most of these volcanoes are buried under kilometers of ice.
• Antarctica is a roof system rather than a subduction zone, unlike the Ring of Fire.

4. Subglacial Lakes and Microbial Life

• There are nearly 700 subglacial lakes in Antarctica.
• Lake Vostok, one of the largest, is over 3,000 feet deep and has been liquid for approximately 15 million years.
• Scientists have sampled a few of these lakes, discovering living microbial life thriving in total darkness and under immense pressure.
• John and his team drilled into Lake Whillans and Lake Mercer, finding living microbial life.
• "I'll never forget it, it kind of changed my life."

5. The Role of Subglacial Water in Ice Sheet Dynamics

• Water pooling under the ice sheet lubricates the base, leading to rapid glacier flow into the ocean.
• Glaciologists are revising ice sheet models to include the effects of liquid water underneath.

6. Volcano-Ice Interaction and Feedback Loops

• Allie's team developed a physical model showing that volcanoes are sensitive to the rate at which ice is removed overhead.
• Ice sheet removal can trigger additional and larger volcanic eruptions.
• "That's the worst possible place that you could put water if you're trying to slow down the loss of ice." - Allie
• This could trigger a dangerous feedback loop: eruptions cause melting, which triggers more eruptions.

7. Historical Evidence: The South Andes and Snowball Earth

• The Southern Andean Volcanic Zone shows an increase in eruption frequency during periods of rapid ice loss.
• The prevailing theory for the end of "snowball Earth" events involves a feedback between volcanism and deglaciation.
• Volcanic activity under the ice caused melting, which in turn affected volcanic activity, eventually leading to a modern climate state.

8. Octopus DNA and Past Ice Sheet Collapse

• Octopus DNA analysis suggests that isolated populations mated around 125,000 years ago, indicating a connection between the Weddell Sea and Ross Sea.
• This supports evidence that the WAIS collapsed during the last interglacial period, when temperatures were similar to today, and sea levels were as much as 10 meters higher.
• DNA is like a time capsule of the past.

9. Conclusion

• The potential feedback loop of volcanic eruptions triggering ice melt, combined with the lubricating effect of subglacial lakes and evidence of past ice sheet instability, is concerning.
• Near-total collapse of the WAIS is more likely than previously thought and could happen as soon as 2300.
• The future of sea level rise remains uncertain, but decisions made today will influence that future.