Overview
In early January 2025, an international team drilling through Antarctic ice hit bedrock at 2,800 meters depth. They pulled up ice more than 1.2 million years old—the oldest continuous climate record ever extracted. Inside those frozen layers sit trapped air bubbles containing pristine samples of ancient atmospheres, offering a direct window into greenhouse gas concentrations across multiple glacial cycles.
The stakes: Scientists want to solve one of climate science's biggest puzzles—why Earth's ice ages suddenly shifted from 41,000-year cycles to 100,000-year cycles around 900,000 years ago. Previous ice cores reached back 800,000 years, missing the crucial transition period. This core spans it completely. Understanding how climate systems reorganized during that shift could illuminate how today's rapidly changing atmosphere might behave.
Key Indicators
People Involved
Organizations Involved
European consortium drilling Antarctic ice to reach 1.5 million-year climate records.
Italy's polar research institute coordinates the twelve-nation Beyond EPICA consortium.
Permanent research facility at 3,233m altitude on Dome C, Antarctica.
Germany's polar research hub develops ice core drilling technology.
Timeline
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Final Drilling Campaign Launches
Field OperationsFifth and final season begins to collect duplicate samples and drill into bedrock beneath ice sheet.
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Laboratory Analysis Begins
Research PhaseEuropean facilities start measuring isotopes in ice and analyzing trapped air bubbles for greenhouse gas concentrations.
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Ice Cores Transported to Europe
LogisticsResearch vessel Laura Bassi carries frozen cores from Antarctica to European laboratories for analysis.
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Bedrock Reached: 1.2 Million-Year Ice Extracted
Scientific BreakthroughTeam hits bedrock at 2,800 meters, confirming continuous ice record extending beyond 1.2 million years—oldest ever extracted.
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1,836 Meters Depth Reached
Progress UpdateThird drilling campaign extends core to 1,836 meters, approaching depth where 1-million-year ice expected.
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808 Meters Depth Reached
Progress UpdateSecond drilling campaign successfully reaches 808-meter depth after overcoming equipment challenges.
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Beyond EPICA Drilling Commences
Research InitiativeInternational team begins drilling at Little Dome C with €11 million EU funding, aiming to capture mid-Pleistocene transition.
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Site Selection for Beyond EPICA Begins
Preparatory WorkGround-penetrating radar surveys identify Little Dome C as optimal location for reaching 1.5 million-year ice.
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EPICA Reaches 800,000-Year Record
Scientific MilestoneDrilling completes at Dome C, reaching 3,270 meters depth. Ice core sets record extending back 800,000 years.
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Original EPICA Project Launches
Research InitiativeEuropean Science Foundation coordinates drilling at two Antarctic sites to extend ice core records beyond previous 400,000-year limits.
Scenarios
Ice Core Confirms CO2 Drove Mid-Pleistocene Shift
Discussed by: Climate scientists quoted in Nature and Science publications, paleoclimate researchers
Air bubbles show atmospheric CO2 declined gradually between 1.2 and 0.9 million years ago, crossing a threshold that triggered longer glacial cycles. This would settle the decades-long debate—confirming that greenhouse gas concentrations, not just orbital mechanics or ice sheet dynamics alone, fundamentally control Earth's climate state. The finding would strengthen projections about how rapidly rising modern CO2 destabilizes climate systems, since the same feedback mechanisms that reorganized glacial cycles would amplify today's warming.
Multiple Factors Converged—No Single Cause Found
Discussed by: Researchers at Penn and AGU publications emphasizing complexity
Analysis reveals CO2 declined, but ice sheet dynamics shifted simultaneously and ocean circulation patterns reorganized. No single variable crosses a clear threshold. Instead, the climate system reorganized through interconnected feedbacks that can't be reduced to one mechanism. This outcome would complicate efforts to predict future tipping points, since it suggests climate transitions emerge from subtle interactions rather than simple cause-and-effect relationships.
Ice Record Contaminated or Discontinuous
Discussed by: Technical concerns raised in ice core drilling literature about basal ice quality
Dating reveals gaps or mixing in the deepest ice layers near bedrock, where geothermal heat and pressure can disrupt stratigraphy. Trapped air bubbles show signs of contamination or the ice-gas age difference becomes too uncertain to establish precise atmospheric measurements. Teams would need to find another drilling site and start over—or accept that direct atmospheric measurements beyond 800,000 years may be impossible from ice cores, forcing scientists to rely on less direct marine sediment proxies.
Historical Context
EPICA Dome C Core (2004)
1996-2004What Happened
The original European Project for Ice Coring in Antarctica drilled 3,270 meters at Dome C, extracting ice dating back 800,000 years. The core revealed eight complete glacial-interglacial cycles and showed that CO2 concentrations never exceeded 300 parts per million during the warmest interglacial periods—far below today's 420ppm.
Outcome
Short term: Revolutionized understanding of greenhouse gas-climate relationships, becoming most-cited paleoclimate dataset.
Long term: Established baseline showing modern CO2 levels unprecedented in 800,000 years, strengthening climate change projections.
Why It's Relevant
Beyond EPICA aims to extend this record to capture the critical period EPICA missed—the transition when glacial cycles fundamentally changed character.
Vostok Ice Core (1970s-1998)
1970-1998What Happened
Soviet and Russian scientists drilled at Vostok Station in East Antarctica, eventually reaching 3,623 meters and extracting ice up to 420,000 years old. The core demonstrated tight correlation between atmospheric CO2 and Antarctic temperature across glacial cycles.
Outcome
Short term: First ice core extending beyond 100,000 years, proving ice age cycles linked to greenhouse gases.
Long term: Sparked debate about whether CO2 drives temperature or vice versa, later resolved showing both through feedbacks.
Why It's Relevant
Vostok pioneered deep ice core drilling in extreme Antarctic conditions, proving the technical feasibility of projects like Beyond EPICA.
Mid-Pleistocene Transition Climate Shift (1.2-0.9 Mya)
1.25-0.7 million years agoWhat Happened
Earth's glacial-interglacial cycles abruptly shifted from regular 41,000-year oscillations (driven by axial tilt changes) to irregular 100,000-year cycles with much larger ice sheets and more extreme climate swings. The transition occurred gradually over roughly 550,000 years.
Outcome
Short term: Northern Hemisphere ice sheets began growing far larger and persisting longer before collapsing rapidly.
Long term: Established the climate regime humans evolved within—long ice ages interrupted by brief warm periods like today.
Why It's Relevant
This is the mystery Beyond EPICA targets. Understanding why stable 41,000-year cycles gave way to volatile 100,000-year cycles could reveal how climate systems respond to gradual forcing—directly applicable to understanding how today's rapid CO2 rise might trigger nonlinear responses.