Scientists unlock 1.2 million years of climate history

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.

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Key Indicators

1.2M

Years of continuous climate data

Previous record was 800,000 years from EPICA Dome C in 2004

2,800m

Drilling depth to bedrock

Nearly two miles through Antarctic ice at -35°C average temperature

300ppm

Historic CO2 ceiling

800,000 years of ice cores never showed CO2 above this—until now it's 420ppm

Research institutions involved

Scientists from 10 European nations coordinated by Italy's CNR-ISP

Interactive

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People Involved

Carlo Barbante

Leading analysis of 1.2 million-year ice core record

Julien Westhoff

Led 2024-2025 drilling campaign

Frank Wilhelms

Leading technical drilling operations

Organizations Involved

Beyond EPICA - Oldest Ice

International Research Collaboration

Active drilling and analysis campaign

European consortium drilling Antarctic ice to reach 1.5 million-year climate records.

CNR Institute of Polar Sciences

Italian National Research Institution

Coordinating Beyond EPICA project

Italy's polar research institute coordinates the twelve-nation Beyond EPICA consortium.

Concordia Research Station

Antarctic Research Base

Provides logistical support for drilling operations

Permanent research facility at 3,233m altitude on Dome C, Antarctica.

Alfred Wegener Institute

German Polar Research Center

Providing drilling technology and expertise

Germany's polar research hub develops ice core drilling technology.

Timeline

Final Drilling Campaign Launches
Field Operations

Fifth and final season begins to collect duplicate samples and drill into bedrock beneath ice sheet.
November 1st, 2025
Laboratory Analysis Begins
Research Phase

European facilities start measuring isotopes in ice and analyzing trapped air bubbles for greenhouse gas concentrations.
August 1st, 2025
Ice Cores Transported to Europe
Logistics

Research vessel Laura Bassi carries frozen cores from Antarctica to European laboratories for analysis.
April 1st, 2025
Bedrock Reached: 1.2 Million-Year Ice Extracted
Scientific Breakthrough

Team hits bedrock at 2,800 meters, confirming continuous ice record extending beyond 1.2 million years—oldest ever extracted.
January 9th, 2025
1,836 Meters Depth Reached
Progress Update

Third drilling campaign extends core to 1,836 meters, approaching depth where 1-million-year ice expected.
January 20th, 2024
808 Meters Depth Reached
Progress Update

Second drilling campaign successfully reaches 808-meter depth after overcoming equipment challenges.
January 15th, 2023
Beyond EPICA Drilling Commences
Research Initiative

International team begins drilling at Little Dome C with €11 million EU funding, aiming to capture mid-Pleistocene transition.
May 1st, 2019
Site Selection for Beyond EPICA Begins
Preparatory Work

Ground-penetrating radar surveys identify Little Dome C as optimal location for reaching 1.5 million-year ice.
January 1st, 2016
EPICA Reaches 800,000-Year Record
Scientific Milestone

Drilling completes at Dome C, reaching 3,270 meters depth. Ice core sets record extending back 800,000 years.
December 1st, 2004
Original EPICA Project Launches
Research Initiative

European Science Foundation coordinates drilling at two Antarctic sites to extend ice core records beyond previous 400,000-year limits.
January 1st, 1996

Scenarios

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Predictions leaderboard

Ice Core Confirms CO2 Drove Mid-Pleistocene Shift

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.

Discussed by: Climate scientists quoted in Nature and Science publications, paleoclimate researchers

Consensus —

Multiple Factors Converged—No Single Cause Found

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.

Discussed by: Researchers at Penn and AGU publications emphasizing complexity

Consensus —

Ice Record Contaminated or Discontinuous

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.

Discussed by: Technical concerns raised in ice core drilling literature about basal ice quality

Consensus —

Historical Context

EPICA Dome C Core (2004)

1996-2004

What 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 Today

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)

1970-1998

What 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 Today

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 ago

What 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 Today

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.