Unique 1.5 million-year-old ice will melt to reveal mystery

2025-07-18 22:09:00, Kuriozitete CNA

An ice core that could be more than 1.5 million years old has arrived in the UK, where scientists will melt it to reveal vital information about Earth's climate.

The frozen cylinder is the planet's oldest ice core, drilled from deep within the Antarctic ice sheet, and contains a wealth of new information dating back thousands of years that scientists say could "revolutionize" what we know about climate change.

“This is a completely unknown period of our Earth’s history,” says Dr. Liz Thomas, head of ice core research at the British Antarctic Survey.

On a work surface next to stacked ice boxes, Dr. Thomas points to the oldest cores, which may be 1.5 million years old. They glow and are so clear that we can see our hands through them.

For seven weeks, the team will slowly melt the hard-earned ice, releasing ancient dust, volcanic ash and even tiny marine algae called diatoms, which were trapped inside when the water turned to ice.

These materials can tell scientists about wind, temperature and sea level patterns more than a million years ago.

The tubes will feed the liquid to machines in an adjacent laboratory, which is one of the only places in the world that can do this science.

It was a huge multinational effort to extract ice cores from Antarctica, at a cost of millions. The ice was broken into 1-meter blocks and transported by ship and then in a refrigerated van to Cambridge.

Engineer James Veale helped extract ice near the Concordia base in East Antarctica.

"Holding it in my carefully gloved hands and being very careful not to drop sections - it was a wonderful feeling," he says.

Two institutions in Germany and Switzerland have also obtained 2.8 km core cross-sections.

The teams could find evidence of a time period more than 800,000 years ago, when carbon dioxide concentrations may have been naturally as high or even higher than they are now, according to Dr. Thomas.

This could help them understand what will happen in our future as our planet reacts to the warming gases trapped in our atmosphere.

"Our climate system has gone through so many different changes that we need to be able to go back in time to understand these different processes and different tipping points," says Liz Thomas.

The difference between today's eras and previous eras with high greenhouse gases is that humans have now caused the rapid increase in greenhouse gases in the last 150 years.

This is taking us into uncharted territory, but scientists hope that the records of our planet's environmental history locked in ice can give us some clues.

The team will identify chemical isotopes in the liquid that can tell us about wind patterns, temperatures and precipitation for a time period between 800,000 and up to 1.5 million years ago or possibly longer.

They will use an instrument called an inductively coupled plasma mass spectrometer (ICPMS) to measure over 20 trace elements and metals.

This includes rare earth elements, sea salts and marine elements, as well as indicators of past volcanic eruptions.

The work will help scientists understand a mysterious shift called the Middle Pleistocene Transition 800,000 to 1.2 million years ago, when the planet's glacial cycles suddenly changed.

The transition from warmer eras to colder ice ages, when ice covered much more of the Earth's surface, had occurred every 41,000 years, but suddenly changed to 100,000 years.

The cause of this change is one of the "most exciting unsolved questions" in climate science, according to Dr. Thomas.

The cores may hold evidence of a time when sea levels were much higher than they are now and when Antarctica's vast ice sheets were smaller.

The presence of dust in the ice will help them understand how the ice sheets shrank and contributed to rising sea levels - something that is a major concern this century./ CNA