Old ice provides insights into major climate change

Mar 23, 2006
New climate data from old ice
The single segments of the ice core are labeled and stored until final analysis in laboratory. Foto: Sepp Kipfstuhl, Alfred Wegener Institute.

All cold periods throughout the past 740,000 years were associated with a significantly larger sea ice cover around the Antarctic than warm periods. At the same time, South America’s south was significantly drier and windier than nowadays, leading to a much higher dust deposition in the Antarctic.

These are some of the results published this week in the scientific journal Nature as part of a study on aerosols retrieved from an ice core 3 kilometres long, carried out by a European team of scientists with participation of the Alfred Wegener Institute for Polar and Marine Research.

Change of Antarctic sea ice cover

The ice core obtained in December 2004 as part of EPICA (European Project for Ice Coring in Antarctica) from Dome C in the eastern Antarctic (75° 06’S, 123° 21’E) covered more than eight consecutive alternations of ice ages and warm periods (glacial cycles). Thus, the core represents the longest continuous ice core archive ever retrieved. For their investigation, the EPICA scientists measured concentrations of aerosols within the ice, tracing the minute particles which had originated at the ocean surface or on continents far away and had been transported by wind to the Antarctic. The concentration of sea salt aerosol, for instance, formed in the process of seawater freezing, indicates a large scale expansion of sea ice cover around the Antarctic during all cold periods.

No increase in biological activity

Rising concentrations of small mineral dust particles during cold periods suggest a drier climate in the neighbouring continents, especially South America. The dust carried into the Southern Ocean by wind, provides additional nutrients for plankton in the surface ocean. However, analyses of sulphate aerosols from the ice core, produced after algal blooms, do not point towards an increase in biological activity in the Southern Ocean. “Our results require a revision of previous perspectives on the biological response to climate change in the Southern Ocean. At least for southern parts of that ocean, our perception about increased biological productivity during ice ages needs to be reconsidered”, suggests Hubertus Fischer, head of the chemical investigations at the Alfred Wegener Institute.

Predicting the future from viewing the past

After the analysis of temperature changes throughout the past eight climate cycles, the recent investigation of dissolved chemical components from the ice core represents another important step towards the evaluation of historical changes in climate. “Our research results reveal a similar succession of identical changes, whenever warm climate conditions alternated with cold ones over the past 740,000 years”, explains Eric Wolff of the British Antarctic Survey, primary author of the current publication. “This leads us to conclude that the Earth follows certain rules in the process of changing climates. If we can understand these rules, we will be able to improve our climate models and hence our predictions of the future.”

Source: Alfred Wegener Institute for Polar and Marine Research

Explore further: What is a terrestrial planet?

Related Stories

Under-ice rover chills with fish at aquatic exhibit

Jun 26, 2015

A school of sardines fluttered by as giant leafy kelp swayed back and forth at the California Science Center in Los Angeles on Monday, June 22. At the bottom of this 188,000-gallon aquatic tank, a bright ...

Ice sheet collapse triggered ancient sea level peak

Jun 10, 2015

An international team of scientists has found a dramatic ice sheet collapse at the end of the ice age before last caused widespread climate changes and led to a peak in the sea level well above its present ...

Sudden draining of glacial lakes explained

Jun 03, 2015

In 2008 scientists from Woods Hole Oceanographic Institution (WHOI) and the University of Washington documented for the first time how the icy bottoms of lakes atop the Greenland Ice Sheet can crack open ...

Recommended for you

What is a terrestrial planet?

10 minutes ago

In studying our solar system over the course of many centuries, astronomers learned a great deal about the types of planets that exist in our universe. This knowledge has since expanded thanks to the discovery ...

Working out in artificial gravity

1 hour ago

Astronauts on the International Space Station (ISS) have a number of exercise options, including a mechanical bicycle bolted to the floor, a weightlifting machine strapped to the wall, and a strap-down treadmill. ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.