Has the mystery of the Antarctic ice sheet been solved?

Feb 28, 2008

A team of scientists from Cardiff University’s School of Earth and Ocean Sciences and Amgueddfa Cymru - National Museum Wales travelled to Africa to find new evidence of climate change which helps explain some of the mystery surrounding the appearance of the Antarctic ice sheet.

Ice sheet formation in the Antarctic is one of the most important climatic shifts in Earth’s history. However, previous temperature records show no evidence of the oceans cooling at this time, but instead suggest they actually warmed, presenting a confusing picture of the climate system which has long been a mystery in palaeoclimatology.

Now Dr Carrie Lear, Lecturer in Palaeoceanography, and her team at Cardiff have presented new temperature records using ancient sea floor mud recovered from Tanzania, East Africa. The shell chemistry of pin-head sized animals called foraminifera (“forams”) reveal that ocean temperatures did in fact cool by about 2.50C.

Dr Lear said: “Forams are great tools for studying climates of the past, which helps us learn about the uncertainties of our future greenhouse climate. These new records help resolve a long-standing puzzle regarding the extent of ice-sheet growth versus global cooling, and bring climate proxy records into line with climate model simulations.

“We have been able to use the chemistry of the Tanzanian microfossils to construct records of temperature and ice volume over the interval of the big climate switch. These new records show that the world’s oceans did cool during the growth of an ice sheet, and that the volume of ice would have fitted onto Antarctica; so now the computer models of climate and the past climate data match up.”

The team at Cardiff University’s School of Earth, Ocean and Planetary Sciences will now look for evidence of the ultimate cause of the global cooling using the forams. They believe the prime suspect is a gradual reduction of CO2 in the atmosphere, combined with a ‘trigger’ time when Earth’s orbit around the sun made Antarctic summers cold enough for ice to remain frozen all year round.

Source: Cardiff University

Explore further: Rocky platforms dissipating wave energy – a new option for coastal defence?

add to favorites email to friend print save as pdf

Related Stories

Climate capers of the past 600,000 years

Nov 17, 2014

If you want to see into the future, you have to understand the past. An international consortium of researchers under the auspices of the University of Bonn has drilled deposits on the bed of Lake Van (Eastern ...

Variations in ice sheet height influence global climate

Nov 03, 2014

In a study published today in PNAS (Proceedings of the National Academy of Sciences), Dr William Roberts of Bristol's School of Geographical Sciences and colleagues use computer models to simulate a Heinrich ev ...

Recommended for you

Better forecasts for sea ice under climate change

2 hours ago

University of Adelaide-led research will help pinpoint the impact of waves on sea ice, which is vulnerable to climate change, particularly in the Arctic where it is rapidly retreating.

"Ferrari of space' yields best map of ocean currents

11 hours ago

A satellite dubbed the "Ferrari of space" has yielded the most accurate model of ocean circulation yet, boosting understanding of the seas and a key impact of global warming, scientists said Tuesday.

Researcher studies deformation of tectonic plates

13 hours ago

Sean Bemis put his hands together side by side to demonstrate two plates of the earth's crust with a smooth boundary running between them. But that boundary is not always smooth and those plates do not always ...

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.