Looking for ancient climate clues beneath 500 metres of Antarctic ice

The West Antarctic Ice Sheet is vast and holds enough ice to raise global sea level by 4-5 metres if it melts completely.  

The ice sheet is protected on one side by the Ross Ice Shelf, the world’s largest  floating ice mass.  

This serves as a buttress slowing the flow of glaciers and ice streams towards the sea.  

As our climate warms, the Ross Ice Shelf is becoming increasingly vulnerable. 

Scientists want to know what global temperature increase would trigger unsustainable melting of the shelf, and the subsequent loss of the ice sheet. 

The SWAIS2C project 

The international team is from the SWAIS2C (Sensitivity of the West Antarctic Ice Sheet to 2°C) project. 

It is drilling for a series of cylindrical samples of mud and rocks from the bedrock deep beneath 500 metres of ice.  

These samples are expected to contain layers of sediment laid down within the past 23 million years. 

This includes periods in Earth’s history when temperatures were warmer than they are today – telling us how higher temperatures could make the ice sheet react in future. 

Chemical clues 

Our geographers, led by Professor Mike Bentley, will analyse the samples to see how the Ross Ice Shelf responded to past warming. 

They will be looking for tiny grains of sand holding chemical clues to their history in the form of cosmogenic isotopes. 

If past warming caused the West Antarctic Ice Sheet to collapse it will have exposed mountains under the ice, leading to the formation of these rare chemicals. 

Mike will examine the sediment taken by the SWAIS2C field team for evidence of the isotopes in grains of sand formed when the mountains eroded. 

Past ice sheet behaviour 

Alongside our work, SWAIS2C will also search for tiny microfossils of marine algae – organisms that need light to survive – in the samples.  

Their presence would point to open ocean conditions in the past and suggest that the Ross Ice Shelf had previously retreated. 

The evidence will help scientists piece together a picture of past ice sheet behaviour in West Antarctica. 

This will inform models looking at the future of the ice sheet, how fast, when and how much of it might melt, and the impact on global sea level rises. 

Find out more 

• Learn more about Professor Mike Bentley. Mike is working closely on SWAIS2C with scientists from Imperial College London, British Antarctic Survey, University College London, University of Exeter and the University of Leeds, as well as the wider multinational team led by New Zealand.   

• Read more about SWAIS2C, an international initiative involving researchers from New Zealand, the United States, Germany, Australia, Italy, Japan, Spain, Republic of Korea, the Netherlands, and the United Kingdom. 

• Our Department of Geography is ranked 11th in the QS World University Rankings by Subject 2025 and second in the UK in the Complete University Guide 2026. Visit our Geography webpages for more information on our undergraduate and postgraduate programmes.