Science Festival: Ice Man in a Warming World

Submitted by edg on Sun, 7 Apr '19 7.24am

When looking for signs of global warming, the melting of the world’s glaciers and ice sheets is often cited as the one of most glaring indicators.

NASA says Greenland lost an average of 286 billion tons of ice per year between 1993 and 2016, while Antarctica lost about 127 billion tons of ice per year during the same time period.

What’s more, as fossil fuel burning increases the level of carbon dioxide, and the planet heats up, this process has been accelerating.

The rate of Antarctica ice mass loss has tripled in the last decade, with scientists predicting sea level rise of a metre or more by 2100. Former NASA scientist James Hansen, who sounded the alarm around climate change in a testimony to US congress in 1988, suggested that sea level rise could be as high 5 metres (18 feet) by 2100 “or shortly thereafter” in his 2012 TED speech.

Professor David J.A. Evans at the Department of Geography at Durham University has been at the melting edge of global warming in a career studying and modelling ancient and modern glaciers and ice sheets.

On Monday 8th April, he will be presenting A Very Short Introduction to...Glaciation at the Edinburgh Science Festival. asked Professor Evans about ice and warming.

Can you describe the work you do as a geomorphologist?

I work on understanding the processes involved in the production of glacial landforms and sediments and then using that knowledge to interpret ancient glacial features and reconstruct past glaciations.

This means that I visit modern glaciers from a range of environments (Arctic Canada, Svalbard, Iceland, New Zealand, Norway, South Georgia) and use my observations from such settings to study glacial features in lower latitudes such as Britain, Ireland and southern Canada, as well as terrains just beyond the modern glaciers in places like Arctic Canada, New Zealand and Norway.

What will your talk be about?

I will cover a range of topics from the operation of glaciers as systems, their processes in eroding and depositing and how to use such information in reconstructing glaciations.

This will be alongside a historical perspective in which I will recount who the main players were in the development of the subject.

In his TED talk, James Hansen suggests that sea level rise could be up to 5 metres if we keep on burning fossil fuels. That seems an incredible amount of ice to melt in a very short time. Given the current rate of melt we are seeing now, what probability would you put on such a scenario playing out?

Such rises would need the melting of a large volume of glacier ice, for example the whole Greenland Ice Sheet or the initiation of the collapse of the West Antarctic portion of the Antarctic Ice Sheet.

These ice sheets retreat rapidly where they contact the warming ocean but such contact areas are small in relation to the total ice sheet size - so it would need a catastrophic break up of such ice sheets to initiate 5m or rise and we are not sure yet whether or not that might be possible in another 100 years.

You've studied ice your whole working life. What it's like to be in the midst of such rapid change?

Although glacier melt is an alarming phenomena, my research actually benefits from such rapid change because glacial processes are normally very slow and hence gathering information is a painstaking process.

Very recently we have been charting the rapid glacier change and at the same time observing the similarly rapid evolution of glacial landforms and sediments, so it is a productive period to be working on glacial geomorphology.