Disappearing Ice Shelves on Antarctic Peninsula

Jessica Robertson: Hello and welcome to USGS CoreCast. I'm Jessica Robertson. Ice shelves are disappearing along Antarctica due to climate change and this poses significant hazards to society. Ice shelf loss can result in glacier retreat and sea level rise, which threatens coastal communities. Today, we are joined by USGS scientist Jane Ferrigno to discuss a project that is for the first time studying coastal and glacier change along all of Antarctica. Thank you for joining us today, Jane.

Jane Ferrigno: Thank you for inviting me. I’m glad to be here.

Jessica Robertson: Can you give us an overview of USGS research on coastal and glacier change on Antarctica?

00:43

Jane Ferrigno: Jessica, I'd love to give you an overview of all the USGS research in Antarctica, but it's pretty extensive. So I'll tell you what we’re doing. We’ve been looking at the coastline of Antarctica to see what the ice is actually doing, whether it's advancing, retreating or staying in one position. And this is the first time that anyone's been able to look at the entire margin of Antarctica in detail because the satellite imagery is now available to make that possible.

We first focused in on the Antarctic Peninsula because it's the Peninsula where most of the obvious change is occurring right now. Some of the ice shelves are disappearing. Many, if not all, are retreating. In fact most of the ice fronts are also being affected. And they all demonstrate that climate change is occurring.

Jessica Robertson: What are the possible consequences from losing ice shelves?

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Jane Ferrigno: The most serious consequence of ice shelf loss would be the resulting retreat of glaciers on the land that are held back by the ice shelves, and the resulting sea level rise, which would pose a threat to coastal communities and low lying islands. The continent of Antarctica is covered almost entirely by ice sheet, which is one type of glacier. The ice sheet is draped all over the continent as frosting is draped on a cake. The ice sheet flows to the perimeter of the continent and then it flows into the water as an ice shelf or an outlet glacier.

02:25

Since ice shelves are already in the water, their loss does not directly contribute to the sea level rise, but it's when the land ice moves into the water that the sea level would be affected. Antarctica holds about 91% of the earth's glacier volume, and change anywhere in the ice sheet poses significant hazards to society.

Jessica Robertson: What are some of the most significant findings from your research?

Jane Ferrigno: Definitely the most significant finding from our research is that the ice fronts along the Antarctic Peninsula have been retreating on the whole over the past 50 or 60 years.

Since the 1940s until the current day, we’ve measured every ice front along the Peninsula and found the ice shelves have disappeared or retreated in the northern, the central and the southern sections of the Peninsula. This has actually been shown on 3 different maps that we've produced.

03:25

The Peninsula has several major ice shelves that people are familiar with—the Wordie, the Larsen, the Wilkins and so forth—but we've looked at not only the major ice shelves, but the minor ice shelves and the outlook glaciers as well. It’s been known that the Wordie Ice Shelf has been retreating, but we've shown that it has completely disappeared. We've also seen the northern part of the Larsen ice shelf no longer exists. An area more than 3 times the size of the state of Rhode Island has broken off from the Larsen Ice Shelf since 1986.

Jessica Robertson: And Jane, can you tell us how did you draw these conclusions?

Jane Ferrigno: We've been able to draw these conclusions because we’ve looked at and studied an immense amount of data, including satellite imagery, historical and more recent maps, and aerial photography. We’ve been lucky to find aerial photography that goes back to the early days of exploration in the Antarctic Peninsula.

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And in 1972, the Landsat satellite was first put into orbit and that created the opportunity of looking at the earth as it never had been looked at before in detail, but covering large areas. And that's been an immense and valuable tool for research and study of Antarctica.

Jessica Robertson: And Jane, in your opinion what has been the most interesting part of this research?

Jane Ferrigno: The research is amazing and interesting for itself because you are able to find out things that people have not been able to find out before. But besides that, this is research that has relevance to everybody on the globe because if the climate is changing, if sea level changes as a result, we’re all going to be affected by that.

05:22

Jessica Robertson: I know that the USGS worked on this project in collaboration with the British Antarctic Survey, the Scott Polar Research Institute, and Germany's Bundesamt fűr Kartographie und Geodäsie. Can you tell us about that collaboration?

Jane Ferrigno: The cooperation with the British Antarctic Survey was especially valuable because they have aerial photography going back from the earliest days of exploration in the Antarctic Peninsula.

The person from the Scott Polar Research Institute who helped us is one of the foremost glaciologists and familiar with Antarctic glaciology. So those cooperative efforts were very valuable.

Jessica Robertson: As you said, the USGS is studying coastal and glacial change along all of Antarctica. So what reports and maps will be coming out next?

06:11

Jane Ferrigno: The next part of our project will be a map that covers Ross Island and the Dry Valleys area. This is an area that's not showing as much coastal change, but it’s an especially important area to the U.S. because our main Antarctic Research base is in that area and a lot of research is done in the Dry Valleys area. So this would be fascinating to see what's going on down there. It also is important as a reference map to the scientists who are working down there.

Jessica Robertson: Thank you for joining us today, Jane. And thank you to all of our listeners. Completed reports in the coastal change and glaciological maps of Antarctica series can be viewed at http://pubs.usgs.gov/imap/2600/.

CoreCast is a product of the US Geological Survey, Department of the Interior.