© New Zealand Broadcasting School 2020

Seals, tropics and glaciers - what connection?

James Fleury
Seals in Antarctica
Seals in Antarctica   Wikimedia Commons

US glaciologist Kiya Riverman spoke to the US Embassy Youth Council in New Zealand about the importance of science in Antarctica, its glaciers, and how climate change impacts the world.

Nearly 40 members of the council across New Zealand met virtually with Riverman, to learn how carbon dioxide levels in the Pacific may have contributed to the reduction in glacial size globally.

Riverman said the motivating question behind her work was finding out how glaciers contribute to sea-level rise. 

The glaciologist, who worked at McMurdo base and on the famous 'doomsday' Thwaites glacier, said it was important to find out the rate at which glaciers were melting, the causes, and whether humans could stop it. 

With the help of seals, scientists were able to build a good understanding of the ocean around Antarctica. 

"As they dive through the water the device on the seal's head records measurements of the properties of the water and when they come up to the surface, their data gets pinged back up to the satellites."

With the data, the scientists discovered why there were large differences in air and ocean temperature across 250 glaciers in the West Antarctic Peninsula. 

In the north, with warm air but cold oceans, the glaciers were not changing as rapidly as those in the south, where the air was cool but the ocean warm. 

"It's kind of a great natural experiment of what glaciers are sensitive to. We are kicking them in the north with the air and kicking them in the south with the ocean."

A strong transition was seen in oceans at 65 degrees south, where the most rapid glacial change was happening.

Riverman said changing winds in the tropics, caused by carbon dioxide emissions, influenced changes in Antarctic glaciers. 

"Small changes in the wind can push the warm water up to the continent which is what is driving a lot of glacial change in Antarctica."

From research conducted on Thwaites glacier, if it were to melt, it would contribute to 60cm of sea-level rise alone. 

Riverman believed this was the first speculative hint that changes in Antarctica may be due to human activity. 

She told the group she wanted to spread the message that glaciers, the ocean, and the atmosphere, were connected with the global system, so understanding how changes affected one another was extremely important in moving forward.