Why are Canada’s ice shelves disappearing? | Ask A Scientist

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KERBENS BOISETTE (Host, Ask a Scientist, Environment and Climate Change Canada):
Last June, a big section of the Milne Ice Shelf broke off into the Arctic Ocean. Aiden from Ottawa has been wondering about this and sent his question to us here at, Ask a Scientist.

AIDEN (Ottawa ON):
My name is Aiden. I have a question for Dr. Derksen.
A big ice shelf recently broke off in the Canadian Arctic.
Why did this happen and what are the consequences?

KERBENS BOISETTE:
Dr. Derksen, can you answer this for us?

DR. CHRIS DERKSEN (Research Scientist, Environment and Climate Change Canada):
Hi, I’m Chris Derksen, a research scientist with Environment and Climate Change Canada, and thanks very much for your question about recent changes to ice shelves in the Canadian Arctic.
So, in June of 2020, over 40% of the Milne Ice Shelf fractured and collapsed into the Arctic Ocean. This happened along a very remote area of coast of Ellesmere Island, but satellite data allowed scientists to keep an eye on what was happening.
So, what is an ice shelf? Well, it’s thick floating ice that’s land fast, so that means it’s attached to land and does not drift or float around like sea ice does.
So, ice shelves in Canada were formed thousands of years ago and they are a really unique part of the Arctic environment, but they are changing quickly in response to climate change.
So, in 2005, the Ayles Ice Shelf disappeared; and between 2009 and 2011 there were major losses in the Markham, Serson, and Ward Hunt ice shelves.
Now scientists were anticipating that the Milne Ice Shelf was perhaps going to change rapidly. A survey in 2008 indicated that it was about eight metres thinner than it was when it was previously measured in 1981.
So, satellite data tells us that only about 5% of Canadian ice shelf areas are still intact compared to about 100 years ago, so this represents the loss of a really unique ecosystem, because freshwater lakes form on ice shelves during the summer and are host to really interesting life, including microbes.
These changes in ice shelves also serve as a canary in the coal mine, warning us and indicating clearly to us what the impacts of climate change have been and will be across the Canadian Arctic.
So, thanks a lot for your question.
I hope this answer was clear, and keep your climate change questions coming in.

KERBENS BOISETTE:
Wow! Very interesting. Thanks for clearing that up for us, Chris. Don’t forget to send us your questions for the next Ask a Scientist.

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Source: Environment and Climate Change Canada

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