Clare Lane: Ice is usually a common winter site on the Great Lakes. But this season ice cover on the Lakes has been distinctly low. Andrea Vander Woude is an oceanographer with the Great Lakes Environmental Research Laboratory in Michigan. She joins us now to share what this means for our lives and ecosystems. Welcome, Andrea.
Andrea Vander Woude: Thanks for having me.
Clare Lane: So the lakes are only about 9% covered in ice. How does that compare to the average expected ice cover from this time of year?
Andrea Vander Woude: The historical average for this time of year, usually we take it from the National Ice Center, is around 40%. This has fluctuated up and down. On February 2023, the lakes were 21% covered. So more than they are today. And that was largely due to temperature fluctuations and cold weather that came across the Great Lakes.
Clare Lane: What contributes to low ice cover on the lakes?
Andrea Vander Woude: The biggest factor that contributes to a low ice cover is temperature changes. So when you have those really prolonged warm temperatures, as we've seen during this past winter, we don't have the build up of ice that we've seen in the past and that 40% of ice cover that has been historically measured.
Clare Lane: And how might climate change affect lake ice cover?
Andrea Vander Woude: We're still working on determining that and we've looked at the 70 year trend of ice in the Great Lakes. And on that time scale, there has been a decline but looking at climate change, those are more on the order to 100 or more years. And so we need to keep recording those measurements in order to make inferences on what's happening in our climate scale.
Clare Lane: And we get a lot of this information about ice cover from the Coast Watch program at the laboratory which you run. Can you tell me a little bit more about that program?
Andrea Vander Woude: Sure, I'd be happy to. We run a program which is funded as part of NOAA's satellite group and we house all of the satellite data for the Great Lakes that is obtained from NOAA satellites and NASA and Canadian satellites. Specifically the Canadian satellites, we have what's called a "memorandum of understanding" to use satellite data that looks through the clouds and is able to determine how much ice is there.
Clare Lane: And in terms of ecosystems, how does the amount of ice on the lakes affect those Great Lakes ecosystems?
Andrea Vander Woude: We have many researchers working on looking at ecosystem dynamics and the Great Lakes and the health of the Great Lakes. And a key factor to determining ecosystem health is ice cover. Many of our fish species and a key economic resource in the Great Lakes rely on that ice coverage in order to basically have their babies during a specific time of year and have a safe haven. And so many species require ice covered conditions in order to thrive.
Clare Lane: And humans, and human activity, how does ice cover impact our daily lives?
Andrea Vander Woude: Again, a key economic resource is not only snowmobiling and snow activities on land but also on the water. So ice fishing is something that people in the Great Lakes region really rely upon and enjoy doing during the winter months. And there have been examples of people getting stuck out on ice floats during these warming conditions where U.S. Coast Guard rescues go into action. So there's been a direct influence to low ice cover and some of the recreational activities that occur on the Great Lakes.
Clare Lane: Andrea Vander Woude is an oceanographer with the Great Lakes Environmental Research Laboratory. Thank you for joining us.
Andrea Vander Woude: Thank you for having me. Appreciate your time.
Clare Lane: And if you have a topic that you want us to cover on our weekly climate segment, you can email firstname.lastname@example.org. This is WBEZ.
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