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The Cold Facts About Melting Glaciers

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Detailed Description

Most glaciers in Washington and Alaska are dramatically shrinking in response to a warming climate.

USGS scientist Edward Josberger discusses research from the past 50 years to measure changes in the mass (length and thickness) of three glaciers in Alaska and Washington. These are the longest such records in North America and among the longest in the world.




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Jessica Robertson:  Hello and welcome to the USGS CoreCast. I’m Jessica Robertson. Most glaciers in Washington and Alaska are dramatically shrinking in response to a warming climate. Over the past 50 years, USGS scientists have measured changes in mass of three glaciers – Alaska’s Gulkana and Wolverine Glaciers and Washington’s South Cascade Glacier. These are the longest such records in North America and among the longest in the world.

Today, I’d like to welcome and introduce you to our guest, USGS scientist Edward Josberger, who will discuss USGS research on glacier behavior. Thank you for joining us today, Ed.

Edward Josberger: You’re welcome, Jessica. It’s my pleasure.

Jessica Robertson: First, can you provide us an overview of your research on glacier shrinkage in Alaska and Washington?

Edward Josberger: Well, Jessica, this fact sheet summarizes a 50-year long program by the USGS to measure changes in glaciers in Washington State and Alaska. These are very detailed measurements and it’s only through a very long-term record that we can determine the impacts of climate change on glaciers, the continuing impacts. And this is one of the longest records that clearly show glaciers in the northeast Pacific quadrant are shrinking and this shrinkage is accelerating as a result of climate change.

Jessica Robertson: You mentioned that you studied three glaciers, but why did you focus on these and what do they represent?

Edward Josberger: These three glaciers represent different climate regimes and they also represent hundreds of glaciers in the area that they exist in. They’re known as the USGS benchmark glaciers and we are using the information from these glaciers to understand the behavior of all the rest of the glaciers that surround them.

Jessica Robertson: What impacts could result from shrinking glaciers?

Edward Josberger: Well, Jessica, the impacts of shrinking glaciers are many. Some of the most important include their contribution to the sea level rise and the resulting impact on coastal communities. And glaciers when they are sort of in equilibrium with the climate produce a certain amount of water and the glaciers are at a certain size.  In the mountains, these glaciers as they melt and shrink will be able to produce less water in the late summer. Hence, this will impact the mountain ecosystems that depend on it and reduce summer run off for water supply issues, which is important for hydropower generation in Washington and the domestic water supply. And finally for Alaska, glacier melt plays a big role in the circulation or the oceanography of the Gulf of Alaska and it’s important in maintaining the very, very valuable fisheries—halibut and salmon—that reside in this body of water.

Jessica Robertson: Many people are surprised to learn that unlike most of America’s glaciers, a few glaciers are actually advancing. So can you explain what is happening in those few instances?

Edward Josberger: Well, these glaciers are responding to unusual and unique local conditions. They probably have a large accumulation area where they are accumulating a large amount of snow throughout the winter. But in summary, most of America’s glaciers are shrinking.

Jessica Robertson: Can you tell us how you study glacier behavior and drew these conclusions?

Edward Josberger: Well, we measure the glaciers by sending field teams out to each glacier where they measure the amount of snow that has fallen on the glacier during the winter and then they measure how much snow and ice has melted off this glacier in the summer. And of course the difference gives us the health of the glacier – was it gaining or losing mass. We use this data to determine the response of the glaciers to weather and climate change over the past 50 years, which gives an understanding of how the glaciers respond to future climate changes.

Jessica Robertson: From your perspective, can you share with us the most interesting part of this research?

Edward Josberger: Well, first, it’s just incredibly interesting and a privilege to be able to do this type of work. And I find it very gratifying that I am carrying on a 50-year record that began with a bunch of scientists saying, “We need to measure glaciers because they will give us an indication of climate change and climate change patterns.” And I hope that in the next 50 years, the USGS maintains this program because it is providing incredibly valuable information.

Jessica Robertson: Well, thank you for joining us today, Ed, and thank you to all of our listeners who joined us for this episode of CoreCast. For more information on the study of glacier change in Washington and Alaska, visit More information about the USGS Benchmark Glacier Program can be found at

As always, CoreCast is a product of the U.S. Geological Survey, Department of the Interior.



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