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How and why are glaciers changing over time?

Glaciers are changing globally, but how are they changing? What are some of the reasons for those changes?

1) Looking at glaciers in Europe

To understand what is happening to glaciers we need to know how the size of glaciers have changed over time.

And to understand why these changes may be happening, we need to look at data (from the same time period and location) collected for factors that may influence glacier size.

Every glacier is unique due to its location, both in terms of the climate and surrounding land, but similar variables act upon the ice of all glaciers.

What might some of those factors be?

2) Focusing on atmospheric conditions.

One way we can learn about what has happened to the environment over time is to look at data about the air temperature along with information about glacier size.

Today we will investigate how the temperature and amount of carbon dioxide in the air has changed over time.

So let’s dive into some data!

3) Reading glacier size data

Scientists use satellite images to calculate changes in glacier sizes over time. Scientists use information about how long the glacier is, how wide it is, how tall it is, etc. Scientists have been doing this since satellite images first became available in the 1970s.

We can look at Landsat satellite images of glaciers from 1972 through 2015 to get an idea of how they have changed. For Hintereisferner glacier in Austria (red pin on left, middle image), observations of this glacier have also been collected by scientists at the Research Station Hintereis.

Why can we look at one glacier in Austria and learn about what is happening around the world? Click here to learn more

So let’s see what the data demonstrates…

4) What has happened to the glacier since the 1970s?

Watch the video of glacier satellite images. The end of the glacier in 1972 is marked by a red star and the yellow stars show the new location for years after 1972. What do you notice about the length of the glacier?

Now, watch it again and look at a different part of the glacier this time. Do you notice any other changes happening over time besides the extent of the glacier?

OK, so it is changing. But how much of a change in the length of the glacier are we talking about anyway?

5) Overall, what has happened to the extent of the glacier since the 1970s?

So we know that the glacier is changing, how much of a change has happened?

What do you notice over time about the extent of the glacier?

OK, we know there has been a change in the extent of the glacier. What else has been changing in the environment that may have caused the glacier to shrink? Let’s explore!

6) Reading air temperature data

Scientists have thermometers near the glacier to record the air temperature. From daily readings, scientists can use the air temperature data to estimate melting rates on the surface of the glacier. Scientists have been doing this since 1935.

So we can look at the average air temperature each year from 1970 to 2009 to get an idea of what kinds of changes have happened to the environment around the glacier over time.

So let’s see what the data demonstrates…

7) Overall, what has happened to air temperature since the 1970s?

Watch the data of air temperature in the graph. What do you notice about the air temperature?

OK, so it is changing as well. Think about what that means for the glacier. A small change in temperature can make the difference between ice melting or staying as ice. Think about an ice cube melting in a glass of cold water. The water isn’t much warmer than the ice, but the ice cube still melts! (Want to explore this more? Check out this interactive!)

What else could be changing in the atmosphere that is related to the changes in air temperature? Let’s look at the amount of carbon dioxide over time from the same area.

If you are interested in exploring more about the relationship among air temperature, precipitation, and glaciers click here.

8) Reading CO2 data

Scientists can use an energy sensor to measure the amount of carbon dioxide in the air. Scientists have been doing this since the 1950s.

We can look at the carbon dioxide data each year from 1970 to 2015 to get an idea of what kinds of changes have happened in the area as the air temperature has changed over time.

So let’s see what the data demonstrates…

To learn more about where these data come from and why we can use measurements from Hawaii as a proxy for other data, click here!

9) Let’s compare air CO2 and temperature over time!

We now know that the air temperature in the area has changed over time as the length of the glacier has changed. We also know that air temperature can be related to the amount of carbon dioxide in the air. But has the carbon dioxide changed over time too in the area? Has it changed in similar ways?

Watch the data on the amount of carbon dioxide in the air in the graph. What do you notice about CO2 in the air?

Now, watch it again and look at the air temperature graph too. What do you notice about how the air temperature and CO2 have changed over time?

OK, so CO2 is changing too. What does that mean for the glacier?

Interested more in how these data are collected? Click Here!

10) So what does this all mean for the glacier?

Look again through all of the data that we have been exploring. Are there overall patterns among the different variables? Do you think they are related to one another?

When using all of these data together, what conclusions can you make about what has been happening to glaciers over time and why?

In fact, Hintereisferner glacier in Austria has retreated 2,800m (over 9,000ft) since 1880!

To learn more about other things that are related to changes in the extent and size of glaciers, check out the interactive tool or this climate/glacier resource.

Acknowledgements:

Dr. Ellyn Enderlin (Science Advisor)

Kristin Hunter-Thomson (Story Design)

Lucas Marxen (Interface Development)

Dan Farnsworth (Data Visualization & Website Development)

10b) NYI

Wind speed?Air temperature?Height of Mountains?Amount of snow?Amount of rain?Amount of dust in the air?Atmospheric CO2? Length of winter?

Photo Credit: INTERACT


Photo Credit: NASA

Research Station Hintereis (upper left image) is near the Hintereisferner (HEF) glacier in the inner Alps, Austria. The University of Innsbruck runs the research station. Glacier length observations began in 1847 and the earliest maps are from 1870. The research station was built in 1966, can fit 8 people, and has no electricity.

1972

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USGS EarthExplorer

1972

Photo Credit: INTERACT

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Photo Credit: ESRL

Photo Credit: ASC

1972

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