Paul Souders/Getty Images

STANDARDS

CCSS: 6.RP.A.3, MP4, MP7

TEKS: 6.4E, 6.4F, 7.4D

Article Options

Presentation View
Teaching Resources

Mapping a  Meltdown

From outer space, up in the air, and deep under the ice, scientists are studying the behavior of glaciers

January 16, 2017
By Jennifer Hackett
PAUL SOUDERS/GETTY IMAGES

Melting ice causes streams of water to flow into Greenland’s Disko Bay.

Flying 1,500 feet above Antarctica, Kirsty Tinto shines a laser beam on the ice below. By timing how long it takes for the beam to be reflected back to the sensor on her plane, she can determine how tall the ice sheet is. Comparing her results with last year’s data lets her see whether the ice grew or shrank. 

Scientists like Tinto are traveling to the ends of the Earth to understand the world’s glaciers. As the average temperatures on Earth rise, these icy areas are the most vulnerable because they’re extremely sensitive to changes in climate. To get the full picture of how glaciers are responding to these changes, scientists are gathering data from as far away as outer space to as close as the rarely seen bases of glaciers themselves. 

A DELICATE BALANCE

Glaciers form in places where winter snow survives through the summer months. More snow falls on top the following year. Eventually, the weight of the new snow compresses the older layers into ice. Glaciers grow or shrink depending on the balance between how much new snow falls on them and how much melts away in the summer. Smaller glaciers typically form high up on mountains, while the land in places like Antarctica and Greenland are mostly covered in a massive type of glacier called an ice sheet. 

As the average temperature of Earth’s atmosphere rises because of climate change, Tinto and other glaciologists are racing to study how the planet’s glaciers are responding. About 95 percent of the world’s 300,000 glaciers are already shrinking. Some will barely survive, but many will vanish completely. 

Photos courtesy of Louis H. Pedersen (1917) and Bruce F. Molina (2005)

Pedersen Glacier covered most of Aialik Bay in Alaska’s Kenai Fjords National Park 100 years ago. In 2005, the bay was nearly ice-free (below).

GLOBAL VIEWS

For more than 40 years, satellites have been taking pictures of Earth’s icy places from space. Scientists at the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado, analyze the photos. 

“Satellite pictures tell us a lot about how glaciers are changing—particularly about how they’re shrinking,” says Ted Sambos, the lead scientist at NSIDC. The satellite data shows when a glacier’s surface starts to melt, how fast the glacier is moving, and more.

Fieldwork, like the research Tinto does while flying over Antarctica, helps confirm what satellites detect. But it also adds another layer of detail. From her aerial vantage point, Tinto can get detailed measurements about the shape, height, and structure of glaciers and ice sheets, which can cover thousands of miles. 

“We measure the ice sheet from the top to the bottom,” says Tinto. 

INSIDE OUT

NORWEGIAN WATER RESOURCES & ENERGY DIRECTORATE

700 feet below the surface of a glacier in Norway, Miriam Jackson uses a chain saw to take a sample.

Sometimes, glaciologists need to get up close and personal with a glacier. That’s the specialty of scientists working at the Svartisen Subglacial Observatory. It’s located about 700 feet below a glacier in Norway. Scientists can reach it only during the winter. They spray hot water from fire hoses to melt a tunnel into the glacier. Then they hike in. At the end of the tunnel, glaciologist Miriam Jackson uses a chain saw to take samples from the glacier bed. That’s the glacier’s bottom, which moves over the land. 

“All the important things are going on in the glacier bed, but it’s the hardest to reach,” says Jackson. 

Unlike the samples taken from the surface, ice samples taken from the glacier bed aren’t exposed to atmospheric processes. This provides invaluable data on how glaciers are moving over land as their temperature and composition change over time.

Paul Souders/Getty Images

A moulin, or waterfall in a melting ice sheet, flows from Greenland’s Ilulissat Konger Iva glacier.

FUTURE FORECAST

Even though most people don’t live near a glacier, glacial meltwater can have global consequences. Glaciers hold about 75 percent of the planet’s fresh water. The meltwater that flows down from them in the summer provides valuable drinking water, irrigates crops, and powers hydroelectric power plants all around the world. As glaciers that supply water in the summer decline, many regions face water shortages. 

Regions far away from glaciers could face a very different crisis. When glaciers melt, the water they once held flows into the ocean, causing sea levels to rise. This could spell major trouble for coastal areas, including in the U.S., and reshape the coast of continents. “Quite simply, we need to understand what our cities far away from ice sheets are going to look like in 100 years,” says Tinto. “It’s important because it affects so many people.”

For Tinto, studying glaciers combines scientific exploration with environmental and human protection. “It kind of runs the full spectrum, from pure science knowledge to being able to form predictions about the next 100 years,” she says. 

MODELING PERCENTS

A percent is a ratio with a denominator of 100 that represents part of a whole. By using a 10-by-10 gridded box, you can visually show percents. Each box represents 1 percent of the total amount. By adding up the total number of shaded boxes, you can find the total percent depicted.  

Use percent models to visually represent information about the Earth’s glaciers.

These three models show the percents mentioned in the facts about the world’s glaciers beneath them. Draw a line to match the percent fact with the model above that represents the same percent. 

Greenland has an area of 2,166,068 square kilometers. The model below shows the percent of Greenland that is covered by an ice sheet.

A. What percent of Greenland is covered by an ice sheet?

B. With Earth’s temperatures rising, the area of Greenland’s ice that is melting is 16 percent higher than it was in 1979. Model 16 percent using the grid below.

A. Snow and ice keep the planet cool by reflecting sunlight. Different types of snow and ice reflect different percentages of light. Here are three types listed in order from most reflective to least reflective: dry snow, wet snow, and bare ice. The models below show the percentage of light each type reflects. Label each model with the type of snow or ice it represents and its percent.  

B. By how many percentage points is dry snow more reflective than bare ice? 

Glaciers shrink when the amount of ice that melts over the summer exceeds the amount of new snow that falls in the winter. The model below shows the maximum amount of winter snowfall that could be lost the next summer from glaciers in the West Antarctic Peninsula.  

A. What percent does the model above show?   

B. What does it mean when one percentage requires two boxes to be modeled? 

Ratios & Proportions
Percents
videos (1)
Skills Sheets (3)
Skills Sheets (3)
Skills Sheets (3)
Games (1)
Lesson Plan (2)
Lesson Plan (2)
Text-to-Speech