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Earth’s History Locked in Ancient Ice

Scientists are learning about the history—and the future—of Earth’s atmosphere by studying ancient ice.

A man wearing a fur hat and gloves holds out a core of ice in a labeled plastic bag.

James Brooks—AFP/Getty Images

Professor Jorgen Peder Steffensen of the University of Copenhagen holds part of an ice core sample that’s housed at the Ice Core Archive.

It’s one of the most talked-about issues: Human-made pollution is changing Earth’s atmosphere and leading to rapid climate change. But how did the atmosphere change before humans began producing pollution, and what can that tell us about the future of the atmosphere? Scientists believe the key to finding out may be the study of ancient ice.

The Ice Core Archive in Copenhagen, Denmark, is a massive freezer full of ice that originated mostly in Greenland. The ice, which is compressed snow rather than frozen water, dates back as far as 120,000 years ago. It’s a snapshot of a time when the atmosphere was unaffected by human activity.

Air temperatures in Greenland were actually warmer 120,000 years ago than they are today—not because of human activity but because of natural atmospheric conditions. The ice cores can help scientists figure out what the atmosphere was like at that time and how it affected sea levels. Using this information, they hope to be able to figure out how much sea levels will rise due to today’s human activity, according to University of Copenhagen glaciology professor Jorgen Peder Steffensen, who manages the Ice Core Archive.

“With ice cores, we have mapped out how greenhouse gases, carbon dioxide and methane vary over time,” Steffensen told Agence Presse-France. “And we can also see the impact of the burning of fossil fuels in modern times.”

Did You Know?

A person uses a large metal cylinder to extra a core of ice from the ground.

NASA Goddard (CC BY 2.0)

In 2017, scientists announced that they had extracted a 2.7-million-year-old ice core in Antarctica.

Fast Facts About Greenland

The Northern lights are in the sky over a city of homes and other small buildings.

© Kell B. Larsen—500px Prime/Getty Images

Fewer than 20,000 people live in Nuuk, the capital of Greenland.

Greenland lies mostly within the Arctic Circle, which explains its icy surface. Beyond that, what do you know about the world’s largest island? Here are a few quick facts.

  • Greenland was first settled in about 2500 BCE by a group of Indigenous people called the Inuit, who migrated there from what’s now Canada.
  • About 80 percent of Greenland is covered by ice and snow.
  • Greenland’s population is about 56,000. Most people live in ice-free areas along the coasts.
  • The average high temperature in Greenland is 23 degrees Fahrenheit (–5 degrees Celsius) in February and 50 degrees Fahrenheit (10 degrees Celsius) in July. But Greenland is a big place, and temperatures vary widely.
  • The official language of Greenland is Greenlandic.
  • Greenland became a Danish colony in the 18th century. It’s now an autonomous nation within the kingdom of Denmark.
  • According to a 2018 report, Greenland is losing about 110 million Olympic-sized swimming pools of water each year as the ice caps melt due to human-caused climate change.

The Bottom of the World

© Paul Souders—Stone/Getty Images

As old as Greenland’s ice is, Antarctica’s is even older. Antarctica is so cold and desolate that it doesn’t even sustain a human population, except for groups of scientists who stay there temporarily. What does live there?

You can learn more at Britannica!






indicative of or occurring in the winter

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