Recovering Ice Cores

I went to invite you to come with me on an expedition to one of the coldest and windiest places on earth. A glacier. Scientists travel all around the world, including Antarctica to study glaciers for weeks or months at a time. Scientists choose glaciers around the world to drill for ice cores. Based on whether they can get a full and accurate history. They don't want to go to locations where the snow melts every summer because then they're losing that record. So instead they pick locations to drill these ice cores where the snow has accumulated year after year after year to give them an accurate record of what's happened. What is an ice core? Let's start with a core. A core is a cylinder of material that is removed from a larger body of material, so an ice core is a cylinder of ice removed from a glacier. Let's use this ice cream cake as an example. If we drill into the ice cream cake with a straw, we can remove a core of ice cream cake. We can see that the layers of core from the cake are the same as the layers in the ice cream cake. Yum. It's the same idea with ice cores. An ice core is a sample or an example of the glacier. Scientists will drill down into the glacier and bring the ice core out to get an idea of what's going on in the different layers within the ice core, which then represents what's going on in the different layers of the glacier. How are ice cores collected? In order to collect the ice cores, scientists need to hike to the tops of glaciers. They bring with them everything they need in order to live for weeks or months at a time in freezing cold weather. They also need to bring scientific equipment and drills in order to collect the ice cores. Once they're actually there, they want to make sure that they collect as much information as possible. So that when they return to the lab, they have all the information that they need in order to do their work. Drilling ice cores is different than putting a nail in the wall because we need to preserve what is in that ice. The scientists have to be careful not to contaminate that ice as they're drilling it. So we need to be able to take the ice cores without changing the characteristics of the ice. Glaciers can be hundreds to thousands of meters thick. Let's compare this to the Washington Monument, which is 169 meters tall. We can see that the glaciers are as thick as 12 Washington monuments stacked on top of each other. How difficult do you think it would be to collect and transport an ice core that long? In order to make the task manageable, scientists drill down into the glacier and bring up about a meter of ice core at a time. They store the ice core in a hole that they dig in the glacier itself in order to keep it cold. And then they'll put the drill back down the hole and continue drilling a meter at a time. And they'll keep doing this until the drill actually hits rock. At which point they have gone the furthest that they can go so they no longer need to drill in that area. How or ice cores transported. Once the scientists have collected the ice cores, they face the problem of getting the cores back to their lab without melting. Scientists have come up with many different solutions. Some scientists will put each ice core tube into a cardboard box filled with freezer packs. The cardboard boxes are carried down the mountain by animals like yaks until they reach a refrigerated truck that is waiting for them. Then the refrigerated truck drives to the airport, the ice cores are transported by air, picked up at the airport by another refrigerated truck, which drives them to the research lab. Once the ice cores have come back to the research center, the scientists are going to do several different things in order to get them ready to be studied. The ice cores are kept in a freezer, of course, at a chilling temperature of -30°F. So they can make sure that the scientists aren't going to lose any of this record that they've taken so much time and effort to get. Scientists think of the ice core as a book with many chapters. Each chapter tells a different part of the story. So scientists will cut the ice core into sections or chapters in order to understand each chapter of history that is stored within the ice. Then those chapters will be cut into smaller sections like pages within a chapter. Scientists will do different kinds of experiments with the sections of ice. Some pieces, they'll put in a clean room, which is a room that is ten times cleaner than a hospital operating room. They'll actually wash the ice with purified water. Just to make sure that any contaminants that are on the outside are then washed away. Some of these sections of the ice core are going to be allowed to melt at room temperature so that the scientists can analyze the materials and the gases that are found within that part of the ice core. By looking at this information, scientists can get an idea of how earth's climate has changed over a long period of time. So that's a brief look at how scientists go about getting ice cores and using the information found within them to help them look at earth's climate history. Thanks for coming along on my expedition and I hope you stay warm.