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Have you heard about scientists who drill ice cores? Ice cores are samples taken from glaciers using special machines that go deep down into the glacier and take out solid tubes of ice and bring them to the surface. Ice cores provide information about ancient earth and help predict our future climate.

When fresh snow falls on top of old snow every year, each layer presses down on the snow below it. The deeper snow slowly turns to ice under the pressure of the many layers. Trapped inside the ice are all kinds of particulates (tiny solid pieces), air bubbles, and chemicals that were in the original snow. 

The layers of ice are like the rings in a tree trunk. Each layer represents one season, and the deeper you go, the older the ice. Every layer is like a time capsule of what the atmosphere was like when the layer was formed. Most ice core sampling is done in Greenland and Antarctica.

Each layer in the ice core gives clues about the temperatures and various gases in the atmosphere during the time it was originally formed. The layers are each carefully tested and examined. The types of particulates, the gases in the air bubbles, and the chemistry of the water all give clues about conditions in that time in history. To make sure the data is accurate, the samples are compared with measurements taken from the air from the same time period, to make sure they match. Core samples tell us about conditions on earth as far back as 800,000 years ago! 

Many types and sizes of drills are used to get the cores. Drills have sharp edges on one end of a hollow tube and rotate as they go into the ice. Other types of drills use heat to melt through the ice. The drill cuts out a solid tube of ice and then brings it up to the surface. The cores are carefully placed in refrigerated boxes and transported to storage where they are examined and stored in metal tubes at �36°C (�33°F). Ice cores can be made with hand drills down to 40 m (130 feet). Scientists can also use machines to drill deeper, to get samples from as deep as 3000 m (1.8 miles)! 

The ice core samples show there is more carbon dioxide in the earth’s atmosphere now than in the past. They also show that the level is increasing much faster than it has over thousands of years. Data taken from core samples from the past are used to make models of conditions in the future. Glacial ice cores are the best tools we have to understand what’s ahead � and how long we might have to change our future!