Ice core drilling helps scientists study past climate. Scientists that study past climate are called paleoclimatologists. Some paleoclimatologists drill out cores of ice from glaciers in the north and south poles to determine the temperatures of past years. Drilling out a core of ice shows different layers of snow, ice, and bubbles depending on the temperature of the time that a certain layer was at the surface.
NASA explains where these ice cores originate. Ice sheets and glaciers form from accumulating snowfall. Each year a new snowfall accumulation falls on top and compresses the previous year’s snow. Eventually, this compression of snow overtime is what makes a glacier. NASA also states that in some areas these layers result in ice sheets that are several miles thick.
According to the American Geosciences Institute (AGI), each ice layer shows the past temperature of the air. Scientists use the bubbles of oxygen molecules in the ice to determine what the temperature was for each layer of ice. Oxygen isn't the only gas that creates bubbles in the ice. Allegra LeGrande of NASA states that “scientists can directly measure the amount of greenhouse gases that were in the atmosphere at that time by sampling these bubbles.” Other gases found in ice cores include carbon dioxide and methane. Aerosols are also found within the ice such as, dust, ash, pollen, sea salts, and other chemicals/toxins.
The picture below is an ice core that was drilled out of Mount Hunter, Alaska by Bradley R. Markle as part of the Denali Ice Core Project. The discolored layers of the ice have bedrock and pebbles incorporated into the ice.
Overall, the study and drilling of ice cores help scientists understand how climate and the content of the atmosphere changed over thousands of years.
© 2019 Weather Forecaster Brittany Connelly