Ice cores provide information about the climate in the past and this allows us to compare it with the current climate to determine how it stacks up. While some of the readers may know a lot about ice cores, this posting provides general knowledge for those of you that are not so familiar with ice cores. The next posting will discuss the results of the information gather at two sites in the Antarctic.
The Vostok location, one of many places where ice cores are drilled, is part of the Antarctic ice cap. At this location the snow falls each year and the temperature doesn’t rise above freezing. In fact this location is called the coldest place on Earth.
This is how the ice sheets are formed. The surface layer of snow contains gaps between the snowflakes containing air. As subsequent season’s experience snow falls, the older snow begins to compress. The compression forms a grainy material (firn) said to resemble the texture of granulated sugar. As the snow above continues to accumulate, the firn eventually densifies and closes off the pores and the air is firmly trapped. The ice sheet now has inclusions which can be analyzed. When the ice is cored out of this ice sheet, large amounts of information can be obtained for analysis. Wiki has this to say about the ice core samples:
“Ice cores contain an abundance of information about climate. Inclusions in the snow of each year remain in the ice, such as wind-blown dust, ash, pollen, bubbles of atmospheric gas and radioactive substances. The variety of climatic proxies is greater than in any other natural recorder of climate, such as tree rings or sediment layers. These include (proxies for) temperature, ocean volume, precipitation, chemistry and gas composition of the lower atmosphere, volcanic eruptions, solar variability, sea-surface productivity, desert extent and forest fires.
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