Hi Marie, I also found it interesting how the earth 's temperature changes because the energy received from the sun is not equal to the energy the earth emits back to space. To answer your question about Ice cores; they are layers of snow and ice that have been collected over a period of time. Change in temperature can affect the texture of the snow. Scientists analyze each layer to get information about the earth's climate in the past. These ice store trapped chemicals. For instance, scientists look for the presence of dust or volcanic ash to detect when volcanic eruptions occurred. They also analyze ice layers for oxygen isotopes for a record of the earth's
