LIFE SCIENCE

Detailed explanation-1: -The icy layers also hold particles-aerosols such as dust, ash, pollen, trace elements and sea salts-that were in the atmosphere at that time. These particles remain in the ice thousands of years later, providing physical evidence of past global events, such as major volcanic eruptions.

Detailed explanation-2: -Ice cores were begun in the 1960s to complement other climatological studies based on deep-sea cores, lake sediments, and tree-ring studies (dendrochronology). Since then, they have revealed previously unknown details of atmospheric composition, temperature, and abrupt changes in climate.

Detailed explanation-3: -By looking at past concentrations of greenhouse gasses in layers in ice cores, scientists can calculate how modern amounts of carbon dioxide and methane compare to those of the past, and, essentially, compare past concentrations of greenhouse gasses to temperature.

Detailed explanation-4: -Antarctic ice cores show us that the concentration of carbon dioxide was stable over the last millennium until the early 19th century. It then started to rise. Now its concentration is now nearly 40 per cent higher than it was before the Industrial Revolution.