About 2 million years ago, the climates (weather conditions in an area measured over 30 years) of countries such as Ireland became much colder. Year after year, snow fell. It began to gather in upland areas, gradually turning to solid ice. The ice began to move slowly to lowland areas under the influence of gravity as great rivers of ice called glaciers . Some glaciers melted, while others joined together to form ice sheets. The ice sheets (figure 1) covered huge areas of the earth’s surface. An ice age had arrived.
Fox Glacier in New Zealand Glacier
Glacial meltwater flowing from the snout (front)
During the ice age, there were warmer periods known as interglacial periods . The average length of an interglacial period is 100,000 years, so it is possible that we are now living in an interglacial period and that the ice sheets will return!
During the last ice age, 14,000 years ago, almost one-third of the earth’s surface was covered in ice. Ice sheets still cover Antarctica and Greenland today.
Managing information and thinking
1. Locate Ireland on the map shown in figure 1. Was it affected by an ice sheet?
2. Using an atlas or Google Maps if necessary, name 10 countries affected by an ice sheet.