Ice cores have been taken from many locations around the world.
Ice cores are also used to find out the temperature back to about half a million years ago.
This is a huge amount higher than at any time during the last 425,000 years, the information for which has been collected from ice cores.
The ice core is 2035 m long and has a diameter of 10 cm.
However, ice cores can reveal the climate records for the past 650,000 years.
Ice cores show that events such as this occur approximately every 150 years on average.
Ice cores help us know what the temperature was on the planet in the past 800 thousand years.
It does not apply in ice cores where the site remains frozen all year.
During this first season, they also dug a few shallow ice cores to test out the site.
Ice cores show it is around 3500-4000 years old.