Ice core provide one of the most direct climatic proxy records. Ice core are cylinders of ice drilled out from ice sheet or glaciers. 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, bubbles of atmospheric gas and radioactive substances. An ice core from the right site can be used to reconstruct an uninterrupted and detailed climate record extending over hundreds of thousands of years, providing information on a wide variety of aspects of climate at each point in time. These recorded atmospheric signatures in the ice make the ice cores such a powerful tool in paleoclimate research.