First Published 1 February Ice cores drilled from the polar regions provide us with excellent records of the history of the climate on earth. They are also very useful in dating the ice caps, as you can count the layers, similar to counting tree rings. These layers are deposited annually, and are relatively simple to read. Although not an exact science, it does provide a good estimate of the age of the ice caps. Naturally, since these ages are said to be over , years old, they disprove the young earth creation science theory that the world is only 6, years old.
Record-shattering 2.7-million-year-old ice core reveals start of the ice ages
How do ice cores allow researchers to see climate change? | Science | The Guardian
The cornerstone of the success achieved by ice core scientists reconstructing climate change over many thousands of years is the ability to measure past changes in both atmospheric greenhouse gas concentrations and temperature. The measurement of the gas composition is direct: trapped in deep ice cores are tiny bubbles of ancient air, which we can extract and analyze using mass spectrometers. Temperature, in contrast, is not measured directly, but is instead inferred from the isotopic composition of the water molecules released by melting the ice cores. Water is made up of molecules comprising two atoms of hydrogen and one atom of oxygen H 2 O. But it's not that simple, because there are several isotopes chemically identical atoms with the same number of protons, but differing numbers of neutrons, and therefore mass of oxygen, and several isotopes of hydrogen. The isotopes of particular interest for climate studies are 16 O with 8 protons and 8 neutrons that makes up All of these isotopes are termed 'stable' because they do not undergo radioactive decay.
Dating Ice Cores
I was wondering how ice cores are dated accurately. I know Carbon 14 is one method, but some ice cores go back hundreds of thousands of years. Would other isotopes with longer half-lives be more accurate? Also, how much does it cost to date the core? How are samples acquired without destroying the ice?
Ice consists of water molecules made of atoms that come in versions with slightly different mass, so-called isotopes. Variations in the abundance of the heavy isotopes relative to the most common isotopes can be measured and are found to reflect the temperature variations through the year. The graph below shows how the isotopes correlate with the local temperature over a few years in the early s at the GRIP drill site:. The dashed lines indicate the winter layers and define the annual layers.