by Jean-Louis Tison
Ice cores are the memory of our Climate. They are not the only one, though!… You can read the climate of the past in ocean sediments, corals, tree rings, stalactites in caves, lake deposits, peat deposits and many others. Not all of these archives give you the same amount of information though. Also, some are easily dated (a must for an archive, of course!), other less easily.
Ice cores are extremely wealthy in information, as you will discover here and in the following blogs. They can give you a very detailed record of the Climate and the Environment on several ten thousands of years. However, they have only gone back in time for less than a million year until now, because snow that turns into ice as it is slowly buried in the ice sheet, deforms under its own weight, and flows both downwards to the bedrock and outwards towards the ocean. It thins up so much under these processes, that no ice is left beyond that age limit! The oldest ice dated today in an ice core goes back 800.000 years in time. However, a new project funded by the European Union aims at finding ice older than 1.5 million years old in Antarctica, and this new drilling project will be the next challenge of the coming decades. Other countries are also involved in this challenging task: Russia, Australia, Japan…
In our Mass2Ant project, as you already know, we will be more focused on the last centuries, to document the transition of the Climate into this new geological period that some of us refer to the Anthropocene: a period where the Climate increasingly feels the influence of Mankind (mostly since the Industrial Revolution).
A climate archive, such as ice cores, always works the same way: you measure a variable/property in the medium (ice for example), what we call a “proxy”, to pull out information on a climate or environmental variable (Temperature, precipitations, winds, air masses circulation, greenhouse gases content of the atmosphere a.s.o..). The Figure here below lists some of these information that you can retrieve from an ice core
Stay with us, and you will learn more on the most important ones as we drill deeper into the ice!…
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