Carbon dating climate change - Climate Change Might Break Carbon Dating | Smart News.


As scientists who study earth’s (relatively) modern history rely on this measurement tool to place their findings in the correct time period, the discovery that it is unreliable could put some in a quandary.

Radiocarbon dating is a 70-year-old technique now used with increasing precision to date anything once alive from the last 50,000 years. It exploits the natural ratio of two isotopes of carbon in the atmosphere. Plants, and the animals that eat them, absorb radioactive carbon-14 and stable carbon-12 from the atmosphere in proportions which – except during the atmospheric nuclear weapons tests in the 1950s and 1960s − have not changed much from the Ice Ages to the beginning of the Industrial Revolution. When the tree dies or the animal becomes old bones, the carbon-14 decays at a predictable rate, and the ratio that remains in the laboratory sample is a measure of the specimen’s age. But Heather Graven, a lecturer in climate physics and Earth observation at Imperial College London , reports in the US journal Proceedings of the National Academy of Sciences that by 2020, as the fossil fuel emissions mount up, the fraction of carbon-14 in the atmosphere could drop to such a level that carbon-dating could become increasingly uncertain.

As the election approaches, a clear choice is likely to be presented to voters on climate change policy: either minor tweaks but otherwise 'business as usual' under National, or tough new legally binding limits on greenhouse emissions under a Labour-led government.


Carbon dating climate change

Carbon dating climate change