Using 100-Million-Year-Old Fossils and Gravitational-Wave Science to Predict Earth’s Future Climate

Image of archaea.
Credit: Steve Gschmeissner/Science Photo Library

A group of international scientists, including an Australian astrophysicist, has used know-how from gravitational-wave astronomy (used to find black holes in space) to study ancient marine fossils as a predictor of climate change.

The research, published in the journal Climate of the Past, is a unique collaboration between paleontologists, astrophysicists and mathematicians – to improve the accuracy of a palaeo-thermometer, which can use fossil evidence of climate change to predict what is likely to happen to the Earth in coming decades.

Professor Ilya Mandel, from the ARC Centre of Excellence in Gravitational Wave Discovery (OzGrav), and colleagues, studied biomarkers left behind by tiny single-cell organisms called archaea in the distant past, including the Cretaceousperiod and the Eocene.

Marine archaea in our modern oceans produce compounds called Glycerol Dialkyl Glycerol Tetraethers (GDGTs). The ratios of different types of GDGTs they produce depend on the local sea temperature at the site of formation.

When preserved in ancient marine sediments, the measured abundances of GDGTs have the potential to provide a geological record of long-term planetary surface temperatures.

To date, scientists have combined GDGT concentrations into a single parameter called TEX86, which can be used to roughly estimate the surface temperature.  However, this estimate is not very accurate when the values of TEX86 from recent sediments are compared to modern sea surface temperatures.

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