Prediction of future weather lies in lessons from the past

10 November 2017
Foto 1 PM MARUM Rovere: Dr Alessio Rovere and PhD student Thomas Lorscheid standing by the Bahamian boulder known as “bull”. Photo: Elisa Casella
Foto 2 PM MARUM Rovere: The boulders known as “cow” (left) and “bull” on the cliff at Eleuthera. Photo: Alessio Rovere

Ancient storms combined with higher sea levels may have resulted in boulders weighing many tonnes being washed onto a cliff in the Bahamas more than 100,000 years ago, a new study has revealed.

The international study involving University of Queensland researchers found that storms with similar intensities to those of today combined with only a few metres increase in sea level, would be sufficient to achieve this.

UQ School of Earth and Environmental Sciences researcher Dr Daniel Harris said the findings were important because coastal regions worldwide were being threatened -by similar conditions.

“Warmer climate conditions can increase the strength of storms and cause more frequent floods which create a growing hazard for coastal populations infrastructure and industries,” he said.

“However, our research suggests that all you need is higher sea levels combined with current levels of storm intensity to reach the super-storm scenario posed by previous studies.”

Dr Alessio Rovere and scientific colleagues from MARUM Center for Marine Environmental Sciences of the University of Bremen and from the Leibniz Centre for Tropical Research, led the research, with scientists from Columbia University, New York, University of Auckland, Royal Netherlands Institute for Sea Research and Utrecht University.

“Our results indicate that a super-storm was not necessary to explain the present positions of the gian boulders,” Dr Rovere said.

“Even if we assume a sea level only six metres higher than that of today, which is comparable to those about 120,000 years ago, the waves produced by Hurricane Sandy would have been sufficient to transport the boulders to their present positions.”

Dr Harris said the study examined how much energy was required for a storm wave to move seven massive boulders to the top of a 15 metre high cliff on the Bahamian island of Eleuthera and whether modern storms possessed the energy to accomplish this. 

The study, Giant boulders and Last Interglacial storm intensity in the North Atlantic, is published in PNAS (doi: 10.1073/pnas.1712433114).

Media: Dr Daniel Harris, Daniel.harris@uq.edu.au, +61 7 336 56084.

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