Knowledge of Australia’s climate history has been expanded to the past 50m years, up from the past 500,000 years, via a major international scientific voyage from Fremantle to Darwin.



The two-month expedition involved drilling of the seabed off the Western Australian coast for study by the Joides Resolution research vessel – one of the world’s largest floating scientific facilities.

The International Ocean Discovery Program-led mission planned to find sediments that would show climate records to 5m years in the past but one section of seabed had a record stretching back to 50m years.

Removed cores of sediment will now be analysed by scientists but it has already become clear Australia’s deserts are among the youngest in the world.

Evidence in the sediments, from dust and sand blown across the continent, shows the desert regions of Australia are 1.5m years old. Separately, the sediments appear to show the monsoonal seasons of northern Australia are far older than have previously been shown.

The $20m mission involved 125 scientists and crew from around the world and managed to extract sediments as far down as 1.1km below the seafloor, before docking in Darwin on Wednesday.

“To get a series of layers of sediment that go back to 50 million years is quite extraordinary and very exciting,” expedition co-leader Prof Stephen Gallagher, told Guardian Australia.

“We have an environmental record that extends in detail to 500,000 years but we can definitely extend that now to five million years and then to 10 million years. The 50 million year record is quite thin, not as complete as the five million year record, but it’s a remarkable snapshot of the climate record no one has seen before.”

On board the research vessel, Joides Resolution. Photograph: Joides Resolution

The north-west shelf, the area off the coast covered by the expedition, is a key system in the ocean circulation and monsoonal seasons that influence the climate of northern Australia.



Ocean sediments in the area contain dust, pollen and other material blown off the land and deposited in the seabed. Scientists are also able to analyse small fossils to determine the chemistry of the ocean.

“These sediments are preserved very well, far better than on continental Australia, where the weather is so harsh that most evidence is destroyed in desert conditions,” said Gallagher. “Ice cores can be examined for the past climate too, but they only go back to a maximum of 800,000 years.”

The research expedition will be used to help broaden the knowledge of contemporary climate change. Carbon dioxide levels are now higher than at any recorded point since a period 3-5m years ago, a time in history when the Earth’s ice sheets were much smaller and the climate warmer and wetter than today.

The release of vast amounts of CO2 from the burning of fossil fuels is the primary cause for the world warming by around 1C over the past century.

“Climate change is happening, we are meddling with the climate system,” Gallagher said. “It’s great to have projections of climate in the future but how will we know how to react if we don’t we know how the climate behaved in the past? It’s like history, you ignore history at your peril.”