Paleoclimatic reconstructions from WA stalagmites show how historic events still determine Australia's climate variability.
Researchers across Australia and the US profiled stalagmites from a cave in WA's Cape Range peninsula to produce a high-resolution, continental paleoclimate record of Australia along the Indian Ocean.
Lead researcher Rhawn Denniston, of Cornell College in the US, said the record, which spanned the last glacial maximum, deglaciation and early to mid-Holocene was the first of its kind.
"The more we understand about how things have occurred in the past, the better we can develop a frame of reference for our current and future climate," Professor Denniston said. "The first thing the results illustrate is how much we still don't know about the nature, timing and drivers of climate variability in this part of the world.
"However, we do see events that are synchronous to and consistent with other regional events, some of which have ties to far-flung regions such as the North Atlantic."
The stalagmite analysis found evidence of such an event, which had global significance.
Professor Denniston said a climate anomaly at the site during a period called Heinrich Stadial 1, about 16,000 years ago, was likely driven by changes in ocean circulation starting in the North Atlantic.
Heinrich Stadial 1 affected other parts of the world too, including the Indo-Pacific, China, Brazil and parts of Africa and Europe, and had been tied to climate variability in southern Australia.
"It is the most prominent event in our record and in other recently published records from the Kimberley suggesting it had a widespread impact across Australia," he said.
The stalagmite samples were sliced in half vertically with material milled out for dating and chemical analysis. The dating involved extracting and measuring tiny abundances of uranium and its radioactive daughter thorium.
The research builds on studies on stalagmites in China, which showed variability in the east Asian monsoon over decades to hundreds of thousands of years.
Other work, largely from lake and ocean sediments, around southern Australia, suggested precipitation moving north was dynamic and influenced the climate over tens of thousands of years.
This article first appeared at sciencewa.net.au