How the formation of Indonesia destroyed Australia's rain forest

Abstract

A little more than 3 million years ago, a climatic upheaval forever changed Australia's western coast. Over the span of 200,000 years the southward flowing waters of the Leeuwin Current cooled by 2°–3°C, decreasing coastal precipitation and converting northwestern Australia's rain forests to semiarid grasslands. By measuring the isotope ratios and chemical composition of preserved shells left by ancient single‐celled organisms, Karas et al. reconstructed the hydrologic signature of the geologic upheaval that triggered the sudden cooling. During the Pliocene (approximately 4–3 million years ago), tectonic activity led to the formation of a number of small islands in the Indonesian Archipelago. This protruding land restricted the Indonesian Throughflow (ITF), a current that carries warm, fresh, tropical Pacific water through the island chain and feeds the Leeuwin Current. (Paleoceanography, doi:10.1029/2010PA001949, 2011)