Glacial geology and climate change

Exposure dating has revolutionised the study of the history of glaciers and ice sheets. By directly dating glacial debris and eroded bedrock, the timing of the advance and retreat of the ice (a sensitive indicator of climate) can be determined with unprecedented reliability. Dr Timothy T. Barrows is using this technique to take a fresh look at the history of glaciation and climate change in Australia, New Zealand, Papua New Guinea and Spain.

Studies of relics of the last Ice Age in the Snowy Mountains and Tasmania have led to a complete revision of the glacial history of Australia. Hypothetical ideas about glacier extent and its timing that stood for nearly a century have been replaced with a robust chronology placing Australia into a global context. It transpires that there was not just one but at least four major advances of glacier ice during the last 70,000 years. The coldest part of the last ice age was about 20,000 years ago and only lasted a few thousand years. The ensuing global warming is the greatest in recent geological history. On the basis of the altitude of the ice age landforms, mean temperatures around Canberra are about 9°C warmer today. This research provides an important baseline from which to assess climate variability and future climate change.

Younger Dryas event in New Zealand Science paper