Antarctic ice cores reveal that Australia’s drought risk is worse than expected

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Antarctic ice core records show that the risk of drought in eastern Australia is higher than expected.

Led by Dr. Tessa Vance of the Australian Antarctic Division Partnership and Dr. Anthony Kiem of Newcastle University, and with the participation of Australian Antarctic Division scientists, the study will have significant impacts on water safety and management across Australia and internationally. Is exerting.

The team has 150-year observations of the Pacific Decadal Oscillation (IPO) Climate Change Index, which controls decades of drought and flood risk in eastern Australia, and a 2,000-year climate from the Antarctic ice core. We compared record-based index reconstructions.

IPO is negative (Rainy climate Eastern Australia) and Positive (Drier climate Eastern Australia) Phase. Previously it was expected to alternate every 15 to 30 years.

These IPO phases change the risk of drought, flood, and fire because they change the probability of a dry or wet period.

“Our new ice core studies show that the negative or wet period of an IPO is much shorter and less frequent than the positive or dry phase,” Dr. Vance said.

“The wet season lasted an average of 7 years, with a 10% chance of occurring, while the dry season lasted an average of 61 years.”

“This can be devastating to almost every catchment area in eastern Australia,” said Dr. Kiem. Soil moisture After a period when drought is likely to occur. “

The difference between the IPO ice core reconstruction and instrumental observations may be due to the unusually long wet period that occurred between 1947 and 1976. This unusually moist period is when much of Australia’s eastern water infrastructure was planned and / or built.

“This means that what happened in the middle of the 20th century distorts our expectations for normal conditions of rainfall and spills,” said Dr. Kiem.

“This has serious implications for drought and flood risk assessments, explaining that the positive dry IPO phase is standard and far more likely than the observations of the last 150 years have suggested. Needs to be recalculated in order to do. “

The study was published in Communication Earth and environment February 18, 2022.

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For more information:
Tessa R. Vance et al, Pacific Decadal Oscillation and Impact on Climate Risk over the Last 2000 Years, Communication Earth and environment (2022). DOI: 10.1038 / s43247-022-00359-z

Quote: Antarctica ice core reveals that Australia’s drought risk is worse than expected (February 18, 2022).

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Antarctic ice cores reveal that Australia’s drought risk is worse than expected

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