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Australia Loses Vital Rain as Climate Change Shifts Winds

Climate change is robbing crucial rain from southern parts of Australia by shifting Southern Ocean westerly winds towards Antarctica, according to a new study.

Lead Australian researcher A/Prof Nerilie Abram of The Australian National University said 2016 was also on track to smash the hottest-year record. “Our findings confirm that climate change is already having an impact on parts of Australia,” she said.

“Antarctica and the Southern Ocean are remote, but this region influences Australia’s heat waves, affects whether our crops get the winter rainfall they need, and determines how quickly our ocean levels rise.”

Winter rainfall in south-western Australia has declined by more than 20% since the 1970s because of the shifting westerly rain belt, and Perth now relies on a desalination plant to supplement its water supplies.

The research, published in Nature Climate Change (http://tinyurl.com/jxn9jqr), showed that climate change was causing westerlies in the Southern Ocean to shift closer to Antarctica. However, Abram said that the bigger picture of the region’s climate trends remained unclear.

“Antarctica and the Southern Ocean experience extreme fluctuations in climate year to year,” she said. “In most cases our short climate measurements in this remote region are not yet long enough for the signal of anthropogenic climate change to be clearly separated from this large natural variability.”

Measuring the surface climate across Antarctica and the surrounding Southern Ocean only became possible with the advent of regular satellite observations in 1979.

The research team investigated how recent Antarctic climate trends compared to past climate fluctuations using natural archives such as ice cores drilled into the Antarctic ice sheet. They also studied how Antarctica’s recent climate changes compared with climate model simulations, including future climate change scenarios.

“At face value, many of the climate trends in Antarctica seem counterintuitive for a warming world,” said lead author Dr Julie Jones of The University of Sheffield. “Scientists have good theories for why, but these ideas are still difficult to prove with the short records we are working with.”