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| The study found storms are reducing rainfall in some areas. (Audience submitted: Hayley Grant) |
Rising greenhouse gases and ozone depletion over the
Antarctic are increasingly pushing rain-bearing storm fronts away from
Australia's west and south, according to a new international study.
The
research, which involved the Australian National University and 16
other institutions from around the world, has just been published in the
Nature Climate Change journal.It found Southern Ocean westerly winds and associated storms were shifting south, down towards Antarctica, and robbing southern parts of Australia of rain.
ANU Associate Professor Nerilie Abram, the lead Australian researcher, said this had contributed to a decline of more than 20 per cent in winter rainfall in southwestern Australia since the 1970s.
"That band of rainfall that comes in those westerly winds is shifting further south, so closer towards Antarctica," Dr Abram, from the ANU's Research School of Earth Sciences and ARC Centre of Excellence for Climate System Science, said.
"So the rain is still there, it's just fewer of those cold fronts make it far enough north to intersect with southern Australia," she said.The study attributed this shift directly to human-induced climate change, primarily from rising greenhouse gases and ozone depletion.
Dr Abram said the loss of rain combined with "2016 being on track to smash the hottest-year record was ominous for communities and the environment".
"Antarctica and the Southern Ocean are remote but this region influences Australia's heatwaves, affects whether our crops get the winter rainfall they need and determines how quickly our ocean levels rise," she said.
The international research team examined how recent Antarctic climate trends compared to past climate fluctuations using natural archives such as ice cores drilled into the Antarctic ice sheet.
They found the bigger picture of the region's climate trends remained unclear because of Antarctica and the Southern ocean's "extreme fluctuations in climate year to year".
Dr Abram explained the climate measurements were not yet long enough "for the signal of anthropogenic climate change to be clearly separated from this large natural variability".
Lead author Dr Julie Jones, from the University of Sheffield in the United Kingdom, said there was still an enormous amount to learn about the Antarctic climate.
"At face value, many of the climate trends in Antarctica seem counter-intuitive for a warming world," Dr Jones said.
"Scientists have good theories for why, but these ideas are still difficult to prove with the short records we are working with."
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