Antarctic snowfall linked to West Australian drought

Ice core
Ice core (Photo: Joel Pedro)
Dr Tas van Ommen collecting an ice core at Law Dome in AntarcticaFeatureless icy landscape

An Antarctic ice core has revealed a link between drought conditions in south-west Western Australia and increased snowfall in Antarctica.

Australian Antarctic Division glaciologist, Dr Tas van Ommen, has analysed a 750 year old ice core from Law Dome in East Antarctica.

The results of his research are published today in the prestigious international scientific journal, Nature Geoscience.

“The ice core shows how much snow fell at Law Dome each year, and we have compared the modern portion of that with meteorological records from Australia,” Dr van Ommen said.

“What we found was amazing. While we were noticing extra moisture in east Antarctica and increasing snowfall, we were seeing dry conditions over south-west Western Australia,” he said.

Since the late 1960s there has been a 15–20% decline in winter rainfall in south-west Western Australia, and at the same time there has been a 10% increase in snowfall at Law Dome.

This study, co-authored by honorary research fellow Vin Morgan, indicates that a change in atmospheric circulation patterns off southern Australia is responsible.

“In the past three decades the strength of persistent high and low pressure systems off southern Australia have increased, directing more warm, moist air south towards the coast of Antarctica and dry, cold air north in winter,” Dr van Ommen said.

“This does not appear to be in the range of natural variability: we can see from the ice core that an event like the increased snowfall at Law Dome would only come along once every 38,000 years without some change in climate patterns and, given the connection we see with Western Australia, it would suggest that the drought is also not a natural event.”

Dr van Ommen believes the change in climate pattern may be due to human-induced atmospheric changes; from reductions in ozone and increased levels of carbon dioxide in the atmosphere. It’s hoped the research will lead to improved projections of future change that can be used to shape land-use policy.

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