WA drought, evidence of dramatic climate change: study

The author behind a new study linking 30-year drought in Western Australia with heavy snowfall in Antarctica says it is strong evidence man-made greenhouse gases have provoked dramatic climate change.

The Antarctic Climate and Ecosystems Co-operative Research Centre in Tasmania said it had found a direct link between snowfall in eastern Antarctica and rainfall in Australia's southwest.

The heavier it snows in Antarctica, the less it rains in southern WA, the centre found.

Principal research scientist Tas van Ommen said the conclusion had been drawn from a study of 750-year-old ice-core samples.

The samples showed that as recently as about 1970, Southern Ocean winds had changed to deposit unusually heavy snow in Antarctica while circulating dry, cold wind - with little rainfall - to the southwest of Australia.

Dr van Ommen said it was the most significant climatic change found in the 750-year-old ice sample, and outside natural variation.

"What we've found is that the last 30 years in our ice core is the largest event in the past 750 years," Dr van Ommen told AAP ahead of the study's release on Monday.

"Large-scale atmospheric circulation in recent decades seems to have stepped up in a way that brings extra warm, moist air to Antarctica - with extra snowfall - and at the same time the recirculation of cold, dry air up towards Western Australia.

"This has actually reduced the winter rainfall and made a significant contribution to the drought.

"The drop occurred around 1970 - it's about a 15% drop in (annual) winter rainfall." Dr van Ommen said that while the ice-core study wasn't conclusive proof of human-induced climate change, there was strong evidence pointing to it.

"There's no doubt in everybody's mind that Western Australia has gone into drought," he said.

"We're seeing a step (step) change in drying from the 1970s onwards.

"The (earth's) atmosphere tends to have a bit of structure in it that has permanent high-pressure and low-pressure systems based around the Southern Ocean.

"This pattern has strengthened in the past 30 years and some of the computer models that reproduce this are showing that it looks like it has happened because of greenhouse gases - carbon dioxide - and also ozone (being depleted).

"We wouldn't claim on the strength of this that it is proven in black and white, but it's another piece of evidence.

"This is strong evidence that human climate change does make a contribution to the West Australian drought."

Dr van Ommen said that while the earth had experienced dramatic climate changes in its history, studies had shown there had been "much more dramatic changes" in recent years.