AUSTRALIA’S big wet could finally be over, with a potentially drought-inducing El Nino weather pattern likely to descend on Australia’s east later this year.
El Nino and its opposite, La Nina, are triggered by Pacific Ocean warming and cooling and can have profound impacts on Australia’s climate. The Bureau of Meteorology confirmed earlier this year that the back-to-back La Ninas of 2010-11 and 2011-12 caused Australia’s wettest two-year period on record.
El Nino, by contrast, can cause widespread drought and high temperatures and, in Victoria, crop failures and the conditions for severe bushfires.
Climatologist Catherine Ganter, from the National Climate Centre, said conditions in the Pacific Ocean were ”sitting on the threshold of El Nino”.
”It’s more likely than not that we’ll have an El Nino,” said Ms Ganter. It is possible for a mild El Nino to bring devastating drought, and for a strong El Nino to have little effect, she said.
”El Nino strength doesn’t relate to the severity of the effect,” she said. With a La Nina, by contrast, ”if it’s a whopping great one it tends to result in us getting a lot of rain”.
According to the Bureau’s three-monthly outlook, there is a 75 per cent chance that maximum temperatures in Victoria will be warmer than usual, and a 65 per cent chance – across most of the state – that Victoria will be drier than usual.
Country Fire Authority chief fire officer Euan Ferguson said Victorians ”could end up with a potentially serious situation” over summer if an El Nino eventuated.
”That would result in forests drying rapidly, grassland having an initial spurt of growth … and then drying. We could end up with a potentially serious situation,” he said.
Mr Ferguson said the amount of grass – a key fuel in bushfires – remained the biggest unknown. ”We’re coming off a very wet winter in the eastern part of the state. With the onset of warming, that could result on a significant flush of grass growth and then potential rapid drying of forest areas.” But ”if it’s warm and dry you may find there’s not a lot of grass growth at all”.
A dry spell over the next two months could also affect Victoria’s grain harvest. The president of the Victorian Farmers’ Federation Grains committee, Andrew Weidemann, said last month that the prospect of an El Nino was making farmers ”nervous”.
Melbourne’s water storages are well prepared for drought at 73.3 per cent, the highest they have been at this time of year since 1997.
This is good for reference in later months, which should prove how deluded climate models and climate scientists are.