OUR dams are full, the lambs are fat and the sprinklers are running again. But weather experts are warning Australia’s east coast to brace for a return to dry conditions, perhaps even drought, as another El Nino event looms.
After two consecutive years of record rainfall and devastating floods brought on by La Nina, the Bureau of Meteorology warned yesterday that climate indicators show a shift towards drier weather patterns, and a potential swing to the opposite phenomenon, El Nino.
Warmer waters in the Pacific Ocean can trigger an El Nino, which brings less rainfall and drought such as the one that drained Warragamba dam to one-third of its capacity five years ago. Cooler waters bring on La Nina and associated wetter conditions, including those that spurred this year’s floods across NSW, and the devastating Brisbane floods the previous summer.
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A full moon rises over Clovelly as an El Nino weather pattern begins to dominate the forecast.3rd July 2012Photo: Wolter Peeters
Surface tension … waves wash onto Clovelly Beach last night under a full moon. Temperatures have been rising in the Pacific Ocean for the past few months, suggesting a return to El Nino and less rainfall. Photo: Wolter Peeters
A bureau climatologist, Acacia Pepler, said conditions along the equator were yet to reach El Nino thresholds, but most climate models were predicting the event would develop in late winter and early spring.
”The chances of us reaching El Nino are growing,” Ms Pepler said. ”It’s not certain yet, but probability is increasing as the weeks pass.”
But the Weather Channel, which measures the event using different indices, called the result early, declaring yesterday that El Nino had returned.
Climate change could alter the El Nino cycle in the Pacific, affecting fish stocks and the distribution of nutrients in the ocean, new research suggests.
Scientists recently noticed that El Nino warming is stronger in the Central Pacific than the Eastern Pacific, a phenomenon they call El Nino Modoki, after the Japanese term for “similar, but different.”
Last year, the journal Nature published a paper that found climate change is behind this shift from El Nino to El Nino Modoki.
While the findings of that paper are still subject to debate, a new paper in the journal Nature Geoscience presents evidence that El Nino Modoki affects long-term changes in currents in the North Pacific Ocean.
The research was done by Emanuele Di Lorenzo, associate professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology.
Michelle Galimba has been moving her livestock across her 10,000-acre Kuahiwi Ranch to higher elevation in Kau on the Big Island in hopes of finding better pastures during a drought that is causing her business and others hundreds of thousands of dollars in losses.
“It’s pretty severe,” she said. “I’d say half of the pastures on our ranch is unusable or going to be unusable very shortly.
“They’re literally turning to dust. The soil’s drying up and blowing away.”
Galimba said South Point received 1.76 inches of rain from January through mid-July, compared with its usual 12 inches.
The National Weather Service said 2010 is bringing the worst drought on record for ranchers and farmers in some parts of the state, including Kau.
“If they don’t have more rainfall at a higher rate in the second half, it could be the driest year on record,” said Kevin Kodama, senior hydrologist for the National Weather Service in Honolulu.