La Nina anomaly behind Australian drought
Pastor Dale Morgan
La Nina anomaly behind Australian drought*
GENEVA, Oct 31 (AFP) Oct 31, 2007
A long-running drought in Australia is linked to an unprecedented
climate pattern which has taken hold in the Pacific basin and Indian
Ocean, the UN weather agency said Wednesday.
The World Meteorological Organisation confirmed in a statement that a
"very clear" disruptive La Nina current was underway across the
equatorial Pacific Ocean, in line with its forecast in July.
It signalled that the event was associated with "climate-related risks"
which needed to be assessed locally in different regions around the world.
However, this year's La Nina differed by producing cooler than normal
sea temperatures off northern Australia and Indonesian islands -- the
opposite of what was expected -- and was unusually combined with
separate sea surface temperature shifts in the Indian Ocean.
"The drought that's going on in Australia right now is a very serious
drought and it is one of the atypical situations associated with this
particular La Nina event," said WMO climate specialist Leslie Malone.
"The textbooks would have said that Australia would have had a problem
with more precipitation than they could handle rather than less," she
told journalists, underlining that the current La Nina was "untypical"
La Nina usually combines tropical wind patterns over the Pacific basin
with cooler than normal sea temperatures off the west coast of Latin
America -- where the ocean is currently 1.5 degrees celsius below normal
-- and warmer sea temperatures in the western Pacific.
Like its Pacific sibling El Nino, it is widely credited with disrupting
weather even further afield.
Malone declined to be drawn on other disruptive effects of this year's
event but said the agency was issuing an update because there was "an
evolution with consequences for people around the world."
"Even in a moderate event there can be severe related impacts somehwere.
What is difficult to say is where," Malone said.
Asked if this year's combination had been seen before, Malone said:
"Since this is such a new pattern recognised in the scientific research
community, probably not."
She emphasised that scientists were unable to clearly tie it with
climate change.
La Nina is expected to continue into the first quarter of 2008.
The WMO had warned in July that La Nina was shaping up the second half
of 2007, with the potential for disruptive impact "of planetary scale."
Its scientists have also linked the pattern with unusually broad and
heavy seasonal floods that recently wrought havoc from East to West Africa.
The WMO is trying to build a global consensus of scientific opinion on
the pattern and impacts of La Nina and El Nino. "Before we can all sing
together, we need more research," said Malone.