The dreaded storm strikes the Pacific and the threat of destruction looms large
EL NINO, the reversal of ocean currents
across the Pacific that periodically
disrupts the world's weather, has won
another round of its cat-and-mouse
game with climate modellers by sneaking up largely unseen. In the past
two months, waters in most of the tropical Pacific have warmed dramatically,
by up to 2'c in places, as surface water
from the western Pacific and storm
systems that normally remain over
Indonesia have migrated eastwards.
The events herald the onset of a new
El Niho, according to an alert issued
earlier this month by the us National
Oceanic and Atmospheric Administration (NOAA).
"The consequences will probably be
felt worldwide over the coming year,"
says David Parker, an El Niho tracker at
Britain's meteorological office, Black-
well. The new El Niho will increase the
risk of serious drought in Australia,
India, Brazil and East Africa. It will also
heighten the danger of torrential rain
and floods in American deserts from
Peru to California, and of forest fires in
Indonesia (New Scientist, Vol 154, No 2084).
El Niho will also add to global
warming. "So far, 1997 is already the
second warmest year ever, so we could
see a new record," says Parker. The
warm surge will probably peak at the
end of the year -just in time for the climax of negotiations at a meeting of the
UN Convention on Climate Change in
Japan in December, which is scheduled
to approve tough new emissions standards for greenhouse gases.
Many climate modellers who have
prided themselves on predicting El Nifio
up to a year ahead have been caught out
this time. "We are scratching our heads
as to why our models didn't anticipate
it," says Stephen Zebiak of the Lamont-Doherty Earth Observatory at Columbia
University,_New York. Zebiak and his
colleague Mark Cane, widely regarded
as the world's top El Niho forecasters,
successfully predicted the onset of the
last two major El Niho events, in 1987
and 1991.
But they failed to predict that the
1991 El Niho would remain for an
unprecedented three years, rather than
the normal nine months or so. And
now the latest event has eluded them -
last November, their forecast was for
11 cooler than-normal conditions through July 1997".
"Our most recently revised
model still isn't seeing it,"
says Zebiak. "It is predicting an El Niho for 1998," he adds.
He has one hope, though:
"It is just possible that this
will prove to be a false start.
Sometimes, it looks like an El
Niho is beginning and then it
falters, returning for real the
following year. Otherwise, its
back to dravhng board. We'll
need to look in detail both at
the model and the data we
put into it."
Most other teams of El Niho forecasters are in the
same position. The failures
suggest a hard task ahead for
climate prediction, being set
up by NOAA, with collaborators from Australia, Brazil, Japan and
Taiwan. The institute's first task is to
improve the forecasting of El Nifio.
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