Researchers Warn of Major Climate Shift

By MATTHEW FORDAHL
.c The Associated Press

LOS ANGELES (Jan. 19) - Unusual weather driven by La Nina cooling in the 
Pacific Ocean may be part of a larger, longer-lasting climate shift, 
researchers said Wednesday after analyzing new satellite data.

If the interpretation is correct, the Southern states, as well as the 
Southwest, could be in for 20 years or more of mild and relatively dry 
winters while the Pacific Northwest and the East could get socked by strong 
winter storms.

Measurements of sea surface temperature show warm water has been developing 
for the last 1 1/2 years in the North, West and South Pacific. La Nina and El 
Nino, its warmer cousin, affect water only near the equator.

''The persistence of ... warmer and colder than average ocean temperatures, 
tells us there is much more than an isolated La Nina occurring in the Pacific 
Ocean,'' said William Patzert, an oceanographer at NASA's Jet Propulsion 
Laboratory.

The Pacific Ocean's surface water temperature is a dominant force behind 
storm intensity as well as the path of the jet stream. The new satellite data 
suggest a shift in the water temperatures. Every 20 years or so, dominant 
warm or cool water flip-flops for reasons still unclear, changing weather, 
especially in North America.

One result of the shifts is that conditions favor either El Nino or La Nina. 
Since the 1970s, the ocean has been in what is called a positive phase, 
marked by warm surface water in the tropics and cooler water in the North 
Pacific. El Ninos are more common.

But many experts argue it's too early to make any conclusions. The unusual 
ocean temperatures may be from a lingering La Nina and not necessarily a sign 
the Pacific is entering a negative phase of cool tropical water and warm 
North Pacific temperatures.

''The point is it won't be for another 10 years before we can say with 
confidence that we've undergone a regime shift,'' said Wayne Higgins, senior 
meteorologist at the U.S. Climate Prediction Center in Camp Springs, Md.

David Battisti, atmospheric sciences professor at the University of 
Washington, agreed.

''It is not at all clear that the pattern that is seen this particular winter 
is part of a decadal change, he said.

AP-NY-01-19-00 1937EST