EL NINO MADE 1997 HOTTEST YEAR TO DATE, SCIENTISTS SAY.
The vast pool of warm Pacific water called El Nino, coming on top of an underlying global warming trend, lifted the Earth's average surface temperature in 1997 to the highest levels ever recorded, government scientists reported Thursday.
The rise in temperature, measured in small fractions of a degree to about 62 degrees Fahrenheit, was not great and did not exceed the previous record by much, and several experts cautioned against making too much of it given the role of El Nino.
But they said that even if El Nino had not been a factor, the 1997 readings would have extended a broad, general trend that has made the 1990s the world's warmest decade since people began measuring temperatures with thermometers in the mid-19th century.
The planet's average surface temperature has increased by about 1 degree Fahrenheit in the 20th century. Mainstream scientists say emissions of heat-trapping gases like carbon dioxide, which is produced by the burning of coal and oil, are responsible for at least part of the warming trend. The government experts restated that judgment Thursday.
``We believe this tendency for increased global temperatures is related to human activity,'' specifically the gas emissions, Thomas Karl, senior scientist at the National Climatic Data Center in Asheville, N.C., said in announcing the latest temperature data at a briefing in Washington.
Other scientists pointed out that the warming trend was heightened last year by El Nino, the expanse of warm water that heated the surface of the tropical Pacific in the latter half of 1997 and continues to do so. The warmth imparted by El Nino accounted for most of the global temperature rise from 1996, not a year of record warmth, to 1997, said David Parker, a climate analyst at the British Meteorological Office.
Despite this, Parker said, ``the underlying warming trend is still there.''
According to the data presented by Karl, combined land and ocean temperatures averaged three-quarters of a degree Fahrenheit above normal last year and exceeded the previous record, set in 1990, by fifteen-hundredths of a degree. The actual average surface temperature last year was a little more than 62 degrees Fahrenheit, according to the report by the National Climatic Data Center.
Even while the globe as a whole warmed, analysts at the center said, the United States posted somewhat average temperatures, with the East and South generally cool and the West generally warm. On balance, ``it was a rather ho-hum year nationally,'' said William Brown, an analyst at the center.
Locally, weather experts were cautious about drawing conclusions on California's warm weather trends, but noted that in 1997 Los Angeles was 2 degrees warmer than in an average year.
The annual average air temperature for Los Angeles is 63 degrees, said Ken Reeves, a senior meteorologist for AccuWeather, a private weather forecasting service based in State College, Pa.
In 1997, the yearly average was 65, as registered at Los Angeles International Airport.
But Reeves pointed out that looking at previous years, Los Angeles had a cooling period in its air temperatures, which differ from surface temperatures. In 1992, the city's average temperature was 64.8 degrees, Reeves said. In 1993, it was 64.1 degrees; in 1994, the average was 63.9; in 1995, it was 64 degrees; and in 1996, the average temperature was 64.2.
But generally speaking, Southern California has been warmer than usual in the past couple of years, said Gary Ryan, a meteorologist at the National Weather Service in Oxnard.
The past November was particularly warm, Ryan noted, with mercury levels throughout Los Angeles County surpassing the century mark and records set all over Southern California. On Nov. 2, the Los Angeles Civic Center hit 99, making it the hottest day ever recorded there that late in the year.
A second report on the worldwide picture, issued by the British Meteorological Office, also showed that the average global temperature last year surpassed the previous record. In the British data set, the record year was 1995. The British figures did not include December readings, but because December was a warm month, experts at the meteorological office said they expected the new record to hold once the information is complete.
Because the two sets of figures contain slightly different data and were also analyzed differently, they produce slightly different results and different record years. But they both document an overall warming trend in both the 1980s and 1990s, the two warmest decades on record.
``You can take the temperature in the mouth or the armpit,'' said Robert Quayle, chief of the global climate laboratory at the Asheville center. However it is taken, Quayle said, ``the trend seems to be holding, and I think that's the chief conclusion.''
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|Publication:||Daily News (Los Angeles, CA)|
|Date:||Jan 9, 1998|
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