1997 Registers on the Cool Side,
According to Satellite Global Temperature Data

Surface Readings, Affected by Early Onset of El Nino,
Show Contrasting Warm Weather Record

SEPP News Release
Contact: Candace C. Crandall
Tel: (703) 503-5064
e-mail: crandall@sepp.org

FAIRFAX, VIRGINIA, JANUARY 8, 1998---Temperature readings taken from U.S. Weather satellites, the most reliable and only global temperature data available, put 1997 among the coolest years since satellite-based measurements began in 1979. With December readings finally in, the year ranked 7 out of 19, with 1 being the coldest, according to a news release from The Science & Environmental Policy Project, a research group based in Fairfax, Virginia.

Satellite readings continued to show the slight downward trend seen over the past two decades, in contrast to ground-based data, which are strongly affected by the so-called "urban heat-island" effect, and show a warming. But for 1997, not only the urban heat island effect but also the early onset of the El Nino, a warm-water current in the eastern Pacific profoundly affecting global climate patterns, helped push surface readings to a new record, .05 degree C above the previous record set in 1995.

Confounding the picture, although the British Meteorological Office confirmed in late 1997 that warmer temperatures were due to the El Nino, there has also been record cold in many locations. Last July saw record Antarctic lows (likely not an El Nino effect), Moscow has just experienced the coldest December in a century, and heavy snow has already fallen across Mexico and the southern United States. Moreover, climatologist Thomas Karl, of the National Oceanic and Atmospheric Administration (NOAA), demonstrated in a research paper published in 1989 that when U.S. surface temperatures are corrected for the urban heat Island effect, the years around 1940 emerge as the warmest, with readings since then showing a downward trend.

But the additional impact of the El Nino is expected to be short-lived," according to Dr. Patrick Michaels, climatologist with the University of Virginia. "Usually El Ninos begin in the early winter and spread over two calendar years," says Michaels. "This one began in late spring and will be largely confined to one year." While this accentuates the El Nino's effect on global average temperatures for 1997, it also means that change is in the offing. The latest NOAA data show a weakening of the El Nino and, according to Michaels, forecasters already surmise that the cold phase--the "La Nina"--will predominate in 1998, lowering global surface temperature significantly.

For a copy of Thomas Karl's graph (from "Urban bias in area-averaged surface air temperature trends," T.R. Karl and P.D. Jones, Bulletin the of American Meteorological Society, 1989) contact Candace Crandall at (703) 503-5064. The Science & Environmental Policy Project, a non-profit, policy research group based in Fairfax, Virginia, was founded in 1992 to foster greater reliance on sound science in decisions affecting health and the environment.

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