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| Environment News Service
GENEVA, Switzerland, (ENS) - The 1990s were, globally, the warmest decade since instrumental measurement started in 1860s, the World Metereological Organization (WMO) said in an end of millenium statement.
The 1990s were the warmest decade and the 1900s the warmest century during the last 1,000 years, the WMO said. The seven warmest years globally in the instrumental record have occurred this decade, with the warmest being 1998. The 1999 global mean combined land-surface air and sea surface temperature is estimated to be between 0.3 to 0.4 degrees Celsius above the 1961-1990 normal. That makes it the 5th warmest year in the 140-year record. 1999 will have been the 21st consecutive year with an above normal global surface temperature, and the ten warmest years have all occurred since 1983. The four warmest years were: 1998 (0.58 degrees Celsius above normal) 1997 (+0.44) 1995 (+0.38) 1990 (+0.35) The high temperature of 1999 is remarkable because it occurred despite the typical cooling influence of the tropical Pacific La Niña, which persisted throughout the year. The global mean annual temperatures at the end of the 20th century are almost 0.7 ºC above those recorded at the end of the 19th century. The regional temperature patterns from January 1999 through October show most of the globe with above average temperatures, except for the Northeast Pacific, equatorial east and central Pacific, western South America and northernmost parts of Eurasia. In central England, where the instrumental record extends back 341 years, it is likely that 1999 will be the warmest year ever. Records in Japan indicate that 1999 will be the 3rd warmest year in their 102-year record. In Canada, 1999 will likely be the second warmest since 1948. 1998 was the warmest. In June/July, Russia experienced one of its longest heat waves of the century, with record temperature departures from normal exceeding 5°C in June in central and north-western regions. Drought and heat led to the outbreak of numerous forest fires. In parts of northern and central Europe, September was the warmest in this century. Northern Germany recorded departures from normal of up to 4.5 degrees Celsius. In September, Norway had departures from normal up to five degrees Celsius and, in November, up to six to seven degrees Celsius.
By contrast, a cold snap in late January of this year brought some of the coldest temperatures experienced in Norway and Western Russia since the late 1800s.
The major 1997/98 El Niño Pacific Ocean warming gave way to La Niña conditions - colder than average equatorial Pacific sea surface temperatures - by mid-1998, which continued through late 1999. The La Niña is expected to continue well into 2000 according to most climate models. Such long-lived cold episodes don't occur often but this La Niña is not unique. Extended cold episodes characterized the periods 1954 to 1957, 1973 to early 1976 and late 1983 to early 1986. The evolution of the 1998/99 La Niña has been similar to, but much stronger than the 1983 to 1986 cold episode, which followed the extremely strong El Niño in 1982/83. The ozone depletion over Antarctica during the austral spring was again very strong this year. Extremely heavy precipitation had devastating consequences in many parts of the world.
Satellite Image: Space Science and Engineering Center More extensive information will be made available in the annual WMO booklet statement on the status of the global climate, to be published in time for WMO's 50th anniversary celebrations on WMO Day, March 23, 2000. Environment News Service: http://www.ens-news.com |
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