1998 global temperature - the highest by a wide margin

The earth’s temperature in 1998 was easily the highest in the global record reaching back to 1860. The final confirmed global mean temperature was 0.56°C above the recent long-term average based on the period 1961-1990. The previous warmest year globally, 1997, was 0.43°C warmer than average.

28 January 1999

Both the Northern and Southern Hemispheres also had their warmest years on record in 1998: respectively 0.64°C and 0.47°C warmer than normal. These results were announced today by NIWA (National Institute of Water and Atmospheric Research) in conjunction with UK’s Hadley Centre and the University of East Anglia’s Climate Research Unit.

Dr Jim Salinger, NIWA Senior Climate Scientist, said "The top ten warmest years have all been since 1983, with seven of them since 1990. 1998 has continued the gradual warming trend seen over the past 100 years: global temperatures in the 1990s are almost 0.7°C above those at the end of the 19th century."

"The leading features that caused the record global temperatures were the El Niño event in the tropical Pacific Ocean, which lasted until May, and the unprecedented warmth of the Indian Ocean."

"In the New Zealand region mean surface temperature calculated by NIWA was 13.40°C, a record 0.86°C above the 1961-90 average" said Dr Salinger. "This was caused by the record warmth of the Indian Ocean during autumn and winter, followed by the current La Niña event in the tropical Pacific Ocean, which developed during the winter of 1998. La Niña events give New Zealand warm weather. The combination produced more frequent warm westerlies and north-westerlies."

"Across the Tasman in Australia, 1998 was also the warmest year since high-quality data records began in 1910. The Australian mean temperature for 1998 was 22.54°C, 0.73°C higher than the average for the 1961-90 average period. This increase was greater than the previous highest of +0.69°C set in 1988."