Heat on world weather

By PHILIP ENGLISH

Last year was the planet's second-warmest since records began in 1860, continuing a trend towards rising global temperatures.

The 10 warmest years have all been since 1983, nine of them since 1990. The warmest on record is 1998.

New Zealand's National Institute of Water and Atmospheric Research (Niwa) and Britain's Hadley Centre and University of East Anglia Climate Research Unit analysed world temperatures to determine the global surface air temperature for the year.

The average temperature last year was 0.44 degrees C above the long-term average for the period 1961 to 1990.

Niwa scientist Dr Jim Salinger said temperatures were about 0.7 degrees higher than at the beginning of last century.

He said one explanation was a return to warmer water in the central and eastern equatorial Pacific Ocean following the end of the La Nina climate pattern last year. Another was global warming brought on by a build-up of greenhouse gases in the atmosphere.

The warmest year on record, 1998, was also the year of the strongest El Nino for 100 years. Scientists have identified conditions which could produce a new El Nino this year.

Dr Salinger said: "Should an El Nino occur, it's likely to be a fairly warm year, well above average globally."

nzherald.co.nz/climate

Intergovernmental Panel on Climate Change (IPCC)

United Nations Environment Program

World Meteorological Organisation

Framework Convention on Climate Change

Executive summary: Climate change impacts on NZ

IPCC Summary: Climate Change 2001