Next year could be the warmest since records began, figures released by the Meteorological Office suggest.
Global temperatures in 2003 are forecast to exceed those in 1998, the hottest year to date, when thermometers rose partly because of the El Niño effect, a weather phenomenon caused by the Pacific Ocean warming up.
Last year was the second- warmest year on record and nine of the 10 hottest years have now been since 1990.
In Britain in the past 12 months, Met Office figures have shown the mean central England temperature was 10.5C (51F) – only 1949, 1990 and 1999 were warmer.
Phil Jones, of the Climatic Research Unit at the University of East Anglia, which compiles weather data with the Met Office, said: "Globally, warm years generally occur during the latter stages of El Niño events in the eastern equatorial Pacific Ocean.
"The warmth of 2002 is remarkable considering how small this effect was during much of the year, compared with the influence of the large 1997-98 El Niño event in the record breaking year of 1998. Given that a moderate El Niño event is taking place, there is a good chance that 2003 will be warmer than 2002."
The Met Office's Hadley Centre for Climate Prediction and Research has forecast the global surface temperature in 2003 will be 0.55C above the average temperature for 1961-90.
A Met Office spokesman said this prediction was the same for the warmest year, 1998, and there was a 50 per cent chance that 2003 would be warmer than four years ago.
Average global temperatures have risen by more than 0.6C over the past 100 years and it is thought the warming over the past 50 years is mainly due to activities such as the burning of fossil fuels.
If weather conditions over the oceans are excluded, the temperature in 2002 equalled 1998, when the average land air reading was 0.88C above the average for 1961-90.
* Householders in areas of southern England were being warned yesterday that heavy rain could lead to widespread flooding. Parts of Kent and Sussex were still saturated with water despite a largely dry weekend and experts fear that rivers will struggle to cope.
Ray Kemp, an Environment Agency spokesman, said: "We are quite worried. There have been no problems today but the ground remains saturated.
"If the forecast rain stays then there will almost certainly be some flooding. If we get less than an inch the system may just about cope with it but any more than that and there will be problems." The alert follows heavy rain on Thursday night, which led to flood warnings on a part of the Medway in Kent and the Ouse in East Sussex.