This year will be the Earth's third or fourth warmest since global temperature records began more than a century ago.
The finding, by British scientists, adds weight to the theory that pollution has already made a detectable difference to climate. Last year was also a very warm year in Britain.
The Meteorological Office is forecasting that it will turn out to be among the 10 warmest years in the central England temperature records, which stretch back to 1659.
The Eighties and the first five years of the 1990s have been the planet's hottest years since about 1860 when reliable temperature records began to be kept for most of the planet's land and sea surfaces.
The warmest year was 1990; almost 0.4 degrees Centigrade above the average for 1951 to 1980, according to scientists at the Met Office's Hadley Centre for Climate Prediction and Research and the University of East Anglia.
They analyse millions of temperature measurements from more than 1,000 weather stations on land and from ships at sea to produce a global average monthly temperature. The next warmest year was 1991.
And, with 11 months data already analysed for 1994, the scientists believe this year will either be third equal with 1988 or just behind in fourth place - at 0.31C above the 1951 to 1980
average of just under 15C. Of the 10 warmest years in the 135- year global record, all but one (1944) have occurred since 1980.
"Nobody really denies that there has been a warming in the 1980s and 1990s," said Dr David Parker, of the Hadley Centre. "The question is whether it's part of the natural variability of the climate system or man-made global warming."
A build-up of carbon dioxide and other man-made `greenhouse gases', such as methane and nitrous oxide, is expected to raise temperatures across most of the globe.
These pollutants, mostly produced by the burning of fossil fuels and tropical forests, act as a heat trap. Their steady accumulation in the atmosphere has been measured over the past few decades. …