Top 11 warmest years have all occurred in the last the 13 years, according to preliminary global temperature figures for 2007 released by the University of East Anglia and the Met Office's Hadley Centre.
The preliminary global figure for 2007 is based on climate data from January to November, which presently places the year as the seventh warmest on records dating back to 1850.
The declaration comes as the Secretary-General of the World Meteorological Organization (WMO), Michel Jarraud spoke at the Conference of the Parties (COP) in Bali.
Researchers and politicians have been in Indonesia discussing plans to cut greenhouse gas emissions that have been associated with rising global temperatures.
"The last few days have provided an important platform for debate and confirms the need for swift action to combat further rises in global temperatures because of human behaviour," Dr Vicky Pope from the Met Office Hadley Centre has been attending the conference and said.
The last time annual mean global temperatures were below the 1961-1990 long term average was in 1985. Since then, mean surface air temperatures have continued to demonstrate a warming trend around the world. 2007 has been no exception to this, even though there has been a La Nina event, which usually reduces global temperatures.
Professor Phil Jones, Director of UEA's Climatic Research Unit, said: "The year began with a weak El Nino - the warmer relation of La Nina - and global temperatures well above the long-term average. However, since the end of April the La Nina event has taken some of the heat out of what could have been an even warmer year".
In January, the Met Office, in conjunction with the University of East Anglia, predicted that 2007 could record global temperature well above the long-term average. There was also a 60 percent probability that 2007 could be the warmest on record and the expected temperature for 2007 is within the range predicted.
"2007 was warmer in the Northern Hemisphere, where the year ranks second warmest, than the Southern Hemisphere, where it ranks ninth warmest," Professor Jones said.
Met Office Climate Scientist David Parker added: "This year has also seen sea-ice extent in the Northern Hemisphere below average in each month of 2007, with record minima sea-ice reported in July, August and September. In the Southern Hemisphere, sea-ice coverage has remained close to average".