The analysis, by climatologists at the NASA Goddard Institute for Space Studies (GISS) in New York City, also showed that 2008 is the ninth warmest year since continuous instrumental records were started in 1880.
The ten warmest years on record have all occurred between 1997 and 2008.
The GISS analysis found that the global average surface air temperature was 0.44 degrees C (0.79 degrees F) above the global mean for 1951 to 1980, the baseline period for the study.
Most of the world was either near normal or warmer in 2008 than the norm.
Eurasia, the Arctic, and the Antarctic Peninsula were exceptionally warm, while much of the Pacific Ocean was cooler than the long-term average.
The research team noted that the relatively low temperature in the tropical Pacific was due to a strong La Nina that existed in the first half of the year.
La Nina and El Nino are opposite phases of a natural oscillation of equatorial Pacific Ocean temperatures over several years.
La Nina is the cool phase. The warmer El Nino phase typically follows within a year or two of La Nina.
"Given our expectation that the next El Nino will begin this year or in 2010, it still seems likely that a new global surface air temperature record will be set within the next one to two years, despite the moderate cooling effect of reduced solar irradiance," said James Hansen, director of GISS.
The Sun is just passing through solar minimum, the low point in its 10- to 12-year cycle of electromagnetic activity, when it transmits its lowest amount of radiant energy toward Earth.
The GISS analysis of global surface temperature incorporates data from the Global Historical Climatology Network of the National Oceanic and Atmospheric Administration's National Climate Data Center; the satellite analysis of global sea surface temperature of Richard Reynolds and Thomas Smith of NOAA; and Antarctic records of the international Scientific Committee on Antarctic Research.