In 2009, global surface temperatures were 1.01 degree above average, which tied the year for the fifth warmest year on record, the National Climatic Data Center said.

And that helped push the 2000-2009 decade to 0.96 degree above normal, which the agency said "shattered" the 1990s record value of 0.65 degree above normal.

The warmest year on record was 2005 at 1.11 degrees above normal.

The findings follow years of gradually rising global temperatures which atmospheric scientists attribute to the warming effect of gases released into the air by human activities, including burning fossil fuels.

Political leaders from around the world have been struggling to find a solution to this growing problem, most recently at the climate conference in Copenhagen, Denmark. Reaching agreement has been difficult amid fears of economic effects of any major change.