Two different plots of global temperature change over the past 130 years.
Weather agencies in Britain, the United Nations and the United States say the decade ending this year is almost certain to go down as the warmest since reliable record-keeping began in 1850.
The year 2009 could also place among the five-warmest on record, based on worldwide data collected through the end of November.
World Meteorological Organization Secretary-General Michel Jarraud told reporters gathering for the Copenhagen climate conference that this year will probably be the warmest on record in areas of central Africa and southern Asia.
The decade 2000-2009 “is very likely to be ... warmer than the 1990s, than the 1980s and so on," Jarraud told a news conference, referring to a chart (similar to those to the right) that plots global temperature trends curving steadily upward.