This year is shaping up to be one of the warmest years on record so far, temperature measurements indicate.
The combined global land and ocean surface temperature was the warmest on record for both April and for the period from January through April, according to the U.S. National Oceanic and Atmospheric Administration, which has records going back to 1880.
The data suggests that 2010 will be in keeping with the recent trend of warmer-than-average years that have been linked to the heating caused by global climate change. Reports at the beginning of this year put the decade 2000 through 2009 as the warmest decade since 1880.
Throughout the last three decades, surface temperature data from NASA's Goddard Institute of Space Studies shows an upward trend of about 0.36 degrees Fahrenheit (0.2 degrees Celsius) per decade.
Based on NASA temperature records, 2005 is the warmest year on record, with a cluster of years — 1998, 2002, 2003, 2006, 2007 and 2009 — tied for second place.
Where 2010 will fall in the rankings will have to wait until December to be determined, but here is how the year is shaping up so far:
· The combined April global land and ocean average surface temperature was the warmest on record at 58.1 F (14.5 C), which is 1.37 F (0.76 C) above the 20th century average of 56.7 F (13.7 C).
· The combined global land and ocean average surface temperature was the warmest on record for January to April at 56.0 F (13.3 C), which is 1.24 F (0.69 C) above the 20th century average.
· Separately, the global ocean surface temperature was 1.03 F (0.57 C) above the 20th century average of 60.9 F (16.0 C) and the warmest on record for April.
· The global land surface temperature was 2.32 F (1.29 C) above the 20th century average of 46.5 F (8.1 C) — the third warmest on record for April. The most prominent warmth was in Canada, Alaska, the eastern United States, Australia, South Asia, northern Africa and northern Russia.
· Arctic sea ice was below normal for the 11th consecutive April, covering an average of 5.7 million square miles (14.7 million square kilometers) — 2.1 percent below the 1979-2000 average extent and the 15th smallest April extent since records began in 1979. It was, however, the largest April Arctic sea ice extent since 2001.
· The North American snow cover extent for the month was the smallest on record for April. Total snow cover over the Northern Hemisphere was the fourth-lowest on record (since 1967).
In other warming news, researchers in Antarctica recently reported that 2009 was the warmest year on record at the South Pole since record-keeping began there in 1957.