It's a tie: Last year equaled 2005 as the warmest year on record, government climate experts reported Wednesday.
The average worldwide temperature was 1.12 degrees Fahrenheit (0.62 degree Celsius) above normal last year. That's the same as six years ago, the National Climatic Data Center announced.
Climate experts have become increasingly concerned about rising global temperatures over the last century. Most atmospheric scientists attribute the change to gases released into the air by industrial processes and gasoline-burning engines.
In addition, the Global Historical Climatology Network said Wednesday that last year was the wettest on record. Rain and snowfall patterns varied greatly around the world.
"The warmth this year reinforces the notion that we are seeing climate change," said David Easterling, chief of scientific services at the climatic data center. Nine of the 10 warmest years on record have occurred since 2000, he noted. The exception was 1998, which is the third warmest year on record going back to 1880.
Easterling said the data "unequivocally" disproves claims that climate warming ended in 2005.
The temperature readings are collected at land stations and from ships and buoys at sea. The "normal" reading they use is the average worldwide temperature for the 20th century, which was 57.0 degrees Fahrenheit.
Temperatures over land surfaces were the warmest on record last year, averaging 1.80 degrees Fahrenheit above normal, while ocean temperatures were the third warmest on record at 0.88 degrees above average.
A La Nina condition took effect at the last half of the year, marked by below normal temperatures in the tropical Pacific Ocean.
While it was the wettest year on record, Easterling declined to link warmer temperatures with the unusual moisture, commenting that much more research would be needed in that area.
Other findings in the annual climate report included:
- There were just seven named storms and three hurricanes in the Pacific, the fewest since the mid-1960s. On the other hand the Atlantic hurricane season was very active with 19 named storms and 12 hurricanes.
- Arctic sea ice cover was the third smallest since records began in 1979, trailing only 2007 and 2008. The ice cover is considered a marker of climate change as global warming tends to be seen first at the poles.
- Despite the overall warmth, 2010 saw record cold and snow in January and February in the Northern Hemisphere, particularly eastern North America.
- From mid-June to mid-August an unusually strong jet stream shifted northward, bringing an unprecedented two-month heat wave to Russia and adding to devastating floods in Pakistan.
- For the contiguous United States it was the 14th consecutive year with above average temperatures.
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