2007 to Be Warmest Year on Record, Forecasters Say
for National Geographic News
|January 4, 2007|
An El Niño weather phenomenon combined with high levels of
greenhouse gases are likely to make 2007 the warmest year ever recorded,
British climate scientists said today.
U.S. government scientists agree with the assessment.
According to the British forecasters, 2007 will probably be 0.97 degree Fahrenheit (0.54 degree Celsius) above the long-term average of 57 degrees Fahrenheit (14 degrees Celsius).
The current record holder, 1998, was 0.94 degree Fahrenheit (0.52 degree Celsius) above the long-term average. (The average is calculated from the years 1961 to 1990.)
This is the seventh year that the United Kingdom Met Office's Hadley Centre for Climate Change in Devon has released their forecast. Over the years the forecast has been remarkably accurate, with a margin of error of 0.1 degree Fahrenheit (0.06 degree Celsius).
According to the researchers, there is a 60 percent chance that 2007 will be the warmest on record. (Related: "Global Warming Likely Causing More Heat Waves, Scientists Say" [August 1, 2006].)
David Parker is a climate-variability scientist with the Hadley Centre who helped prepare the forecast.
The new calculations add to the "ongoing evidence that global warming is real and is sort of getting worse," he said.
According to Parker, 2007's record-breaking warmth will result from an El Niño weather pattern that is riding on top of warmer global temperatures caused by greenhouse gas emissions. (Related: "Hurricane Season May Fizzle Further Due to El Nino" [September 5, 2006].)
El Niño is a periodic warming of the tropical Pacific Ocean off the northwest coast of South America that affects climate all around the globe.
"It puts more heat into the air, and that gets carried around the world by the wind," Parker said.
This warm El Niño air adds to global temperatures already boosted by increasing levels of greenhouse gases in the atmosphere, he added.
Scientists believe greenhouse gases, such as carbon dioxide produced from the burning of coal and oil, are driving up global temperatures by nearly 0.36 degree Fahrenheit (0.2 degree Celsius) per decade, Parker said.
So when El Niño warming combines with greenhouse gas warming, record-breaking heat is likely.
"Generally the greenhouse gas warming provides the long-term warming and the El Niño provides the interannual variability," Parker said.
There was a strong El Niño in 1998, the current warmest-year record holder.
Thomas Karl is the director of the U.S. National Oceanic and Atmospheric Administration's National Climatic Data Center in Asheville, North Carolina.
He said the British forecast makes sense given the moderate El Niño already in place.
"This, in combination with the observed and projected increases in atmospheric greenhouse gases, will likely produce a record warm year in 2007, averaged across the globe," he said by email.
Karl added that with each succeeding El Niño event, new warmest-year records are likely to be set.
"This does not imply that it is only during El Niños we could see new record highs. But in general temperatures will continue to rise as greenhouse gases increase," he said.
But, he added, a major volcanic eruption could throw thick clouds of light-blocking chemicals into the air and "upset such a prediction."
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