2008 Set To Be About 10th Warmest Year - Expert
NORWAY: November 12, 2008
OSLO - This year is on track to be about the 10th warmest globally since
records began in 1850 but gaps in Arctic data mean the world may be slightly
underestimating global warming, a leading scientist said on Tuesday.
A natural cooling of the Pacific Ocean known as La Nina kept a lid on
temperatures in 2008 despite an underlying warming trend, said Phil Jones,
director of the Climatic Research Unit at the University of East Anglia in
England.
"This year is about 10th," he told Reuters in a telephone interview. "La
Nina in the Pacific lasted longer than we envisaged."
Jones's unit is one of the main sources of global climate data for the
United Nations.
The warmest year on record was 1998, followed by 2005 and 2003, with other
years this century closely bunched. Tenth place would make 2008 the least
warm since 1999.
The update marginally cools an estimate from January, when Jones's unit and
the British Met Office (Britain's meteorological service) estimated that
2008 would be "another top 10 year", near the bottom of the ranking.
The UN Climate Panel says human emissions of greenhouse gases, mainly from
burning fossil fuels, are blanketing the planet. Rising temperatures will
bring more floods, heatwaves, more powerful storms and rising sea levels, it
says.
Jones said temperature records may fractionally underestimate warming
because of gaps in measurements in the Arctic for 1961-90, the benchmark
years for judging change, and problems in verifying ocean temperatures.
"The world is probably a little warmer than we are measuring," he said.
ICE THAWS
Arctic sea ice shrank to a record low in summer in 2007 and almost matched
the low again in 2008. UN studies say the region may be warming twice as
fast as the world average.
Ships are travelling more often in the Arctic and "now there are temperature
measurements coming back. But we can't use the data because we don't have
the 1961-90 averages", he said.
He said scientists suspected that ocean temperature measurements from buoys,
widely deployed since about 1990, underestimated temperature rises perhaps
by up to a 0.05 Celsius (0.08 Fahrenheit), compared to previous ship-based
readings.
"There's nothing wrong with the land measurements but we might be
underestimating the oceans," he said.
Scientists were now scouring records of ships over the past 15 years to try
to pin down when they were close to buoys. That would let them compare
thermometer readings and see if there was a consistent mismatch.
"It's an awkward thing to try to find them when they were close together,"
Jones said, adding that the hopes the findings will be published in 2009.
Sceptics about a human cause of global warming say climate change has
stopped because 1998 was the warmest year. But Jones said 1998 was warmed by
a shift in the Pacific Ocean known as El Nino, the opposite of the La Nina
effect.
"1998 was the anomalous year. if you take out the El Nino and La Nina
effects we are still warming," he said.
Natural variations such as El Nino or volcanic eruptions that dim the sun
accounted for swings of about 0.2 C a year, while global warming was adding
about that much per decade.
-- For Reuters latest environment blogs click on: http://blogs.reuters.com/environment/
(Editing by Michael Roddy)
Story by Alister Doyle, Environment Correspondent
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