Perilous Times and
Climate Change
19 March 2012 Last updated at 12:37 ET
2010 now listed as world's hottest year
By Mark Kinver Environment reporter, BBC News
The Arctic is warming faster than any other region on the planet,
data shows
Researchers have updated HadCRUT - one of the main global
temperate records, which dates back to 1850.
One of the main changes is the inclusion of more data from the
Arctic region, which has experienced one of the greatest levels of
warming.
The amendments do not change the long-term trend, but the data now
lists 2010, rather than 1998, as the warmest year on record.
The update is reported in the published in the Journal of
Geophysical Research.
HadCRUT is compiled by the UK Met Office's Hadley Centre and the
Climatic Research Unit (Cru) at the University of East Anglia, and
is one of three global records used extensively by climatologists.
The other two are produced by US-based researchers at Nasa and the
National Oceanic and Atmospheric Administration (Noaa).
Cru's director, Phil Jones, explained why it was necessary to
revise the UK record.
"HadCRUT is underpinned by observations and we've previously been
clear it may not be fully capturing changes in the Arctic because
we have had so little data from the area," he said.
"For the latest version, we have included observations from more
than 400 (observation) stations across the Arctic, Russia and
Canada."
Prof Jones added: "This has led to better representation of what's
going on in the large geographical region."
Despite the revisions, the overall warming signal has not changed.
The scientists say it has remained at about 0.75C (1.4F) since
1900.
Kicking the bucket
Another change adopted in the HadCRUT dataset is the way sea
surface temperature (SST) is recorded, allowing scientists to
revisit and recalibrate past calculations.
With advances in technology in recent years, ships now have
electronic sensors that can accurately record SST.
This development has highlighted a systematic anomaly in
traditional methods of collating the data in the past.
This included differences in the buckets used to collect sea water
for measurement, and the locations where those measurements were
recorded.
Improvements in the way SST is collected has now allowed
scientists to recalculate data, making amendments to the data
collected in previous years.
"An example of this is the rapid change in the kinds of
measurements we see in the digital archives around the Second
World War," explained Peter Stott, head of climate monitoring and
attribution at the Met Office.
"Research has shown readings from buckets were generally cooler so
when the database changes from one source to another, you see
artifical jumps in the temperature.
"We have quantified these effects and corrected them, providing a
clearer view of the evolution of global temperatures."