2005 warmest on record in north
This year has been the warmest on record in the Northern Hemisphere, say scientists in Britain.
It is the second warmest globally since the 1860s, when reliable records began, they add.
Ocean temperatures recorded in the Northern Hemisphere Atlantic Ocean have also been the hottest on record.
The
researchers, from the UK Met Office and the University of East Anglia,
say this is more evidence for the reality of human-induced global
warming.
Their data show that the average temperature during 2005 in
the Northern Hemisphere is 0.65C above the average for 1961-1990, a
conventional baseline against which scientists compare temperatures.
The
global increase is 0.48C, making 2005 the second warmest year on record
behind 1998, though the 1998 figure was inflated by strong El Nino
conditions.
The Northern Hemisphere is warming faster than the
south, scientists believe, because a greater proportion of it is land,
which responds faster to atmospheric conditions than the ocean.
Northern Hemisphere temperatures are now about 0.4C higher than a decade ago.
“The
data also show that the sea surface temperature in the northern
hemisphere Atlantic is the highest since 1880,” said Dr David Viner,
from the Climatic Research Unit at the University of East Anglia (UEA).
Error bar
No
measurements of average temperature can be completely accurate, and Dr
Viner believes the team’s calculations are subject to an error of about
plus or minus 0.1C.
However, he says, the long-term trend is clearly
upwards – rapidly over the last decade – indicating the reality of
human-induced global warming.
“We’re right, the sceptics are wrong,” he told the BBC News website.
“It’s
simple physics; more greenhouse gases in the atmosphere, emissions
growing on a global basis, and consequently increasing temperatures.”
However,
Fred Singer from the Science & Environmental Policy Project in
Washington DC, a centre of the “climate sceptics” community, disputed
this interpretation.
“If indeed 2005 is the warmest northern
hemisphere year since 1860, all this proves is that 2005 is the warmest
northern hemisphere year since 1860,” he told the BBC News website.
“It
doesn’t prove anything else, and certainly cannot be used by itself to
prove that the cause of warming is the emission of greenhouse gases.
“It
requires a more subtle examination to know how much of warming is due
to man-made causes – there must be some – and how much is down to
natural causes.”
Eight of the 10 warmest years since 1860 have occurred within the last decade.