Activity 'Not The Cause Of
By Steve Connor
11 July, 2007
that increased solar activity is the cause of global warming - rather
than man-made greenhouse gases - have been comprehensively disproved
by a detailed study of the Sun.
Scientists have delivered
the final blow to the theory that recent global warming can be explained
by variations in the natural cycles of the Sun - a favourite refuge
for climate sceptics who dismiss the influence of greenhouse-gas emissions.
An analysis of the records
of all of the Sun's activities over the past few decades - such as sunspot
cycles and magnetic fields - shows that since 1985 solar activity has
decreased significantly, while global warming has continued to increase.
Mike Lockwood, of the Rutherford
Appleton Laboratory in Chilton, Oxfordshire, said: "In 1985, the
Sun did a U-turn in every respect. It no longer went in the right direction
to contribute to global warming. We think it's almost completely conclusive
proof that the Sun does not account for the recent increases in global
The study, published today
in the journal Proceedings of the Royal Society A, shows there is no
doubt that solar activity over the past 20 years has run in the opposite
direction to global warming, and therefore cannot explain rises in average
Dr Lockwood and his colleague
Claus Fröhlich, of the World Radiation Centre in Davos Dorf, Switzerland,
have produced the most powerful counter argument to suggestions that
current warming is part of the natural cycle of solar activities. "There
is considerable evidence for solar influence on Earth's pre-industrial
climate, and the Sun may well have been a factor in post-industrial
change in the first half of the last century," they write.
However, since about 1940
there has been no evidence to suggest that increases in global average
temperatures were caused by solar activity. "Our results show that
the observed rapid rise in global mean temperatures seen after 1985
cannot be ascribed to solar variability, whichever of the mechanisms
is invoked and no matter how much the solar variation is amplified,"
the two scientists said.
The theory that past changes
in solar activity may have explained some changes in the climate before
the industrial revolution is not in dispute. In previous centuries,
for instance, notably between about 1420 and 1570, when the Vikings
had to abandon their Greenland settlements, solar minima corresponded
with unusually cool weather, such as the "little ice age"
of the 17th century.
But climate sceptics have
exploited this to dispute the idea that man-made emissions are responsible
for global warming. In the recent Channel 4 programme The Great Global
Warming Swindle, the rise in solar activity over the latter half of
the 20th century was erroneously presented as perfectly matching the
rise in global average temperatures.
Dr Lockwood said he was outraged
when he saw the documentary, because of the way the programme-makers
used graphs of temperature rises and sunspot cycles that were cut off
in the 1980s, when the two trends went in the opposite direction.
"The trouble is that
the theory of solar activity and climate was being misappropriated to
apply to modern-day warming. The sceptics were taking perfectly good
science and bringing it into disrespect," Dr Lockwood said.
The Royal Society said yesterday:
"There is a small minority which is seeking to confuse the public
on the causes of climate change. They are often misrepresenting the
science, when the reality is that the evidence is getting stronger every
© 2007 Independent News
and Media Limited
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