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Researchers at the
University of Tromsø
have undermined a
hypothesis that claims
that it is the Sun, and not
greenhouse gases, that
causes global warming.
Is climate change
man-made or is global
warming due to solar
insolation?
Climate change can be confusing, especi-
ally because a number of researchers have
come forward and criticized the UN Panel
on Climate Change (IPCC) – which is
enough to confuse anyone.
"The effect of solar activity on climate
change is one of the things for which there
remains some uncertainty in the IPCC's
work," says Kristoffer Rypdal, a physics
professor at the University of Tromsø, who
is currently debating the issue with physi-
cists Nicola Scafetta and Bruce West.
Is the Sun's effect under
estimated?
In 2008, Scafetta and West published an
article entitled "Is climate sensitive to solar
variability?" The article argues in support
of their hypothesis that there is a subtle
complex link between the Sun's activity
and variations in the Earth's climate. In
essence, this hypothesis means that solar
activity plays a crucial role in climate
change on Earth. The two researchers used
a statistical review of variations in soil
temperature and solar radiation to support
their view.
The Sun can account for as much as 69 per
cent of the increase in the Earth's average
temperature. Some forecasts predict that
the Sun will cool over the next few deca-
des. Scaffetta and West believe this is good
news because this cooling will stabilize
the Earth's climate and we will avoid the
disastrous consequences predicted in the
IPCC's report.
They believe that the IPCC has grossly
underestimated the Sun's influence on
global warming.
"Scafetta and West are very active
advocates for the Sun as the crucial factor
in determing climate, and they are very
skeptical about global warming. The
methods they use are also quite unfa-
miliar to climatologists who argue that
it is greenhouse gases that cause global
warming. That means that climatologists
often don't have the right scientific tools
to contradict Scaffetta and West, and
have largely ignored their research. In any
case, this research focuses on complexity
linking. My colleagues and I have much of
the same academic background as Scafetta
and West, and we wondered about their
interpretation of the statistical data," says
Rypdal.
Complex relationships
With his son, mathematician Martin
Rypdal, Rypdal decided to investigate the
statistical arguments that Scafetta and
West use to support their hypothesis. In
their article "Testing Hypotheses about
the Sun-Climate Complexity Linking " in
14
•••
Labyrint E/11
– University of Tromsø
Should we blame
the sun?