[asa] The Chilling Stars A new theory of climate change (Book Review)

From: Janice Matchett <janmatch@earthlink.net>
Date: Sun May 20 2007 - 17:18:13 EDT

More reviews here:
The Chilling Stars A new theory of climate change
- Henrik Svensmark & Nigel Calder

~ Janice

The Chilling Stars A new theory of climate change (Book Review)
Popular Science UK ^ | Brian Clegg
Posted on 05/17/2007 8:26:05 AM EDT by Valin

The Chilling Stars A new theory of climate change
- Henrik Svensmark & Nigel Calder

Every once in a while you come across a book that
really makes you think, because it presents a
theory that's a surprise, yet the more you read
the text, the more it seems to make sense. The
Chilling Stars is just such an book. In it,
science journalist Calder and scientist Svensmark
put forward a striking case for the argument that
cosmic rays - high speed particles from outside
the solar system - have a huge impact on our global temperature.

At first sight this seems crazy, and Svensmark
and his colleagues had to put up with a huge
amount of resistance when they initially came up
with their theory, but with time, many
observations have raised the likeliness of this
theory to something like that of dark matter -
one that we aren't certain of, but has a lot in its favour.

The idea is that these high energy particles (or
more precisely the secondary particles that are
generated when the cosmic rays impact the
atmosphere) act as triggers for cloud formation.
When there are a lot of cosmic ray particles
getting through, there are more clouds, when
there are less cosmic rays there are less clouds.
This is significant for climate change because
low clouds cool the planet. This is frustrating
for climate change modellers because, though
mostly recognizing that low clouds do have a
cooling effect, climate change models can't
predict cloud effects, so tend to ignore them.

The level of cosmic ray bombardment we suffer is
largely in the hands of two mechanisms - the
sources out in the galaxy from which the cosmic
rays originate, and the Sun. The solar wind
provides us with a barrier that significantly
reduces cosmic ray impact on the Earth.
Variations in both mechanisms have resulted in
big changes in the cosmic ray impact on the
Earth. Svensmark and his colleagues have evidence
that strongly suggests a link between cosmic ray
levels and historical warming and cooling. The
result is a whole new take on global warming.

Perhaps the only unfortunate aspect of the book
is a bitter approach to conventional climate
change scientists, who are portrayed as having a
vested interest in showing that carbon dioxide
levels are the only driver of global warming.
It's particular sad that the book was used as
part of the basis for a much criticized and
highly unbalanced TV documentary that didn't do
justice to Svensmark's theories because of its
negative attitude to human-caused climate change
theories. It seems likely that both mechanisms
have contributed to recent climate change effects
- and Calder and Svensmark don't do enough to
reflect the increasing reality of climate change
impact on the world - but it's not surprising
they are a little defensive after the reception
this theory first received. It's important to
stress that this book's theory could well provide
an explanation for the cycles of heat and cold
that have happened in the Earth's past, but that
cosmic ray climate change cannot be used in an
attempt to dismiss the major contribution of
human-caused global warming: this is now pretty well universally accepted.

I would also say, although Calder uses the tricks
of a good science writer, bringing in a human
touch on a regular basis, The Chilling Stars
doesn't always sparkle as a great popular science
book should - but I think the importance of the
subject and the fascinating nature of the tie-in
of cosmic rays to Earth weather is more than
enough to overcome this and make this a well-deserved five star read.

Reviewed by Brian Clegg

By Henrik Svensmark & Nigel Calder

1 A lazy Sun launches iceberg armadas

Our ancestors endured shocking variations in
climate - Events often matched changes in the
Sun’s behaviour - Rare atoms made by cosmic rays
signal those changes - When their production
increased, the world was chilled - But are the
cosmic rays the agent, or merely a symptom?

A less public-spirited finder might have put the
oddity up for sale on eBay, so the archaeologists
of Bern Canton were grateful when Ursula
Leuenberger presented them with an archer’s
quiver made of birch bark. They were amazed when
radiocarbon dating showed the quiver to be 4,700
years old. Frau Leuenberger had picked it up
while walking with her husband in the mountains
above Thun. There, the perennial ice in the
Schnidejoch had retreated in the unusually hot
summer of 2003, revealing the relic hidden beneath it.

The hiking couple had unwittingly rediscovered a
long forgotten short-cut for travellers and
traders across the barrier of the Swiss Alps. To
keep treasure-hunters away, the find remained a
secret for two years while archaeologists scoured
the area of the melt-back and analysed the finds.
By the end of 2005 they had some 300 items - from
the Neolithic Era, the Bronze Age, the Roman period and medieval times.

The various ages of the items clustered in
intervals when the pass of Schnidejoch was open,
offering a quick route to and from the Rhone
valley south of the mountains. There were no
substantial human remains to compare with the
murdered Ötztal ‘ice man’, found with a similar
quiver high in the Italian Tyrol in 1991 and
dated to 3300 BC. But the emergent history of
repeated openings and closures of Schnidejoch
gave a far more interesting picture of climate change.

The Ötztal man is a prize exhibit for those who
assert that the climate at the start of the 21st
century is alarmingly warm. The ice that
preserved his mummified corpse lay unmelted,
3,250 metres above sea level, for more than 5,000
years - since the world was in its warmest phase
following the most recent ice age. Then, so the
story goes, the manmade global warming of the
industrial era outstripped all natural variations
and released the body as a warning to us all.

Quite different is the impression given by the
relics found in the pass of Schnidejoch, at an
altitude 500 metres lower than the Ötztal man’s
ice-tomb. They tell of repeated alternations
between warm periods when the pass was useable
and cold periods when it was shut by the ice. The
discoveries also cleared up a long-standing
mystery about a Roman lodging house found on the
slopes above the present-day town of Thun, where
there was a Roman temple and settlement. The head
of the cantonal archaeological service, Peter
Suter, explained his satisfaction at the outcome:
‘We always asked ourselves why the lodging house
was there. Now we know that it was on the route
leading across the Schnidejoch.’

The youngest item found by the archaeologists was
part of a shoe dating from the 14th or 15th
century AD. It corresponds with the end of an
interval known as the Medieval Warm Period.
Thereafter the Schnidejoch was blocked by the
glaciers of the Little Ice Age, the most recent
period of intense cold. Nominally the Little Ice
Age ended around 1850, but the gradual retreat of
the ice took a century and a half to clear the
pass, until its rediscovery early in the 21st century.

Here is a tale of natural variations in climate
having a practical influence on the lives and
travels of Europeans over 5,000 years. The
climate was particularly cold in two periods
around 800 BC and 1700 AD. Effects of the latter
episode, the Little Ice Age, persisted in the
Schnidejoch for so long that even the locals
forgot that a useful pass was ever there.

The Medieval Warm Period and the Little Ice Age
were an embarrassment for those who, in recent
years, wished to play down the natural variations
in climate that occurred before the Industrial
Revolution. A widely publicised but now
discredited graph of temperatures, produced in
1998 by Michael Mann of the University of
Massachusetts and his colleagues, tried to iron
out the variations. Lampooned as the hockey
stick, Mann’s graph showed the world remaining
almost uniformly cool through most of the past
1,000 years until 1800. Then temperatures began
to climb towards unprecedented highs in the late
20th century - so making the toe of the hockey
stick and the supposed onset of an unprecedented
episode of man-made global warming.

The relics from the Schnidejoch mock this
Orwellian effort to make real-life events that
were not politically correct disappear from
climate history. They show that warming spells
very like that of the past 100 years occurred
repeatedly, long before the large-scale use of
fossil fuels and the associated emissions of
carbon dioxide gas were a possible factor.
Attempts to argue that such events were not
global are contradicted by abundant evidence for
the Medieval Warm Period and the Little Ice Age
from East Asia, Australasia, South America and
South Africa, as well as from North America and
Europe. Probing the errors that generated the
hockey stick can be safely left to the
statistical pathologists, while we explore the
character and rhythms of climate change over centuries and millennia.

Sunspots missing in the Little Ice Age

Atomic bullets raining down from exploded stars,
the cosmic rays, leave behind them business cards
that record their split-second visits to the
Earth’s atmosphere. They take the form of unusual
atoms created by nuclear reactions in the upper
air. Especially valued by archaeologists as an
aid to dating objects is radiocarbon, or
carbon-14, made from nitrogen in the air.

Taken up into carbon dioxide, the gas of life by
which plants grow, the carbon-14 finds its way
via the plants and animals into wood, charcoal,
bones, leather and other relics. The initial
carbon-14 content corresponds to the amount
prevailing in the air at the time of death. Then,
over thousands of years, the atoms gradually
decay back into nitrogen. If you see how much
carbon-14 is left in an old piece of wood or
fibre or bone, you can tell how many centuries or
millennia have elapsed since the plant or animal was alive.

There’s a snag about this gift from the stars, as
archaeologists soon discovered. Some of their
early radiocarbon dates seemed nonsensical, even
contradictory - for example, a pharaoh of Egypt
dated as being younger than his known successors.
Hessel de Vries of Gronigen found the explanation
in 1958. The rate of production of carbon-14
varies. Measurements in well-dated annual rings
of growth in ancient trees sorted out the
problem, and the archaeologists had more
reliable, though often ambiguous dates. And
physicists could see changes over thousands of
years in the performance of the Sun, as the chief
gatekeeper of the cosmic rays. Its magnetic field
protects us by repelling many of the cosmic rays
coming from the Galaxy, before they can reach the
Earth’s vicinity. The variations that confused
the archaeologists followed changes in the Sun’s
mood. Low production rates of carbon-14 meant
that the Sun was very active, magnetically
speaking. When it was lazy, more cosmic rays
reached the Earth and the production of carbon-14 shot up.

The discovery opened the way to modern
interpretations of the link between the Sun and
the Earth’s everchanging climate, beginning in
the 1960s. Roger Bray of New Zealand’s Department
of Scientific and Industrial Research traced the
variations in the Sun’s activity since 527 BC. He
was able to connect increased production of radio
carbon by cosmic rays to other symptoms of feeble solar magnetic activity.

A scarcity of dark spots on the face of the Sun,
which are made by pools of intense magnetism, was
one such sign. Reports of auroras, which light
the northern skies when the Sun is restless, were
also scanty when the cosmic rays were making lots
of radiocarbon. And most significantly, Bray
linked solar laziness and high cosmic rays with
historically recorded advances of glaciers,
pushing their cold snouts down many valleys. The
advances were most numerous in the 17th and 18th
centuries, which straddled the coldest period of the Little Ice Age.

2 posted on 05/17/2007 8:27:35 AM EDT by Valin

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