Sunday, June 20, 2010

The Chilling Stars – A New Theory of Climate Change

Review by Dr P D Hopewell, B.Eng, Ph.D, C.Eng, MIET

In recent years industry and the public alike have, rightly, become less tolerant of pollution and much progress has been made to 'clean up our act'. However there is a new cause for concern; climate change is now recognised to have a major impact on the world's people and economies. Publication of the authoritative and comprehensive 'Stern Review' in 2006 put the UK at the forefront of attempts to assess the economic cost of climate change, the costs of tackling global warming and the policies required to address the problem. With widespread acceptance in the media and Government of CO2 as the de-facto cause of climate change and global warming, it would seem to the layman that there is no longer any scientific debate or doubt about this assertion. Svensmark and Calder's book is one of the very few recent publications to
present an alternative view.

Given the strong emotions associated with global warming, Svensmark and Calder's work may be seen by many to be unfashionable at best, or irresponsible at worst. However, an open-minded reader is likely to be intrigued by the theories and analysis presented and may well begin to question the mainstream CO2 = global warming link.

Henrik Svensmark is one of a number of largely Danish researchers who have been investigating the subject now known as 'cosmoclimatology' for over a decade, so far with very little funding and recognition for their work. In the mid 1990s they identified a strong link between the rate of cosmic rays received into the Earth's atmosphere and the rate of cloud production. Furthermore, they corroborated the strength of cosmic rays with accepted proxies for temperature. They also used satellite data to develop an understanding of the repulsive effect of the Sun's magnetic field on the cosmic rays. From this work they deduced that a more magnetically active Sun (as indicated by high levels of sunspot activity) tends to deflect cosmic rays away from the Earth. This results in less cloud formation and hence more sunlight reaching the Earth, since cloud tops reflect light out of the atmosphere and in to space.

In 'The Chilling Stars', the authors cite archaeological evidence which suggests that the Earth's climate has often undergone rapid transitions, both cooling and warming. For example, summer 2003 saw the retreating perennial ice of the Schnidejoch in the Swiss Alps yield a 4700 year old archer's quiver. Subsequent finds demonstrated that the Schnidejoch had been unfrozen and open to human passage many times since the last Ice Age and that there were four periods during the past 5000 years that were warmer than the present day.

Over a period of hundreds of millions of years, Earth has experienced many climate change episodes, oscillating between icy and hot and Svensmark and Calder have unearthed evidence to link these to the changing levels of cosmic rays and their role in cloud formation. Indeed the authors argue that as the Earth, Solar System and Galaxy have travelled through space, the background of cosmic rays has played a major role in shaping the Earth’s environment since primordial times. When compared to these timescales and magnitudes, mankind’s potential for impact surely appears small.

Despite this, there is clear and unquestioned evidence that the Earth is presently undergoing a period of warming. However cosmoclimatolgy tells us that the human influence on the cause of such warming is much less than supposed in contemporary climate models (with the consequence that many of the worst excesses of rapid warming predicted should not come to pass). If this is indeed the case then it would surely be prudent to direct humanity's efforts towards adapting to a warmer world rather than trying to mitigate the unmitigatable. As Svensmark and Calder say, “...among the thousands of human generations, ours may be the first that was ever frightened by a warming.”

At risk of flying in the face of the received wisdom, the theory presented in this very readable book appears plausible and may withstand Occam's Razor equally as well as, if not better than, the mainstream CO2 explanation. Read it and draw your own conclusions, but be prepared for a possible change in your perception of global warming.

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