10 of 10 people found the following review helpful
A Snow job or a revelation?,
This review is from: Snowball Earth: The Story of the Global Catastrophe That Spawned Life as We Know it (Hardcover)
Gabrielle Walker's first book portrays the struggle of a renegade scientist to establish a theory of evolution's progress. Charles Lyell's established "uniformitarianism" in geology, followed by Charles Darwin's application of it in his theory of evolution by natural selection. The concept of gradual change in life as reflected in the fossil evidence is being challenged by some scientist. Paul Hoffman's research in Namibia indicated that Earth was subjected to an intense Ice Age prior to the Cambrian, severely interrupting life's progress. Walker introduces us to Hoffman and other major contestants in this game of reading the rocks. She presents him and the arguments with dynamic style, giving the book a certain panache.
Even under Walker's admiring scrutiny, Hoffman doesn't appear as an endearing figure. Yet, the very characteristics some find irritating are the same drives that kept the theory of Snowball Earth alive. Walker shows how combative science can be, with contenders sniping and quarreling like feuding families. They all have fossils, climate mechanisms and glacial processes on show. Walker attempts to give them all a hearing, but the opponents make but cameo appearances. She gathered her evidence by extensive journeys - her travel budget must have been prodigious. Walker reveals their peccadilloes and their strengths. When you are done, you feel a sense of identity, even intimacy with them.
Whether you are convinced of the thesis remains problematic. Walker's own sketchy knowledge forces a pause, wondering about the validity of her presentation. Her admission of being a "Snowball Earth groupie" erodes credibility. She offers many assertions as givens, such as the asteroid dinosaur extinction thesis. Theory popularity is good journalism, but sketchy science. Her journalist role leads her to overuse of buzzwords - "Slimeworld", the habit of bacteria to form mats - achieves fatiguing redundancy.
The predominant question, which Walker addresses only superficially, examines what process life underwent under these conditions. There was life before the Cambrian - clearly multi-cellular. How complex was it, and how resistant to the environmental crisis evoked by the Snowball Earth hypothesis? Ediacaran life was shallow sea bottom or surface dwelling. An ice blanket a kilometre or more thick would have been devastating to this population. Walker and her "group" are unable to form a coherent thesis of how life achieved complexity after the Snowball's meltdown, only that it must have happened - otherwise "we wouldn't be here". A valid statement, but one needing further support for how it might have occurred.
Walker's personalised account makes engaging reading, presenting a new idea needing more attention. While various modifications of the Snowball Earth notion have been offered, final judgment remains deferred. This is a good, but limited, overview of the debate and the participants. At some point, someone qualified will enlighten us further. [stephen a. haines - Ottawa, Canada]