Snowball Earth : The Story of a Maverick Scientist and His Theory of the Global Catastrophe ThatSpawned Life As We Know It

Rating:
Summary: A Biography and Detective Story, Plus a Little Science
Review: I will start with a brief synopsis of the science. In the last six years, many scientists have come to think that an ice age of incredible severity gripped the Earth for a few million years, ending about 590 million years ago. The ocean surface apparently froze all the way to the equator, although the ice may have been thin and patchy near the equator. The Earth's average temperature was about -40 degrees Fahrenheit. Volcanoes belched out greenhouse gases for a few million years, and the atmospheric CO2 levels rose to many times what we have today. The ice receded from the tropics, and the greenhouse effect accelerated, driving the average planetary temperature above 100 degrees Fahrenheit (compared to about 60 today) within a few thousand years or less. This super ice age was the last of 4 to 6 such ice ages, with the first one occurring about 2.4 billion years ago, and the others between 750 and 590 million years ago. These ice ages may have occurred when all of the continents were strung around the equator. (The book presents a theory on why this might be so.) Finally, complex multi-cellular life forms first appeared in the Ediacaran period, shortly after the last super ice age. The book suggests that the last super ice age somehow spurred the appearance of complex life, but does not provide a good explanation of why this might be. (Maybe there is an assumption that "right after X" must mean "because of X.") Finally, the book asserts that such a calamity may occur again about 250 million years in the future.

The book is oddly written: part biography and part detective story, with some science scattered throughout. At no point does the book lay out a comprehensive exposition on the snowball hypothesis. Rather, the scientific theory comes through in bits and pieces as the book goes along. The book is, in large part, a biography of the four men who invented the snowball Earth theory: Paul Hoffman, Brian Harland, Joe Kirschvink, and Dan Schrag. It presents lots of extraneous information about these four guys, especially Hoffman (e.g., his exploits in running marathons). The book hops back and forth between the lives of the fantastic four, all the while letting the scientific mystery play itself out. This is something like a detective story. Many readers will probably like this approach, but I would have preferred that the first chapter explain the "snowball Earth" theory in detail. The rest of the book could then have dealt with how the theory came about, and the people who invented it. Moreover, the book is too narrowly oriented towards geology. Additional emphasis on atmospheric sciences, biology, and astrophysics would have been welcome. (For example, the sun's luminosity has increased about 1% every 200 million years for the last 3 billion years. During the various snowball epochs, the sun's brightness was about 88% to 97% of today's value. At what point is the sun too hot to allow a snowball epoch?)

The book also contains some errors. For example, it states that bacteria survived a trip to the Moon on an Apollo mission in 1967. The first Apollo moon landing was in 1969. Also, the book fails to consider the possibility that complex life may have provided an additional feedback mechanism for regulating CO2 levels in the air. In other words, it may have been that complex life caused an end to the snowball epochs, more so than the snowball epochs stimulating the appearance of complex life.

Finally, the book should, but does not, have pictures, illustrations, and maps.

Rating:
Summary: Snowfights
Review: It is always exciting to learn about new ideas on the cutting edge of any science. The idea of a Snowball Earth has sparked many debates and arguments. Snowball Earth, by Gabrielle Walker does more than defend the theory in face of academic scrutiny. She manages to introduce the reader to the man behind the theory, and in effect, write a story that resembles, the relationship between the man and his theoretical construct. This is what makes Snowball Earth, such a fascinating work. We are allowed to witness the man at his best, and at his worst. We are given an honest and open-minded view of the individual and his sometimes-sour relationships with others (generally those who do not follow his ideas). His arrogant and egotistical nature is not excused in any way, more fittingly it is used as a reason for his genius. The capacity to strongly trust what he believes in, makes Dr Paul Hoffman such a champion of his Snowball Earth Crusade, and more of the protagonist in the tale, than the theory itself.

The book opens with a chapter that accurately describes the manner in which Dr Hoffman approaches both life and his work. When still a young Postgraduate student with a passion for distance running, and on his very first attempt at the Boston Marathon, managed to come in a very respectable 9th place. His conviction to the cause, and self-will were the fuels which drove him on in the race, and remain to this day the fuels which drive his ambitions to prove to the world that the world has been through periods of massive freezing, the entire globe has been entirely frozen over, including the equatorial regions. This theory has been contested many times since it was first proposed to the Geological community, due to the fact that perhaps the most fundamental principle in Geology - Uniformitarianism, states that everything in the world behaves today as it always has. Processes, which are occurring today, have been occurring throughout Geological time. This means that we have the capacity to interpret past events through direct observation of present day functions. The idea of a Snowball Earth, then flies in the face of uniformitarianism.

Gabrielle Walker accurately describes the manner in which this affects the relationships between Dr Hoffman and his critics and compatriots. His driven belief in his own abilities (as proven by his Boston Marathon performance) often causes him to bash heads with those around him, not winning him many personal friends in support of his outlandish theory.

Critics of the snowball model (such as Nick Christie-Blick, Hoffman's chief adversary) insist that if at any time the entire surface of the earth was frozen over, the amount of insolation absorbed within the atmosphere, would greatly decrease, due to the nature of ice. The reflection of this radiation back into space would mean that ice depths would increase, and the earth would remain locked in a state of ice indefinitely. Dr Hoffman's Snowball Earth theory entails the periodic covering of the entire surface of the earth, under a layer of ice around 20km thick. This ice would then be thawed eventually after around 100 000 years or so due the combined action of volcanoes, and the releasing of gases such as CO2. These gases are released in the atmosphere, and they, along with the surface of the earth, absorb the incoming solar radiation and re-radiate it back down to the earth's surface. The net effect of this, is that enough internal heat is stored within the atmosphere to raise global temperatures, and in doing so, begin the melting process, which relieve the earth of its frozen blanket, to more closely resemble those conditions we know of today. The way, in which Walker describes complicated scientific processes, is simple and easy to follow, which is the mark of a good scientific biography.

Walker is giftedly able to place the reader in the company of Hoffman and his colleagues as they scour parts of the globe looking for evidence for rocks that would prove the earth had indeed frozen over entirely. We are taken from places as diverse as Svalbard Norway, to closer to home, Namibia. The signs and signatures of rocks that had been frozen are searched for. In order for Hoffman to prove the entire surface had indeed frozen, he needed evidence that showed that the rocks at the equator had frozen too. To do this he needed to identify the mark of rocks that had been frozen, then place them at the equator through the study of palaeomagnetism. When newly formed rock solidifies, it holds with it the magnetic signature of the Earth's magnetic field. By knowing the alignment of that field, you can work out the approximate latitude of that rock at formation. The work of Joe Kirschvink, enabled Hoffman to show that there had indeed been equator rock which at some stage had been frozen. The specific time period searched for by Hoffman was between 750-590 million years ago, the time before the Cambrian explosion. The reasons for this are made very clear by Walker, and explain the draw and attraction of the theory to the layman. Before this time, all life that existed on earth was in the form of a primordial sludge of single celled organisms. After the Cambrian explosion, the world entered a period of massive diversification, in which single celled organisms became multicellular life. We saw the birth of shells, and scales, and spines. Teeth and external and internal skeletal structures. The ancestors of life on earth as we know it today. This is why Dr Hoffman is so interested in finding these specifically aged rocks, with these specific palaeomagnetic signatures. Snowball Earth may then prove to be the catalyst that sparked the emergence of complex life on earth. The cooling and rapid warming of the earth may have created an environment stressful enough to cause single cells organisms to huddle together for survival. Creating specific functions for each cell, and uniting them to form a single complex entity.

The way in which Gabrielle Walker approaches the tropic is informed and passionate. Her capacity to convince the reader of the validity of the theory may even rival that of Dr Paul Hoffman himself. Snowball earth is a fascinating read, with massive contemporary appeal in the wake of modern existential reasoning. We may have found the source of complex life, floating in a glass of cool drink.

Rating:
Summary: Excellent writing but .... no pictures
Review: This book is about the theory that, over 600 million years ago, the earth underwent periods when it was completely covered with ice, hence, Snowball Earth. Although many scientists have contributed to this theory over the past few decades, the book focuses mainly on the efforts of Dr. Paul Hoffman, the main scientist responsible for developing and promoting the theory, thus raising its status to level that it has today. This is a very well-written book. It vividly describes the way in which science works, as well as the fact that scientists are all too human. It also contains well-written discussions on the science involved. Such a book should contain diagrams, figures, charts, photos, maps, etc., to better illustrate the locations, ideas and facts presented in the text. Unfortunately, the book contains none of the above - no picture whatsoever; if it did, I would have easily given it 5 stars. Despite this shortcoming, the book is definitely worth the read.

Rating:
Summary: Earth's History and How Science Is Trying to Read It
Review: This book offers a fascinating look at a possible explanation of how life went from single cell organisms to multicellular organisms. Also shows how different scientists can view and interpret the same data in different ways to support their different views. I have a lot of respect for Ms. Walker. Not only does she interview the main scientists that are involved in this debate, she has gone to some pretty remote areas of the world to see the very rocks that these scientists are basing their views on. That is alot more than most people would expect from someone just relating a story.

If you are interested in early life on Earth, you should read this book. If you are interested in how science tries to determine what has gone before, you should read this book. In short, if you are curious about life/science/the earth , "read this book."