Every once in a while my daughter lets me post something she’s written. Lately she’s been thinking about getting a PhD. in environmental engineering and another in Archaeology so she can take the knowledge of past environmental disasters and apply it to our modern emergency.
For those of you who don’t know about my kiddo, she’s currently 11 years old and a junior at a local high school. She likes her privacy, so I won’t tell you any more than that- other than to say that she’s quite happy with her life and please don’t recommend any books because she’s probably already read them!
Duck under the fold to find out what’s in store…
In Under a Green Sky, Peter Ward chronicles the discovery of the cause of most ancient mass extinctions and explains what effects this cause may have on our world today. Originally, most scientists thought that impact by a meteor was the cause of all mass extinctions. The root of this belief was evidence of extraterrestrial impact in the form of helium isotopes most commonly found in space and other debris characteristic of impact. However, one problem with that hypothesis was that the clear signs of asteroid impact in the Cretaceous rock strata were not present in strata from other eras.
According to Ward, chemical markers left by extinct species indicated that there were large amounts of hydrogen sulfide in the water and atmosphere near the extinction borders. There were also indicators of low oxygen content and warmer water. The hypothesis developed from this data was that large amounts of carbon dioxide had been released into the air, causing warming, glacial melting, and a disruption of the conveyor currents that maintain oxygen levels in the modern ocean. The ocean then began to stratify and bottom-dwelling organisms, robbed of oxygen, died out. Ward says that bacteria that did not require oxygen and produced hydrogen sulfide as a waste product (these bacteria are still present in a few areas today) thrived and produced amounts of this gas that were large enough to kill many land animals after the gas bubbled to the surface.
Today, humans introduce unnaturally high amounts of carbon dioxide into the atmosphere. Ward says that melting of the polar ice caps has already begun because of the increase in temperature resulting from the rise in greenhouse gases. If carbon dioxide release is not stopped soon, the conveyor currents will be disrupted, the ice caps will melt over a period of a few hundred years, and the patterns of climate will be drastically altered. According to Ward, this will cause another mass extinction.
I recommend Under a Green Sky to anyone who is interested in the past or the environmental movement. The author’s enthralling writing style and the anecdotes accompanying the discoveries complement the scientific information that anchors the book. For the first time, there is proof that the increase in carbon dioxide levels will have (and has had) a severe impact. I came away from the book determined to find ways to reduce my carbon footprint and to work towards the goal of greenhouse gas emissions reduction.
