In Heatstroke, author and paleoecologist Barnosky carefully lays out his observations and describes how others involving climate change have resulted in the extinction periods of the past. His writing style and level of detail combine to make this book a page turner. He quickly presents the information that most people who are drawn to the book probably already know, and then proceeds to his areas of expertise.
Global Warming a Recipe for Disaster
The first few chapters briefly bring the reader up to date on warming trends and discuss how humans and the rest of nature are coping. That is, climate change is happening faster than it ever has during the existence of life on Earth. Species are unable to evolve fast enough to keep up. Habitats have been fragmented by cities, towns, large scale agriculture, and roads so that plant and animal species cannot find their way to other areas where they might be able to continue to evolve through natural selection.
What is Normal for Nature
In the second section he travels to various parts of the U.S. and Africa to observe nature in large preserves where its intricate trial and error is still reflected. U.S. National Parks like Yosemite and Yellowstone as well as places like the Kalahari are large ecosystems that show us what the rest of the earth might look like without such a heavy human footprint.
In light of the Ken Burns documentary on the National Parks that appeared on Public Broadcasting stations in the fall of 2009, his presentation in this section is particularly interesting. The United States National Parks system was championed by individuals who were among the first to define (Joseph Grinnell) and understand the implications of the ecological niche. That is, that certain plants and animals are distributed according to their ability to thrive given certain climatic conditions. Barnosky notes the skills that saved and documented special preserves.
However, he notes, these “last great places” that were relatively undisturbed are beginning to show holes. We are in danger of losing ecological legacies.
Uncharted Terrain Lies Ahead
Finally, in the last portion of the book, the author gets to the point: warming is going to cause some dramatic changes in the order of nature – that includes human nature – on Earth. But that’s not all.
The human footprint has directly influenced 83 percent of the land surface of the Earth. Coastal settlement, fishing, pollution and invasive species are impacting the oceans.
These changes are impacting ecological interactions in many ways so that ecosystems will be lost. We are even losing those that we sought to protect, examined in section two, not just because of warming, but due to the fact that the plants and animals are unable to move to more suitable habitats. Nature exists on islands surrounded by human-made barriers.
Among the most intriguing chapters in the book is one concerning the diminishing genetic diversity. He cites an article by John Varley in Yellowstone Science. It notes that because biodiversity was preserved in Yellowstone, the human genome was sequenced and the great strides have been made in human genetics and biotechnology all unfolded in the last two decades because of this, in areas from pharmaceuticals to genealogy.
Also interesting in this section are his discussion on the correlation he has found between warming, biodiversity decline and the mass extinction periods of the past. During those periods of extinction, whole branches of the Linnaean family tree where loped off and can never return, reducing the overall genetic diversity of the planet. Today, we are working with a genetic “skeleton crew.”
Moving species around has also flattened diversity. Species moved by humans from one eco-zone or continent to another lead to invasive species dominating the environment. Monocultures of invasive species are out competing natives in certain areas and reduce biodiversity.
Heatstroke and Hope for the Future
The author also provide cautiously hopeful words: “Luckily, there is something else different about Earth today: for the first time in humanity’s history, we have both the knowledge and the technology to chart at least the broad paths we want the future to follow. No other generation in history has been so uniquely poised to exercise those uniquely human qualities, foresight and directed action. In the case of global warming we are in the arguably fortunate position of knowing it’s here and probably will get worse, but also having the ability to slow it … The trick now, of course, is to actually use our foresight and abilities not only to dodge but also to deflect the bullets heading our way.”
Sara E. Lewis - Sara E. Lewis is a writer and publications consultant. As a freelancer, she writes and produces marketing materials and especially enjoys ...
