| OUR FRAGILE MOMENT How Lessons from Earth's Past Can Help Us Survive the Climate Crisis Michael E. Mann New York: PublicAffairs, 26 September 2023 |
Rating: 5.0 High |
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| ISBN-13 978-1-5417-0289-9 | ||||
| ISBN-10 1-5417-0289-1 | 306pp. | HC/BWI | $30.00 | |
Several disparate lines of scientific research come together in Dr. Mann's first chapter: "Our Moment Begins." He summarizes the history of our world from the time of the dinosaurs through the rise of hominin ancestors to hominids (the several species of humans) and finally human civilizations during the latest interglacial period. These civilizations pioneered agriculture which supported the development of cities and empires like the Empire of Akkad in the Fertile Crescent — and also exposed them to risk when climatic conditions turned against them.
Previous shifts in climate doomed civilizations in certain regions of the planet — the Empire of Akkad, the Anasazi in the American southwest, the Tiwanaku in Peru — but always allowed migration to areas unaffected by the changes. Our time is different. We live in the Anthropocene, when human actions affect the entire globe.
As we can see, the story of human life on Earth is a complicated one. Climate variability has at times created new niches that humans or their ancestors could potentially exploit, and challenges that caused devastation, then spurred innovation. But the conditions that allowed humans to live on this Earth are incredibly fragile, and there's a relatively narrow envelope of climate variability within which human civilization remains viable. Today, our massive societal infrastructure supports more than eight billion people, an order of magnitude beyond the natural 'carrying capacity' of our planet (the resource limit of what our planet can provide in the absence of human technology). The resilience of this infrastructure depends on conditions remaining the same as those that prevailed during its development. The concentration of carbon dioxide (CO2) in the atmosphere today is the highest since early hominids first hunted on the African savannas (sic). It is now already outside the range during which our civilization arose. If we continue to burn fossil fuels, it is likely that the planet will warm beyond the limit of our collective adaptive capacity. How close are we to the edge? In the pages that follow, I set out to answer that question. – Page 3 |
The book amounts to a layman's course in climatology, touching on related sciences like geology and biology and specific techniques such as dating samples by means of radiocarbon and other isotopes. There is a lot of science in the book, so it requires careful reading. But it will repay that care, because Dr. Mann explains a number of areas where the science is not settled. These, in general, have to do with the speed of things like sea-level rise and when we might pass tipping points.
For example, there's dispute over the well-known Marine Ice Sheet Instability, which indicates the readiness to collapse of ice sheets like the Thwaites Glacier which enter the ocean. Observations and modeling of these glaciers have led to a projection of 3 feet of sea-level rise by 2100.
We've known about MISI since the late 1970s. But it is no longer simple theory; it's reality. The tenuous marine glaciers of the WAIS hold enough ice to yield ten feet of sea level rise. Two in particular—the Thwaites and Pine Island Glaciers—are often called the "weak underbelly" of the WAIS, as their collapse would ensure the loss of a large chunk of the WAIS. Thwaites has been called the Doomsday Glacier because its collapse alone would cause more than two feet of sea level rise. – Page 75 |
However, in 2016 Rob DeConto and David Pollard introduced the Marine Ice Cliff Instability. This adds another mechanism for ice sheet collapse, and potentially doubles the amount of sea-level rise by 2100. (See pp. 174-180 for details.)
This example, and other details that are not completely understood, show us the level of uncertainty that still exists in the big picture of climate change. But make no mistake: while the big picture may be fuzzy in certain spots, it remains intact — and it grows increasingly grim.
None of this means that it is too late for concerted actions to lessen the impacts of climate change. If you take nothing else away from this book, or from everything Michael E. Mann has written and said, take that to heart. Feeling despair is understandable, but it is not warranted.2
Inevitably, some of the more fundamental scientific uncertainties are unlikely to be definitively resolved on the timeframe we might like, namely the next dew years during which we have to make critical decisions about climate policy. We must fall back, once again, on the evergreen principle that uncertainty is not our friend. It is a reason for more, not less, urgent action. – Page 200 |
Despite the scientific complexities it presents, this book is well written for general readers. I think most readers will enjoy it and get something worthwhile from it. Dr. Mann, it is notable, here shifts from the confrontation of previous books to emphasizing explanation and cooperation.3 Those are the things we need most in this time of American confusion and tribal opposition to coherent governance. A number of charts and graphs and several black-and-white pictures augment the text. The book has extensive endnotes and a good index. I give it full marks and rate it a keeper.
To contact Chris Winter, send email to this address.