Though we all know that the present is the key to the past, The Earth After Us takes geological investigation one step further. By asking ‘What precisely will mankind's legacy be 100 million years hence?’, the book offers a unique and thought-provoking insight into anthropogenic climate change.
The premise is simple: a future race of geological explorers chances upon a widespread and charismatic event stratum and this, the prologue tells us, relates to a planet-wide environmental crisis and a widespread mass extinction. But such hyperbolae are swiftly set aside. This is not some wild fantasy about alien geologists (or indeed a future species of hyper-intelligent rock-studying rodent as Zalasiewicz wryly observes), instead it is well thought-out and rigorous, taking an almost Lyellian approach and using the principles of soft rock geology to investigating the role of Man in the Earth system.
This book, however, is not just a new window on the late Quaternary world. It offers a deep time perspective on current climate change set against the Earth's long history of evolution, extinction, ice ages and shifting seas. After setting the picture, the first few chapters lay the foundation of basic geoscience, introducing the concepts of tectonics, eustasy and stratigraphy in an entertaining account that draws together evidence for global change in a veritable whodunit of investigation and anecdote. From this the reader garners not only the background with which to address what hints of Man's brief reign may remain in the rocks, he or she is also equipped with a wealth of information showing the intrinsic link between life and environment on a dynamic, ever-changing planet. Having gained this knowledge of ancient climates and long-dead ecosystems, the narrative returns to the present to examine the anatomy of recent environmental change.
Here the story shifts: we are taken into a detective story of how a future race may infer the workings of the human world, perhaps to see how a widespread civilization wreaked climatic havoc on its own environment. The text examines first how short-lived climatic events may be recognized in the stratigraphic record, before making the case for the contemporary climate change being recorded in a series of ubiquitous event beds. The focus then shifts towards the Rosetta Stone that might link Mankind with its environmental impact using the principles of taphonomy and ichnology to assess precisely how we will be found in the fossil record. In the final chapters we see how the preserved workings of a low-lying flood plane city may leave vestiges of our organized civilization. The cemeteries of such cities being, of course, the final piece needed to link up the puzzle, concomitant with indirect evidence of Man the agriculturalist and Man the earth-mover found elsewhere in the strata.
This book provides an entertaining insight into the geological sciences. It will not only reach out to the general audience and the interested students meeting geology for the first time, it also conveys a broader message to the scientific community, showing clear evidence of Man's influence on the evolution of the global environment.