Two-Mile Time Machine: Ice Cores, Abrupt Climate Change, and Our Future

by Richard B. Alley

In the 1990s Richard B. Alley and his colleagues made headlines with the discovery that the last ice age came to an abrupt end over a period of only three years. In "The Two-Mile Time Machine," Alley tells the fascinating history of global climate changes as revealed by reading the annual rings of ice from cores drilled in Greenland. He explains that humans have experienced an unusually temperate climate compared to the wild fluctuations that characterized most of prehistory. He warns that our comfortable environment could come to an end in a matter of years and tells us what we need to know in order to understand and perhaps overcome climate changes in the future.

In a new preface, the author weighs in on whether our understanding of global climate change has altered in the years since the book was first published, what the latest research tells us, and what he is working on next.

Genres: Nonfiction, Science, Geology, Geography

246 pages, ebook

First published January 1, 2014

Reviews

[Sydney Hedberg · Rating 5 out of 5]

In this captivating novel, Richard B. Alley, one of the world’s leading climate scientists, tells the story of Earth’s climate history that has been revealed from studying Greenland’s ice cores. He draws on his research to explain first, how ice cores can be indicative of climate history, second, how different events have large capabilities to alter Earth’s climate, and third, what these findings could possibly mean for our future.

By extensively studying the ice layers of a two-mile long ice core, Alley and his research team determined a relative history of Earth's temperatures for the past 100,000 years. They additionally discovered patterns of atmospheric concentrations throughout history, as gas bubbles are trapped within ice layers. Alley explains their main findings from this extensive study. Their two main discoveries include: 1) that past climate has been much more variable with significantly larger climate shifts than those experienced in the industrial/ agricultural era and 2) that climate usually remains relatively stable unless there is a phenomenon ‘pushing’ climate to change, commonly causing a rapid jump in climatic conditions, rather than a gradual one.

Alley concludes by describing the futuristic implications of their study. He examines the possibility of an Atlantic conveyor shutdown, which would largely impact worldwide temperature distributions. He additionally points out that the observed increase in carbon dioxide concentrations alone are likely only going to increase global temperature by 1℃. However, he describes the how various positive feedback loops within Earth's system can amplify this temperature increase. Above all, Alley stresses the uncertainty behind his predictions. He remains certain about the evidence that his research team provides but acknowledges that they are not certain about its implications in our future. This strengthens his credibility because while he is supporting his predictions with evidence, he is honest that it cannot be known for certain.

Richard Alley conveys this information in an effective way to a non-scientific audience, opening my eyes to what this study shows about the past, as well as possible futuristic implications. He does a good job at explaining the meaning behind specific scientific terms and uses a minimal amount of scientific jargon. This allows the book to be directed at a wider audience, not limited to scientific experts. Additionally, Alley does a good job at addressing contrarian viewpoints, and refuting them with evidence. My main criticism of the book is that Alley delves into a lot of detail on certain topics, while seemingly skimming over others. Overall, I believe the book conveys a meaningful story about Earth’s climate, past and present.

Providing a look into the past that unravels the climate history of Earth, The Two-Mile Time Machine encourages and facilitates thought on what the future climate of our planet will look like and what implications this will have on our lives for many years to come.

[Juno · Rating 5 out of 5]

Although the book is touted as a nontechnical explanation of historic and current climate change, it requires a strong attention span to get through. I often found myself reading the same page three times, and when the author got to explaining ice isotopes, I had to skip that section entirely. Still, the scientific content is as fascinating as it is advanced.

When you learn about historic climate in school, maybe for only a lesson or two in your whole childhood, you get the impression that we got long ice ages and long warm ages pretty predictably over long long periods of time. The author instead reveals the erratic and complicated patterns within earth caused by factors that you’d never expect. I learned a lot: large ice sheets can pretty much melt themselves, earth can lower greenhouse gases in response to increasing sun energy, and so much more.

[Kyra Wolf · Rating 5 out of 5]

This is the best nontechnical explanation of climate science that I've ever read.

[Neil · Rating 5 out of 5]

A wonderful extrapolation of, and science behind the deciphering of Greenland glacial ice cores, and its pertinence to some more positive outlook on climate changes irretrievably coming our way.
Amazing science, dedicated scientists, and a long term perspective that is refreshing in its outlook.