Customer Reviews

Plows, Plagues, and Petroleum: How Humans Took Control of Climate

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This book is NOT about global warming. At least, not directly about the global warming of the Industrial Age over which extremists from both environmental and industry/government groups loudly wrangle about. Ruddiman's theme is global warming beginning far earlier -- 8000 years earlier. His expertise is in paleoclimatology, study of the climate in long-past eras. He presents a very persuasive case that starting about 8000 years ago, an increased "unnatural" output of carbon dioxide from early human agricultural endeavors began to measurably effect the earth's climate (with the effect intensified a few thousand years later by increased methane emissions from rice farming). It is Ruddiman's conclusion, very clearly presented and well supported with evidence, that this "extra" carbon dioxide has offset the "normal" global cooling that otherwise would have ended the present comfortable "interglacial" period and plunged us once again into an era of heavy glaciation. In short, into yet another Ice Age.

Ruddiman's work challenges us to jettison many comfortable myths, among them being that "Mother Earth" is naturally a stable benign guardian and that pre-industrial humans lived in some idyllic, low impact manner.

Like "Guns, Germs and Steel", this is a book that has fundamentally changed my perception of the distant past. It is both an important book and a book that makes for fascinating reading. I can scarcely recommend it too much. My advice: Buy it. Read it. Think about it.

Bruce Trinque's review said much of it, but here is more support. Ruddiman's work offers possible hypotheses to explain many puzzling effects. It is clearly written, accessible to non-experts, and of my 3-feet-wide bookshelf on climate issues, if somebody wanted one book, this is what I would recommend.

Ruddiman offers two basic hypotheses. The first, as Bruce described, is that humans have been modifying climate for 8000 years via forest-clearing and agriculture. This inhibited the otherwise-natural temperature decline back into an overdue glaciation, as compared with past inter-glacial periods. That's the good news.

The bad news, of course, is the current warming that will take us to levels of CO2 and temperature unprecedented for millions of years, and will do so even if we all stopped using oil/gas/coal tomorrow, and he discusses why.

The second hypothesis is the most plausible explanation I've seen for some of the puzzling short-term temperature/CO2 gyrations of the last 2000 years. He proposes that major plague pandemics have caused sufficient die-offs, abandoment of farms, and reforestration to temporarily lower CO2 and temperature. This could explain the later-Roman/Dark Ages lower temperatures, followed by the relatively disease-free Medieval Warming Period, in which Greenland was settled, and UK vineyards spread again to current levels, if not quite as far as early Roman. He ascribes the Little Ice Age drop to Bubonic plagues in Europe, and especially, to the death of estimated 50 million native Americans from smallpox and other European diseases. He does enough math to make these claims at least worth further study. He carefully observes that "correlation is not causation" and goes on to calibrate the mechanisms by which pandemic can lead to lower CO2.

Ruddiman refreshingly understands the differences between early hypotheses and well-tested theories. He often starts with an observed behavior, then carefully evaluates alternate explanations for it, rather than just offering an answer.

This is an exemplary approach to science, and while the hypotheses certainly need testing, this seems like a very productive line of thought that should incite useful further research. Climate analysis always faces the serious problem of extracting trends, and their causes from a very noisy signal. Compared to many competing hypotheses, Ruddiman's seem to be able to explain some gyrations that have often caused people to say "temperatures go up and down randomly anyway."

Finally, the book is clearly and calmly written, with careful delineation of facts and conjectures, with plenty of backup. Even more technical details can be found in his earlier articles.

Finally, I suspect Edward Tufte would be gladded by many of the charts, which are often simple, but compelling, and far better than words.

Ruddiman presents an interesting hypothesis, but his reasoning leaves out too many factors, and does not give enough weight to unknown factors.

Milankovitch cycles are explained extremely well, and Ruddiman attributes ice ages and glaciation periods almost exclusively to these cycles. It is true that ice age/glaciations line up with the Milankovitch cycles, but... we know that further back in planetary history there were Milankovitch cylces that did not result in ice ages. This would indicate that other factors may be required to set off such a radical change in global climate. Ruddiman does not address this, to the detriment of his hypothesis.

Ruddiman also states that orbital changes control monsoon cycles, yet research has shown that monsoon cycles can change more rapidly and more often than the long orbital cycles would indicate. Ruddiman also attributes monsoons to heat, stating more heat, more monsoon. This is not an adequate explanation of monsoons. Areas that were very wet 9,000 years ago are undergoing increased desertification today, with increasing heat.

Entirely too much is supposed in terms of early human development, the amount of agriculture practiced, and it's effect on climate. As one example, Ruddiman supposes that early nomadic humans spaced children four years apart. There is absolutely no evidence cited for this supposition, and given the high mortality rate and shorter life spans, this type of "spacing" may not have been enough to maintain populations. Too little is known about prehistoric agriculture and population levels to come up with a reliable formula on amount of acres farmed for each person, and amount of methane released per acre.

In matching plagues with CO2 levels, Ruddiman does not acknowledge that many climatologists and anthropoligists place cooling weather before the plague events. CO2 levels would have been reduced before as well as durring the plague events.

Ruddiman does not give climate enough weight when considering human development and population levels, as well as when considering extincition events at the end of the pleistocene/start of the Holocene. Studies of central american and mesopotanian civilizations have shown that climate changes have had a huge impact on humanity. Climate change has also been linked to the extincions mentioned above. Humanity played a role, but the size of that role is debatable.

Ruddiman relies far too heavily on the reasoning that "the only difference was humans, so we must have caused it". This is false logic, as there could have been any number of differences that we can't or haven't picked up on. Given the number of variations possible, it is naive to think we were the only one.

The portion of the book that deals with politics is severely lacking. Ruddiman repeatedly takes "alarmists" to task, yet fails to identify the alrmists or the specific claims that are out of line. Same problem with the contrarians. This portion of the book is far too simplistic, and seems to be there only to demonstrate what a reasonable guy Ruddiman is.

Lastly, I think Ruddiman goes out of his way to soft-peddle the changes in store. He ignores problems already being seen, such as persistent droughts, in Africa, the U.S. and Australia, to name a few places. Ruddiman also ignores the possibility of rapid climate change. Studies that predate this book have shown that climate can and does change rapidly. Not to be hysterical, but this is something that needs to be considered.

Despite what I think are some serious shortcomings, I would recommend this book as Ruddimant is not afraid to put out a hypothesis that is somewhat radical. There are too many unsupported leaps in reasoning, but the overall hypothesis may have some validity, and definitely is interesting.

The climate of the Earth has never been stable over the long expanse of geological time. This book is an excellent treatment of the very complex subject of global climate change for the educated but non-specialist reader. This book treats the major controls on natural climate change such as orbital forcing and greenhouse gasses and deftly explains how these variables have resulted in periodic ice ages over the past few million years as well as how and why climate has fluctuated over the greater span of geological time. The book is short, concise, and very well illustrated with maps, tables, and graphs. It is not written in standard scientific format with numerous references in the text, however, a chapter-by-chapter bibliography and credits for the illustrations are provided.

The major thesis of the book is that the influence of human activity on climate is not a recent phenomena related to the industrial revolution and burning of fossil fuels but began 8000 years ago with the advent of agriculture. This slow trend of increasing atmospheric greenhouse gasses, due to deforestation and other agricultural activity, may have had the effect of warding off, for the time being at least, a coming ice age. This ice age is predicted on the basis of the variations of the Earth's orbit around the sun that is responsible for the repeated glaciations since the Late Pliocene Epoch about three million years ago. However, the effect of rapidly increasing CO2 during the past 250 years with the industrial revolution has yet to be felt and may be profound. Just as the hottest days of the summer follow by a month or more the summer solstice, the full effects of the current dramatic increase in CO2 emissions will not be felt for some decades. Therefore the political decisions that will be made during the next 10 years will not have an immediate impact on the current warming trend, but will affect the magnitude of future warming.

Another subject that the author treats is what will happen with the inevitable end of the era of fossil fuels within the next 50 to 150 years when the industrial contribution to greenhouse gasses in the atmosphere begins to drop. Inevitably, this percentage of CO2 will leave the atmosphere and enter one of the long-term geological sinks for carbon. Will agricultural anthropogenic greenhouse gas emissions be enough to stave off the orbitally forced ice age that is now overdue?

The author Dr. William F. Ruddiman has an excellent reputation in the scientific community in the field of climatology with numerous published scholarly papers to his credit. He very carefully guides the educated lay reader through his thesis and is quite careful to point out that his ideas about long term effect of human activity on climate will need far more data before they all are borne out. Never the less, Ruddiman has presented an intriguing hypothesis as well as produced a very well written book. I already have recommended this book to a number of my colleagues in academia and the petroleum industry as a very well thought out and even handed treatment of this complex and politically charged subject. I also will be assigning this book, for extra credit, in the Historical Geology class that I am now teaching.

In the current furor of so much smug certainty about climate change (from all over the place), here is a gent - and scientist - with a different slant. We humans indeed do affect the global climate, he claims, but we started doing so a very long time ago. He concludes the beginning somewhere between 8,000 and 10,000 years ago. The first effects came from man's developing agricultural products: from burning forests to create farmlands mainly, thus putting tons of carbon dioxide into the atmosphere. Then there came the insertion of a much stronger greenhouse gas, methane, from cattle husbandry and rice growing. This thesis has and will certainly spark much more discussion, and more importantly, research. Mr. Ruddiman had written a summary of this in Scientific American Magazine previously. Much of this book is his discussion to back up his thesis.

Maybe the best strength of this book is its readability. The author's style is easy to understand, as is most of his science. The science gets a little more obscure when he is defending his stance against selected opposing arguments from fellow scientists. This is unfortunate, because some readers will come away from that chapter wondering if he covered the debate, or just danced around them. If your political tendencies tend to the left, you might be upset that the author does not loudly and immediately condemn modern western industrial man for his evil environmental ways. If you tend to the right, you might be upset that he points a definite finger at homo sapiens for being a contributor to climate change. This is why reading this is good for everyone! Since Ruddiman is a scientist, we can assume that he is merely trying to convince us that his research is on the mark. Fair enough.

Unfairly enough, the author-scientist does not quite succeed in keeping his balance as the book gets closer and closer to the end. In spite of his claim that he kept his editorializing until the epilog, the last chapters paint a despairing picture of mankind and what we are doing - and cannot do for the future - to our environment. For a scientist, it should strike the reader as odd that he wrings his hands at the thought of humans never being able to solve our way out of a basically scientific-technological issue: climate change. The fact that there is no serious mention in this book of nuclear energy, low-fuel consumption single transportation, or the many current greenhouse gas absorption projects, clues us that these matters are out of his field. Still, the basic point of this book is new and refreshing, and is worth the price of purchase.

This is a fine book that ties with When the Rivers Run Dry: Water--The Defining Crisis of the Twenty-first Century and falls slightly below The Weather Makers : How Man Is Changing the Climate and What It Means for Life on Earth and The Winds of Change: Climate, Weather, and the Destruction of Civilizations all of which I read in this week-end's series. Better books in the larger scheme of things include E. O. Wilson's The Future of Life and J. F. Rischard's High Noon 20 Global Problems, 20 Years to Solve Them.

The books is blessed with many useful figures.

The author focuses on farming, which requires deforestation through burning, as preceding the impact of cities on climate.

He titillates with his discussion of 6 billion humans producing methane in huge quantities via rice irrigation, livestock tending, biomass burning, and human waste.

I especially appreciated the author's discussion of climate studies as being relatively new, and his itemization of the number of specializations that now bear on climate study, including geologists, geochemists, meteorologists, glaciologists, ecologists, biological oceanographers, climatologists, etc.

The book is somewhat mis-titled in that the humans are not in CONTROL of the climate as much as impacting upon it in ways not fully understood but largely understood to be negative (e.g. hurricanes twice as intense as 30 years ago, witness New Orleans and KATRINA).

It takes 50 years to raise a forest.

Plagues are a form of natural control. People die, farms are abandoned, forests grow back, and emissions are reduced.

For a taste of the future, the author shows us the past, when Africa and India and China had much greater moisture across their regions. The author ably argues that the water cycle is as important if not more important than the energy cycle in relation to the future of life.

Page 152, the author provides a superb discussion of climate response time, noting that the land mass is much more responsive, which the varied layers of the ocean run from months-years at the top to years-decades in the middle, and centuries in the deep ocean--with the average being decades.

On page 182 the author demonstrates a lack of understanding of politics when he says "Politicians generally vote for policies their constituents want." Not so fast, bubba. Read Breach of Trust: How Washington Turns Outsiders Into Insiders; Running on Empty: How the Democratic and Republican Parties Are Bankrupting Our Future and What Americans Can Do About It; and The Broken Branch: How Congress Is Failing America and How to Get It Back on Track (Institutions of American Democracy) among many other works on corruption in Congress, where the bottom line is money from special interests, or privileges and committee assignments from the party that demands one vote the party line rather than as constituents' desire.

The author is the only of the four that I really felt made the point that BOTH extremes are bad: the extremists that deny climate change, and those that demand draconian corrective measures. He points out, in a very balanced way, that pollution is as old as the earth itself.

As with other authors who value the truth in this arena, this author makes it a point to lament the unethical and unreasoned "alternative universe" of industry-funded contrarians and the actively malicious mis-representation and disinformation they purvey. I was quite pleased to read his suggestion that citizens need to get organized and "follow the money" in order to out the connections from industry to "front organizations" to specific liars and agents of influence seeking to deceive the public.

He discusses the concept of ecosystem services and the costs to replace, something E. O. Wilson does in a more thorough and readable manner in The Future of Life but the coverage here is useful if you do not wish to buy many books.

Finally, the author concludes that global warming is not the most vital issue--that energy and then water scarcity are more important, followed by the issue of topsoil replenishment (no longer from clean natural ice melts, now from petroleum-based fertilizers).

There are no notes in this book, with disconcerted me a bit.

As stated more eloquently in other reviews, this book puts forth the hypothesis that human activities have led to an interruption in the glacial/interglacial cycle that has been occurring in the Northern hemisphere over the last 3-4 million years. The author's treatment of the Milankovich orbital cycles will be instructive to those who have yet to be exposed to this data.

It was refreshing to see his hypothesis put forth in scientific dispassion vice the usual strident pro or anti climate change debate. In true scientific method, the author makes a hypothesis and humbly accepts that there must be debate, validation or refutation before his hypothesis can either be discarded or accepted as theory. VERY refreshing.

What I found most interesting, however, was the adherence to scientific rigor in the debate and test of the hypothesis. This author is the first I have seen to actually quantify the magnitude of the components to the carbon cycle. Instead of ranting about how the sky is falling all because of human activities OR ranting about how no matter how many humans there are there will be no discernable effects, the author actually uses metrics- how many acres are cultivated per person, how much CO2 an acre of forest binds or releases, how many people died in the Black Death, how long it takes nature to reforest clear cut land, etc. He even boldly admits it when his figures fall short of a perfect match and offers alternative explanations.

BTW- another reviewer of this book has erroneously referred to CO2 levels 20X current rates as having been discovered in ice core data. This is incorrect. Ice core data is limited to 400K years at the most- this from the Vostok cores in Antarctica. The Greenland cores (nearly 2 dozen) are both more accurately annually defined and are limited to 100K years. The 20X CO2 concentration is from the Cambrain period- 540 MYA- as in 540 million years ago. No ice cores go back that far. This is an example of the unreferenced hype that the author takes pains to avoid.

"Plows, Plagues, and Petroleum: How Humans Took Control of Climate" is a controversial extension of anthropogenic global warming back as far as the earliest farmers ten thousand years ago. Ruddiman argues that human effect upon carbon dioxide and methane concentrations between around eight thousand years ago and the beginning of the Industrial Revolution was as great as that observed since 1800.

In the first part of "Plows, Plagues, and Petroleum", Ruddiman looks at early human history and the evolution of the human species. Whilst his overview is far from illogical, I must disagree with him about the evolution of human intelligence, which he says was not helped by the cold and frequent climate change. Cooling of the planet is undoubtedly decisive in evolving highly intelligent beings: Tim Flannery shows how environments without glaciation have extremely infertile soils and oceans so that species of human-like intelligence could never evolve. Frequent climate change would probably actually necessitate a better knowledge of the variety of possible conditions and still larger brains.

Ruddiman's explanation of how Milankovitch cycles cause glacial/interglacial cycles on Earth is clear and efficient, with a very good number of graphs even if most are rather coarsely drawn. Nonetheless, he does not take into account how very ancient records show temperatures can change without the levels of carbon dioxide changing or vice versa - even if this does not contradict anthropogenic global warming as sone assume. Ruddiman's claim that continental drift cannot have played a role in causing climate change is however doubtful. The creation of a north-flowing current from the formation of the Isthmus of Panama is known to have increased snowfall in eastern North America. Without warm air from the south northeastern North America would probably receive too little snow to form large glaciers. (Ruddiman does not mention, as a serious student of Ice Ages should, how Siberia, lowland Central Asia, Manchuria, parts of Alaska and the Yukon, plus Argentine Patagonia, have always been too dry for glaciers).

Recent refinement of glacial/interglacial cycles strongly disputes his claim that the interglacial corresponding to marine isotope stage 11 can definitively show human influence before the Industrial Revolution. It also disputes his temperature graph and predictions of further long-term cooling because between 900,000 and 450,000 years ago it is probable areas like Nunavik and the areas of Baffin Island he mentions were never deglaciated.

Ruddiman the goes on to show quite skilfully that modelled concentrations of carbon dioxide do not agree with calculations based upon previous interglacial cycles. "Plows, Plagues, and Petroleum" argues that anthropogenic emissions of methane from rice paddies and carbon dioxide from forest clearing account for the rises in greenhouse gases since eight thousand years ago when wet-rice cultivation began. He then suggests they have stopped ordinary accumulation of ice in northeastern Canada, from which the Laurentide Ice Sheet spread southward to around New York and Omaha. This part is not badly argued, but as I mentioned earlier recent research does question what he is saying.

When Ruddiman turns his attention to plagues supposedly having caused the Little Ice Age, he becomes even more dubious. For one thing, the falls in carbon dioxide he observes correlate very poorly with known coolings during the Dark Ages and Little Ice Age. Whereas Ruddiman says they are linked, in fact cooling began long before every pandemic he mentions struck and did not increase following it. Although I do agree with him that it is unlikely drought followed by famine could cause the same population reductions pandemics can, my knowledge of climate records suffices to view his claim "the likelihood of drought striking vast areas of Eurasia simultaneously is unlikely" as more or less false, especially should ENSO combine suitably with other influences. In the summer of 1911, for instance, deficient rainfall affected the vast bulk of tropical and temperate Eurasia from the Pacific to the Atlantic.

The last part, dealing with the influence of fossil fuels, is extremely bland compared with the rest of "Plows, Plagues, and Petroleum". He suggests, reasonably, that the effect of burning all the fossil fuel we have is quite uncertain and that there is potential for vast warming to be followed by a gradual natural cooling once the fossil fuels run out (reminiscent of Tim Flannery).

All in all, whilst Ruddiman has plenty of ideas, he does often go too far about trying to criticise humanity. "Plows, Plagues, and Petroleum" is an interesting and very easy read, but there are a lot of problems that could almost serve as ammunition for sceptics of global warming.

Mr. Ruddiman does not proselytize. He has his opinions, but he does a nice job of separating them from the science, which is nicely reviewed here. He does defend his central hypothesis, that man's impact on climate change began thousands of years ago with the beginning of agriculture as opposed to ~100 years ago with the beginning of the industrial revolution, but he does it fairly and openly.

A couple of comments. This book was published before the recent findings on the 56 million year arctic core were published, and hence is largely based on two previous cores representing only the past 400,000 years. It will be interesting to hear what Mr. Ruddiman has to say about his hypothesis in light of this new data.

Secondly, in the future looking chapter at the end, Mr. Ruddiman dismisses the current state of carbon capture technologies seemingly unaware of the potential of integrated gasification combined cycle (IGCC) coal-fired power plants and the current debate over its potential to significantly mitigate carbon emissions over the next 50 years.

Five stars on the climate science; not a good summary of policy options.

Out of the many available books on climate change, Ruddiman provides a refreshing perspective on the subject. His thesis is simple: human beings have been changing our climate since far before the Industrial Revolution. It all started 8000 years ago with the beginning of farming. He doesa good job at delivering his message on the science side but falls short on the more pragmatic side. He does not really answer the critical question of this debate: now, so what? he smartly leaves that to the reader. However, you are not really left alone in the dark since he gave some insights to make a more educated choice.