The World According To Pimm: A Scientist Audits the Earth [Hardcover]

There are approximately 130 million square kilometers of land surface producing an average of about 1,000 tons of biomass a year. Of this 130 billion tons we use 42% (60 billion tons) for food, grazing, wood for building and burning, etc. Pimm's comment is "Man eats Planet! Two-Fifths Already Gone!" (Chapter 6).

Professor Pimm also audits the ocean and gives us similar bottom-line figures. He explains how he gets the information, how he collates it and how his various sources agree and don't agree. He is in the field and on the ocean, floating down Amazon rivers and flying over the African veldt. He recalls the land before industrialization and tells us how it has changed. He tells the story of the great American westward expansion and what that expansion did to the forests and the prairies. He recalls the tragedy of Easter Island. Pimm writes in a witty and fascinating style that makes the dry numbers come alive and sparkle like fish in incandescent water. One gets the sense in reading him that here is somebody who knows what he is talking about, somebody who has worked hard to understand how the planet's various systems work, and what is happening to them because of human consumption and waste. His tone is balanced and calm and conversational. He appears to have no axes to grind, no favorites to play. Although he claims in the Prologue that his book is "unashamedly optimistic" (p. 8), the implications of the numbers he presents are nonetheless alarming.

For example, Pimm reports that our population has nearly doubled since 1970 but the amount of cropland has only increased from 14 million square kilometers to 15. He notes that "Agriculture feeds far more people from almost the same area of land." He adds, "In this statistic, eternally optimistic Panglossians see continuing progress that allows us to push the envelope of our environmental constraints. In the same statistic, worried Cassandras notice the constraints on the area of croplands that prevent it from expanding with our growing population." (p. 106)

He notes that virtually all of the best cropland is already being used, but not necessarily for cultivation. A significant percentage is under the concrete and asphalt of our cities. Furthermore the drier lands in places like California's central valleys, the soils are quickly becoming salinized by irrigation so that they yield less and less per acre. In some place the salt content from irrigation of the soil is too high for food plants to grow. All over the world this problem exists and as Pimm notes there is no solution in sight. The croplands that benefit from rainwater, that is, water that is distilled by the water cycle, do not turn salty, but the amount of that land is strictly limited and shrinking because of urban sprawl.

Pimm uses a party metaphor to highlight the situation. Some guests he says pick out the cashews from the bowl of mixed nuts. "Not for them the lowly sunflower seeds, still in their husks...The high-graders who...[got the cashews] are now demanding the even more expensive Macadamia nuts. The doorbell is ringing, announcing the arrival of more guests..." (p. 107)

Pimm also looks at the fisheries and what affect our fishing has on them. His conclusion: "Humanity does not use all of the oceans' production, but what we do use is already enough to damage the oceans, seriously and perhaps permanently. (p. 127) He also notes that without government subsidies, in places like Canada, Russia, the US, Japan and Europe, fishing on a large scale would be impossible because it no longer pays. In Johannesburg where there is a world wide conference on ecology taking place as I write this, one of the main topics is how farm and fishing subsidies in first world countries are keeping the farmers and fishermen in third world countries poor. Food prices are kept artificially low so that African and Asian farmers cannot compete in the marketplace. That is one (unintended, one would hope) consequence of subsidies, but another is that the intense use of land and sea are rapidly reducing the yields, in some cases to the point of no return.

The land and the ocean are the first two parts of the book. In part three, on biodiversity, Pimm sheds some light on taxonomy and how difficult it is to count species. In an Epilogue, he addresses solutions and his hope for the future. Pimm is optimistic. I wish I could be. But until we feel the pain of lost resources, and actually have to give up some of our comfort, I don't think anything substantial is going to be done toward the avowed goal of sustained growth. (Actually, I think "sustained growth" may be an oxymoron dreamed up by some transnational corporations to excuse their continued pillaging of the planet's resources.) At any rate, humans act out of necessity. By the time the real necessity kicks in for most of the first world, much of the planet's resources will be gone.

The good news though, according to Pimm, is that most of those resources are renewable. The forests of the Eastern US have largely returned (without much of their animal wildlife or flora diversity, I must point out) and while the wild salmon may go the way of the dodo, there will be farm salmon, and if we lose the swordfish, there will still be tuna, etc.

This is an important book that anyone concerned about the future of our planet should not miss. It is in a sense fundamental to an understanding of the most important issues facing us today.