Half-Earth: Our Planet’s Fight for Life. Edward O. Wilson. Liveright Publishing Company, 2016.

Edward O. Wilson, the noted biologist, naturalist, and writer, has written a book on the extinction crisis. Species are going extinct about 1000 times as fast as the “normal” rate of extinction. The “solution,” argues the author, is dramatic and simple: “only by committing half of the planet’s surface to nature can we hope to save the immensity of life-forms that compose it” (p. 3).

Half of the Earth? Wow. That should get everyone’s attention. But there are some ambiguities with this idea. Which half of the earth goes to wilderness? How would we decide? Wilson is clear on many things, but parts of his proposal are left tantalizingly vague.

The strong point of Wilson’s book is that he understands the complexity of nature on earth, and he brings some new information to the table. And for someone who is new to this issue, this book would explain quite a bit; much of the book is given over to impressing the reader with the huge complexity of life on earth.

Wilson does give a list of some specific disappearing ecosystems which could be saved, continent by continent. Often, there are people who know how to restore ecosystems, at least to the point of modern European contact. For example, there are people trying to restore the longleaf pine savanna of the deep South. But, disturbingly enough, there are also people out there who are actually arguing for less biodiversity. Their argument is, roughly, that there is no point in trying to preserve the pre-human ecological habitats, that the old ecosystems are pretty much broken already, and that we are entering a new era, the Anthropocene, and we should try to make the best of it.

It’s also interesting that there is a way of quantifying how many species will be lost from habitat destruction. It is that the species that can survive are the fourth root of the habitat still available. (You’ve heard of square roots and cube roots? This formula concerns the fourth root.) It’s not the specific formula which is of interest, but just that the species loss from habitat destruction is well understood and can be quantified.  The bottom line is that if the habitat is 50% destroyed, about 85% of the species could remain; if 90% of habitat is destroyed (so that 10% remains), then roughly half of the species could survive extinction.

The weak point of Half-Earth, and it is unfortunately a significant problem, is that Wilson never really delivers on his promise of a specific plan, despite the title. It takes him a long time to get to the discussion of his idea; we are through nearly 80% of the book before we get to his solution. He does have some specifics, but seems unwilling to engage with any economic or agricultural implications, except to try to minimize them.

Is the “half of the earth” he proposes to allocate to wilderness just going to be places like Greenland, the Sahara Desert, and Antarctica, some of the most desolate places on earth? A map outlining his ideas would be useful, or even better, some more specific criteria he would use to divide the areas allocated to wilderness and the human domain.

Actually, in the September 2014 issue of Smithsonian magazine, there’s an article which has an interview with Wilson, “Can the World Really Set Aside Half of the Planet for Wildlife?”  This article does have a map at least of the United States and Canada. He should have included something like this map and a discussion in this book. But while this map is quite radical in contemporary terms, it is something considerably less than what I would call “half-earth.” Many of the areas allocated for wilderness are relatively convenient for the humans, in areas that don’t seem to be biologically productive and most are far away from agricultural or urban areas.

I kept expecting Wilson to say something about “limits to growth,” or make a passing reference to livestock agriculture or human overpopulation. Nope, nothing like that. Wilson seems to think that the economy will get bigger and better in every way, through the miracle of the free enterprise system (chapter 20, “Threading the Bottleneck)”. Interestingly, the bibliography has some references to sources talking about the “end of economic growth,” but none of that has crept into the text.

Half-Earth really is a good book, but if you are a nonspecialist (as I am) and want to know more about the extinction crisis, I’d suggest also taking a look at the Smithsonian magazine article referenced above, or at Anthony Barnosky’s Dodging Extinction. Barnosky actually understands that there are too many people and too many cows on the planet. Wilson seems to soft-pedal the influence of economic growth on the extinction crisis. But Wilson has described the crisis in quite knowledgeable detail, and he knows at least in very broad outline what needs to be done.