Thursday, September 11, 2014

reviews of "Harvesting the Biosphere: What we have taken from Nature" by Vaclav Smil

Harvesting the Biosphere: What We Have Taken from Nature by Vaclav Smil

My limited goal here was initially to extract factual information from the reviews of Vaclav Smil's book about the real environmental state of the planet. I then added other information from the reviews which gave some impression of the flavour of the book.

From the Bill Gates review:

The biosphere means all plant and animal life in the air, ground and oceans.

How much life is in the biosphere? The dry mass (take out the water) of all living things equals 1.6 trillion metric tons.

What percentage of the biosphere's primary productivity - the plant life generated by photosynthesis - is consumed by humans? Roughly we harvest 17% of each year's new growth (may be as low as 15% or as high as 25%)

12% of the Earth's land mass is now devoted to farmland.

The dry mass of all living humans = 125 million metric tons
The dry mass of all domesticated animals = 300 million tons
The dry mass of all wild vertebrates = 10 million tons

Dry mass of:
  • Plants = 1100 Gt
  • Bacteria = 500 Gt
  • Protists = 10 Gt
  • Fungi = 5 Gt
  • Animals = 2.5 Gt
From one of the amazon reviews (Chad M):
  • about 40% of all terrestrial phytomass - trees, brush, grass - has been removed by human activity
  • land and ocean mammals are at 10% of historic levels

Smil examines all harvests -- from prehistoric man's hunting of megafauna to modern crop production -- and all uses of harvested biomass, including energy, food, and raw materials (official blurb)

the ocean's zoomass or animal matter is perhaps that most vulnerable area in next few decades, according to the author. This is well described in the final chapter (amazon reviewer)

Smil surprises with a somewhat optimistic final chapter on long-term trends. He ends with a set of recommendations, well supported by the evidence in this book, that we need to stabilize our global population, eat less meet, waste less food, share the world's resources more equitably, and manage the demand for wood (amazon reviewer)

The collective weight of all domestic animals destined to be our meat is 25 times the weight of all wild animal on earth (amazon reviewer)

Smil gives as clear and as numeric a picture as is possible of how humans have altered the biosphere. The book is a bit dry and I had to look up a number of terms that were unfamiliar to me, but it tells a critical story. (Bill Gates)

It is amazing how little meat was available in most diets as recently as 1800: just a few kilograms per year, versus about 100 kg of meat per year in an average American diet today. (The average Indian, by contrast, eats about 10 kg of meat each year.) The world now harvests far more crops to feed animals that produce meat, dairy, and eggs than to feed humans. (Bill Gates)

But in some ways we've been less responsible in the sea than on land. We don't harvest a high percentage of all the life in the sea, but we concentrate on a very few species—especially carnivorous fish, like cod and tuna. Smil writes that most of the traditionally targeted species and major fishing areas are now being fished to capacity if they're not already overfished, near collapse, or collapsing (Bill Gates)

I was a bit surprised that he didn't talk more about innovations that will help avoid some of the problems he's concerned about. For example, he writes a lot about the impact of meat-eating on the biosphere. Producing meat is very inefficient: To get 1 kg of edible meat from a cow, you have to feed it about 10 kg of grain. But he doesn't mention the possibility of making alternatives to meat, which could reduce the inefficiency and the need for additional crops (Bill Gates)

I truly appreciate the work that has gone into this volume, and I am impressed by the diligence and attentiveness of the author in his pursuit of perfect human biomass impact calculation. As a scientific study it is thorough and boring. While it offers an overview, it contributes little to our understanding – save for the elusive numbers. And it is the numbers, I feel, which are the true protagonists here (Anna Krzywoszynska)

No comments: