Climate change has been on my mind a lot lately. The topic seems to be in the media recently especially with the publication of Bill McKibben’s Falter: Has the Human Game Begun to Play Itself Out? and David Wallace-Wells’s The Uninhabitable Earth. I am planning to read both of them.
A colleague referred me to another book on the subject, Harvesting the Biosphere: What We Have Taken from Natureby retired University of Manitoba professor, Vaclav Smil. Smil is a polymath and the 2013 book has an academic tone being published by MIT Press. I skimmed through most of the initial chapters that define the topic and read in depth the final chapters look to the future. Bill Gates is a big fan of his and after reading his book and watching a few of his videos, I am too!
The term “harvesting the biosphere” refers to humanity using the earth to survive. This includes agriculture, mining, fishing, animal husbandry, construction, transportation, etc. Humanity has transformed the planet “…no species has been able to transform the Earth in such a multitude of ways and on such a scale as Homo sapiens. “
The changes have been so profound and because of the short lifespans of humans, we are not conscious of them. Dr. Smil puts these changes in perspective looking at the problem in a systems and statistical manner. Below are my notes from my reading:
- Humans have reduced the biosphere’s phytomass (all plants, including photosynthetic plankton) by 35-40% through the invention of agriculture. This includes almost 100% of the best soils in large, populated nations and in 2010, farms occupied 12% of all ice-free land.
- Population growth will put a big strain on the earth’s resources. Growth has slowed since its 2% peak in the 1960s and its annual addition of 90 million people annually in the 1980s. UN estimates that we will pass the 10 billion mark in the 21st century. From 1900 to 2000, total human biomass has increased 3.7 times. This is not only in numbers, but the sizes of individuals. For example, the average 20-year old male in Japan in 1900 weighed 53 kg, but in 2000, the average is 65.4 kg. Smil also takes 1into account when quantifying human biomass by assigning a greater average to the USA (33% obesity rate in 2000) than Japan (3.9% obesity rate). The mean weight for the 6.1 billion humans in 2000 was 50 kg.
- Animal husbandry also has severely transformed the planet. There are 4.3 billion domesticated animals including 1.65 billion cattle. This has played a part in the reduction of Earth’s wild fauna.
- Smil and others are against biofuels because it contributes to increased loss of forests.
- I was surprised about Smil’s focus on household food waste because I didn’t know the scale of the problem. Waste in the USA increased from 28% of total food supply in 1974 to 40% in 2004. UK households waste 31% and even Japan, the least wasteful affluent country, loses 25% of its food supply. This food waste not only occurs at homes, but in the harvesting and distribution of food. This is unacceptable, especially in light of obesity rates and the over indulgence of citizens in affluent countries. I would like for us to reduce waste in our school cafeteria.
- He is pessimistic on future production of the oceans. Acidification, higher temperatures and over-harvesting have permanently decreased ocean productivity.
Smil’s prescription for minimizing human claims on the biosphere’s productivity are as follows:
- Stabilize population at < 9 billion
- Optimize agriculture thru best practices including crop rotations instead of monoculture
- Average food requirements per capital should be limited levels that support healthy and long lives instead of excessive carnivore and obesity-inducing diets.
- Pay more attention to post harvest food losses and household food waste.
- Develop staple grain crops that fix nitrogen.
- Properly manage forests and live within production capacities of forests for wood output.
- Wood demand should be set by maintaining sensible material comforts rather than striving to perpetuate extravagant consumption delivered in “wasteful throw-away packaging”. In one of his videos, he mentions the $20,000 bathroom re-model that many North Americans go through. Who needs a $20,000 bathroom for a toilet, bathing and grooming?
- It may be unrealistic, but to share resources to reduce existing inter- and intranational inequalities.
- Support research leading to new tree cultivars that combine superior productivity with hardiness.
I also liked that he included the benefits from increased CO2 in the atmosphere and increased temperatures in his analysis of climate change. Will these increase plant productivity? Will the intake of carbon by forests increase or decrease? How will a warmer and more acidic ocean impact marine phytoplankton?
I will be watching his videos and looking into further publications from him.