Feeding extra 4 billion people
Last week this article
“Redefining agricultural yields: from tonnes to people nourished per hectare” (http://iopscience.iop.org/1748-9326/8/3/034015/) caught my eye. After going through the paper’s abstract I became very interested and read the whole thing. The numbers presented in this paper are very thought provoking with huge implications. I decided to share some of the major numbers of the paper to help disseminate its massage to a greater audience.
(apologies for long post; lot of interesting things needed to be said)
(Paraphrasing the article’s text for the sake of coherence)
Introduction – Human population is projected to increase by 60-120% by the year 2050. Economic growth in many countries (roughly 40% of world population) is fueling a ‘Livestock Revolution’ which is likely to push these rising economies to more meat-based western diet. Which means that more and more % of the world’s crop yields will be diverted to feeding the Livestock animals.
Livestock production is the single largest anthropogenic use of land right now. 75% of all agricultural land (including crop and pasture land) is dedicated to animal production. Livestock production is responsible for around 18% of the total greenhouse gas emissions.
Search for alternative fuels is also starting to divert substantial crop yields to bio-fuels (around 6% of global production in 2010).
With billions of more people coming in future, this way of resource allocation is completely unsustainable.
Method – Researchers used satellite imagery data to map crop-land. They also used national-level data of crop allocation of various countries around the world to see what countries produce and what % goes where.
Results – India, China, Brazil, and US represent around 43% of global crop area and produce 48% of global calorie production.
India: *77% of crop protein goes to human food*;
18% to animal feed; 5% other uses.
China: 50% of crop protein goes to human food;
42% to animal feed; 8% other uses.
Brazil: 16% of crop protein goes to human food;
79% to animal feed; 5% other uses.
US: 14% of crop protein goes to human food;
80% to animal feed; 6% other uses.
Calorie conversion efficiency:
40% for dairy; 22% for eggs;
12% for chicken; 10% for pork;
3% for beef
Protein conversion efficiency:
43% for dairy; 35% for eggs;
40% for chicken; 10% for pork;
5% for beef
[10% calorie or protein conversion efficiency means that after feeding an animal 100 calories or 100g protein we get 10 calories or 10g of protein in return]
Indian croplands currently feed around 5.9 people per hectare (in India) and could feed 6.5 people after diet change and no bio-fuel.
China feeds 8.4 people per hectare and could feed 13.5 people.
Brazil feeds 5.2 people per hectare and could feed 10.6.
US feeds 5.4 people per hectare and could feed 16.1.
See the attached figure to see the distribution of how people eat around the world. Greener and redder shades represent more plant-based and meat-based diets, respectively.
Globally we produce around 9.5 quadrillion calories in plant form, of which 55% goes to direct human consumption. 36% of these
calories go to animal feed, of which 89% is lost due to the inefficiencies in generating animal products. Remaining 9% of calories are completely lost due to bio-fuels and industrial applications. In total 41% of crop produced calories are lost and never reach human mouth.
A quadrillion calories are just enough to feed around 1 billion people on a 2700 calorie/day diet. Eradicating beef usage and using only chicken and pork could feed around 357 million more people. Shifting to completely ovo-lacto vegetarian diet (milk+egg+plant food) would add 815 million additional people. Shifting to a completely plant-based diet will add 4 billion people to the current population which can be sustained by present day crop production.
The implications of changing diet and ditching conventional bio-fuel practices could help humanity on a major scale. I think in future when more people are educated, they will (I hope) start thinking about these issues more. We must start using science in everyday life and habits if we want to have a future. Optimization should be given priority over consumerism and wasteful consumption.
Such kind of scientific studies should be a part of popular media as the methods employed and the results of these studies can be easily grasped by
anyone people with basic knowledge of nutrition.
I hope these numbers have at least made you to think about it.
Buddhini Samarasinghe Rajini Rao Robby Bowles Allison Sekuler Chad Haney