Transcript Another Inconvenient Truth

Another Inconvenient Truth:
the adverse effects of animal foods
on the environment
Paul Appleby
(with thanks to Nigel Winter and Stephen Walsh)
Oxford Friends Meeting House
9 March 2007
Some quotes
• Livestock are one of the most significant contributors to
today's most serious environmental problems. Urgent
action is required to remedy the situation. UN Food and
Agriculture Organisation official Henning Steinfeld
• If the impacts of climate change are as bad as predicted we
may need to go back to (food) rationing. Environment
Minister Ben Bradshaw MP
• The world must create five billion vegans in the next several
decades, or triple its farm output without using more land.
Dennis Avery, Director of the Center for Global Food
Issues,The Hudson Institute
• Each of us could make a bigger contribution to reducing
emissions of greenhouse gases by becoming a vegan than
by converting to an eco-friendly car. Environmental
campaigner Jonathon Porritt
Production of animal foods
• Worldwide meat production reached 265 million
tons in 2005, equivalent to 42 kg per person
• Global meat production has increased fivefold
since the 1950s and more than doubled since
the 1970s
• Meat production is projected to increase to 465
million tons in 2050
• Milk production is projected to increase to over
1000 million tons in 2050 (from 580 million tons
in 2000)
Livestock numbers
More than 50 billion animals are slaughtered
for food each year
At any one time we share the planet with
• 15 billion poultry
• 1.3 billion cattle
• 1.7 billion small ruminants (sheep, etc)
• 0.9 billion pigs
The world’s human population of 6.5 billion is
projected to increase to 9.1 billion by 2050
Land use and degradation
 Livestock production accounts for 70% of all
agricultural land (including 33% of arable land
used to grow feed) and 30% of the land surface of
the planet
 About 20% of the world’s pastures and rangelands
have been degraded to some extent (73% of
rangelands have been degraded in dry areas),
mostly through overgrazing, compaction and
erosion caused by livestock
 70% of previously forested land in the Amazon is
now pasture (and most of the rest is used to grow
feed, principally soy beans)
Is land used efficiently?
1200
1057
Pounds of protein per acre
1000
814
800
708
600
400
306
318
245
218
200
96
0
Soya
Potatoes
Wheat
Rice
Eggs
Milk
Pork
Beef
A vegan diet uses half the amount of land used to produce a vegetarian diet
and one fifth of that used for a European omnivorous diet.
(Calculations by Stephen Walsh using data from Gerbens-Leenes et al, A Method to Determine Land Requirements
Relating to Food Consumption Patterns, 2002; FAOSTAT, 2006; and The Composition of Foods, 6th Edition, 2002.)
Kilograms of protein required to be fed to an
animal to produce one kilogram of animal protein
Source: Council for Agricultural Science and Technology
Water scarcity and water use
“The world is moving towards increasing problems
of freshwater shortage, scarcity and depletion, with
64 percent of the world’s population expected to
live in water-stressed basins by 2025” (UN FAO).
Already, more than 1 billion people lack enough
safe water to meet minimum levels of health.
“Food and agriculture are by far the largest
consumers of water. They require one thousand
times more than we use to drink and one hundred
times more than we use to meet basic personal
needs” (World Water Development Report, 2003).
Litres of water used to produce one
kilogram of various foods
(according to various sources)
Food
Pimentel
Beef
100000
Lamb
Chicken
3500
Soya beans
2000
Grains
Rice
1910
Maize (corn) 1400
Wheat
900
Potatoes
500
Reijnders
S.I.W.I.
20000
15000 (or more)
10000
6000
750
400-3000
4700 (irrigated)
1400
The net amount of water required for a 3000 kcal/day mixed diet with 20%
animal foods has been estimated as 1300 cubic metres per person per
year, whereas for a purely vegetarian diet it is about half as much.
(Water - more nutrition per drop, Stockholm International Water Institute & International Water Management Institute, 2004)
Water pollution
• “The livestock sector accounts for over 8% of
global human water use and is probably the largest
sectoral source of water pollution” (UN FAO)
• US livestock are responsible for an estimated 55%
of erosion and sedimentation, 37% of pesticide
use, 50% of antibiotic use, and one-third of the
nitrogen and phosphorus contamination of
freshwater
• 200 million tons of undiluted excreta are produced
on UK farms each year
• Of the 4254 UK agricultural pollution incidents in
1999, more than two-thirds arose from livestock
rearing compared with 7% from arable farming
Threats to biodiversity
• Species loss is estimated to be 50-500 times
higher than background rates
• Livestock production is the main cause of
deforestation, and a major cause of land
degradation, pollution, climate change, overfishing, and sedimentation of coastal areas
• 23 out of 35 global biodiversity hotspots
identified by Conservation International are
affected by livestock production
• “The livestock sector may well be the leading
player in the reduction of biodiversity” (UN FAO)
Relative environmental impact of
meat to soy protein production
Environmentally relevant effect
Land use
Water requirement
Fossil fuel requirement
Phosphate requirement
Emission of acidifying substances
Emission of biocides
Emission of copper
Relative impact
6-17
4.4-26
6-20
7
>7
6
>100
Based on Table 1 of Reijnders and Soret, American Journal of Clinical Nutrition, 2003.
Livestock and greenhouse gases
• Livestock production is responsible for 18% of
greenhouse gas emissions measured in CO2
equivalent (more than global transport), including
• 9% of anthropogenic CO2 (largely as a result of
deforestation)
• 37% of anthropogenic methane (with 23 times the
global warming potential of CO2)
• 65% of anthropogenic nitrous oxide (with 296 times
the global warming potential of CO2)
• Livestock also account for 64% of anthropogenic
ammonia, a significant contributor to acid rain and
the acidification of ecosystems
Diet and global warming
A study by researchers at the University of Chicago compared
the amount of fossil fuel needed to cultivate and process
various foods, and factored in emissions of methane and
nitrous oxide produced by livestock.
The researchers found that the typical US diet, to which animal
foods contribute about 28% of the energy intake, generates
the equivalent of nearly 1.5 tonnes more carbon dioxide per
person per year than producing the same amount of food
energy from plant foods alone.
In comparison, the difference in annual carbon dioxide
emissions between driving a typical saloon car and the most
energy-efficient car on the US market, based on average
annual mileage figures, was just over one tonne.
Methane and climate change
• Methane is the most important non-CO2 greenhouse gas,
responsible for nearly as much global warming as all other
non-CO2 greenhouse gases combined
• Human activities produce 1½ times as much methane as all
natural sources combined (compared with just 3% for CO2)
• Livestock rearing is the largest anthropogenic source of
methane (37%)
• Lower methane emissions quickly translate to a cooling of
the Earth’s atmosphere because methane cycles out of the
atmosphere in just 8 years (in contrast, CO2 can remain in
the air for more than 100 years)
• “Switching to a vegan diet is a faster way of reducing global
warming than cutting CO2 emissions” (Earthsave
International)
Fish production
• 132.5 million tons of seafood (fish, crustaceans,
etc) was 'harvested' in 2003, equivalent to 21 kg
per person, including 54.8 million tons (41%) from
aquaculture (fish farms)
• The collapse of all wild fisheries has been predicted
by 2050 (collapse is defined as 90% depletion of
stocks)
• 1.2% of global oil production is used to catch wild
fish
• The energy used to obtain fish protein may be up to
14 times higher than for the same amount of plant
protein
Is aquaculture the answer?
• Aquaculture is the fastest growing animal
food producing sector
• 3-4 kg of wild fish are required to produce
1 kg of farmed salmon
• The chemicals used to keep farmed fish
free of parasites and disease are a major
source of environmental pollution
• The environmental impacts of aquaculture
may be of the same order of magnitude as
conventional animal husbandry
Evaluation of the environmental impacts of
various diets using lifecycle assessment
An Italian study* compared the overall environmental impact of 7 diets
using lifecycle assessment, taking into account effects on human health,
ecosystem quality and resource use. The diets were as follows:
• NORM-INT a ‘normal’ Italian diet, equivalent to the average Italian
weekly diet, with food from conventional farming
• OMNIV-INT a prudent (low meat and fish) omnivorous diet based on
food from conventional farming
• OMNIV-BIO as above but based on food from organic farming
• VEGET-INT a vegetarian diet based on food from conventional
farming
• VEGET-ORG as above but based on food from organic farming
• VEGAN-INT a vegan diet based on food from conventional farming
• VEGAN-BIO as above but based on food from organic farming
* Baroni, Cenci, Tettamanti and Berati, European Journal of Clinical Nutrition, 2006.
Average environmental impact (in points) of
the 7 diet types
6
5
4
3
2
1
0
NORM-INT
OMNIV-INT
OMNIV-ORG
VEGET-INT
VEGET-ORG
VEGAN-INT
VEGAN-ORG
Resources
3.7
1.415
0.798
0.878
0.594
0.544
0.455
Ecosystems Quality
0.65
0.268
0.265
0.167
0.177
0.112
0.0714
Human Health
1.06
0.458
0.2
0.335
0.18
0.15
0.0397
The study concluded that “vegetarian and vegan diets could play an
important role in preserving environmental resources and in reducing
hunger and malnutrition in poorer nations”.
In defence of livestock
Livestock provide a livelihood to 1.3 billion people
(20% of world population), provide essential
draught power, manure and fuel (dung, biogas) in
developing countries, and can be reared on land
unsuitable for crop production.
Animal foods can make an important contribution
to the diet of the under-nourished, and can have a
lower environmental impact than plant foods (e.g.
air-freighted plant foods or vegetables grown in
heated greenhouses).
Conventional solutions
• Improve the resource use efficiency of
livestock production
• Price natural resources (land, water, etc)
to reflect the full economic and
environmental costs of livestock
production
• Remove damaging subsidies
• Provide payment for environmental
services
• Develop the necessary institutional and
policy frameworks
Green solutions
“Government policy should encourage vegetarian diets.
Possible mechanisms include an environmental tax on meat,
a shift in farm subsidies to encourage plant agriculture over
animal agriculture, or an increased emphasis on vegetarian
foods in government-run programmes.”
Noam Mohr, Earthsave International
“The production of meat and dairy products has a much
bigger effect on climate change and other environmental
impacts than that of most grains, pulses and outdoor fruit and
vegetables. Many people could benefit from eating a larger
proportion of fruit and vegetables and less saturated fat.”
Buying food: greener choices, UK Government website
What you can do
• Eat fewer animal foods, or none at all
• Buy locally produced, seasonal, organic
food as far as possible
• Grow your own fruit and vegetables, and
gather edible wild foods
• Compost your kitchen and garden waste
• Cut down on car journeys for food
shopping
• Use tap water instead of bottled water
• Avoid unnecessary packaging or choose
biodegradable or recyclable packaging
Sources and Resources
• Livestock’s long shadow: environmental issues and options. UN Food and
Agriculture Organisation, 2006.
• Luciana Baroni et al. Evaluating the environmental impact of various
dietary patterns combined with different food production systems.
European Journal of Clinical Nutrition, 2006.
• Lucas Reijnders & Sam Soret. Quantification of the environmental impact
of different dietary protein choices. American Journal of Clinical Nutrition,
2003.
• Gidon Eshel & Pamela Martin. Diet, energy, and global warming. Earth
Interactions, 2006.
• Noam Mohr. A New Global Warming Strategy. Earthsave International,
2005.
• Mark Gold. The Global Benefits of Eating Less Meat. Compassion in World
Farming Trust, 2004. www.eatlessmeat.org
• www.direct.gov.uk/en/Environmentandgreenerliving/Greenerfoodanddrink/
(UK Government web site offering advice on ‘greening’ your diet)
• www.earthday.net/footprint (Calculate your ecological footprint)