Lecture 11: The climate costs of farming

Question 1

CO2 the only greenhouse gas?

Answer 1

NO, methans, nitrous oxide, CFC’s

– we release less amounts but have higher warmer effects, so lead to greater warming

Question 2

global argo-food systems accounts for __ of total anthropogenic GHG emissions

Answer 2

19-29%

Question 3

where are the major GHG emissions from global food system the coming from?

Answer 3

life cycle analysis’ tells us agriculture (growing of food) accounts for 80-86% of total agri-food GHG emissions (direct and indirect)

Question 4

IPCC estimate direct emissions from agriculture account for __ of total GHG CO2 equivalents

Answer 4

10-12%

indirect (deforestation and biomass burning) = 6-18%

Question 5

deforestation =

Answer 5

• primary source of new agricultural land in the tropics

- forests major land use before agriculture

Question 6

what drives deforestation? (indirect sources)

Answer 6

• economics
• South america; cattle ranching
• Amazonia; soy
• Southeast Asia; palm oil
• smallholder agriculture is important (i.e. in Africa) BUT big business is coming

Question 7

Agriculture sources of methane

Answer 7

• rice paddies
• – anaerobic conditions in flooded rice paddies
• – methanogenic bacteria
• bacterial fermentation in multi-chambered stomachs of ruminants (cattle & sheep)

Question 8

CO2 equivalents

Answer 8

take into consideration of all GHG and relates them to CO2

Question 9

carbon costs of meat

Answer 9

Beef (ruminant animals) is very high, meat is much greater than grains and vegetables

Question 10

animal agriculture are fed

Answer 10

a lot are fed food that could be eaten by people = barley, soy bean etc

• i.e 75% of soy bean crop is fed to animals
• animals aren’t efficient in turning plants to meat, so energy is lost (cows and sheep particularly inefficient)

Question 11

perks to animal agriculture

Answer 11

they can live where crops can’t be planted, on marginal land

Question 12

Advances in N fertilisers positives and negatives

Answer 12

• allows us to feed growing population
• is cheap but if you over apply it feeds denitrification which feeds nitrous oxide emissions
• application of excess nitrogen is the issue

Question 13

agricultural sources of nitrous oxide

Answer 13

• naturally produced by soil denitrification

- enhanced by synthetic fertiliser and manure

Question 14

how can vegetables obtain costly ghg costs

Answer 14

• airfreight
• • flying out of season crops around the world
• hothouses (heated greenhouses)
• paddy rice (methanogens = methane)

Question 15

food waste =

Answer 15

1/3 of food produced is wasted globally

• developed countries waste it at sale & consumers
• less well developed = storage and post harvest

Question 16

____ is the main contributor to food GHG emissions

Answer 16

agriculture

- transport, processing and cooking have effect but direct & indirects from agriculture is more

Question 17

more than __ billion of adults are overweight

Answer 17

1. 9 billion

- - twice the number of obese people in the world in comparison to those malnourished

Question 18

issues with being overweight

Answer 18

increased risk of heart disease, stroke, diabetes, many cancers
–> more deaths worldwide than undernutrition

Question 19

greater wealth increases:

Answer 19

meat consumption and overconsumption

– meaning greater risks of diseases

Question 20

mitigating GHG emissions from the global food system =

Answer 20

• halt forest clearance for agriculture
• reduce agricultural inputs (e.g. fertiliser)
• better soil and crop management
• reduce waste
• promote dietary change

Question 21

improving soil and crops

Answer 21

• reduce tiling

- crop rotations etc