15. Delineating the food system Flashcards
True or false: nitrogen can only come from proteins.
True.
What is dynamic equilibrium?
When there is as much output as input. Each time the input is increased, it takes longer for the feedback to react, but there will always be equilibrium in the end.
What are the three challenges ahead for food supply?
- By 2050 we will need 100% more crops because of more people with more affluence
- For food security we need to double yield/ha
- For sustainability we need to quarter impacts/ton
Which three PBs are most overshot?
- Biodiversity loss
- Nitrogen cycle
- Climate change
What is the main driver of overshooting of all the Planetary Boundaries in general?
Food production
How does the natural carbon cycle work?
- Carbon dioxide is in the air
- Plants can use the carbon dioxide
- Plants are eaten by animals and humans (humans can also eat animals to get the carbon dioxide)
- After decomposing of bodies, carbon dioxide returns to the air
How is the carbon cycle disturbed by humans?
Climate change adds carbon dioxide to the atmosphere through the combustion of coal and oil. Every year we add 1-2% to the atmosphere.
Describe the natural nitrogen cycle.
- N2 is in the air
- N2 can be turned into ammonia synthesis (N3) by lightning or bacteria
- Plants use ammonia for protein
- Animals and humans eat the plants
- Bacteria degrade the ammonia
- Ammonia returns to atmosphere in N2
How is the natural nitrogen cycle disturbed by humans?
- Acceleration: +100-200% in one century increase of N2->NH3 by Haber-Bosch process for fertilizer
- Because of this extra ammonia emissions.
Name 2 examples of consequences of overfertilization.
- Algal bloom in the Gulf of Mexico
- Dead zone in the Baltic Sea
What would happen if we stop making N-fertilizer today?
In 5-10 years the global population would be half of what it is today.
What is the ratio of protein efficiency for animals:plant
1:6
How much of all arable land is used for feed crops?
1/3
Name 3 options to reduce impacts of food production.
- Biorefinery “cascade” required: food > feed > fibre > feedstock > fuel
- Innovation: crop (algae), irrigation (drip), site (urban)
- Novel Protein Foods (low in energy & egg white)
- Upgrade rest streams (pigs, insects, fish)
- Reduce food waste (presently 25-30%)
- Diet change (less meat and dairy)
How much do we overconsume in the EU?
200%
