TODAY

1. TODAY • Food Futures: Will there be enough food for the 21st century? • Opportunities to improve output • Feeding the World: A Challenge for the 21st Century. 2000. Vaclav Smil. MIT Press. • Institutional & Policy Changes to end hunger • Ending Hunger in Our Lifetime. 2003. CF Runge, B. Senauer, PG Pardey, & MW Rosegrant. IFPRI & Johns Hopkins U. Press.

2. Reasons for Concern • Population growth • To 8-10 billion by 2050 (50% more than today!) • Dietary transitions • Moving up on the food chain • Changes in agriculture/environment • Potential for slowing growth or even stagnation or decrease

3. Food Crisis now • World food prices are up ~50% since last year • The World Food Programme announced a $500 million deficit for 2008 • http://www.freerice.com/ • Low-income countries that are net food importers; have been hit hardest • Already, 37 countries--21 of which are in Africa--are in a food security crisis according to the FAO • The World Bank recently announced that the current food situation could push 100 million people into deeper poverty • Poor households spend between 60 to 80% of their income on food, compared to only 10-20% in most industrialized countries.

4. Raising Output: 4 major issues • Photosynthesis and crop productivity limits (last time) • Land, water/irrigation, (last time) and nutrient (NPK) limits • Agroecosystems and biodiversity • Environmental change

9. 2) Nutrient limits I • Crop nutrient (NPK) limits • Typically need 10s of kg P & K and 100s kg N per ha in modern high output agriculture • Complete recycling of ALL organic residues from all harvested land and confined animals NOT able to supply all the NPK needed for high-yield agriculture (i.e., more removed by harvesting than could be replaced) • Only way to feed 10 b this way (all organic) would be to increase cropped area 2 - 3 times (e.g., all tropical rainforests)

10. 2) Nutrient limits II • Nitrogen is the key element • We do not know annual rates of biofixation of N with certainty • Clover alfalfa etc. fix about 150-200 kg/ha • Beans about 70-100 kg/ha • Bacteria in rice fields ~ 30 kg/ha • Earth may be able only to support 3-4 billion w/o synthetic N added

11. 2) Nutrient limits III • Nitrogen continued • 50 gm protein/capita/day for 6 b people in 2000 => only 19 m tons Nitrogen/yr removed from soil • Current synthetic nitrogen production about 80 m tons/yr • Energy cost to produce N: • 40 giga joules/ton of N fertilizer (40% energy; 60% feedstock) • This equals only 7% of world's total natural gas -- so energy is not a limit in the short run

12. 2) Nutrient limits IV • Phosphorus (P) • Complete recycling not able to support high-yield farming • But - mined rock not in short supply • Potassium (K) • Needed in even smaller quantities • Thus only N is a nutrient bottleneck

13. 3) Agroecosystem & Biodiversity • Basic ecology • => Increased species diversity => increased net primary productivity and nutrient retention • But NO clear link between natural system stability and diversity

14. 3) Agroecosystem & Biodiversity II • Concern: a very narrow biotic base of modern ag • Traditional systems use far more species than do modern monocultures (e.g., wheat in USA plains) • 250,000 higher plants known; 30,000 edible; 7,000 have been cropped • Only 15 major crop species • 15 species produce 90% of all food • Corn, wheat, rice produce 2/3 kcal and 1/2 plant protein!

15. 3) Agroecosystem & Biodiversity III • Crop rotations, intercropping, and new crops • Perfected rotations => better yields, soil protection, reduce pests (but not all are so good) • Introduction of legumes in rotations can be very helpful • Microorganisms (soil flora an fauna primarily) • diversity apparently NOT down overall but this is NOT a well studied field • correct applications of modern inputs does not seem to hurt soil microbes (but not well studied)

16. 4) The last major concern is Environmental Change • Changing soils • Environmental pollution • Climate change

17. Changing soils I • Erosion - most talked about issue • Mismanagement => excess erosion on 180 m ha crop fields (about 1/5 of all cropped land) • Data are uncertain and scarce • Varies with soil type and cropping type • BUT evidence is lacking to prove widespread productivity loss

18. Changing soils II • Qualitative soils degradation - often subtle and long-term • Even more difficult to prove or gather data • Again little hard data to prove widespread problems (but vice versa) • Salination is easier to show - but not significant in global sense • Loss of productivity hard to see because of changes cultivars, fertilization, irrigation, etc. • Retention of soil organics via using crop residues etc. probably key here

19. Environmental Pollution I • Has been implicated in reducing crop yields • Agriculture is a major polluter itself • Nitrogen issues • Compared to pre-industrial era humans now have doubled all inputs of nitrogen to soils & atmosphere • Nitrates are widespread contaminates in surface and sub-surface water • Atmospheric deposition of nitrogen should => increased production – but good data are scarce

20. Environmental Pollution II • Ozone • Loss of stratospheric ozone => higher levels of ultraviolet radiation => damage to crops • High levels of surface ozone also degrades agriculture production in places like W Europe; E North America; E Asia

21. Climate Change I • Mostly due to increase in greenhouse gasses • Key issues for agriculture • Surface heating (~ 2º C - greater more pole-ward) • Intensified water cycling (more in high latitudes) • Uncertain local effects but droughts, storms, or surplus water quite possible

22. Climate Change II • Probably increasing instability in climate system (i.e., storm intensity and variability) • Agriculture is a major contributors to greenhouse warming • Releasing CO2 form biomass and soils; • N2O emissions from fertilizers; • Methane from rice fields and cow farts

23. Food’s contribution to climate change • Worldwide, agriculture contributes to nearly 14% of total greenhouse gas emissions. • In the U.S., the food we eat accounts for 17% of our total fossil fuel consumption (which is huge per capita). • The annual carbon footprint of an average American diet is 0.75 tons CO2-eq, without accounting for food transportation. • On average, food travels 1,500 miles between the production location and the market. • Meat products have a larger carbon footprint than fruits, vegetables, and grains: the carbon footprint of the average meat eater is about 1.5 tons CO2-eq larger than that of a vegetarian.

24. CO2 emissions due to land use

25. Climate Change III • Consequences for agriculture • Overall agriculture output may not change much in near term – but regionally there may be problems • Increased CO2 => increased crop yields (assuming no other constraints); lower water loss thru leaves (transpiration); better ability to withstand env. pbms. etc. • Doubled CO2 should boost yields in well fertilized crops of about 7-30% (C3 species benefit most - all staple cereals except corn and sorghum)

26. Climate Change IV • Consequences for agriculture II • Rising temps • Improve efficiency of C3 plants (if too high => lower yields) • Temporal timing also key (all in summer? all in winter? – all this is unclear); but too hot could => drought-like stress • Increase cropping area overall in higher latitudes

27. Climate Change V • Consequences for agriculture III • More rapid water cycling • More water available for irrigation but regionally much more uncertain • Changes may be gradual so adaptation may help • Regional scenarios: high latitude areas may benefit (Canada, Russia); drier tropics and sub-tropics may be big losers (SS Africa etc)

28. Opportunities to improve things I(see details at end) • More efficient fertilization • Reduce losses • Proper timing • Choosing varieties that need less • More natural N fixation • Better use of water • Pricing to reduce waste • Better irrigation loss control • Precision farming and low till • Rationalizing animal food production

29. Opportunities to improve things II • Precision farming and low till • Within field adjustments (GPS/GIS technology) • No till ag to reduce nutrient and CO2 losses • Rationalizing animal food production • No real need to eat animals (but humans seem to be omnivores) • More efficient use of animal products (in order) • Milk • Eggs • Chickens • Pork • Fish • Beef

30. Opportunities to improve things III • Reducing harvest & storage losses • 15+% lost in traditional ag • Post-harvest storage losses • Maintain vitamins etc.

31. Opportunities to improve things: Higher cropping efficiency via more efficient fertilization • Late 1990s global use of N fertilizers (80 m tons/yr) about 60% to 3rd world – in future will account for more (predicted to grow at 2%/yr) • Most need in SS Africa where soil losses in NPK are not matched by fertilizer applications

32. More efficient fertilization II • Asia is reverse – HYVs and heavy fertilizer use • Problem is much applied nutrient does not serve plants at all (leaching, and erosion especially of N) and pollutes • N losses are commonly 10-15% of applied ammonia and 30-40% of manures (aggregate perhaps 45-50% loss in rain-fed and 30-40% loss in irrigated)

33. More efficient fertilization II • Reducing fertilizer losses • Soils testing • Use of more stable fertilizers • Unbalanced (excessive) N use is a main problem • Proper timing • Proper application

34. More efficient fertilization III • Increased reliance on biofixation (rotation with legumes primarily and use of green manures) and nutrient recycling • N recovery from green manures is higher than for synthetic N fertilizers • Problem is needed output is forsaken by growing of green manures • Choosing cultivars that require less (e.g, Brazil’s choice of soy with low N need => low use of N fertilizers) • Possible to inoculate fields with N-fixing bacteria to set up self-sustaining N fixation

35. Better use of water • Water seldom priced appropriately to regulate use • Irrigation efficiencies • Losses maybe 60-70% of initial total; 20-30% improvements possible => enough water to feed 100 m more people • Reduce loss in canals • Plant more water efficient crops • Better timing of water application • Simple devices to judge soil water need • Manage tillage to reduce soil water loss • Use new efficient pumps and motors

36. Rationalizing animal food production • Justification for animal use • There is no need to eat animals to lead healthy lives • But humans seem to be adapted to omnivory by evolution • Globally humans eat ~ 10-20 kg meat annually - a quite small amt. by US standards (70-110 kg annually + 300 kg milk) • Adding meat and milk to diets is an “easy” way to improve protein, calcium, vitamin, and etc.

37. Animal food production II • As long as animals eat foods we cannot they do not compete with humans • But the problem is that increasingly we feed grain to animals; in 1900 ~10% of grain to animals; by late 1990s ~45%!; > 60% in USA • If all grain fed to animals were devoted to humans => 1-3 billion could be fed!!

38. Animal food production III • Efficiencies and resource use of animals • Milk: inherently efficient energy conversion • feed: 30-40% of feed to edible energy; ~30-40% of feed to protein • land: need about 1-1.5 sq meter land per million kcal; 19-28 sq meter land per kg protein • water: 10-15 gm water/kcal; 200-300 gm/g protein • Eggs: • feed: 20-25% feed to edible energy; ~ 30-40% of feed to protein • land: need ~ 1.5-2 sq m / m kcal; 19-25 sq meter land per kg protein • water: 1.5 gm water/kcal; 15 gm/g protein

39. Animal food production IV • Efficiencies and resource use of animals • Chickens: • feed: 15-20% feed to edible energy; ~ 20-30% of feed to protein • land: need ~ 2.5-3 sq m / m kcal; 13-15 sq meter land per kg protein • water: 6 gm water/kcal; 50 gm/g protein • Pork: inherently efficient due to low basal metabolism; rapid reproduction and growth • feed: 20-25% feed to edible energy; ~ 10-15% of feed to protein • land: 5 gm water/kcal; 150-200 gm/g protein • water: need ~ 2.0-2.5 sq m / m kcal; 80-100 sq m/kg protein

40. Animal food production V • Efficiencies and resource use of animals • Fish: • feed: farmed carp etc. 15-20% feed to edible energy; ~ 20-25% of feed to protein; • farmed salmon 35-40% feed to edible energy; ~ 40-45% of feed to protein (but carnivorous => need high protein feed) • Beef: US-style feedlot • feed: 6-7% feed to edible energy; ~ 5-8% of feed to protein • land: need ~ 6-10 sq m / m kcal; 180-310 sq meter/kg protein • water: 25-35 gm water/kcal; 700-800 gm/g protein

41. Opportunities for meat and milk • Benefits of animal food are the ability to turn non-edible stuff into relatively high quality protein • Improved feeding: fine-tune feeding quantity and quality to improve efficiencies (as has been done in US over past 50 yrs) • Major costs/problems are wastes (e.g., 1 dairy cow produces 20 tons feces & urine annually) • Can be reused as manure – especially in places with concentrated industries • But cheap synthetic nitrogen fertilizers and transport/storage costs etc. make manures less attractive

42. Opportunities for meat and milk II • Strategies • Milk: efficiency of milk => a good place to put efforts • Pigs: since they are 40% of ALL meat consumed worldwide and are omnivorous and can gain on many foods (e.g., cassava, bananas, brans, brewery byproducts, etc.) • Water buffalo: since they are more efficient converters of roughage to protein than cows

43. Opportunities for meat and milk III • Strategies • Fishing: • Yield is poor in open ocean; far better inshore on continental shelves due to greater nutrient availability • As of late 1990s the ocean is fully fished (no opportunities for expansion, probably contraction)

44. Opportunities for meat and milk IV • Strategies • Aquaculture: • Now provides about 20% of all fishes; 80% of all mollusks; ~ 1/5 of all shrimp; 1/3 of all salmon • Total greater than all mutton and lamb and ~ 1/3 all chicken • Tilapia is especially attractive: likes warm climates; is omnivorous; an be raised intensively or extensively; mild taste • Has many advantages: improved diets; can be integrated into agriculture systems (e.g., rice) • e.g., Chinese carp polyculture system is good: 2-4 tons/ha (700kg protein) of fish plus other vegetables etc. on very small farms (0.2-.05 ha)

45. Opportunities for meat and milk V • Strategies • Aquaculture – problems: • Humans have less experience raising fish (especially outside Asia) so predicting expansion is harder • More intensive production is possible • But pollution problems already

46. Changes in crop yield by the 2080s, under scenarios of unmitigated emissions Rosenzweig, C., M. L. Parry, G. Fischer, and K. Frohberg. 1993. Climate change and world food supply. Research Report No. 3. Oxford: University of Oxford, Environmental Change Unit.

48. Changes in crop yield by the 2080s, under scenarios of stabilization of CO2 at 750 ppm

49. Changes in crop yield by the 2080s, under scenarios of stabilization of CO2 at 550 ppm