Do Now:

1. Do Now: Identify and discuss 2 factors that may limit food production in the future.

2. Turn and Talk • Can we survive without soil?

3. Aim: What Environmental Problems Arise from Food Production?

4. Producing Food Has Major Environmental Impacts • Harmful effects of agriculture on • Biodiversity • Soil • Water • Air • Human health

5. Natural Capital Degradation: Food Production Fig. 12-10, p. 289

6. Natural Capital Degradation Food Production Biodiversity Loss Soil Water Air Pollution Human Health Loss and degradation of grasslands, forests, and wetlands in cultivated areas Erosion Water waste Emissions of greenhouse gas CO2 from fossil fuel use Nitrates in drinking water (blue baby) Aquifer depletion Loss of fertility Increased runoff, sediment pollution, and flooding from cleared land Pesticide residues in drinking water, food, and air Salinization Emissions of greenhouse gas N2O from use of inorganic fertilizers Waterlogging Fish kills from pesticide runoff Desertification Pollution from pesticides and fertilizers Contamination of drinking and swimming water from livestock wastes Killing wild predators to protect livestock Emissions of greenhouse gas methane (CH4) by cattle (mostly belching) Increased acidity Algal blooms and fish kills in lakes and rivers caused by runoff of fertilizers and agricultural wastes Loss of genetic diversity of wild crop strains replaced by monoculture strains Bacterial contamination of meat Other air pollutants from fossil fuel use and pesticide sprays Fig. 12-10, p. 289

7. Do you understand how the envrionment is degraded?

8. Topsoil Erosion Is a Serious Problem in Parts of the World • Soil erosion • Movement of soil by wind and water • Natural causes • Human causes • Two major harmful effects of soil erosion • Loss of soil fertility • Water pollution

9. Topsoil Erosion on a Farm in Tennessee Fig. 12-11, p. 289

10. Natural Capital Degradation: Gully Erosion in Bolivia Fig. 12-12, p. 290

11. Wind Removes Topsoil in Dry Areas Fig. 12-13, p. 290

12. Natural Capital Degradation: Global Soil Erosion Fig. 12-14, p. 291

13. Serious concern Some concern Stable or nonvegetative Fig. 12-14, p. 291

14. Drought and Human Activities Are Degrading Drylands • Desertification: productive potential of topsoil fails • Moderate (10-25% drop) • Severe (25-50% drop) • Very severe (over 50% drop) • Human agriculture accelerates desertification • Effect of global warming on desertification

15. Severe Desertification Fig. 12-15, p. 291

16. Natural Capital Degradation: Desertification of Arid and Semiarid Lands Fig. 12-16, p. 292

17. Do you understand how soil erosion leads to desertification?

18. Excessive Irrigation Has Serious Consequences • Salinization • Gradual accumulation of salts in the soil from irrigation water • Lowers crop yields and can even kill plants • Affects 10% of world croplands • Waterlogging • Irrigation water gradually raises water table • Can prevent roots from getting oxygen • Affects 10% of world croplands

19. Natural Capital Degradation: Severe Salinization on Heavily Irrigated Land Fig. 12-17, p. 292

20. Agriculture Contributes to Air Pollution and Projected Climate Change • Clearing and burning of forests for croplands • One-fourth of all human-generated greenhouse gases • Livestock contributes 18% of gases: methane in cow belches • Grass-fed better than feedlots

21. Food and Biofuel Production Systems Have Caused Major Biodiversity Losses • Biodiversity threatened when • Forest and grasslands are replaced with croplands – tropical forests • Agrobiodiversity threatened when • Human-engineered monocultures are used • Importance of seed banks • Newest: underground vault in the Norwegian Arctic

22. Genetic Engineering Could Solve Some Problems but Create Others • Pros • Cons

23. Trade-Offs Genetically Modified Crops and Foods Advantages Disadvantages Unpredictable genetic and ecological effects Need less fertilizer Need less water Harmful toxins and new allergens in food More resistant to insects, disease, frost, and drought No increase in yields Grow faster More pesticide-resistant insects and herbicide-resistant weeds May need less pesticides or tolerate higher levels of herbicides Could disrupt seed market May reduce energy needs Lower genetic diversity Fig. 12-18, p. 294

24. There Are Limits to Expanding the Green Revolutions • Usually require large inputs of fertilizer, pesticides, and water • Often too expensive for many farmers • Can we expand the green revolution by • Irrigating more cropland? • Improving the efficiency of irrigation? • Cultivating more land? Marginal land? • Using GMOs? • Multicropping?

25. Industrialized Meat Production Has Harmful Environmental Consequences • Advantages • Disadvantages

26. Trade-Offs: Animal Feedlots Fig. 12-19, p. 295

27. Trade-Offs Animal Feedlots Advantages Disadvantages Increased meat production Large inputs of grain, fish meal, water, and fossil fuels Higher profits Greenhouse gas (CO2 and CH4) emissions Less land use Reduced overgrazing Concentration of animal wastes that can pollute water Reduced soil erosion Use of antibiotics can increase genetic resistance to microbes in humans Protection of biodiversity Fig. 12-19, p. 295

28. Producing Fish through Aquaculture Can Harm Aquatic Ecosystems • Advantages • Disadvantages

29. Trade-Offs Aquaculture Advantages Disadvantages High efficiency Large inputs of land, feed, and water High yield Large waste output Loss of mangrove forests and estuaries Reduced over- harvesting of fisheries Some species fed with grain, fish meal, or fish oil Low fuel use Dense populations vulnerable to disease High profits Fig. 12-20, p. 296

30. Summary: • Do the advantages of industrialized farming and aquaculture outweigh the disadvantages? Support your answer using evidence from case studies.