1.74 | Fall 2020 | Graduate

Land, Water, Food, and Climate

SECTION 3 | Reconciling Demand and Supply: Context


How can we achieve a sustainable balance between food supply and demand in a diverse and changing world?
What do we need to consider in our search for practical ways to reconcile food supply and demand?

The readings and supplementary information provided in Section 2 make some points that we need to consider when looking for ways to reconcile food demand and supply:

  • Demand reductions alone will probably not be sufficient to meet the nutritional needs of the 21st century global population. Food production will also need to increase. The amount of increase required will depend on uncertain changes in per capita demand and population.
  • At the same time, agricultural technology and management practices will need to be more sustainable than they have been, so that increases in production can be maintained over the long term.
  • The agricultural system will need to be more resilient so it is able to respond to climate change, disease, and uncertain trade policies.
  • Food will need to be more accessible to populations that are vulnerable to malnutrition.

In this section we examine several topics that provide context for our subsequent discussions of strategies for meeting projected demand for food.

Class 5 considers the critical role of crop yield. The strategy of sustainable intensification, which we have already encountered, relies on finding environmentally acceptable ways to increase yield. This can be done i) by increasing potential yield, which is the yield that can be obtained for a particular crop under ideal conditions, or by ii) reducing sources of stress that cause actual yield to be below potential yield. The readings for this class provide good introductory discussions of the factors that both limit yield and contribute to high yield variability. Class 5 provides background for our later discussion, in Class 11, of yield increases in the Green Revolution and beyond.

Class 6 considers the effects of agriculture on the environment, with an emphasis on important ecosystem and nutrient cycle changes that could impact future production. The readings deal with depletion of water supplies, impacts of nutrient and pesticide application, soil degradation, and ecosystem changes. We consider these topics so we can properly evaluate the environmental impacts of increasing crop inputs such as irrigation water, fertilizer, and pesticides.

Class 7 takes a closer look at smallholder farmers, who produce and consume large fractions of the global food supply. This discussion is useful for assessing the challenge of improving food security for everyone, including the rural poor in developing regions. Class 8 considers climate changes of particular relevance to agriculture, with an emphasis on impacts that could affect crop yield, smallholder farmers, and pest control.

Class 9 discusses two new technologies, genetically engineered crops and precision agriculture, that could have significant impacts on crop production. Class 10 examines the roles of trade and optimization as strategies for making better use of limited and unevenly distributed resources. Trade has the effect of transferring land and water over time and space, reducing regional or seasonal imbalances between supply and demand.

Our readings on these topics, together with the Supporting Information, provide important background needed to evaluate the management options considered in Section 4.

Section 3 Class Topics

Class 5: Crop Yield
Class 6: Environmental Impacts of Agriculture: Protecting Natural Resources
Class 7: Smallholder Farming: Focus on Africa
Class 8: Climate Change and Agriculture
Class 9: New Technologies and Practices: Genetic Engineering, Precision Agriculture
Class 10: Trade and Optimal Resource Allocation

Section 3 Supporting information (SI)

S9. Soil Properties, Soil Suitability Measures, and Changes in Soil Quality
S10. Global and Regional Farm Characteristics
S11. World Greenhouse Gas Emissions: 2016
S12. Adoption of Genetically Engineered Crops in the USA

Course Info

As Taught In
Fall 2020
Learning Resource Types
Lecture Notes
Instructor Insights