1.74 | Fall 2020 | Graduate

Land, Water, Food, and Climate

SECTION 4 | Reconciling Demand and Supply: Options


What are the primary options for reconciling food demand and supply? What are their advantages and disadvantages?

Our discussion so far provides background we need to evaluate options for reconciling food demand and supply. The available options are constrained by physical factors such as the land and water available for growing crops and by human factors such as income, dietary preferences, and attitudes about pesticides or genetically engineered crops. Before we consider particular proposals for achieving sustainable food security it is helpful to step back and review some of issues revealed in our readings.

We have seen that increasing production beyond present levels could conflict with the need to maintain a sustainable agricultural system that functions well over the long term. In particular, the inputs and practices needed to increase yield have already had, and will likely continue to have, adverse environmental impacts that threaten the land, water, and soil resources we need to grow food. Of course, we would like to have a win-win solution (sustainable intensification?) that is both sustainable and sufficiently productive to support our growing population. But that may not be so easy to achieve.

We have seen that food security varies greatly with location, time, and income so that, while global analyses give some overall perspective, they are not sufficient to assess the feasibility and desirability of alternative food security proposals. For example, we have seen that current global food production appears to be enough to feed everyone on the planet a nutritious diet. But several hundred million people are still chronically malnourished.  There are many more examples where geographical and economic variability are critical to an assessment of food security problems and solutions.

It is worth highlighting some critical regional differences that affect food security. Land suitability (e.g. soil, terrain, and growing season length) and water availability vary greatly, with the best conditions generally found in areas that have been cultivated for centuries, primarily in the northern hemisphere. Prospects for new cropland opening up are limited, although climate change could shift the areas that are most suitable. In general, tropical and subtropical areas in the global south appear more likely to be adversely affected by climate change but some northern hemisphere areas such as the Mediterranean and western North America could also suffer. The level of economic development in different regions also has an important impact on crop production and food security. Africa stands out for its low per capita income, higher malnutrition rates, and lower life expectancies as well as its low crop yields. But there are pockets in all regions where the food supply is currently insecure or is threatened by poverty, political instability, and/or climate change.

Regional diversity has led to differences in the way that farming is conducted. It is helpful to distinguish three broad crop production systems that have global extent 1) commercial export-oriented, 2) small high-input, and 3) small low-input farms (see S13 for a quick comparison):

Commercial export-oriented farms tend to be in the areas most favored for crop production, especially in the more economically developed countries of North America, southern Latin America, Europe, and Oceania. Farms in major food exporting countries are generally large, employ small fractions of their national populations, and provide farmer incomes that compare well to incomes in other occupations. These farms supply most of the essential food needs of their regions while also exporting enough food (calories) to feed as much as one third of the global population (see Class 10). They tend to use high levels of inputs (e.g. water, nutrients, pesticide), rely on modern high-yield cultivars, have better market access, and are more mechanized and less labor intensive than farms in the other two groups.

Small high-input farms, especially small farms in Asia, have benefitted from the twentieth century Green Revolution, which introduced new cultivars selectively bred for robustness and high yield. Farms that rely on these cultivars typically use high levels of fertilizer and pesticides and achieve yields nearly as high as commercial farms. However, they tend to be much smaller, more labor intensive, and provide less income for their operators than farms in the first group. The reason for the persistence of small farms in Asia is debated. Some researchers suggest that there has not yet been sufficient time for a transition to large farms such as those that occurred in Europe and North America, when farm labor productivity increased and many rural workers left for urban jobs. Others feel that small high-input farms survive in Asia because they work well and are appropriate for local conditions (see Class 7).

Small low-input farms generally do not follow the high input/high yield model of the other two groups. Farms in this third group often do not have ready access to essential inputs, are labor intensive, have low yields and revenues, and are limited by inadequate infrastructure and market access. Poor smallholder farms prevail in sub-Saharan Africa but are also found in parts of Asia and Latin America, as discussed in Class 7. Their future is uncertain and there are many who believe that they cannot survive.

Each of these farming systems currently feeds a sizable fraction of the global community. They tend to cluster in particular regions, as revealed in part by the striking field size map shown in Figure S10. All three systems are relevant to our consideration of future food production options in a world with a few billion more people, higher per capita consumption, and a changing climate. Each provides a possible model for future agriculture and, moreover, a place to start when considering other models that are different from any of these present-day options.

In Section 4 we start by reviewing, in Class 11, the twentieth century Green Revolution that was instrumental in creating the small high-input Asian model of agriculture. Then we consider whether a repeat or extension of the Green Revolution could provide a sustainable global food security solution for the 21st century. In Class 12, we examine the primary ideological alternative to the Green Revolution model—agroecology. This option advocates reliance on ecological principles and a suite of smart low-input (or alternative input) farming practices. In some ways, agroecology can be viewed as an improved version of the small low-input model production system. As we explore the common areas and differences between the Green Revolution model and the agroecological model we will also be looking for hybrids and totally new options that may suggest a way to achieve both food security and sustainability.

It should be easy for you to identify the advocates for different perspectives in our readings. There are relatively few papers that give equal weight to food security and sustainability. The debate over the merits of the Green Revolution vs. agroecology is linked to debates we have already encountered over genetically engineered crops, sustainable intensification, and the desirability of encouraging smallholder agriculture. Although we have read only a few selections from the large literature on these topics our examples are sufficient to illustrate the high degree of controversy found in discussions of food security. This applies to the scientific community as well as the economic and policy communities. We will need to recognize this controversy when discussing a path forward in Section 5.

Section 4 Class Topics

Class 11: Green Revolutions Past and Future
Class 12: Agroecology

Section 4 Supporting information (SI)

S13. Comparison of Three Crop Production Systems

Course Info

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Fall 2020
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