Food Access and Climate Change

If Thomas Malthus is the customary jumping-off point for discussions of food availability, economist Amartya Sen dominates introductory paragraphs in discussions of food access. Recalling the definition above, food access refers to the ability of an individual to acquire food, either through its production or its purchase. Sen referred to these means of food acquisition as "entitlements", and he won the Nobel Prize in part for showing how famines were a result of households or entire regions periodically lacking entitlements. His basic insights hold today: for a farmer, entitlements are the means of food production available to her (e.g., land and labor), and her access to food is secure if she can command sufficient amounts of these factors to produce enough food. For those who don't farm, access to food is a function of incomes and prices - how much money one has to spend on food, and how much the food costs. Food access then can deteriorate when non-farm incomes fall, when food prices rise, or when the productivity of farm households suffers.

Determining the effects of climate change on food access for a given household therefore requires addressing the role of climate change in relation to four basic questions: how households earn their income, the nature of their exposure to food prices, how well integrated their local food markets are with global markets, and their broader longer-run prospects for livelihood improvement.

The first question concerns the extent to which a given household is dependent on agriculture for its income. If agriculture will be one of the sectors most affected by climate change, then the greater a household's livelihood depends on agriculture, the more that household is sensitive to the impacts of climate. While good systematic data on sources of household income in the developing world are hard to come by, there have been multiple recent efforts to try to systematize the available survey data on household income and to discern basic patterns across the developing world.1

1 See, for example, the RIGA project (Davis et al. 2007, Ivanic and Martin 2008), IFPRI's HarvesChoice Project, Stanford's ALP Project, and Banerjee and Duflo (2007).

Ghana 1998 Malawi 2004 Nigeria 2004 Guatemala 2000

Ghana 1998 Malawi 2004 Nigeria 2004 Guatemala 2000

poorest median richest poorest median richest poorest median richest poorest median richest

Fig. 2.5 Percentage of rural household income derived from agricultural sources, by income quintile for selected countries (Davis et al. 2007). Black = on-farm income; dark grey = agricultural wage income; light grey = off-farm income; white = transfer income/other. For instance, the poorest 20% of rural Ghanian households derive about 80% of their income from farm activities poorest median richest poorest median richest poorest median richest poorest median richest

Fig. 2.5 Percentage of rural household income derived from agricultural sources, by income quintile for selected countries (Davis et al. 2007). Black = on-farm income; dark grey = agricultural wage income; light grey = off-farm income; white = transfer income/other. For instance, the poorest 20% of rural Ghanian households derive about 80% of their income from farm activities

Recall from the Smith data that most of the food insecure live in rural areas. Figure 2.5, adapted from data in Davis et al. (2007), shows the percentage of rural household income derived from agriculture in a set of poor countries for which good income data were available. The general trend from these data is clear: rural households in many developing countries depend to a significant extent on agriculture for their livelihoods, and this dependence tends to rise the poorer the household is. For the poorest of these households, two-thirds or more of income is earned on average through agriculture - a total that includes income from sales of crop and livestock goods in the marketplace, as well as the value of such goods produced by the household for home consumption. Such an agricultural dependence suggests that the income effects of a decline in agricultural productivity (all else equal) could be significant.

Importantly, however, few households even in rural areas are fully dependent on agriculture. The inherent seasonality and year-to-year variability of agriculture encourages diversification of income sources, and in the dry season or in particularly bad years many rural households seek additional income in non-agricultural wage labor or self-employment. As Fig. 2.5 shows, these sources of income can be important, and introduce a second main aspect of climate change and food access, the nature of a household's exposure to food prices.

All households are consumers of food, and as consumers benefit when food prices are low. But rural households are often producers of food as well, selling surplus in local markets. As a result, such households benefit as consumers but are hurt as producers when food prices fall. So if climate change induces changes in the supply of food that in turn affect food prices, the net impact of these price changes on food access in a given household will depend on the particular net consumption position in that household - that is, whether they spend more on food purchases than they earn from selling what they produce.

Estimating net consumption position again requires the use of household surveys, in this case surveys that have detailed information on both agricultural production and consumption behavior. As with income, there have been some recent efforts to characterize household net position for staple grains across a subset of developing countries (Fig. 2.6). These data show, unsurprisingly, that urban households are largely net consumers of food, purchasing nearly all of what they consume. More surprising perhaps is that the majority of rural households in many poor countries are also net consumers of food, with even farm households using non-farm income to purchase what they are unable to produce. These net-consuming households will likely be helped if prices fall, or hurt if climate change makes food more expensive.2

Finally, the extent to which these net consuming households are affected by changes in food prices depends on how much of their income they spend on food, and on what types of food they buy. For instance, most households in wealthy countries are substantial net consumers of food, but because they spend such a small percentage of their total income on food, they are little affected if the price of food changes. This is not the case in poorer households, who can spend half or more of their income on food (Fig. 2.7), and for whom changes in food prices can have serious effects on the quantity and quality of food consumed. Because climate change might also affect the relative prices of different staples (for instance if warming hurts one cereal more than another), the particular diet composition of o

Fig. 2.6 Percent of households who are net sellers of staple crops, selected countries (Ivanic and Martin 2008). Dark grey = urban households; light grey = rural households

2 There are cases where the longer-run effects of high prices might actually benefit net consumers, for instance if in response to the incentives of higher prices they are able to expand their own production and become net sellers of food, or if higher food prices induce expansion of production on other farms and raise the total demand for agricultural wage labor. For a more complete treatment of these longer-run dynamics, please see Singh et al. (1986).

India 1998

Ghana 1998

Uganda 2000

Malawi 2004

India 1998

Ghana 1998

Uganda 2000

Malawi 2004

poorest median richest poorest median richest poorest median richest poorest median richest

Fig. 2.7 Food expenditure as a percent of total household expenditure, by expenditure quintile. India data are for Bihar and Uttar Pradesh. Data from Stanford's ALP project (Karen Wang, pers. comm.)

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W.Africa

Sahel Cent.Africa E.Africa

S.Africa

S.Asia

SE.Asia

Fig. 2.8 Average percent of dietary calories derived from different crops for selected regions. Data are from FAO (2009), as calculated in Lobell et al. (2008)

W.Africa

Sahel Cent.Africa E.Africa

S.Africa

S.Asia

SE.Asia

Fig. 2.8 Average percent of dietary calories derived from different crops for selected regions. Data are from FAO (2009), as calculated in Lobell et al. (2008)

poor households can also be important. As Fig. 2.8 shows, this composition can vary greatly from region to region, with the three primary cereals (rice, wheat, and corn) accounting for over 75% of calories consumed in parts of Asia, to less than 20% throughout much of Africa.

The third important determinant of climate change's effects on food access concerns how well integrated local food markets are with global markets. As discussed in later chapters, the effects of climate change on agricultural productivity will likely vary by region, and so it is important whether in a given area local food prices and availability are driven primarily by local shifts in production, or whether that area is well integrated with regional or global food markets such that local prices track global price movements. This degree of integration could play a large role in the welfare effects of climate in a given region. For instance, a region that suffers large productivity losses under climate change but whose food markets are well integrated with global markets could see little change in the price of food if it is able to import food to cover losses. Conversely, a country well integrated with global markets could see food prices rise even if it doesn't experience local climate effects.

The final determinant of the effects of climate change on food access concerns the degree to which longer-run prospects for growth in income and food security are climate sensitive. This question is undoubtedly the most contentious of the four, because there is remarkably little agreement on the underlying causes of economic development, and thus little understanding of the relative importance of climate in determining why some countries become rich and others remain poor over the long run.

The economics literature offers perhaps three main explanations of why some countries have succeeded economically over time and others have not (Easterly and Levine 2003). The first explanation, argued prominently by Bloom and Sachs (1998) among others, suggests that geography is central to long-run economic success. Noting the high correlation between tropical location and underdevelop-ment, proponents of this explanation argue that a country's geographic location directly shapes various factors fundamental to long-run economic success - for instance the quality of the country's soils, the favorability of its climate for agriculture and habitation, the prevalence of various diseases, and the ease with which goods can be traded within and across its borders.

A second strain of thought places primary emphasis on the role of institutions in economic development. This explanation, promoted by Acemoglu et al. (2001) and Easterly and Levine (2003) among others, argues that economic progress has less to do with a country's soils and climate and much more to do with the quality of its institutions - in particular, factors such as limited corruption and institutional respect for private property and the rule of law.

A final explanation focuses on the role of particular policies in explaining longrun economic performance. Proponents in this camp (Williamson 1990) argue that even with favorable geography and well-functioning institutions, countries with bad economic policy are destined for poor economic growth. They point to instances in which poor economic management resulted in the collapse of otherwise prosperous countries as evidence of the primacy of good policy.

A casual observer might suspect that all three explanations - geography, institutions, and policies - play some role in shaping long run economic success. But if one explanation is relatively more important than another - a possibility that each camp adamantly claims is the case - then climate change could have a greater or lesser effect on longer run prospects for the alleviation of poverty and hunger. In particular, if the climate worsens, and it is in fact geography that constrains eventual economic success, the aggregate effects of climate change on food security could be great. If on the other hand institutional quality dominates long-run success, then climate change could have little effect on long-run progress.

Aside from these important questions about the long run determinants of economic progress, however, it should be clear that climate plays an important and direct role in the immediate food security of a large number of the world's poor. For households who eat much of what they produce, or who face food prices tightly linked to local agricultural production - and these households number in the hundreds of millions - the welfare effects of a negative supply shock can be large and lasting. Various studies demonstrate the persistent welfare effects of short-term adverse climate shocks for rural households, as for instance households in crisis sell productive assets to meet immediate consumption needs (Dercon and World Institute for Development Economics 2002; Hoddinott 2006). If climate change alters the likelihood of these shocks, we could expect large effects on rural household welfare in poor countries, even if the economy-wide consequences are minimal.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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