Developing World's Subsistence Farmers: Who Pollutes More?

Agriculture is the leading source of pollution in many countries. Pesticides, fertilizers, and other toxic farm chemicals can poison freshwater, marine ecosystems, air, and soil. These chemicals can remain in the environment for generations, and many pesticides are suspected of disrupting the hormonal systems of people and wildlife. While farming is the only viable livelihood option for three-quarters of the global population living below the poverty line, the environmental impact of agriculture is a significant concern. This is especially true in the context of subsistence farmers in developing countries, who make up about 25% of the world's population and are particularly vulnerable to the effects of climate change and pollution.

Subsistence farmers' vulnerability to climate change

Subsistence farmers are among the people most vulnerable to climate change. Climate models predict that climate change will lead to warmer temperatures, increasing rainfall variability, and increasing severity and frequency of extreme weather events. These changes are expected to decrease agricultural productivity in the developing world by 10% to 20% over the next 40 years.

Subsistence farmers in the developing world find it particularly difficult to cope with climate-related hazards as they do not have the capital to invest in new adaptive practices. Their vulnerability to climate change also stems from being predominantly located in the tropics, where the effects on crop production brought about by climate change will be more intense due to the link between extreme temperatures and lower crop yields.

Additionally, water availability is crucial for subsistence agriculture, especially in dryland regions. Dryland farming relies solely on natural precipitation and is thus highly susceptible to the adverse effects of climate change, particularly in areas with erratic weather patterns. This type of farming, known as "slash and burn" agriculture, involves migrating with animals in search of fodder. It is a common way of life in parts of Asia, Africa, and Eurasia, and those who practice it are often sophisticated agriculturalists.

To address the challenges posed by climate change, development practitioners have proposed agroforestry, or the intentional use of trees in the cropping system, as a potential strategy. Research in western Kenya has shown that agroforestry techniques can improve household resilience by enhancing farm productivity, off-farm incomes, wealth, and the environmental conditions of farms. However, it is important to note that the impacts of climate change on smallholder and subsistence farming systems are complex and influenced by various factors, including the specific crops and livestock involved, as well as non-agricultural strategies employed.

The impact of global warming on crop yields

While agriculture is the leading source of pollution in many countries, it is important to note that wealthy countries, particularly the United States and Western European nations, have emitted the majority of greenhouse gases that have led to the climate crisis. This crisis will have a significant impact on crop yields globally.

A NASA study predicts that climate change may affect the production of maize (corn) and wheat as early as 2030, with maize yields projected to decline by 24% and wheat yields potentially increasing by about 17%. The change in yields is attributed to increased temperatures, altered rainfall patterns, and higher surface carbon dioxide concentrations from human-caused greenhouse gas emissions. Higher temperatures also shorten the growing season and accelerate crop maturity, resulting in reduced grain production.

The impact of climate change on crop yields will depend on various factors, including the type of crop, the magnitude of warming, geographic location, and adaptive measures implemented. For instance, wheat and rice, classified as "C3" crops, can benefit significantly from elevated CO2 levels through carbon fertilization. On the other hand, maize, millet, and sorghum, known as "C4" crops, exhibit minimal response to increased CO2 levels, except during drought conditions.

Geographically, high-latitude or temperate countries may experience less severe climate impacts and potential yield increases, despite facing additional extreme weather events. In contrast, farmers in the tropics and subtropics are expected to encounter the most significant yield declines, coupled with a lower capacity to adapt. This disparity arises because crops in the warmer tropics are already near their optimal growing temperature, and further warming will push them beyond this threshold. Moreover, crops that do not benefit significantly from carbon fertilization, such as maize, millet, and sorghum, are predominantly grown in these warmer regions, exacerbating the negative impact of increased temperatures on yields.

According to studies, climate change has already resulted in a 5% decline in the yields of key crops, and without adaptation, further losses are projected. By mid-century, global crop yields could decrease by 3–12%, and by the end of the century, this decline could reach 11–25% under a vigorous warming scenario.

Agricultural pollution and soil degradation

Agriculture is the leading source of pollution in many countries. Pesticides, fertilizers, and other toxic farm chemicals can poison freshwater, marine ecosystems, air, and soil. These chemicals can remain in the environment for generations, with many pesticides suspected of disrupting the hormonal systems of people and wildlife. Fertilizer run-off impacts waterways and coral reefs, and excessive fertilizer use can cause a buildup of salts in the soil, heavy metal contamination, and the accumulation of nitrates, which are harmful to humans.

Soil degradation is a decline in soil condition caused by its improper use or poor management, usually for agricultural, industrial, or urban purposes. It is a serious environmental issue, as soils are a fundamental natural resource and the basis for all terrestrial life. Soil degradation can be physical, chemical, or biological and includes water and wind erosion, loss of organic matter, fertility decline, soil acidity or alkalinity, and the effects of toxic chemicals.

Subsistence farming is most common in developing countries, and it is estimated that about 2 billion people in 500 million households in rural areas of developing nations survive as "smallholder" farmers, working less than 2 hectares of land. Subsistence farming generally features small capital/finance requirements, limited use of agrochemicals, and low yields. While it is a common misconception that those practicing "slash and burn" agriculture are unsophisticated, these farmers are often quite knowledgeable and migrate with their animals in search of fodder.

The vulnerability of subsistence farmers to climate change comes from their predominant location in the tropics and various socioeconomic, demographic, and policy trends limiting their capacity to adapt. Water availability is crucial for subsistence agriculture, especially in dryland regions, and climate change can have ill effects on crop production in these areas. Soil degradation forces farmers to look for new land, and the effects of degradation pose a major threat to food security, especially in poor regions.

Pesticides, fertilisers, and other toxic farm chemicals

Subsistence farming, defined as "farming and associated activities that form a livelihood strategy where the main output is consumed directly, with few or no purchased inputs and only a minor proportion of output marketed", is most common in developing countries. It is estimated that about 2 billion people in 500 million households in rural areas of developing nations survive as subsistence or "smallholder" farmers. These farmers often have limited access to resources and finance, and their farming practices may include the limited use of agrochemicals such as pesticides and fertilisers.

Pesticides are chemical substances used to kill pests and control weeds. While they have been effective in increasing agricultural yields, their improper use and management can lead to environmental pollution. Pesticides can contaminate the air, water, soil, and crops, and their toxic residues can remain in the environment for generations. For example, groundwater pollution due to pesticides is a worldwide problem, and pesticide contamination has been detected in the groundwater of more than 43 states over the past two decades. In India, a survey found that 58% of drinking water samples from Bhopal were contaminated with Organo Chlorine pesticides above the EPA standards.

The use of pesticides and fertilisers in agriculture can have adverse effects on human health and ecological systems. Certain pesticides are known as endocrine disruptors, which can mimic or antagonise natural hormones in the body. Long-term exposure to these chemicals has been linked to immune suppression, hormone disruption, diminished intelligence, reproductive abnormalities, and cancer. Additionally, the abuse of pesticides in grain storage, as seen in some African countries, has led to insect pesticide resistance and severe environmental complications.

To mitigate the negative impacts of pesticides and fertilisers, proper usage and safety precautions are essential. Banning obsolete toxic chemicals and replacing them with less toxic alternatives can help reduce the environmental and health risks associated with their use. Creating awareness about the dangers of these chemicals and providing education on alternative farming practices can also help subsistence farmers make more informed decisions.

The impact of urbanisation on subsistence farming

Urbanization has had a significant impact on subsistence farming, particularly in developing countries. This impact has been felt through various factors, including population growth, migration, climate change, and changing land use.

Firstly, urbanization has led to a decline in subsistence farming as more land is transformed into urban areas. This has resulted in a loss of agricultural land, especially in peri-urban areas, affecting the livelihoods of subsistence farmers. Urban expansion has also disrupted traditional farming practices and contributed to environmental degradation, such as soil fertility loss and biodiversity loss.

Secondly, urbanization has caused a shift in the demographics and income levels of rural areas. As cities expand, they attract higher-income individuals and industries, leading to an income gap between urban and rural residents. This can make it challenging for subsistence farmers to maintain their livelihoods and compete with commercial farming practices. Additionally, urbanization has been associated with industrialization, which, in some cases, has led to rural unemployment and increased poverty for those unable to move to urban areas.

Thirdly, urbanization has influenced food production and consumption patterns. The growing urban population has increased the demand for food, requiring more intensive agriculture that utilizes more land, water, energy, and greenhouse gas emissions. This has impacted subsistence farmers, who may struggle to adapt to changing market demands and compete with large-scale commercial farms. However, small family farms with good market connections can compete by producing higher-end foods, such as fresh fruits and vegetables.

Furthermore, urbanization has been linked to rural-urban migration, which can be both a cause and consequence of changes in farming practices. Climate change, environmental stressors, and a decline in agricultural yields can drive migration from rural to urban areas. At the same time, successful rural development and income diversification can support urban growth by generating demand for goods and services from farmers and rural households.

Lastly, urbanization has had varying impacts on the welfare of farm households, with those near urban centers experiencing different effects than those in more distant regions. Households near urban areas may face challenges such as lower consumption expenditures and asset ownership due to the negative impacts of urbanization. On the other hand, urban proximity can provide access to markets and income diversification opportunities, supporting farming innovation and intensification.

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