Resource provision

Farming types and farming systems

Farms are classified in two ways: by who the food is for, and by what is produced. Subsistence farming grows food for the farmer's own family, with little or nothing sold, and it usually relies on family labour, simple tools and local rainfall. Commercial farming produces crops or livestock to sell for profit, using machinery, fertilisers, hired labour and often irrigation. Arable farming is the growing of crops, pastoral farming is the rearing of animals, and mixed farming does both on the same farm, which spreads the risk because a poor harvest can be offset by the livestock.

Three modern farming types grow plants without soil. Hydroponics grows plants with their roots in a nutrient solution, or in an inert material such as gravel or rockwool that is regularly flooded with that solution. Aeroponics suspends the plants so that the roots hang in the air and are sprayed or misted with a nutrient solution, which uses very little water. Aquaponics combines fish farming with hydroponics: the fish are kept in tanks, their waste provides the nutrients for the plants, and the plants take those nutrients out of the water, which then returns to the fish. All three can be used indoors, stacked in layers and placed close to the customers in a city, so they save land and water and cut food miles, but they need large capital investment, a reliable electricity supply and trained staff, so they are almost always commercial.

Any farm can also be described as a system. Inputs are what is put in: physical inputs such as land, water, sunlight, temperature and soil, and human inputs such as labour, machinery, seeds, fertiliser, pesticides, buildings, capital and technology. Processes are what happens on the farm: ploughing, sowing, irrigating, weeding, feeding, milking, harvesting and storing. Outputs are what comes out: crops, milk, meat, eggs, wool, timber, profit - and also unwanted outputs such as waste, pollution, greenhouse gases and eroded soil. Some outputs are fed back as inputs, as when manure is spread on the fields or part of the harvest is kept as seed.

Global patterns of food supply and demand, and the globalisation of food

Calorie intake measures how much energy a person's food provides, and it varies enormously between countries. Intakes are highest in high-income countries and in the wealthier parts of MICs, where people eat more meat, dairy products, sugar and processed food, and lowest in parts of sub-Saharan Africa and South Asia, where diets are based on a staple grain or root crop and are often short of energy and protein. The pattern is not simply rich world against poor world: within a country, wealthier households eat more and better food than poorer ones, and urban households usually eat differently from rural ones.

The reasons for the variation fall into four groups. Wealth decides what a household can afford, and richer households buy more food and more expensive food, including meat. Agricultural productivity decides how much food a country produces: irrigation, fertilisers, high-yielding varieties, machinery and good roads raise yields, while a lack of them keeps them low. Natural conditions set the limits, with rainfall, temperature, soil fertility and the length of the growing season, and hazards such as drought, floods and pests. Human and political factors often decide whether the food that could be grown actually reaches people: war and insecurity, poor roads and storage, unequal land ownership, and the choice to grow export crops rather than food crops.

World production and consumption of food are both changing. Production has risen because of a growing population, more farmland, irrigation, higher-yielding crop varieties, fertiliser and pesticide use, mechanisation, and better storage and transport. Consumption has changed because incomes have risen and people eat more meat and dairy products, which need far more land, water and grain than a plant-based diet does; because populations have grown and become more urban; because supermarkets and advertising shape what people want; and because food is now traded globally. Biofuels are a further claim on the same land, and climate change is already affecting yields in some regions.

Globalisation of food supplies means that what is on a plate in one country may have been grown, processed and packed in several others. It happened because refrigerated containers and containerisation made it cheap to move perishable food long distances, because air freight brings fresh produce and out-of-season vegetables quickly, because trade agreements lowered tariffs and quotas, because TNC supermarkets and food companies buy from wherever the price is lowest and sell through their own global networks, because ICT allows orders, stock and logistics to be managed across continents, and because consumers in richer countries now expect any food at any time of year.

The impacts cut both ways. Consumers gain a wider choice, food that is out of season locally, and often lower prices, and producers in exporting countries gain income, employment, technology and investment in cold stores, ports and roads. Against that, food travels much further and generates greenhouse gases, producing countries use their land and water for crops for export, small farmers can be undercut and pushed out, local food cultures and crop varieties are lost, a country that depends on imported food is vulnerable to a distant price rise or a disrupted shipping route, and cheap processed food has contributed to obesity and diet-related disease.

• Calorie intake is highest in HICs and the wealthiest parts of MICs, and lowest in parts of sub-Saharan Africa and South Asia.
• Reasons for variation: wealth, agricultural productivity, natural conditions, and human and political factors such as conflict, land ownership and export cropping.
• Production rose through population growth, irrigation, high-yielding varieties, fertiliser, mechanisation and better storage and transport.
• Consumption changed as incomes rose, diets shifted towards meat and dairy, populations urbanised, and food came to be traded globally.
• Globalisation of food was driven by containerisation and refrigerated shipping, air freight, trade agreements, TNC food companies and ICT.
• Impacts: choice and lower prices, but food miles, water and land use in producing countries, pressure on small farmers, and vulnerability to distant shocks.

The challenges of food supply and food insecurity

Food security means that everyone has reliable physical and economic access to enough safe, nutritious food. Food insecurity is the opposite, and its causes are both human and natural, and usually combined. Human factors include poverty, because food security is mostly about whether a household can afford to buy food, not whether any exists; conflict and war, which destroy crops and livestock, drive farmers off their land and block the roads that trade and aid use; poor infrastructure and storage, which waste a large share of the harvest after it is gathered; unequal land ownership, which leaves small farmers with too little land; the choice to grow cash crops for export instead of food for local people; overgrazing and poor farming practices that degrade the soil; and rapid population growth, which divides the same land and harvest among more people.

Natural factors include drought, the single most common trigger of food crises; floods and storms, which drown or flatten a harvest; pests and diseases such as locust swarms and crop infections; soil erosion and nutrient depletion, which lower yields year after year; salinisation, where heavy irrigation in a hot dry climate leaves salt in the topsoil and land goes out of production; and climate change, which is making rainfall less reliable and heat extremes more common in many already marginal farming areas. Where drought, poverty and conflict occur together, a food crisis follows quickly: the rain fails -> the harvest is lost -> food prices rise in the market -> households that were already poor can no longer afford to buy food -> children go without and become undernourished.

The problems caused by food insecurity differ with the level of development. In LICs the consequences are direct and severe: undernutrition and stunting in children, a higher death rate from ordinary infections, and a workforce too weak to farm well, which traps families in poverty. People migrate to the cities or across borders, and shortages can lead to unrest. In MICs the problem is often that food exists but the poorest cannot afford it, so rising world prices cause real hardship in cities, and countries can face the double burden of undernutrition in rural areas alongside obesity and diabetes in the towns. In HICs food insecurity rarely means famine, but it does mean food poverty: families relying on food banks, children going without meals in the school holidays, and diet-related disease, alongside very high levels of food waste.

Increasing food supply and the role of food aid

Strategies to increase food supply work on the amount produced, the amount wasted and the amount a household can afford. To raise production, farmers can use irrigation - canals, reservoirs, wells and drip systems that deliver water straight to the roots and lose very little to evaporation - high-yielding varieties of wheat and rice combined with fertiliser and pesticide, which is what the Green Revolution of the 1960s and 1970s was, and mechanisation, which lets one farmer work much more land. Land reform gives landless families plots of their own, training and extension services spread better technique, and genetically modified crops can carry resistance to pests, drought or salt, though they are controversial and expensive for small farmers.

Other strategies attack waste and add new types of production. Better storage - sealed silos, drying, cold stores - protects the harvest from pests and spoilage, and improving roads gets food to market before it rots. Reducing food waste in shops and homes matters most in HICs, where a great deal of edible food is thrown away. Urban and vertical farming, hydroponics, aeroponics and aquaponics produce fresh food close to city customers on very little land and water, and aquaculture - fish farming - adds protein without taking more from the sea. On the economic side, fair prices and fair trade raise farmers' incomes so that they can invest, and removing trade barriers lets food move from regions of surplus to regions of deficit.

Food aid is the emergency version of this, and it has to be evaluated rather than simply praised. Its strengths are that it saves lives when a crisis hits, that it can be targeted at the most vulnerable people - young children, pregnant women, the sick - and that nutrition programmes and school feeding improve health and school attendance. Cash transfers and local purchase are usually better than shipping food from far away, because the money is spent in local markets, supports local farmers, and gets help to people faster and more cheaply. Food-for-work schemes pay people in food for building terraces, roads or irrigation, so the aid leaves something behind.

Its weaknesses matter just as much. Food aid often arrives late, after the crisis has peaked, because it must be bought, shipped and distributed. Delivered free, it can undercut local farmers and put them out of business, which makes the next crisis worse, and it can create dependence on repeated deliveries. It is expensive to transport, it can be diverted by corrupt officials or seized by armed groups, and it is often concentrated in cities where distribution is easier, missing the poorest rural households. Above all, it treats the symptom rather than the cause: aid does not stop drought, end a war or fix unequal land ownership. That is why development aid, fair trade, debt relief and long-term investment in farming are usually judged to do more good in the long run, with food aid kept for genuine emergencies.

• Raise production: irrigation (especially drip), high-yielding varieties with fertiliser, mechanisation, land reform, training, GM crops.
• Cut losses: sealed storage, drying, cold chains, better roads, less waste in shops and homes.
• Grow food differently: urban and vertical farming, hydroponics, aeroponics, aquaponics and aquaculture.
• Raise incomes and move food: fair prices and fair trade, and removing trade barriers.
• Food aid: saves lives quickly, but can arrive late, undercut local farmers, create dependence and be diverted - and it does not fix the cause.

Managing desertification and soil erosion

Desertification is the process by which land in dry areas becomes less productive and eventually unusable, and it is caused mostly by people putting too much pressure on fragile land. Overgrazing strips the vegetation that holds the soil, so wind and rain take it; over-cultivation exhausts nutrients and leaves the ground bare between harvests; deforestation for fuelwood and clearance removes the roots and canopy that protect the soil; poor irrigation in a hot dry climate raises the water table and leaves salt in the topsoil; and drought turns a stressed area into a failed one. Soil erosion by wind and water is the mechanism that carries the fertile topsoil away, and the chain runs slowly: vegetation is stripped -> the soil is left bare -> wind and rain remove the topsoil -> the land holds less water and fewer nutrients -> yields fall. Because it is gradual, it is easy to ignore until yields have already dropped.

The techniques that work keep the soil covered, slow the water down and return organic matter to the ground. On slopes, terracing cuts steps into the hillside so that water soaks in instead of running off, and contour ploughing and strip cropping plough and plant across the slope rather than up and down it. Shelter belts of trees and stone lines or bunds across a field break the wind and trap soil and water. Afforestation and agroforestry, which mixes trees with crops, hold the soil, provide fuelwood and fruit, and shade the ground. Mulching with crop residues and adding manure or compost protects the surface and replaces nutrients, and crop rotation with legumes restores nitrogen to the soil.

Grazing and water have their own answers. Rotational grazing moves animals between paddocks so that pasture recovers, and reducing the number of animals takes pressure off land that cannot carry them. Drip irrigation delivers water to the plant rather than the whole field, which saves water and reduces the salinisation caused by flooding fields, and drainage can flush salt out of already damaged soil. Sand dune fixation with planted grasses and fences stops dunes moving onto farmland. Because much of the damage is done by people collecting fuelwood, efficient stoves and alternative fuels cut the demand for wood, and because land is often farmed by people with no security of tenure, community land management and education matter as much as any technique. The Great Green Wall is the best-known large-scale attempt to restore land across the Sahel: a partnership of African countries planting and protecting a mosaic of trees, grassland and farmland to hold back the desert.

Evaluate these strategies honestly. Most of the techniques are cheap, use local materials and work with the farmer's own land, and many raise yields as well as protect the soil. But they need labour, they need knowledge and training, and they only work if the farmer has a reason to invest in land that may not be theirs. Terracing and shelter belts take land out of production and take years to show a return, reducing livestock cuts a herder's income immediately, and a single severe drought can undo years of improvement. Large schemes work best when they are combined with secure land rights, fair prices for what the land produces, and enough cash or food aid to get households through the years before the new techniques pay off.

Types of energy and the global pattern of supply and demand

Energy resources are sorted into renewable and non-renewable. Renewable resources are replaced by natural processes as fast as they are used, so they will not run out: biomass, geothermal, hydroelectric power (HEP), solar, tidal, wave and wind. Non-renewable resources exist in a fixed store that is used far faster than it forms: the fossil fuels - coal, gas and oil - and nuclear power, which uses uranium mined from a limited ore body. Fuelwood - wood burned for cooking and heating - is the interesting case: it is renewable where trees grow back at least as fast as they are cut, but it becomes non-renewable in practice where people cut faster than the woodland can regrow, which is what drives deforestation around many cities in LICs.

Global production and consumption of energy have risen steeply for several reasons. Population growth means more homes, more cooking and more transport. Economic development brings industry, mining, cement, steel and manufacturing, all of which are very energy-intensive, and rising incomes let households buy appliances, vehicles and air conditioning. Urbanisation concentrates demand and requires pumping, lighting and public transport, and transport and freight have grown with global trade. More recently, digital demand - data centres, networks and devices - has added a new and rapidly growing load, and electrification of heating and vehicles is moving demand from oil and gas onto the electricity grid rather than reducing it.

The result is a global pattern of energy surplus and deficit. Countries whose reserves of oil, gas or coal far exceed their own needs are in surplus and export the difference: the Gulf states, Russia, Norway, Canada and Australia are the clearest examples. Countries with high demand and few reserves are in deficit and must import, which describes Japan, most of Europe and many small island states. Many of the poorest countries have neither reserves nor the money to buy fuel, so a large share of their people still rely on fuelwood or have no electricity at all, and the type of energy a household uses varies sharply within a country too: city households with a grid connection cook with gas or electricity, while rural households may depend on wood or charcoal.

Energy security means having a reliable, affordable supply of energy that is not easily disrupted. It matters because energy underpins everything else: without it, hospitals, water pumping, factories, transport and food distribution all stop. The threats are dependence on imported fuel and on a single supplier, price shocks when world markets move or a supplier uses energy as a political weapon, conflict and sabotage of pipelines and shipping routes, extreme weather that takes out power lines, and ageing or inadequate grids. Countries improve their security by diversifying - using more than one type of energy and buying from more than one supplier - by holding fuel reserves and storage, by developing domestic renewables that no one can cut off, by improving efficiency so that less energy is needed, and by building interconnectors so that electricity can be imported from neighbours. Each of those has a cost: storage and interconnectors are expensive, and a country that relies on its own fossil fuels gains security but keeps its emissions high.

Which energy a country uses depends on its natural resource endowment, its level of development, its government policy and the price and availability of imported fuel. A country with volcanic heat, steep wet valleys, strong winds or reliable sunshine has options that a flat, dry country of the same wealth does not; a wealthy country can afford the high capital cost of nuclear or offshore wind, while a poorer one cannot; and subsidies, taxes and regulations can make one source cheaper than another. That is why the energy mix of two countries with similar incomes can be completely different.

The impacts of energy production and managing supplies sustainably

Every energy source has advantages and disadvantages, and the strongest answers give both and say who bears the cost. The fossil fuels are concentrated, easy to store and transport and available on demand, which is why they still dominate world supply, but they are finite, they must be mined or drilled, and burning them releases carbon dioxide, sulphur dioxide and particulates that drive climate change and acid rain, as well as damaging land and water where they are extracted. Nuclear power gives a large, steady, low-carbon output from a small amount of fuel, but it produces radioactive waste that must be stored for thousands of years, costs a great deal to build and carries the risk of a serious accident.

The renewables share free fuel, low running costs and little or no carbon dioxide when generating, but their output is often smaller for the same investment and several depend on the weather. HEP needs a steep, wet valley and floods land and displaces communities; tidal needs an estuary with a large tidal range and alters the ecology of the mudflats; wave devices are still experimental and easily damaged by storms; wind is intermittent, takes up visible space and can kill birds and bats; solar needs strong sunlight and large areas of land, and panels and batteries need mined minerals. Geothermal is available at all hours but only pays where the crust is hot. Biomass and fuelwood are renewable if regrown and can be burned on demand, but burning them still releases carbon dioxide and smoke, growing fuel crops competes with food, and burning fuelwood indoors on an open fire causes serious lung disease and drives deforestation. Every renewable also needs backup or storage to cover the times when it produces nothing.

Strategies to increase energy supplies include building more generating capacity of any type, developing domestic resources so that imports fall, extending the grid to reach people who have no electricity, and importing liquefied gas or electricity through interconnectors. Managing supplies sustainably is the other half, and it usually means getting the same result from less energy. Conservation and efficiency are the cheapest and quickest options: insulating buildings, using efficient appliances and lighting, switching off standby loads, using public transport, and shifting heavy electricity use to times of day when demand is low. Recycling saves energy as well as material, because making aluminium, steel, glass and paper from recycled material takes far less energy than making them from raw materials, and reusing and repairing products avoids manufacturing them again. On the supply side, sustainable management means adding renewable capacity, storing surplus electricity in batteries or pumped storage, capturing methane from landfill and farms to make biogas, using waste heat from power stations and industry instead of dumping it, and putting a price on carbon so that the polluting options cost more.

Evaluating these strategies, the cheapest and least controversial are efficiency and recycling, but their potential is limited: a household or a factory can only cut its use so far. Renewables cut emissions and improve energy security, because the sun and the wind cannot be embargoed, but they need land, capital and storage, and their output varies. Nuclear is low-carbon and reliable but expensive and politically difficult. Fossil fuels remain because they are dense, storable and available on demand, and countries that export them earn heavily from them, which is why the transition is slower than the science suggests. The most secure approach for most countries is a mix: renewables for the bulk of the electricity, storage and interconnectors for the gaps, efficiency to hold demand down, and recycling to cut the energy embodied in the materials the country uses.

• Fossil fuels: reliable, dense and easy to store, but finite and polluting.
• Nuclear: low-carbon and steady, but expensive, with long-lived radioactive waste.
• Renewables: free fuel and low running costs, but often intermittent, capital-hungry and land-hungry, and some cause ecological damage.
• Conservation and efficiency: the cheapest, fastest way to close an energy gap, but limited in how far it can go.
• Recycling saves the energy needed to make materials from raw materials; reusing products saves even more.
• Storage, interconnectors, biogas from waste and waste-heat recovery all help to make a variable supply usable.