Mission 1: In 2023 the world's food supply came to about 3,000 calories per person per day. So why did around 645 million people go hungry in 2025?

Calories per person

• FAO's dietary energy supply (DES) is the food available per person per day, in kilocalories (kcal).
• World: 2,825 kcal in 2010; 3,016 kcal in 2023.
• 2023: Europe 3,490 · Americas 3,438 · Oceania 3,137 · Asia 2,991 · Africa 2,556 kcal.
• It measures supply, not intake: food later wasted in shops and homes still counts as supply.

Undernourishment: a regional pattern

• Prevalence of undernourishment (PoU): the share of people whose calorie intake is insufficient.
• 2025: 7.8% of the world's population, around 645 million people, down from 8.1% in 2024.
• Africa: 20.0%, about 309 million people, against 292 million in Asia. Africa now has more hungry people than Asia.
• More than half of Africa's people (56.6%) faced moderate or severe food insecurity in 2025.

Indicators of malnutrition

• Stunting: low height-for-age, a sign of long-term (chronic) undernutrition. Wasting: low weight-for-height, a sign of recent, acute undernutrition.
• Malnutrition also includes vitamin and mineral deficiencies, and overweight and obesity.
• 150 million children under five are stunted (SOFI 2026).
• 30.7% of women aged 15–49 had anaemia in 2023 (SOFI 2025).

A composite index: the Global Hunger Index (GHI)

• The GHI combines four indicators:
  • undernourishment and child mortality: one-third of the score each;
  • child stunting and child wasting: one-sixth each.
• Scores run from 0 (no hunger) to 100. Bands: low (≤9.9), moderate (10.0–19.9), serious (20.0–34.9), alarming (35.0–49.9), extremely alarming (≥50.0).
• Using both stunting and wasting captures chronic and acute undernutrition.

The GHI's global pattern, 2026

• World score: 18.1 (moderate), higher than in 2018, which interrupts the decline since 2000.
• Hunger is serious in Africa south of the Sahara and South Asia.
• Eight countries are alarming. Four have scores: Somalia 47.0 (122nd of 122 ranked), the Democratic Republic of the Congo 39.5, Chad 38.0 and Madagascar 36.5.
• Burundi, South Sudan, Sudan and Yemen are rated alarming provisionally, without a score, because data are missing.

The Global Food Security Index (GFSI)

• Economist Impact's index scores 113 countries on 68 drivers in four pillars: affordability, availability, quality and safety, and sustainability and adaptation.
• 2022 (its 11th edition, the latest found): Finland top with 83.7, then Ireland (81.7) and Norway (80.5).
• It found food security "continued to deteriorate after hitting its peak in 2019".
• It was "Developed by Economist Impact and supported by Corteva Agriscience", an agribusiness.

Exam move: judging indicators (AO3)

• Supply (DES), outcome (PoU, stunting, wasting) and composite (GHI, GFSI) indicators answer different questions.
• DES is supply, not intake, and a national average hides who goes without.
• PoU is a modelled estimate; the GHI leans on child indicators and cannot score countries with missing data, such as Yemen and Sudan.
• The GFSI figures date from 2022, and its sponsor sells seeds and crop chemicals: check the date, and ask who funds an index.
• Exam move: name the indicator, say what it measures, and give one limitation before you use its numbers.

Mission 2: In 2022, 149 million young children were stunted while 2.5 billion adults were overweight. How can the world have too little food and too much at once?

The nutrition transition (Popkin)

• Barry Popkin's nutrition transition describes how diets and activity shift as societies change:
  • Pattern 2, famine: settled farming societies with recurrent famine;
  • Pattern 3, receding famine: "famine begins to recede as income rises";
  • Pattern 4, nutrition-related non-communicable disease: more processed food, more eating away from home, more edible oils and sugar-sweetened drinks, and less physical activity;
  • Pattern 5, behavioural change: people deliberately eat better and move more.
• Pattern 1 was the diet of hunter-gatherers.

Faster, and earlier

• Popkin and Ng: in lower-income countries "changes are occurring at great speed and at earlier stages of countries' economic and social development".
• Asia's food supply rose from 2,694 to 2,991 kcal per person per day (2010–2023).
• Animal products' share of Asia's protein supply rose from 34% to 37%, "reflecting rising incomes and changing consumption patterns in the region".

Physical processes behind food consumption

• Climate, soils and relief set which crops and livestock can be produced locally, and so shape traditional diets.
• Hazards cut harvests and raise prices. In Bangladesh in 1974, nationwide flooding sharply raised food prices and destroyed a crop, cutting work for farm labourers.
• Physical limits matter less where trade, irrigation and income let people buy food from elsewhere.

Human processes behind food consumption

• Income: richer households buy more animal products, oils and processed food (Asia, screen 2.2).
• Urbanisation: city jobs, less physical work, and more ready-made food.
• Prices and trade: the cost of food against people's income.
• Culture and religion: food customs and dietary rules.
• Marketing and conflict: advertising shapes choices; conflict cuts supplies (Missions 8 and 9).

The double burden of malnutrition

• The double burden of malnutrition is "the coexistence of undernutrition along with overweight, obesity or diet-related noncommunicable diseases".
• 2022: 2.5 billion adults were overweight, including 890 million living with obesity; 390 million adults were underweight.
• 2022: 149 million children under five were stunted, 45 million wasted and 37 million overweight.

Why the double burden is growing

• A 2020 Lancet review finds the double burden "affects most low-income and middle-income countries", and has increased in the poorest of them, mainly because overweight is rising.
• Causes: "the availability of cheap ultra-processed food and beverages", and "major reductions in physical activity" at work, in transport and at home.
• Indonesia is "the largest country with a severe DBM".

The trends

• Child stunting fell from 26.4% (2012) to 23.2% (2024) (SOFI 2025).
• Child wasting: 7.4% to 6.6%; child overweight: 5.3% to 5.5% (2012–2024, SOFI 2025).
• Adult obesity rose from 12.1% (2012) to 16.2% (2024) (SOFI 2026).
• Undernutrition is falling slowly; obesity is rising.

Exam move: linking food and health (synthesis)

• Diet links the two geographies. Overweight and obesity are metabolic risk factors for non-communicable diseases such as heart disease and diabetes.
• So the nutrition transition feeds the epidemiological transition (Mission 3).
• Limits of the model: the patterns overlap within one country, and poorer groups can reach pattern 4 before famine has fully receded: the double burden.
• Exam move: in "Examine" answers, show the link both ways: poor diets raise disease, and disease (such as diarrhoea) worsens undernutrition.

Mission 3: In 2000, non-communicable diseases caused 58% of the world's deaths. In 2023 they caused 74%. Good news or bad news?

Healthy life expectancy: the global pattern

• Healthy life expectancy (HALE): the years a newborn can expect to live in full health. World HALE in 2023: 62.8 years.
• By WHO region, 2023:
  • Western Pacific 67.3 · Europe 66.7 · Americas 64.4
  • South-East Asia 61.3 · Eastern Mediterranean 60.4 · Africa 56.2.
• HALE has recovered more slowly than life expectancy since COVID-19; it was still 0.4 years below its 2019 level in 2023.

Outcomes: infants and mothers

• IMR: deaths before age 1 per 1,000 live births. MMR: maternal deaths per 100,000 live births.
• IMR, 2024: world 27.7 per 1,000; low-income countries 46.7; high-income countries 4.2.
• About 260,000 women died during and after pregnancy and childbirth in 2023: an MMR of 197 per 100,000 live births.
• Sub-Saharan Africa had around 70% of maternal deaths. Nigeria's MMR was 993; Japan's was 3.

Inputs: sanitation and doctors

• Inputs are resources put into health; outcomes (HALE, IMR, MMR) are what results.
• 2024: 58% of the world used safely managed sanitation, and 3.4 billion people lacked it; 354 million practised open defecation.
• WHO African Region 27%; Europe 80%; Niger 9%.
• Doctors per 10,000 people (2024): high-income countries 34.5; low-income countries 3.2.

The epidemiological transition (Omran, 1971)

• Abdel Omran described three successive stages:
  • "The Age of Pestilence and Famine";
  • "The Age of Receding Pandemics";
  • "The Age of Degenerative and Man-Made Diseases".
• Over time, "pandemics of infection are gradually displaced by degenerative and man-made diseases".
• It runs alongside the demographic transition: falling death rates first, then longer lives.

The diseases continuum

• Diseases of poverty: mostly communicable, such as diarrhoea, malaria and tuberculosis, plus undernutrition and deaths in childbirth.
• Diseases of affluence: non-communicable diseases (NCDs): cardiovascular disease, cancers, chronic respiratory disease and diabetes.
• WHO's four main behavioural NCD risks: tobacco, physical inactivity, harmful use of alcohol and unhealthy diets.
• The label "affluence" misleads: 82% of the 18 million NCD deaths before age 70 in 2021 were in low- and middle-income countries.

The evidence for the transition

• NCDs caused 58% of deaths worldwide in 2000 and 74% in 2023.
• Eight of the ten leading causes of death in 2023 were NCDs.
• In 2023, for the first time, communicable diseases caused less than half of all deaths in low-income countries. The transition is uneven: in the poorest countries, infections still cause a large share of deaths.

Ageing and the disease burden

• By 2030, 1 in 6 people will be 60 or over. People aged 60+ will rise from 1 billion (2020) to 2.1 billion (2050).
• People aged 80+ are expected to triple to 426 million by 2050; 80% of older people will live in low- and middle-income countries.
• Common conditions: hearing loss, cataracts, back pain and osteoarthritis, COPD, diabetes, depression and dementia.
• Dementia rose from the 19th to the 5th leading cause of death between 2000 and 2023.

Exam move: one transition, uneven outcomes (AO3)

• The guide notes the transition "does not apply equally to all sectors of society".
• Between countries: low-income countries face infections and NCDs together, a double burden of disease. Within countries, poorer groups often keep the diseases of poverty while gaining the risks of the nutrition transition (Mission 2).
• Limits: Omran's model rests mainly on Western experience. Olshansky and Ault (1986) proposed a fourth stage, "the age of delayed degenerative diseases".
• New and re-emerging infections, such as HIV and COVID-19 (Missions 11–12), do not fit a one-way shift.
• Exam move: when you use the model, say where and for whom it fits, and where it does not.

Mission 4: Of every 100 calories the world's crops produce, how many reach people's plates as meat, milk or eggs?

Food production as a system

• Inputs: sunlight, rain and irrigation water, seed, fertiliser, animal feed, fuel, labour and capital.
• Stores: soil, groundwater, grain stores, livestock.
• Transfers: animals eating feed, processing, transport.
• Outputs: food, waste, greenhouse gases and polluted runoff.
• The merit of the systems approach: it shows where energy and water enter and leak out, so different farms and places can be compared.

Energy efficiency

• Energy efficiency compares the energy put in with the food energy that comes out.
• A US study (2003) found producing 1 kcal of plant protein needs about 2.2 kcal of fossil energy; animal protein averaged 25 kcal.
• Ratios ranged from 4:1 for broiler chicken to 40:1 for beef and 57:1 for lamb.
• Each step up a food chain loses energy, so feeding crops to animals is less efficient than eating the crops.

Water footprints

• A water footprint measures the fresh water consumed or polluted to make a product.
  • Green: rainwater stored in the soil and used by plants.
  • Blue: water taken from rivers, lakes or groundwater.
  • Grey: the fresh water needed to dilute pollution to meet water-quality standards.
• Global averages: beef 15,400 litres per kg; pork 6,000; chicken 4,300.

Per calorie and per gram of protein

• Per calorie, beef's average water footprint is 20 times that of cereals and starchy roots.
• Per gram of protein, milk, eggs and chicken need 1.5 times as much water as pulses.
• Exam move: say which unit you are comparing (per kg, per calorie, per gram of protein), because the gap changes with the unit.

Relative sustainability in different places

• The same product can have very different footprints. Animal products from grazing systems have smaller blue and grey water footprints than those from industrial systems.
• A study of 38,700 farms found environmental impact "can vary 50-fold among producers of the same product".
• But "impacts of the lowest-impact animal products typically exceed those of vegetable substitutes".

Place example: groundwater in north-west India

• NASA's GRACE satellites measured groundwater falling by 4.0 cm a year (17.7 km³ a year) beneath Rajasthan, Punjab and Haryana (including Delhi).
• From August 2002 to October 2008 the loss was 109 km³: double the capacity of India's largest surface reservoir.
• Rainfall was close to normal, so the authors judge pumping for irrigation and other uses the likely cause; 114 million people live in the region.
• High yields here rest on a blue-water store that is being used faster than it refills.

Exam move: strengths and limits of the systems approach (AO3)

• Strengths: a common framework for comparing farms, foods and places; it shows leaks of energy, water and nutrients.
• Limits: the energy ratios come from US systems in 2003; global averages hide local scarcity; calories and litres leave out nutrition, land suitability and jobs; the "up to 70%" ignores grazing land unsuited to crops and the nutritional value of animal foods.
• Exam move: "Evaluate" means weigh strengths against limitations, then judge.

Mission 5: By 1980, new high-yielding seeds grew on about 40% of Asia's cereal land; by 2000, about 80%. Why did they spread fast in some places and slowly in others?

Diffusion

• Diffusion: the spread of an idea, innovation or disease from its source (hearth) across space over time.
• Expansion diffusion: the phenomenon spreads while staying in the hearth.
  • Contagious: to nearby people and places first.
  • Hierarchical: through a hierarchy, from large cities or key people downwards.
• Relocation diffusion: carriers move, taking it to new places.
• These ideas come from Torsten Hägerstrand's work on innovation diffusion.

Adoption over time, and barriers

• Adoption usually follows an S-curve: a few early adopters, then rapid take-up, then a slow finish.
• Adoption/acquisition: Everett Rogers (1962) grouped adopters as innovators, early adopters, early majority, late majority and laggards.
• Distance decay: places closer to the hearth, or better connected to it, adopt sooner.
• Barriers may be physical (mountains, climate), economic (cost, credit) or political (laws, borders). Absorbing barriers stop diffusion; permeable barriers slow it.

An agricultural innovation: Asia's Green Revolution

• High-yielding modern varieties (MVs) of wheat and rice spread across Asia from the late 1960s.
• About 40% of Asia's cereal area grew MVs by 1980, and about 80% by 2000.
• Asia's cereal production rose from 313 to 650 million tonnes a year between 1970 and 1995.

Why it spread fast where it did

• The new varieties "worked best for wheat and rice in the best-irrigated areas".
• Governments built input and credit systems and subsidised "fertilizer, power, and water".
• By 1972, Asian countries spent an average of 15.4% of government spending on agriculture.
• Heavily irrigated north-west India shows the long-term cost of this model: falling groundwater (Mission 4).

Barriers to the Green Revolution

• Physical: rain-fed and drought-prone areas gained less; varieties suited to poorer regions came only "within 10 to 15 years".
• Economic: seed, fertiliser and water cost money, so credit decided who could adopt.
• Political: governments decided where input and credit systems were built. Land tenure shaped who gained: "where the land system was more feudal, poverty reduction was more limited".
• Costs: falling groundwater, salt build-up and heavy chemical use. Green revolutions "are not necessarily pro poor or environmentally benign".

Diseases diffuse, and meet barriers too

• Air travel carries diseases between big cities (relocation, often hierarchical); local spread is contagious (Mission 12).
• Physical: cold highlands limit malaria, but in warmer years it reaches higher altitudes in Ethiopia and Colombia.
• Economic: the ability to pay for vaccines and treatment. Political: quarantine, travel restrictions and border checks.
• Barriers slow diffusion; few stop it completely.

Representing diffusion (skills)

• Sequence maps: shade or date areas by when the disease or innovation arrived.
• Flow maps: arrows show routes and volumes.
• Cumulative line graphs: the S-curve of adoption or cases.
• Cluster maps: researchers in Haiti mapped cholera clusters by date along a river (Mission 7).
• Exam move: annotate a map with dates and arrows, and say what the pattern shows.

Mission 6: Malaria killed an estimated 610,000 people in 2024. Why does it kill mostly in one continent, and mostly young children?

A vector-borne disease

• A vector-borne disease is carried between people by a living organism, the vector.
• Malaria is caused by Plasmodium parasites (five species infect humans; P. falciparum and P. vivax are the most dangerous).
• It spreads mainly through the bites of infected female Anopheles mosquitoes. Symptoms usually start 10–15 days after the bite.

Incidence and pattern

• 2024: an estimated 282 million cases and 610,000 deaths in 80 countries.
• The WHO African Region had 95% of cases (265 million) and 95% of deaths (579,000).
• Nigeria had the largest share of deaths, 31.9%, followed by the Democratic Republic of the Congo (11.7%) and Niger (6.1%). WHO's wording calls these shares of the Region's deaths, but the base is unclear: they add to only 49.7%.

Physical factors

• Temperature: a model validated with African data puts optimal transmission at 25 °C, with transmission falling sharply above 28 °C.
• Rainfall: pools of still water are breeding sites for mosquitoes.
• Altitude: cooler highlands limit transmission. In warmer years, malaria reached higher altitudes in the highlands of Ethiopia and Colombia.

Human factors

• Poverty and housing: open eaves and unscreened windows let mosquitoes in; nets and treatment cost money.
• Health systems: access to testing and treatment. Conflict and instability disrupt health services.
• Funding: US$3.9 billion was invested in 2024, less than half of the US$9.3 billion target for 2025.
• Urban spread: An. stephensi "thrives in urban settings, endures high temperatures and is resistant to many of the insecticides used in public health".

Diffusion and resistance

• Relocation diffusion of a vector: An. stephensi is native to parts of South Asia and the Arabian Peninsula and has now invaded 9 African countries.
• Drug resistance: partial resistance to artemisinin, the key drug, is confirmed in Eritrea, Rwanda, Uganda and the United Republic of Tanzania.
• Resistance is confirmed or suspected in at least 8 African countries: resistance diffuses too.

Demographic impacts

• Children under 5 accounted for about three-quarters of malaria deaths in the WHO African Region.
• Infants, children under 5, pregnant women and girls, travellers and people with HIV or AIDS are at higher risk of severe malaria.
• WHO notes symptoms may be milder for people who have had malaria before. Young children have had few infections, so they have little protection.

Socio-economic impacts (AO3)

• Gallup and Sachs (2001): countries with intensive malaria had 1995 incomes only 33% (about a third) of those without malaria.
• Allowing for other factors, they grew 1.3% less per person per year (1965–1990).
• Evaluate: this is a correlation across countries. The authors argue that high malaria in poor countries is "not mainly a consequence of poverty"; but the link can also run the other way, since poverty limits nets, housing and treatment.
• Lost school and work days, and spending on treatment, fall hardest on poor households.

Responses

• Prevention: insecticide-treated nets and indoor residual spraying; vaccines RTS,S (recommended 2021) and R21 (2023), now used routinely in 24 countries.
• Treatment: artemisinin-based combination therapies.
• Nigeria: the R21 vaccine was introduced in Kebbi (north) and Bayelsa (south) in December 2024, with 1 million doses: 846,200 from Gavi and 153,800 bought by the government.
• Tools prevented an estimated 170 million cases and 1 million deaths in 2024.

Mission 7: In October 2010, cholera was reported in Haiti. By February 2019 there had been 820,000 cases. How did it arrive, and why did it spread so fast?

A water-borne disease

• A water-borne disease spreads through contaminated water, often from human faeces.
• Cholera is "an acute diarrhoeal infection caused by consuming food or water contaminated with the bacterium Vibrio cholerae".
• Symptoms appear 12 hours to 5 days after infection. Most infected people have no symptoms but pass the bacteria in their faeces for 1–10 days, so it spreads unseen.

Global incidence

• WHO estimates 1.3 to 4.0 million cases and 21,000 to 143,000 deaths a year.
• In 2025, 47 countries reported 451,499 cases and 7,870 deaths to WHO, which WHO says are likely below the true burden.
• Cholera is linked to limited safe water, sanitation and hygiene, and to conflict, displacement, floods and drought.

Haiti, October 2010

• "The first cholera outbreak was reported in Haiti in October 2010".
• Researchers mapped the first cases. The earliest cluster was near Mirebalais (16–19 October) "next to a United Nations camp with deficient sanitation"; the next ran along the Artibonite River (20–28 October).
• They concluded their findings "strongly suggest that contamination of the Artibonite and 1 of its tributaries downstream from a military camp triggered the epidemic".

How it spread

• Relocation: this was Haiti's first reported outbreak, so the bacteria were brought in; the first cluster was beside the camp.
• Expansion along the river: in the researchers' model, communes downstream of the camp and communes on the coastal plain each had roughly 4.6–4.9 times the risk of other communes.
• Centrifugal spread: three further clusters in November, as cases moved outward.
• Skill: this is a cluster map by date. Like John Snow's 1854 map of cholera deaths around the Broad Street pump in London, it links cases to a contaminated water source.

Why Haiti was so vulnerable

• Basic sanitation, 2010: Haiti 25% of people; rural Haiti 17%.
• The Dominican Republic, on the same island, had 83%.
• Basic drinking water, 2010: Haiti 64%.
• With little sanitation, contaminated faeces reach rivers that people use; with unsafe water, the bacteria reach new hosts.

Impacts

• Demographic: 9,792 deaths and 820,000 reported cases (2010–2019).
• Socio-economic: illness kept people from work and school, and households paid for care. The UN's later plan included material help for the families most affected.
• Trust: the UN Secretary-General said the outbreak had "cast a shadow upon the relationship between the United Nations and the people of Haiti".

Response and accountability

• In December 2016 the UN Secretary-General said: "we apologise to the Haitian people." "We simply did not do enough with regard to the cholera outbreak and its spread in Haiti." "We are profoundly sorry for our role."
• Track One: cut cases (rapid response, vaccination, water, sanitation, health systems). Track Two: material assistance to those most affected, dependent on voluntary funding.
• The last confirmed case was in January 2019, at L'Estère in the Artibonite department.

Why cholera returned in 2022

• On 2 October 2022, two confirmed cases were reported in greater Port-au-Prince; the outbreak centred on Port-au-Prince and Cité Soleil.
• Context: violence had displaced several thousand people; fuel shortages and insecurity blocked supplies; access to safe water and sanitation was limited.
• By 2024, still only 29% of Haitians had basic sanitation.
• Oral cholera vaccine: only single doses have been used since October 2022, because of a global shortage.

Mission 8: From 2016, many packaged foods in Chile carried black "high in" warning labels, with limits on marketing them to children. Did families buy less?

International organisations

• WFP works in over 120 countries and territories and is "entirely funded through the generous voluntary contributions" of donors. It won the Nobel Peace Prize in 2020.
• WFP described a "40 percent reduction in funding" in 2025: US$6.4 billion projected against US$9.8 billion in 2024, a fall of about 35% on those figures. In Haiti, in-kind food aid was cut to half rations for about 575,000 people.
• FAO compiles the food balance sheets behind calorie data and, with IFAD, UNICEF, WFP and WHO, publishes the yearly global hunger report.
• WHO sets health guidance, such as its 2023 guideline on food marketing to children.

Governments and NGOs

• Governments run the largest programmes: Brazil's school meals law (Mission 10); Nigeria co-funded its malaria vaccine rollout.
• NGOs measure and challenge: Welthungerhilfe and partner organisations publish the Global Hunger Index; Oxfam and Save the Children reviewed the slow response to Somalia's 2011 famine.
• NGOs and UN agencies depend on donors, so their reach changes when budgets change.

TNCs: agribusiness power

• An expert panel, IPES-Food (2017), warned that after a wave of mergers just three companies "could control more than 70% of agrochemicals, and more than 60% of proprietary seeds worldwide".
• A handful of commodity traders have been "estimated to account for up to 90% of global grain trade".
• Concentration gives a few firms influence over seeds, prices and farming methods. IPES-Food is critical of this concentration, so check its figures against other sources.

TNCs and the media: shaping what we eat

• WHO (2023): food marketing "continues to negatively affect children's food choices, intended choices and their dietary intake".
• WHO now recommends "comprehensive mandatory policies to protect children of all ages" from marketing of foods high in fat, sugar and salt.
• WHO's Dr Francesco Branca: "Calls to responsible marketing practices have not had a meaningful impact".
• Cheap ultra-processed food is a driver of the double burden (Mission 2).

A government response: Chile's food law (2016)

• Chile's Law of Food Labelling and Advertising was "the first national regulation" to combine three measures:
  • front-of-package warning labels;
  • limits on marketing aimed at children;
  • a ban on school sales of foods and drinks over set limits for sugar, salt, saturated fat or calories.
• It targets the drivers of the double burden in Mission 2: processed food and marketing.

Did it work? Evaluating the evidence (AO3)

• A study of 2,383 urban households compared purchases with a prediction based on the trend before the law.
• Purchases of "high in" drinks fell by 22.8 mL per person per day: 23.7%.
• Limits stated by the authors: it is observational, so it cannot prove cause; it cannot separate the three measures, or tell whether companies reformulated drinks or families changed habits.

Gender and food production

• 36% of working women and 38% of working men work in agrifood systems; in southern Asia, 71% of women's jobs against 47% of men's.
• Women in agricultural wage work earn 82 cents for every dollar men earn.
• Men have greater ownership or secure rights over farmland in 40 of 46 countries.
• Women's food insecurity exceeded men's by 4.3 percentage points in 2021, up from 1.7 in 2019.

Gender, food acquisition and health

• Acquisition: women are often "responsible for ensuring household food and nutrition security". In times of scarcity they tend to put others first, and "women and girls may eat a lower quantity and/or poorer quality food".
• Health: women live longer (76.1 against 70.6 years, 2023) but spend more years in less than full health: 12.0 against 9.1.
• Why men die younger: "Men are much more likely to die from preventable and treatable noncommunicable diseases and road traffic accidents", and "men often seek health care less than women".
• Women's risks: in low-income countries "1 in 41 women dies from a maternal cause"; 30.7% of women aged 15–49 had anaemia in 2023.

Exam move: stakeholders' perspectives (Ev)

• TNCs want sales and may reformulate products to avoid warning labels.
• Governments weigh health costs against jobs and trade. WHO favours mandatory rules.
• WFP and NGOs depend on donors' priorities.
• Women farmers need land, credit and fair wages. There is a 24% gender gap in farm productivity; FAO models that closing farm gender gaps could add nearly $1 trillion to global GDP and cut food-insecure people by 45 million.
• Exam move: "Discuss" answers present each stakeholder's view, then judge whose power is greatest, and where.

Mission 9: Early warning systems forecast a likely emergency in Somalia in August 2010. Famine was declared in July 2011. Why did a warning not prevent disaster?

What counts as famine

• The IPC (Integrated Food Security Phase Classification) defines Famine (Phase 5) by three thresholds in one area:
  • at least 20% of households face an extreme lack of food;
  • at least 30% of children under five are acutely malnourished;
  • more than 2 non-trauma deaths per 10,000 people a day (or 4 per 10,000 children under five).
• An independent Famine Review Committee checks every Famine classification.

Famine is about access (Sen)

• Amartya Sen showed that famines have happened when food supply was not much lower than in earlier years without famine, and that famine areas sometimes exported food.
• In Bangladesh in 1974, floods raised food prices and destroyed a crop; farm workers' real incomes "declined so much that this group was disproportionately stricken by starvation".
• The key term is entitlement: whether people can command food through work, wages, trade or aid.

Somalia, 2011: the causes

• A joint study by FAO's Somalia unit and FEWS NET looked at the areas "most affected by the 2010-11 drought, subsequent spikes in staple food prices, and constraints on humanitarian access".
• The UN declared famine on 20 July 2011.
• Taken together, these point to a physical trigger (drought), an economic shock (prices) and a political obstacle (access). The study did not evaluate the humanitarian response.

How severe?

• An estimated 258,000 people died between October 2010 and April 2012, including an estimated 133,000 children under five.
• In southern and central Somalia, an estimated 4.6% of the population and about 10% of children under five died.
• Lower Shabelle, Mogadishu and Bay were hardest hit. Deaths peaked at about 30,000 a month from May to August 2011.
• Hunger and disease interact: weakened bodies resist infection less well, so many famine deaths come from disease.

Governance and access to aid

• Much of the famine area was controlled by al-Shabaab, an armed group. It banned WFP in January 2010, and later banned 16 international organisations.
• A study for the Overseas Development Institute found that restrictions by both al-Shabaab and donors "hindered attempts to address the famine".
• Donor counter-terrorism rules restricted aid to al-Shabaab areas; USAID humanitarian funding fell by 88% between 2008 and 2010.
• By September 2011 the famine had spread to six regions, with the UN warning that 750,000 lives were at risk; it "predominantly affected Al-Shabaab areas".

Early warning, aid and the media

• "Sophisticated early warning systems first forecast a likely emergency as early as August 2010".
• The full-scale response "was not launched until July 2011".
• Oxfam and Save the Children argued that "a culture of risk aversion caused a six month delay": donors wanted proof of catastrophe first.
• High-profile media coverage came as the response was launched. The UN's coordinator: "we could have done more before famine was declared".

Governance and the media: Sen's argument

• Sen: "no substantial famine has ever occurred in any independent and democratic country with a relatively free press".
• His reasoning: elected governments face pressure to act, and a free press raises the alarm.
• In 2011, much of the famine area was controlled by an armed group rather than an elected government, and international attention came late.
• Exam move: use a theory, then test it against your case study.

Were lessons learned? Somalia, 2022

• A study for Somalia's health ministry, WHO and UNICEF estimated that 43,000 excess deaths "might have occurred in 2022" in the drought, half among children under five.
• Famine was "averted for now", and UNICEF judged "there could have been many more deaths had humanitarian assistance not been scaled up".
• Both the 2011 and 2022 figures are modelled estimates, so compare them with care.

Mission 10: Brazil left the UN's Hunger Map in 2014, fell back onto it, then left again in 2025. What does it take to end hunger, and to keep it ended?

Solutions at different scales

• Raise supply: better seeds, irrigation, storage (local to national).
• Improve access: jobs, cash transfers, food prices, school meals (household to national).
• Cut loss and waste: from farm to fork (all scales).
• Build resilience: early warning and safety nets for shocks (national to global).
• Causes and solutions often sit at different scales: a local drought can need a national safety net and global aid.

Food loss and waste

• Food loss: over 13% of food is lost after harvest and before retail.
• Food waste: 1.05 billion tonnes in 2022, including inedible parts: almost one-fifth of the food available to consumers, or 132 kg per person.
• Households wasted 60%, food services 28% and retail 12%.
• Loss and waste cause 8–10% of the world's greenhouse gas emissions.

Waste reduction: target and policy

• SDG 12.3: "By 2030, halve per capita global food waste at the retail and consumer levels and reduce food losses along production and supply chains, including post-harvest losses".
• UNEP reports cuts in food waste of 31% in Japan and 18% in the UK; in the UK, partnerships helped cut "over a quarter of household food waste per capita from 2007-18".
• France, law of 11 February 2016: supermarkets over 400 m² must seek a partnership with a food-aid charity to donate unsold food, and destroying unsold food that is still edible is banned.
• The French source does not measure the law's effect: judge a policy by evidence, not intent.

Case study: Brazil

• The Zero Hunger (Fome Zero) project, launched in October 2001, became the government's main strategy from 2003.
• Bolsa Família gives cash to poor families who keep their children in school and attend health check-ups.
• By 2013 it reached nearly 14 million households, about 50 million people or a quarter of the population, at around 0.5–0.6% of GDP.

Brazil: school meals and family farms

• Law 11.947 (16 June 2009): at least 30% of federal school-meal funds must buy food directly from family farms.
• In 2025 a new law raised the minimum to 45%.
• School meals are a right of pupils in public schools. The same money feeds children and gives small farmers a steady market.

Brazil: results and setbacks

• Brazil first left the Hunger Map in 2014: undernourishment below 2.5%.
• It returned between 2019 and 2022, after an economic crisis and COVID-19.
• It left again in 2025: undernourishment averaged below 2.5% in 2022–2024 under the Brasil Sem Fome (Brazil Without Hunger) plan.

Exam move: evaluating Brazil (AO3)

• Strengths: it tackled access (Sen) through cash, school meals and farm incomes together.
• Limits: it costs public money, depends on political and economic continuity, and was reversed by crisis.
• Evidence: much comes from government and agency sources; check independent evaluations.
• Exam move: "To what extent" answers weigh success (two exits) against fragility (one return).

Genetically modified (GM) crops

• US National Academies (2016) review:
  • "no substantiated evidence of a difference in risks to human health" from the GM crops then on sale;
  • insect-resistant crops reduced insecticide poisonings;
  • "no evidence that GE crops had changed the rate of increase in yields";
  • some weeds evolved resistance to glyphosate.
• Small farmers gained early, but lasting gains depend on credit, inputs, advice and markets.

Golden Rice, Philippines

• Golden Rice has extra beta-carotene to tackle vitamin A deficiency, which affects more than 15% of Filipino children under six.
• "In July 2021, the Philippines became the first country in the world to approve Golden Rice for commercial propagation".
• In April 2024 the Court of Appeals granted a writ of kalikasan (an environmental-protection petition) and revoked the permit; the ruling was modified in August 2024. PhilRice, the state rice institute, petitioned the Supreme Court.
• A political and legal barrier to diffusion (Mission 5).

Singapore's food-security problem

• Singapore imports over 90% of its food, with only about 1% of its land available for food production.
• In November 2025 its "30-by-30" local-production goal was replaced by targets for 2035: local farms to supply 20% of fibre and 30% of protein eaten.
• Reasons given by the minister: supply-chain disruption, higher energy and labour costs, and harder financing.

Vertical farming: energy against land and water

• Vertical farming grows crops indoors in stacked layers under artificial light.
• Lettuce from an indoor plant factory needs 247 kWh of purchased energy (electricity-equivalent) per kg dry weight; a Dutch greenhouse needs 70 kWh.
• But plant factories use water, CO₂ and land more productively.

In vitro (cell-based) meat

• Meat grown from animal cells rather than slaughtered animals. Singapore was the first country to approve it for sale, in 2020.
• Possible advantages (FAO, 2022): it may "provide more sustainable ways of producing animal protein"; antibiotic use "is drastically reduced or can be eliminated"; and the chance of passing diseases from animals is "considerably lower" than in livestock farming.
• FAO: its environmental impact, energy and water use "can only really be done properly on the basis of large-scale production".
• Singapore notes alternative proteins faced "higher production costs and weaker than expected consumer acceptance globally".

Mission 11: New HIV infections have fallen 65% since their peak in 1994. Was that prevention or treatment, and why are some groups still left behind?

Prevention or treatment?

• Prevention stops infection: vaccines, nets, clean water and sanitation, condoms, pre-exposure medicines.
• Treatment cures or controls disease in people already ill: oral rehydration, antimalarials, antiretroviral therapy (ART).
• Prevention protects whole communities before harm is done; treatment saves the people already sick. Most strategies need both.
• The best mix depends on the means of infection, who is at risk, and what a government chooses to fund.

HIV: scale and trends

• HIV spreads through sexual contact, blood and from mother to child.
• 2025: 41.0 million people living with HIV; 1.2 million new infections; 570,000 AIDS-related deaths.
• 32.1 million people (78%) were on antiretroviral therapy.
• New infections are down 65% since the 1994 peak; AIDS-related deaths are down 73% since 2004.

Treatment as prevention (scientific intervention)

• The HPTN 052 trial (2011) enrolled 1,763 couples in nine countries in which one partner had HIV.
• Of 28 transmissions linked to the infected partner, only 1 was in the group that started ART early.
• So early treatment lowers the amount of virus and sharply cuts onward spread: treatment is also prevention.
• In July 2025 WHO recommended lenacapavir, "the first twice-yearly injectable PrEP product", to prevent infection.

Social marginalisation

• Compared with all adults aged 15–49, UNAIDS reports HIV risk 18 times as high among gay men and other men who have sex with men, 17 times among sex workers and transgender women, and 34 times among people who inject drugs.
• Where these groups face stigma or criminal penalties, they are less likely to seek testing, prevention or treatment.
• Reaching marginalised groups is a geographical question: where services are, and who feels safe using them.

Government priorities

• At the peak of South Africa's epidemic, the government, "going against consensus scientific opinion", argued that HIV did not cause AIDS, and declined donated nevirapine and Global Fund grants.
• A Harvard modelling study estimated that more than 330,000 lives were lost because a feasible ART programme was not implemented in 2000–2005, and 35,000 babies were born with HIV.
• Government priorities decide whether science reaches people.

Exam move: matching strategy to the means of infection

• Water-borne (cholera): treatment with oral rehydration saves lives; prevention needs water and sanitation, which Haiti still lacked (Mission 7).
• Vector-borne (malaria): nets and spraying prevent; artemisinin drugs treat, but resistance is spreading (Mission 6).
• Sexual and blood-borne (HIV): ART treats and prevents; PrEP and condoms prevent.
• Exam move: judge prevention against treatment for a named disease and a named place.

Mission 12: In September 2019 a global board warned: "The world is not prepared" for a fast-moving respiratory pandemic. Months later came COVID-19. Why did a warned world still lose an estimated 14.9 million lives in 2020 and 2021?

From outbreak to pandemic

• Epidemic: more cases than normally expected in an area or community. Pandemic: an epidemic that spreads across several countries or continents.
• 31 December 2019: a cluster of pneumonia cases was reported in Wuhan, China.
• 13 January 2020: the first recorded case outside China, in Thailand.
• 30 January 2020: WHO declared a Public Health Emergency of International Concern (PHEIC), its 6th since the International Health Regulations of 2005. 11 March 2020: WHO said COVID-19 "can be characterized as a pandemic".

Epidemiology: how it spread

• The virus "spreads through the air via infectious respiratory particles"; transmission "is more likely in close contact or shared indoor spaces".
• Older adults, people with underlying conditions and unvaccinated people are at higher risk of severe illness.
• Air travel moved it between cities (relocation and hierarchical diffusion); crowded indoor spaces spread it locally (contagious diffusion).
• Key terms: incubation period (infection to symptoms), reproduction number, R (the average number of people each case infects) and pre-symptomatic spread (passing it on before feeling ill).

Prior awareness

• In September 2019 the Global Preparedness Monitoring Board warned of "a very real threat of a rapidly moving, highly lethal pandemic of a respiratory pathogen".
• It said such a pandemic could kill "50 to 80 million people" and wipe out "nearly 5% of the world's economy".
• Its verdict: "The world is not prepared."
• Prior local awareness: South Korea controlled its early-2020 epidemic without a "Great Lockdown". A review credits "legal and organizational reforms enacted after the MERS outbreak in 2015".

The toll: two ways to count

• WHO estimates about 14.9 million excess deaths in 2020–2021 (range 13.3 to 16.6 million): deaths above the number expected without the pandemic.
• 84% were in South-East Asia, Europe and the Americas. Middle-income countries had 81%; high-income 15%; low-income 4%.
• Reported COVID-19 deaths since December 2019: more than 7.1 million, which WHO says is likely an undercount.

International action

• The Independent Panel (May 2021) found that after the 30 January PHEIC "too many countries took a 'wait and see' approach".
• It found "gaps and failings at every critical juncture of preparedness for, and response to, COVID-19".
• COVAX delivered nearly 2 billion vaccine doses to 146 economies, nearly 90% of them to lower-income economies, before closing on 31 December 2023.
• But access was unequal. In May 2022 COVAX reported that "Only 16% of people in low-income countries have received a single vaccine dose", against 80% in high-income countries.

The role of the media

• The media spread public-health advice quickly, and tracked cases and deaths.
• WHO: an infodemic is "too much information including false or misleading information in digital and physical environments during a disease outbreak".
• An infodemic "leads to mistrust in health authorities and undermines the public health response".

Lessons learned

• The Independent Panel called for a Global Health Threats Council, WHO authority "to publish information about outbreaks with pandemic potential immediately", and a pandemic convention.
• On 20 May 2025 the World Health Assembly adopted the WHO Pandemic Agreement (approved in committee by 124 votes to 0, with 11 abstentions).
• Manufacturers joining its access system (PABS) would aim to give WHO rapid access to 20% of their real-time production of pandemic products. The Agreement opens for signature only once the Assembly adopts the PABS annex, and enters into force after 60 ratifications.
• The negotiators' co-chair said on 1 May 2026: "We are not there yet". On 19 May 2026 the Assembly decided to continue negotiating the annex, for the May 2027 Assembly or a special session in 2026.
• It gives WHO no power to impose lockdowns or vaccine mandates on countries.

Exam move: scale of causes and solutions (Sy/Ev)

• Causes worked at every scale: a local outbreak, global air links, national delays, and unequal vaccine access.
• Solutions also span scales: local ventilation and testing, national health systems, and global agreements.
• Stakeholders disagree: governments guard sovereignty; poorer countries prioritise vaccine access; manufacturers weigh profit and supply.
• Exam move: in "Evaluate" answers, match each lesson to the scale where it can be acted on.

How Option F is examined (Paper 1)

• Paper 1 examines the options: two at SL, three at HL. The guide allows "45 minutes per option question", and each option carries 20 marks.
• Each option has a structured question (10 marks) and one extended answer from a choice of two (10 marks).
• Paper 1 is 35% of the grade at both SL and HL. SL: 1 hour 30 minutes, 40 marks. HL: 2 hours 15 minutes, 60 marks.
• Structured questions often open with a map, graph or table: describe the pattern with figures before you explain it.

What the top band rewards (extended answer, 9–10 marks)

• "In-depth and question-specific (topic and command term)".
• Examples, statistics and details are integrated and explained, not listed: Somalia's 258,000 deaths, Haiti's 25% sanitation.
• Evaluation includes "cause and effect relations, other perspectives; strengths and weaknesses of evidence", such as reported against excess deaths, or an observational study in Chile.
• The conclusion is balanced and matches the evidence. Maps and diagrams are annotated and support the argument.

Command terms to know

• Examine: "Consider an argument or concept in a way that uncovers the assumptions and interrelationships of the issue".
• Evaluate: "Make an appraisal by weighing up the strengths and limitations".
• Discuss: "Offer a considered and balanced review that includes a range of arguments, factors or hypotheses".
• To what extent: "Consider the merits or otherwise of an argument or concept".

The big ideas

• No single indicator measures food or health: use calories, undernourishment, the GHI and GFSI, HALE, IMR and MMR, and know each one's limits.
• The nutrition transition brings a double burden; the epidemiological transition shifts deaths to NCDs as populations age, unevenly.
• Systems thinking shows energy and water losses; sustainability depends on place (north-west India).
• Innovations and diseases diffuse, slowed by physical, economic and political barriers (Green Revolution; malaria; cholera in Haiti).
• Stakeholders hold unequal power: TNCs, governments (Chile), UN agencies, NGOs; gender gaps in farming and health.
• Famine is about access and governance (Somalia 2011); solutions need sustained access (Brazil) and balanced prevention and treatment (HIV, COVID-19).

Final screen. Score, the mission list ticked, and "Next: test yourself in the Verify stage" (links to the Verify quiz).