The Green Revolution refers to the development that began around the middle of the 20th century, where agricultural productivity increased due to the introduction of new grain varieties and new technology. New high-yielding wheat, maize, and rice varieties, widely deployed in Latin America and Asia in particular in the mid-1960s, combined with enhanced use of fertilizers, pesticides, and irrigation, proved successful in food production. The term “green revolution” was probably first used in this sense by William S. Gaud, an official of the United States Development Agency, in his speech 8.3.1968.

While caring for the needy may have been a feature of human communities throughout human history, before 1945 the problem of world hunger received little academic and political attention. This is despite the fact that in the 1930s, more than one in five residents in Western Europe and the United States suffered from malnutrition. One of the major funders of the Green Revolution, the Rockefeller Foundation, took hunger and agriculture on its agenda, especially since the early 1950s (see a letter from Warren Weaver, the Foundation’s Director of Science, to Chester I. Barnard, President of the Foundation). The UN Universal Declaration of Human Rights, adopted by the UN General Assembly on 10 December 1948, also mentions food as part of human rights: 

“Everyone has the right to a standard of living adequate for the health and well-being of himself and of his family, including food, clothing, housing, and medical care and necessary social services […]” (article 25).

Although the launch of the Green Revolution is accompanied by an element of international cooperation, especially through scientific agricultural research, and although charity played a key role in funding the Green Revolution, we can safely assume that in the post-World War II geopolitical situation defined by Cold War, the motivation for rich countries to help poor countries was imperialist rather than humanitarian.

The Green Revolution helped feed the growing population

It is debatable how the Green Revolution affected the world’s population. Population change is, of course, the result of the relationship between mortality and birth rate, but these in turn are affected by many factors. It has been estimated in the scientific literature that the Green Revolution reduced both birth rates and mortality, and thus the overall effect is unclear. It is clear, however, that the Green Revolution helped feed the world’s population, which had grown at an unprecedented rate since World War II. 

However, it is clear that since World War II, the world’s population has grown at an unprecedented rate. At the beginning of the Common Era, in the first millennium, the number of people is estimated to have hardly increased, due to the ongoing wars and diseases in Europe. After that, the population began to grow slowly. Only the Black Death, a mid-14th-century plague pandemic, killed so many people that the world’s population last declined. In the 18th century, the population began to grow much faster due to the development of agricultural production methods and the Industrial Revolution. Mortality fell, especially as hygiene conditions improved, and the world's population exceeded one billion in the early 19th century. The second billion was exceeded just over a hundred years later in the 1920s. The third billion was exceeded about 40 years later, in 1960, and after that, it took only 14 and 13 years to exceed the fourth and fifth billion, and only 12 years to exceed the sixth (1999) and seventh billion (2011). 

Figure presents the development of the world population since 10 000 BCE.

There are differing estimates of the continuation of demographic trends, but exponential population growth is expected to end soon, and by the end of this century, 10-11 billion people are expected. Humankind has probably already surpassed the largest number of children under the age of 15 that the planet has ever had or will have in the foreseeable future. The average number of children for women has also halved from five in the mid-1960s.

The Green Revolution boosted cereal yields

The population increased 2.4-fold in the second half of the 20th century. However, agricultural production grew even faster during this period. Although per capita food production in the world increased significantly, malnutrition in the world did not decrease but, on the contrary, doubled between 1960 and 2000, indicating an unequal distribution of food on Earth. While 8.8 percent of the world’s population suffers from malnutrition, 13 percent (in 2016, according to the WHO) of the adult population is obese (i.e., a body mass index greater than 30 kg/m²) and 39 percent is overweight (25-30 kg/m²).

Although the research that enabled the Green Revolution had been started as early as the 1940s and 1950s, the actual beginning of the Green Revolution can be pinpointed quite accurately into the 1960s with the establishment of two research institutes in the Philippines (International Rice Research Institute, in 1960) and in Mexico (International Center for Maize and Wheat Improvement, in 1967). The latter was established on the basis of a program that had studied wheat until the late 1940s. This program had been led by Norman Borlaug, an American agricultural scientist who is considered to be the “father” of the Green Revolution. Borlaug received the Nobel Peace Prize for these merits in 1970. Funding for these two research institutions that started the Green Revolution came from national aid organizations and donors, the most important of which were the Ford and Rockefeller foundations. 

Research activities produced new seed varieties whose seeds could produce much larger yields per hectare if there was sufficient fertilizer and irrigation. The most important plants of the Green Revolution were wheat and rice. Crossbreeding produced dwarf genetic varieties that used more energy for seeds and less for straw and leaves, but whose short, stiff straws nevertheless helped support a heavier grain weight. These varieties also respond better to fertilizers than traditional varieties. In this way, developing countries, where the population doubled over the next 50 years, could triple grain production, even though cultivated land increased by only 30 percent at the same time. It took humanity around 10,000 years to reach the annual level of one billion tons of food grain production that was reached in 1960. In contrast, the level of two billion tons was reached only 40 years later at the turn of the 21st century.

Impacts of the Green Revolution

What kind of impact did the Green Revolution then have? The pros and cons of the Green Revolution have been debated since at least the late 1960s when it began to become apparent that the Green Revolution also causes environmental problems and increases social inequality. Estimates are of course complicated by the fact that we will never be able to be sure of what would have happened if the development known as the Green Revolution had never started. To this end, however, model studies have been developed which assume, for example, that the productivity gains achieved would not have taken place in developing countries or that there would have been no international funding for research.

It is common ground that the new varieties, combined with the use of fertilizers and pesticides, and irrigation systems, significantly increased the yields per hectare of agriculture. This, in turn, has lowered food prices globally, which has benefited everyone, but relatively the poor in particular, as the poor spend a relatively larger share of available funds on food. As food prices fell, caloric intake was higher, which in turn improved people’s health and life expectancy. Based on model studies, it has been estimated that world food and feed prices in 2000 would have been 35-65% higher without the Green Revolution. Calorie intake in developing countries would have been 11-14 percent lower than realized. 

However, a review of more than 300 studies on the Green Revolution published in 1970-89 shows that around 80% of studies drawing conclusions about the income distribution effects of new technologies found that inequalities increased between farms and between regions. In much of Latin America, the privileged rural elite owns farmland and the elite could get loans to purchase inputs such as fertilizers required by the Green Revolution. The state also supported the commercial agricultural elite in many ways in the procurement of machinery, fertilizers, and pesticides, prompting the elite to quickly accept new seeds. With the Green Revolution, the position of farmers who did not adopt new, more productive varieties, pesticides, or fertilizers, or whose cultivation conditions were not most favorable for new varieties, deteriorated. As the price of grain fell as production increased, so did incomes for those farmers who were unable to increase their production. In Asia, however, farming was not in the hands of a small elite, but smaller family farms were more typical. These family farms also had the opportunity to irrigate. As a result, social inequality did not increase in Latin America in the same way with the Green Revolution.

In Africa, especially in the early decades of the Green Revolution, the situation was much more difficult than in Latin America and Asia. Varieties developed for the local conditions of the latter did not produce similar harvests under African conditions. Although the Green Revolution is often equated with the success of the 1960s and 70s in growing wheat and rice crops in Latin America and Asia, the development of grain varieties has, of course, continued since then. Significantly more research institutes such as those set up in Mexico and the Philippines have since been set up elsewhere, and research has spawned thousands of new high-yielding varieties into many other kinds of cereal in addition to wheat and rice. It can rightly be argued, then, that the Green Revolution should be understood as a long-term trend in output growth rather than a single leap in output growth in the 1960s. With the ever-evolving varieties and production techniques, Africa has also had better results in agriculture since the 1980s. However, this does not eliminate the fact that the number of deprived people in sub-Saharan Africa remains the highest globally. 

The figure shows the change in the cereal yield and land used for cereal production between 1961 and 2018. To view the change by country and region, select ‘add country’. Cereal yield refers to the amount of grain produced per unit area. The development is presented in relation to 1961, which is the 0-point of the review. For example, in the global analysis, the amount of cereal yield has tripled over the period under review (+ 200%), but the area used for cereal production has increased by only 12%. By country, the successes of the Green Revolution in terms of cereal yield are Mexico, India, China, and Brazil. In Africa, the land used for cereal production has increased more than the cereal yield, meaning that the increase in cereal production comes, on average, more from an increase in the area under cultivation than from more efficient cultivation. Although cereal production has increased significantly, Africa has had difficulties keeping pace with its growing population. The situation is particularly difficult in sub-Saharan Africa, where, in many countries, cereal yields vary greatly from year to year, which is problematic for food security.

Environmental impacts

At the heart of the Green Revolution was not only the development of crop varieties but also the increasing use of fertilizers and pesticides and irrigation systems, which has rightly been linked to a wide range of environmental problems such as soil depletion, chemical pollution, groundwater depletion, and salinization. Environmental impacts also differed between Latin America and Asia. State aid encouraged excessive irrigation and the use of fertilizers and pesticides, leading to increased emissions to air and water. On the other hand, at the same time, poor farmers who did not adopt new varieties used too little fertilizer, leading to soil depletion and thus deforestation and the introduction of more fragile lands for agriculture.

From a scientific perspective, it is a very difficult, and perhaps poorly formulated, question what exactly the environmental impact of the Green Revolution has been. It is clear that the Green Revolution was aimed at increasing production, and the impact on the environment was not a priority. It remains clear that rapidly growing food production in recent decades has contributed to pushing humanity’s footprint to and beyond the planetary boundaries, and that the Green Revolution is a major factor in the historical development that has led to the current global food system. Still, it is difficult for us to answer very precisely what the contribution of the Green Revolution is to environmental degradation. It requires a counterfactual analysis – that is, a reflection on what global development could have been without the Green Revolution – which is always full of uncertainties and sensitive to selected assumptions, as mentioned earlier.

One big question about the environmental impact of the Green revolution is how many people would live on Earth if the Green Revolution had not taken place. Quite often popular texts mention that the Green Revolution, or Norman Borlaug, prevented a billion people from starving, which would indicate that there would be a billion fewer people in the world without the Green Revolution. This figure is not based on scientific modeling. Instead, Gollin and co-authors (2021) have published in the Journal of political economy an assessment of the impact of the Green Revolution on world population development. In their assessment, they compare the effects of the Green Revolution with a hypothetical situation where the Green Revolution would not have existed or would have started later. It is estimated that the Green Revolution slowed the growth of the world’s population. This is based on the fact that, with the Green Revolution, the economies of developing countries grew significantly, which on the one hand contributed to a reduction in mortality, and in particular child mortality, but on the other hand, the birth rate decreased even more. The overall effect was thus slower population growth. Indeed, Gollin et al argue that if the Green Revolution had started 10 years later, the population of developing countries would have been 223 million larger in 2010.

Very different estimates have been made of the effects of scientific breakthroughs, including those linked to population growth. This discrepancy in the results suggests that large scientific inventions typically have difficult-to-assess, often unintended consequences. One good example of this is the Haber-Bosch method. It is used to produce ammonia from atmospheric nitrogen and methane from natural gas, which is used to make nitrogen fertilizers. The method was developed in 1908 by the German Fritz Haber and later developed by his compatriot Carl Bosch on an industrial scale. Both of the researchers were awarded Nobel Prizes for these merits. Haber’s motivation was to respond to the growing demand for food and to replace nitrogen that escapes from fields in agriculture. In addition, the motivation was to provide raw material for explosives that need reactive nitrogen. Instead, Haber could not predict the ensuing environmental impact.

Erisman and co-authors (2008) in Nature Geoscience map out these different effects: On the one hand, Haber’s invention had a major impact on both world wars and other conflicts, and with it, the Haber-Bosch process is linked to 100-150 million deaths in armed conflicts during the 20th century. Second, the Haber-Bosch method made it possible to produce fertilizers on a completely new scale, which in turn made it possible to significantly increase cereal yields, as explained in this part of the course. Erisman et al. estimate that since the invention of the Haber-Bosch method, nitrogen fertilizers have made it possible to feed almost half of all people born. Accordingly, without the Haber-Bosch method, the world would have almost half the population.

The environmental impact of the Haber-Bosch method is also significant. Most of the nitrogen used in fertilizers is lost to nature, causing significant disruption to ecosystems. The Haber-Bosch process also emits 450 million tonnes of carbon dioxide per year, which is about one percent of all anthropogenic emissions and more than any other industrial chemical reaction.

So there are good reasons to think that the current population of the world would not be possible without the Green Revolution and the associated massive increase in the use of fertilizers. However, if the explosive population growth of the late 20th century had taken place, it is very unclear how developing countries could have met their needs with less environmental impact if the increase in grain production described by the Green Revolution had not taken place. At the same time, it should be clear that meeting the nutritional needs of a growing world population cannot in the future take place in the same way as it did in the Green Revolution, but that the food system must change radically.

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