The term Green Revolution refers to the renovation of agricultural practices beginning in Mexico in the 1940s. Because of its success in producing more agricultural products there, Green Revolution technologies spread worldwide in the 1950s and 1960s, significantly increasing the number of calories produced per acre of agriculture.
History and Development of the Green Revolution
The developing world witnessed an extraordinary period of food crop productivity growth over the past 50 y, despite increasing land scarcity and rising land values. Although populations had more than doubled, the production of cereal crops tripled during this period, with only a 30% increase in land area cultivated.
Dire predictions of a Malthusian famine were belied, and much of the developing world was able to overcome its chronic food deficits. Sub-Saharan Africa continues to be the exception to the global trend.
The beginnings of the Green Revolution are often attributed to Norman Borlaug, an American scientist interested in agriculture. In the 1940s, he began conducting research in Mexico and developed new disease resistance high-yield varieties of wheat.
The word “Green Revolution” was coined by William S. Gaud of the United States Agency for International Development (USAID) in 1968, for the introduction of new technology and policies implemented in the developing nations with aids from industrialized nations between the 1940s and the 1960s to increase the production and yield of food crops.
Many high-yielding varieties (HYVs) were introduced as part of the Green Revolution to increase agricultural productivity. These genetically improved varieties of wheat and rice were developed by the International Maize and Wheat Improvement Centre (CIMMYT), Mexico, and the International Rice Research Institute (IRRI), Philippines, respectively.
By combining Borlaug’s wheat varieties with new mechanized agricultural technologies, Mexico was able to produce more wheat than was needed by its own citizens, leading to them becoming an exporter of wheat by the 1960s. Prior to the use of these varieties, the country was importing almost half of its wheat supply.
Due to the success of the Green Revolution in Mexico, its technologies spread worldwide in the 1950s and 1960s. The United States, for instance, imported about half of its wheat in the 1940s but after using Green Revolution technologies, it became self-sufficient in the 1950s and became an exporter by the 1960s.
In order to continue using Green Revolution technologies to produce more food for a growing population worldwide, the Rockefeller Foundation and the Ford Foundation, as well as many government agencies around the world funded increased research.
In 1963 with the help of this funding, Mexico formed an international research institution called The International Maize and Wheat Improvement Center.
Countries all over the world, in turn, benefited from the Green Revolution work conducted by Borlaug and this research institution. India, for example, was on the brink of mass famine in the early 1960s because of its rapidly growing population.
Borlaug and the Ford Foundation then implemented research there and they developed a new variety of rice, IR8, that produced more grain per plant when grown with irrigation and fertilizers. Today, India is one of the world’s leading rice producers and IR8 rice usage spread throughout Asia in the decades following the rice’s development in India.
Plant Technologies of the Green Revolution
The crops developed during the Green Revolution were high yield varieties – meaning they were domesticated plants bred specifically to respond to fertilizers and produce an increased amount of grain per acre planted.
The terms often used with these plants that make them successful are harvest index, photosynthate allocation, and insensitivity to day length. The harvest index refers to the above-ground weight of the plant.
During the Green Revolution, plants that had the largest seeds were selected to create the most production possible.
After selectively breeding these plants, they evolved to all have the characteristic of larger seeds. These larger seeds then created more grain yield and heavier above-ground weight.
This larger above-ground weight then led to an increased photosynthate allocation. By maximizing the seed or food portion of the plant, it was able to use photosynthesis more efficiently because the energy produced during this process went directly to the food portion of the plant.
Finally, by selectively breeding plants that were not sensitive to day length, researchers like Borlaug were able to double a crop’s production because the plants were not limited to certain areas of the globe based solely on the amount of light available to them.
Much of the success was caused by the combination of high rates of investment in crop research, infrastructure, and market development, and appropriate policy support that took place during the first Green Revolution (GR). I distinguish the first GR period as 1966–1985 and the post-GR period as the next two decades.
Large public investment in crop genetic improvement built on the scientific advances already made in the developed world for the major staple crops, wheat, rice, and maize, and adapted those advances to the conditions of developing countries.
The GR strategy for food crop productivity growth was explicitly based on the premise that, given appropriate institutional mechanisms, technology spillovers across political and agroclimatic boundaries could be captured. However, neither private firms nor national governments had sufficient incentive to invest in all of the research and development of such international public goods.
Private firms operating through markets have limited interest in public goods because they do not have the capacity to capture much of the benefit through proprietary claims; also, because of the global, nonrival nature of the research products, no single nation has the incentive to invest public resources in this type of research.
International public goods institutions were needed to fill this gap, and efforts to develop the necessary institutional capacity, particularly in plant breeding, were a central part of the GR strategy.
Based on the early successes with wheat at the International Maize and Wheat Improvement Centre (CIMMYT) in Mexico and rice at the International Rice Research Institute (IRRI) in the Philippines, the Consultative Group on International Agricultural Research (CGIAR) was established specifically to generate technological spillovers for countries that underinvest in agricultural research, because they are unable to capture all of the benefits of those investments.
After CGIAR-generated knowledge, invention, and products (such as breeding lines) were made publicly available, national public and private sectors responded with investments for technology adaptation, dissemination, and delivery.
Despite that success, in the post-GR period, investment in agriculture dropped off dramatically into the mid-2000s. However, the need for continued investments in agricultural innovation and productivity growth is as important today as it was in the early years of the GR.
Low-income countries and lagging regions of emerging economies continue to rely on agricultural productivity as an engine of growth and hunger-reduction. However, sustaining productivity gains, enhancing smallholder competitiveness, and adapting to climate change are becoming increasingly urgent concerns across all production systems.
Since the mid-2000s and heightened after the 2008 food price spikes, there has been renewed interest in agricultural investment, and there are calls for the next GR, including those calls made by the former Secretary-General of the United Nations Kofi Annan and Sir Gordon Conway.
Simultaneously, there is recognition of the limitations of the first GR and the need for alternative solutions that correct those limitations and unintended consequences.
Impacts of the Green Revolution
Since fertilizers are largely what made the Green Revolution possible, they forever changed agricultural practices because the high yield varieties developed during this time cannot grow successfully without the help of fertilizers.
Irrigation also played a large role in the Green Revolution and this forever changed the areas where various crops can be grown. For instance, before the Green Revolution, agriculture was severely limited to areas with a significant amount of rainfall, but by using irrigation, water can be stored and sent to drier areas, putting more land into agricultural production – thus increasing nationwide crop yields.
In addition, the development of high-yield varieties meant that only a few species of say, rice started being grown. In India, for example, there were about 30,000 rice varieties prior to the Green Revolution, today there are around ten – all the most productive types. By having this increased crop homogeneity though the types were more prone to disease and pests because there were not enough varieties to fight them off. In order to protect these few varieties then, pesticide use grew as well.
Finally, the use of Green Revolution technologies exponentially increased the amount of food production worldwide. Places like India and China that once feared famine have not experienced it since implementing the use of IR8 rice and other food varieties.
Diffusion and Impact of Crop Genetic Improvements
Positive impacts on poverty reduction and lower food prices were driven in large part by crop germplasm improvements in CGIAR centers that were then transferred to national agricultural programs for adaptation and dissemination.
The productivity gains from crop germplasm improvement alone are estimated to have averaged 1.0% per annum for wheat (across all regions), 0.8% for rice, 0.7% for maize, and 0.5% and 0.6% for sorghum and millets, respectively. Adoption rates of modern varieties in developing countries increased rapidly, reaching a majority of cropland (63%) by 1998.
However, global aggregates mask great geographic disparities. In Asian countries (including China), the percentage of area planted to modern varieties was 82% by 1998, whereas improved varieties covered only 27% of the total area planted in Africa.
This difference may be, in part, because of the later introduction of CGIAR research programs focused on Africa as well as the lag in breeding efforts for the orphan crops, crops that did not benefit from a backlog of research conducted before the GR period but had improvement that came during the GR and post-GR periods, such as cassava, sorghum, and millet which are of greater relative importance to the African poor.
For instance, the first CIMMYT maize program focused on Africa only began in the late 1980s. Although the International Institute for Tropical Agriculture research for cassava started in 1967, its impact was felt only since the 1980s.
Although it lagged behind in the GR period, Africa has witnessed positive growth in the post-GR period. Adoption of improved varieties across sub-Saharan Africa reached 70% for wheat, 45% for maize, 26% for rice, 19% for cassava, and 15% for sorghum by 2005.
Impact on Productivity and Food Prices
The rapid increase in agricultural output resulting from the GR came from an impressive increase in yields per hectare. Between 1960 and 2000, yields for all developing countries rose 208% for wheat, 109% for rice, 157% for maize, 78% for potatoes, and 36% for cassava.
Developing countries in Southeast Asia and India were the first countries to show the impact of the GR varieties on rice yields, with China and other Asian regions experiencing stronger yield growth in the subsequent decades. Similar yield trends were observed for wheat and maize in Asia.
Analysis of agricultural total factor productivity (TFP) finds similar trends to the partial productivity trends captured by yield per hectare [TFP is defined as the ratio of total output to total inputs in a production process. For the period 1970–1989, the change in global TFP for agriculture was 0.87%, which nearly doubled to 1.56% from 1990 to 2006.
Crop genetic improvement focused mostly on producing high-yielding varieties (HYVs), but the decrease in time to maturity was also an important improvement for many crops, allowing for an increase in cropping intensity. The rapid spread of the rice-wheat system in the Indo-Gangetic plains (from Pakistan to Bangladesh) can be attributed to the shortening of the crop growing period.
Other improved inputs, including fertilizer, irrigation, and to a certain extent, pesticides, were also critical components of the GR intervention. Asia had already invested significantly in irrigation infrastructure at the start of the GR and continued to do so throughout the GR and post-GR periods.
Widespread adoption of GR technologies led to a significant shift in the food supply function, contributing to a fall in real food prices.
Between 1960 and 1990, the food supply in developing countries increased 12–13%. Estimates suggest that, without the CGIAR and national program crop germplasm improvement efforts, food production in developing countries would have been almost 20% lower (requiring another 20–25 million hectares of land under cultivation worldwide).
World food and feed prices would have been 35–65% higher, and average caloric availability would have declined by 11–13%. Overall, these efforts benefited virtually all consumers in the world and the poor relatively more so, because they spend a greater share of their income on food.
Limitations of GR-Led Growth Strategies
The GR contributed to widespread poverty reduction, averted hunger for millions of people, and avoided the conversion of thousands of hectares of land into agricultural cultivation.
At the same time, the GR also spurred its share of unintended negative consequences, often not because of the technology itself but rather, because of the policies that were used to promote rapid intensification of agricultural systems and increase food supplies.
Some areas were left behind, and even where it successfully increased agricultural productivity, the GR was not always the panacea for solving the myriad of poverty, food security, and nutrition problems facing poor societies.
Poverty and Food Insecurity Persisted Despite the GR Success
There is a large econometric literature that uses cross-country or time-series data to estimate the relationship between agricultural productivity growth and poverty. These studies generally find high poverty reduction elasticities for agricultural productivity growth. In Asia, it has been estimated that each 1% increase in crop productivity reduces the number of poor people by 0.48%.
In India, it is estimated that a 1% increase in agricultural value-added per hectare leads to a 0.4% reduction in poverty in the short run and a 1.9% reduction in the long run, the latter arising through the indirect effects of lower food prices and higher wages.
For low-income countries in general, the impact on the poverty headcount has been found to be larger from agricultural growth relative to equivalent growth in the non-agricultural sector at a factor of 2.3 times. In sub-Saharan Africa, agriculture’s contribution to poverty reduction was estimated to be 4.25 times the contribution of an equivalent investment in the service sector.
Because the GR strategy was based on the intensification of favorable areas, its contribution to poverty reduction was relatively lower in the marginal production environments. In South Asia, the poorest areas that relied on rain-fed agriculture were also the slowest to benefit from the GR, contributing to widening interregional disparities and an incidence of poverty that still remains high.
Technologies often bypassed the poor for a number of reasons. Among these reasons were inequitable land distribution with insecure ownership and tenancy rights; poorly developed input, credit, and output markets; policies that discriminated against smallholders, such as subsidies for mechanization or crop and scale bias in research and extension; and slow growth in the nonfarm economy that was unable to absorb the rising numbers of rural unemployed or underused people.
Migration from less-favored rural areas has been cited as a strategy for poverty reduction; however, when migration out of rural areas occurs faster than the growth in employment opportunities, only a transfer of poverty results rather than true poverty reduction associated with agricultural transformation.
Sex played a major role in determining the distribution of benefits from the GR. Women farmers and female-headed households are found to have gained proportionally less than their male counterparts across crops and continents.
Technology transfer largely focused on male farmers, with few measures to address women’s technology needs or social conditions, and thus, they largely missed women farmers. Cross-country empirical evidence shows that women farmers are no less efficient than their male counterparts when using the same productive assets; however, women consistently face barriers to accessing productive resources and technologies.
Nutrition: Calorie Availability Increases but Micronutrient Intake Is Still Lagging
Between 1960 and 1990, the share of undernourished people in the world fell significantly. Improved availability and decreased staple food prices dramatically improved the energy and protein consumption of the poor.
The pathways through which the GR improved nutritional outcomes depended on whether a household was a net producer or net consumer; however, for virtually all consumers, the supply shifts and GR-driven rise in real incomes had positive nutritional implications.
A 10-y study in southern India found that increased rice production resulting from the spread of HYVs accounted for about one-third of the substantial increase in energy and protein consumption of both farmers and landless workers, controlling for changes in nonfarm income sources.
The fall in staple prices as a result of the GR also allowed for more rapid diet diversification, even among poor populations, because savings on staple food expenditures improved access to micronutrient-dense foods.
In Bangladesh, for example, the steady fall in real rice prices from 1992 to 2000 led to greater expenditures per capita on nonrice food and a significant improvement in child nutrition status. The amount of rice consumed did not change, but households spent more on nonrice foods as their rice expenditures declined.
Nutritional gains of the GR have been uneven; although overall calorie consumption increased, dietary diversity decreased for many poor people, and micronutrient malnutrition persisted.
In some cases, traditional crops that were important sources of critical micronutrients (such as iron, vitamin A, and zinc) were displaced in favor of the higher-value staple crops. For example, intensive rice monoculture systems led to the loss of wild leafy vegetables and fish that the poor had previously harvested from rice paddies in the Philippines.
Price effects of such supply shifts also limited access to micronutrients, because prices of micronutrient-dense foods rose relative to staples in many places. In India, the increasing price of legumes has been associated with a consequent decline in pulse consumption across all income groups.
Policy and structural impediments, as well as a weak private sector, limited the supply responsiveness for vegetables and other nonstaples. Policies that promoted staple crop production, such as fertilizer and credit subsidies, price supports, and irrigation infrastructure (particularly for rice), tended to crowd out the production of traditional nonstaple crops, such as pulses and legumes in India.
More recent evidence does suggest that diets are shifting in urban and rural Asia to include fewer cereals and more milk, meat, vegetables, and fruits. Evidence from India shows a marked increase in protein and fat intake between 1975 and 1995 across all income groups, suggesting that all consumers have benefitted from some nutritional improvements. However, micronutrient deficiencies among the poor persist, indicating that this dietary shift has not yet fully compensated for the decline in vitamin intake associated with cereal-dominant diets.
Biofortification (breeding micronutrients into staple crops, such as the vitamin A-enhanced, orange-fleshed sweet potato) offers a new solution for improving nutrition outcomes, particularly for the rural poor, who depend on their own production for a large proportion of their daily caloric intake.
Environment: Impacts Have Been Mixed
GR-driven intensification saved new land from conversion to agriculture, a known source of greenhouse gas emissions and driver of climate change, and allowed for the release of marginal lands out of agricultural production into providing alternative ecosystem services, such as the regeneration of forest cover.
HYVs more responsive to external inputs were central to the productivity achievements; however, in many cases, appropriate research and policies to incentivize judicious use of inputs were largely lacking.
Unintended consequences in water use, soil degradation, and chemical runoff have had serious environmental impacts beyond the areas cultivated. The slowdown in yield growth that has been observed since the mid-1980s can be attributed, in part, to the above degradation of the agricultural resource base. These environmental costs are widely recognized as a potential threat to the long-term sustainability and replication of the GR’s success.
The environmental consequences were not caused by the GR technology per se but rather, the policy environment that promoted injudicious and overuse of inputs and expansion of cultivation into areas that could not sustain high levels of intensification, such as the sloping lands.
Output price protection and input subsidies, especially fertilizer, pesticide, and irrigation water, distorted incentives at the farm level for adopting practices that would enhance efficiency in input use and thereby, contribute to sustaining the agricultural resource base.
Where the policy incentives were corrected, farmers quickly changed behavior and adopted more sustainable practices. For example, the removal of pesticide subsidies in Indonesia in the early 1990s led to a dramatic drop in insecticide use.
Marginal Production Environments
The original purpose of the GR was to intensify where returns would be high, with a focus on irrigated or high rainfall areas. The international breeding programs aimed to provide broadly adaptable germplasm that could then be grown across a wide set of geographies, but adoption was greatest in favorable areas. Technologies in the GR period did not focus on the constraints to production in more marginal environments, especially tolerance to stresses such as drought or flooding.
Whereas HYVs of wheat provided yield gains of 40% in irrigated areas with modest use of fertilizer, in dry areas, gains were often no more than 10%. Almost full adoption of wheat and rice HYVs had been achieved in irrigated environments by the mid-1980s, but very low adoption in environments with scarce rainfall or poor water control (in the case of rice) had been achieved.
In India, specifically, adoption was strongly correlated with water supply (3). Worldwide, improved seed–fertilizer technologies for wheat were less widely adopted in marginal environments and had less of an impact there than in favored environments.
More often than not, marginal environments were left behind, because the climate and resource constraints were such that returns to investment in GR varieties were low. Despite relatively low adoption of improved varieties, people living in marginal environments benefitted from the GR through consumption and wage linkages, such as lower food prices.
Farm employment and growth in the nonfarm rural economy provided labor benefits to the landless rural poor and those people living in marginal production environments. Multicountry case studies of rice environments in Asia show that labor migration to more productive environments resulted in wage equalization and was one of the primary means of redistributing the gains of technological change from favorable to marginal areas.
Similar results were found for wheat grown in high- and low-potential environments in Pakistan. There is also a growing body of evidence of spillovers from the productive regions that benefit the more marginal environments. These spillovers involve not only technology transfer and capital investments but also the software of development, such as local institutions, property rights, and social capital.
Poorly endowed environments, nevertheless, pose a tremendous challenge to researchers and policymakers alike to identify new agricultural research and development (R&D) opportunities and facilitate the adoption of technologies and appropriate institutions to meet the needs of the poor living there.
In the post-GR period, new investments in R&D for stress-tolerant crops and increased demand for feed grains have changed the prospects for agricultural production in marginal areas.
Drought- and pest-resistant varieties, such as submergence-tolerant rice and drought-tolerant maize, provide options that reduce farmers’ risk and improve incentives to invest in productivity-enhancing technologies. Changing market contexts also create new opportunities for farmers in more marginal areas to produce for the feed and biofuel markets.
Criticism of the Green Revolution
Along with the benefits gained from the Green Revolution, there have been several criticisms. The first is that the increased amount of food production has led to overpopulation worldwide.
The second major criticism is that places like Africa have not significantly benefited from the Green Revolution. The major problems surrounding the use of these technologies here though are a lack of infrastructure, governmental corruption, and insecurity in nations.
Despite these criticisms though, the Green Revolution has forever changed the way agriculture is conducted worldwide, benefiting the people of many nations in need of increased food production.
Developing country agriculture is faced with a growing set of challenges: meeting the demands of diet diversity resulting from rapidly rising incomes; feeding rapidly growing urban populations; accessing technologies that are under the purview of proprietary protection, and gearing up for the projected negative consequences of climate change. Even as it absorbs the new challenges, the food policymaking community continues to grapple with its traditional preoccupation with the persistence of hunger and poverty in low-income countries, particularly in sub-Saharan Africa, and lagging regions of emerging economies.
At the country level, public policy can play an important role in ensuring that new innovations reach and benefit smallholders and encouraging the sustainable use of natural resources. This role requires policies that (i) emphasize agriculture as an engine of growth and poverty reduction, (ii) enhance the competitiveness of modernizing agricultural systems, and (iii) focus on sustaining the resource base by correcting distortions that create incentives for unsustainable use. Both infrastructure investments and institutional reform can help create the enabling environment for smallholder productivity growth.
- Briney, Amanda. “History and Overview of the Green Revolution.” ThoughtCo, Aug. 27, 2020, thoughtco.com/green-revolution-overview-1434948.
- Pingali, P. L. (2012). Green revolution: impacts, limits, and the path ahead. Proceedings of the National Academy of Sciences, 109(31), 12302-12308.