The Green Revolution was a period of rapid agricultural transformation that occurred primarily in the mid-twentieth century with the goal of increasing food production, particularly in developing countries experiencing rapid population growth. It called for the introduction of new technologies and practices including the use of high-yielding varieties of crops, the promotion of farm mechanization, and the extensive use of chemical fertilizers, synthetic pesticides and modern irrigation systems.
The Green Revolution was successful in greatly increasing the production of grains, mostly wheat, rice and maize (corn), thus helping to avert famine in some countries including India, Pakistan and Mexico. It also helped preserve natural ecosystems in some regions because the increasing yields per unit of land reduced the amount of additional land that was converted to agriculture.
However, there have also been some serious negative effects, and they portend badly for the future. Among them has been rapid soil degradation, including increased erosion and salinization, the lack of organic matter replenishment, and nutrient depletion from the intensive use of chemical fertilizers and pesticides. Moreover, the greatly expanded use of these chemicals has led to increased resistance of pests and diseases to them, thus necessitating the use of even more potent and harmful substances. Additional effects on the soil have been increased soil pH due to the alkaline nature of the chemicals and the harming of beneficial soil microbes essential for nutrient cycling and plant growth.
Another harmful effect has been with regard to water. The Green Revolution greatly expanded the use of fresh water because it requires extensive irrigation, thus further depleting groundwater and exacerbating fresh water shortages. Moreover, water bodies have become increasingly contaminated through the intensive use of chemical fertilizers and pesticides, including causing eutrophication and harming aquatic ecosystems.
Localized air quality has also been affected and greenhouse gas emissions have increased. This is because the use of agricultural machinery and the production of pesticides and fertilizers are dependent on fossil fuels. Also, faster growth cycles of crops in some regions have led to more frequent controlled burning to prepare fields for the next cycle, thus further increasing the output of both localized air pollutants and greenhouse gases.
Yet another harmful result of the Green Revolution has been a reduction in the biodiversity of agricultural crops because it has encouraged the replacement of traditional varieties and the reliance on only a few high-yielding varieties. This makes crops more susceptible to pathogens and has led to the loss of valuable genetic traits found in traditional varieties.
The Green Revolution has additionally created serious health risks for farmers and local communities from the widespread exposure to toxic chemicals while applying them to crops and from their increasing concentration in drinking water. They include respiratory problems, skin conditions, reproductive issues, neurological disorders, DNA damage and cancer. This situation could intensify with the continuing accumulation of these chemicals in the environment and in the food chain.
The fact that the Green Revolution has resulted in greatly increased consumption of rice and wheat at the expense of traditional grains (e.g., pearl millet, sorghum, minor millets, ancient wheats, barley and rye) could also be adding to health risks and could be another factor in the globally rising rates of chronic diseases such as obesity, high blood pressure and diabetes. This is because rice and wheat, while high in carbohydrates, are lower in essential micronutrients than traditional grains. Moreover, the high-yielding varieties of these grains may have even lower concentrations of important minerals than the conventional varieties because of breeding to maximize yield rather than nutrition.
Although the Green Revolution has not directly caused antibiotic resistance similar to that which has occurred with animal agriculture, there is concern that its focus on intensive farming practices, including the massive use of chemicals, has altered ecosystems and potentially increased the presence of antibiotic-resistant bacteria in the soil and water, which could eventually spread to humans.
The Green Revolution has also had major economic and social consequences. In particular, it has increased economic disparities, as it has favored large-scale farmers who could afford new technologies, and has led to accumulating indebtedness, social polarization and the displacement of small farmers, who often struggle to afford the necessary inputs, including machinery and the commercial seeds for high yield crop varieties that must be purchased from large corporations. This has resulted in large-scale migration to cities and increased social tensions.
While not a fundamental part of the original Green Revolution, genetic engineering is now becoming crucial for maintaining it, and it is often referred to as the "Green Revolution 2.0." This technology has been able to further boost crop yields and improve crop traits, but it also compounds the problems caused by the original Green Revolution, including the heavy use of toxic chemicals, soil depletion, water contamination and adverse social effects.
Thus, although the Green Revolution has to date been successful in preventing mass starvation, it is likely that it has just postponed the problem and also has created conditions that could produce famine and starvation on a much greater scale in the future. This is both because it is not sustainable and also because of the continuing rapid increase in the human population in the developing countries that it has facilitated. Moreover, this situation is likely to be exacerbated by the increasingly adverse effects of climate change on agriculture.