The toxic legacy left by the Green Revolution

The toxic legacy left by the Green Revolution

There are more than 390,000 identified plant species in the world, but just three -- rice, maize, and wheat -- account for roughly 60% of the plant-based calories in our diets. The dominance of these three grains is largely the result of major technological breakthroughs, particularly the development of high-yielding varieties (HYVs) of rice and wheat during the Green Revolution of the 1960s.

These innovations have yielded enormous benefits, significantly increasing access to staple foods and rescuing hundreds of millions of people from hunger. But ramped-up agricultural output has also brought a host of other problems, particularly when it comes to the cultivation process. Notably, the enhanced productivity of HYV seeds depends heavily on the availability of reliable irrigation and the application of various chemical inputs, especially fertilisers and pesticides.

Consequently, the adoption of HYV seeds has led to the overuse of canal irrigation and subsequent waterlogging problems, forcing farmers to rely on groundwater irrigation, even in semi-arid regions. Similarly, the use of nitrogen-based fertilisers has dramatically increased following the shift to HYV-based agriculture.

The inherent vulnerability of these varieties to pests, together with the tendency to cultivate them in monocultures, has led to frequent infestations and the widespread, often indiscriminate use of chemical pesticides, resulting in residual toxicity in plants and grains. With pests developing resistance to these chemicals, it became necessary to seek out new technological solutions, including the development of genetically modified crops designed to be naturally resistant to (at least some) pests.

In addition, although these technologies are scale-neutral, access to the required inputs and markets typically is not. As a result, large farmers benefited disproportionately, adding to agrarian inequality.

As if these challenges were not daunting enough, experts are growing increasingly concerned about the deteriorating nutritional content of high-yield crops. For example, a recent study suggests that although the Green Revolution has helped India achieve food self-sufficiency, it has undermined the country's nutritional security.

By analysing the quality and potential toxicity of roughly 1,500 rice and wheat varieties developed and introduced in India from the 1960s to 2018, the authors trace the long-term effects of HYV-focused breeding programs. These programs, they find, have modified the grains' nutritional makeup, resulting in significantly reduced dietary benefits and a higher concentration of toxins.

In short, although enhancing nutrition was the primary goal of cultivating these grains, the emphasis on increasing yields has significantly compromised their nutritional value. Notably, the levels of vital nutrients like zinc and iron in rice and wheat, India's two most important food staples, have declined markedly. Specifically, rice experienced a 33% drop in zinc and a 27% decrease in iron, while the zinc and iron content in wheat fell by 30% and 19%, respectively. Even worse, arsenic levels in rice surged by 1,493%.

In particular, the authors highlight "strong evidence" that "oral ingestion of metal toxicants" could lead to serious health problems like "lung cancers or chronic respiratory diseases, cardiovascular diseases, hyperkeratosis, renal toxicity, and impaired bone calcification." Increased consumption of staples like rice and wheat -- the goal of the Green Revolution -- could end up exacerbating India's disease burden.

This is also true for many other countries that have relied heavily on HYVs to boost yields and increase the production of staple crops. The recently rebranded Alliance for a Green Revolution in Africa continues to advocate an outdated industrial model of agriculture that has failed to deliver the expected nutritional benefits.

Nutrition should not be viewed only in terms of total calorie consumption based on mono-cropped cultivation. While the superior nutritional value of a diverse diet is now widely recognised, achieving it requires not just technological innovation but also a shift in focus towards cultivating a variety of crops best suited to the local environment and climate.

In India and elsewhere, it is clear that adopting agroecological practices based on smallholder farming is the most effective way to develop food systems that are both sustainable and nutritionally rich. But this requires moving towards a model that benefits the actual producers and consumers of food. © 2024 Project Syndicate

Jayati Ghosh, Professor of Economics at the University of Massachusetts Amherst, is a member of the Club of Rome's Transformational Economics Commission and Co-Chair of the Independent Commission for the Reform of International Corporate Taxation.

Do you like the content of this article?