Over much of the world, the growing season of 2050 will probably be warmer than the hottest of recent years, with more variable rainfall. If we continue to grow the same crops in the same way, climate change will contribute to yield declines in many places. With potentially less food to feed more people, we have no choice but to adapt agriculture to the new conditions.

To some extent, adaptation can be done by moving crops to more favourable areas and by agronomic tweaks. But that will almost certainly not be enough. We will have to give crops a genetic helping hand, infusing them with new genes to allow them to better cope with new climates, and the new pests and diseases they will bring. Where are these genes going to come from?

Some of them could come from completely unrelated organisms, to be spliced into their new genomic homes using advanced biotechnologies. However, there is significant public resistance to that strategy, and it is still unclear how effective genetically modified crops are at coping with heat and drought. We cannot risk putting all our eggs in that basket.

Another source of genes for crop improvement are traditional heirloom varieties, often called landraces, which are still grown by subsistence farmers in many parts of the world, although they are fast disappearing. Large collections of their seeds have been made over the years, creating genebanks that are scoured by plant breeders searching for crop diversity, and which helped spur the Green Revolution in agriculture from the late 1960s.

But there’s a limit to the diversity found in domesticated species, imposed by domestication itself. Cultivated species usually contain a fraction of the genetic diversity found in their closest wild relatives — a legacy of the ‘domestication bottleneck’. Ancient farmers selected relatively few plants from the progenitors of modern crops, in a limited number of places. Although there has been continuous gene flow between crops and their wild relatives where they coexist, a lot of genetic diversity has been lost as agriculture has developed.

We know that the ‘lost’ genetic diversity includes genes for resistance to high temperatures and drought, and to pests and diseases, as well as taste and nutritional composition, and even yield. If there was ever a time to go back and reclaim this diversity, that time is now. In fact, it is already being used more than many people realize. For instance, there is probably no widely grown rice cultivar that does not have some genes obtained by breeders from its wild relatives. But we could be making much more effective, and systematic, use of the reservoir of diversity our Neolithic ancestors left behind.

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Four decades ago, farmers in Prabhu Pingali’s small eastern-Indian village began planting a new rice variety known as IR8. The high-yielding strain dramatically increased the productivity of rice cultivation in the region. Record harvests and profits allowed Pingali’s family to send their son to school and then to college, launching him on a path that led to his current position as Deputy Director of Agricultural Development at the Bill and Melinda Gates Foundation.

“I think of myself as being here today because of what the Green Revolution did,” said Pingali, speaking at the Center on Food Security and the Environment’s Global Food Policy and Food Security Symposium series.

Pingali’s story, and many others like it, came about as a result of the rapid advances in agricultural technology that characterized the “Green Revolution” of the 1960s and 1970s. Agricultural scientists from the International Rice Research Institute and the International Maize and Wheat Center worked aggressively to bring modern farming techniques, including high-yielding crop varieties, to the developing world.

The first Green Revolution proved that, “innovation, technological change, and just plain old human ingenuity” can overcome seemingly insurmountable obstacles to global food security.

Their efforts sparked a surge in agricultural productivity and incomes that lifted millions of small farmers out of poverty and dispelled widespread fears of famine in Asia’s developing countries. Pingali cited a 2003 study that found that today’s global per capita calorie consumption would be nearly 15 percent lower, and child malnutrition 6-8 percent higher, had the Green Revolution not occurred.

Production surpluses also exerted downward pressure on global food prices, increasing the purchasing power of poor food buyers in both urban and rural areas.

But even direct beneficiaries, including Pingali, acknowledge the Green Revolution’s unintended consequences. “As an Indian, I feel we could have done a lot better.”

Pingali noted that the Green Revolution largely bypassed Sub-Saharan Africa, home to some of the world’s most food-insecure populations. Unlike the developing nations of Eastern Asia, he said, most African countries still lack the market infrastructure to support rapid expansion of the agricultural sector. Low population densities, resulting in weak local food demand, and insufficient government support for agricultural development, have further inhibited productivity gains in these countries.

Additionally, many African farmers rely primarily on minor “orphan” crops, such as cassava, rather than on the global staple grains – rice, wheat, and maize – that received most attention from Green Revolution scientists. Although modern crop breeders have begun to develop high-yielding orphan crop varieties, research in this area remains sparse. Major breakthroughs and significant yield gains may not occur for decades.

Speaking after Pingali, University of Minnesota Professor Philip Pardey reiterated the Green Revolution’s welfare-enhancing consequences. Pardey provided a more rigorous quantitative analysis, presenting data that showed that yields of major cereal crops more than doubled, and real food prices fell by over 50 percent, between 1960 and 2005.

However, Pardey expressed concern about an apparent slowdown in progress since the end of the 20^th century. He cited declining yield growth rates, and the food price spikes of 2008-2010, to emphasize the need for a renewed commitment to agricultural science and food security policy. 

Both Pingali and Pardey also drew their audience’s attention to the unevenness of the Green Revolution’s benefits. The yield gains of the 1960s and 1970s, Pardey said, were accompanied by increasing spatial concentration of food production, as some regions and countries benefited disproportionately from emerging agricultural research.

Even if scientists do develop improved crop varieties for Africa, Pingali said, increasingly stringent intellectual property laws could inhibit their distribution to poor rural farmers. Up until the 1990s, issues of intellectual property had little bearing on agricultural development, permitting the wide distribution of crop varieties. Now the networks that fostered the Green Revolution are in danger of disappearing because of restrictions on the transfer of intellectual property. What was once a public endeavor is increasingly a private concern, and Pingali expressed uncertainty about how private capital should be harnessed to help the rural poor.

Meanwhile, looming challenges such as population growth and global climate change will further complicate the future path of agricultural development.

Like Pardey, Pingali warned against complacency. Though the advances of the 1960s and 1970s were impressive, he concluded, researchers will need to “reach beyond the low-hanging fruit” to continue to increase productivity – intensifying the study of orphan crops, for example, and developing new crop strains that will grow well under extreme climate conditions.

According to Pingali, the first Green Revolution proved that, “innovation, technological change, and just plain old human ingenuity” can overcome seemingly insurmountable obstacles to global food security. Four decades later, agricultural development faces a new round of challenges. Despite these obstacles, Pingali concluded on a note of confidence, arguing that the Green Revolution can overcome problems that currently seem intractable. “We’ve done it before,” he declared, “and I’m sure we can do it again.”

Trade-offs between food and biofuels:

Biomass supply and demand:

Biofuels, land-use, and economic transition:

Biofuels, food prices, and the poor:

Climate and crops, diversification and irrigation: