Seed company mergers have been all over the news lately. First, there was Monsanto’s rebuffed attempts to buy Syngenta, followed by a proposed merger between DuPont and Dow. Then, a Chinese company expressed interest in buying Syngenta, which lead to Syngenta’s renewed interest by Monsanto. As this chart by Michigan State University’s Phillip Howard shows, all this recent merger activity is the culmination of about two decades of the world’s largest seed companies swallowing up smaller companies by the score.

And while most of these developments have been reported as business stories, they also have huge implications for agriculture and our food supply.

Yes, these mergers would have big economic ramifications. For example, as I’ve noted, the growing economic power of seed companies, and the gene and crop patents they own, often keep farmers from being able to save seeds. This allows the companies to jack up prices, which results in a higher percentage of farmer profits going to seed purchases than before and lowers profit margins per acre for farmers. This trend puts upward pressure on farm size, which often contributes to simplified farming practices that lead to environmental harm.

But lost in the legitimate concerns about economics, have been the implications of mega seed companies when it comes to the impact of climate change on farming.

The Threat of Climate Change and the Need for Crop Diversity

Climate change is a well-recognized threat to crop production, and research has shown that it is probably already reducing the productivity of some major crops. Increased temperatures and droughts cut productivity, as do extreme precipitation events and floods, causing possible increased pest invasions, and harm to important crop helpers like pollinators.

How we grow and breed our crops can either make them more climate resilient or more vulnerable. And one key element of resilience against climate change is crop genetic diversity. Sadly, when large industrial agriculture companies exert their influence, diversity is generally reduced. That means fewer types of crops and less genetic diversity within each crop.

And a seed company landscape made up of fewer, larger companies will likely make this problem worse.

These mergers would also probably lead to a reduction in research. As Brett Bergemann, Monsanto’s Chief Operating Officer, has said, “The crop chemicals industry is bound to consolidate because target companies are spending too much on research and development for new products.” Meanwhile, commercial farming has become increasingly dependent on private sector research to develop potentially useful traits.

Recent research supports the increased climate resilience of diverse cropping systems that rely on agroecology, like using long crop rotations, cover crops, manures and mulches, intercropping, perennial plants, and so forth. Yields averaged seven and 22 percent higher for corn and soybeans, respectively, grown in more diverse crop rotations under hot and dry conditions. Greater drought tolerance has also been observed with increased varieties of a single crop in Ethiopia.

Large seed companies aren’t the only factors driving U.S. farms to become less diverse; the demands made by food retailers and processors and our nation’s farm policies also play a large role. But they’re a big piece of the puzzle.

These seed companies put most of their breeding efforts into a small number of major crops like corn, soybeans, and cotton, which increases their economic competitiveness compared to other crops. Recent research published in PLOS One found that cropping systems are becoming simpler especially in places like the U.S. Midwest, where these major crops are particularly dominant. The researchers attributed this trend to be in part due to the concentrated seed industry.

Many of the crops that have been replaced around the world by corn and soybeans are more climate-resilient. For example, sorghum, millet, pigeon peas, and cassava are generally more heat and drought tolerant. As the big seed companies grow, and push their varieties on international markets, they may further displace local crops.

And the big seed companies also foster poor genetic diversity within the crops that they favor. For example, National Academy of Sciences member and internationally respected geneticist and corn breeder Major Goodman noted at a summit about crop breeding in 2014 that the big companies rely heavily on just a few basic types of corn, to which they add a few additional traits. Meanwhile, the much more genetically diverse native varieties of maize—and its wild relative and progenitor, teosinte (which can supply even more adaptive traits to corn)—are being lost from their regions of origin in Mexico and Guatemala.

It is much more expensive to produce many diverse locally adapted varieties, and more time-consuming. So big seed companies generally narrow their focus to reduce costs. The more the seed and breeding industries and communities become concentrated in a few mega-companies, the more these harmful trends will be exacerbated. But we’re reducing our adaptability just at the moment when we will need it the most.

Small Farmers Hold the Key

By contrast, small farms, and especially indigenous farmers who are under pressure from companies and governments around the world, are the keepers of the types of genetic diversity that we will all need to continue to adapt to a changing climate. They have developed, nurtured, conserved, and traded these diverse local crop varieties for millennia. In fact, they should be celebrated and supported for doing the original crowdsourcing, or “seed-sourcing.”

But all is not lost. As researchers Maywa Montenegro and Dianne Rocheleau pointed out in their recent papers, the loss of small and peasant farms has slowed in recent years in some areas, sometimes through active resistance. In fact, many of these farmers continue to plant diverse crops and varieties.

However, we cannot be complacent about the vitality of the stewards of our genetic inheritance. Big seed companies and the high-profit crop varieties that they favor, will continue to displace or absorb small and peasant farms into a system that sees them primarily as potential customers.

We need to actively support small farms and their communities through public policies, and public participatory breeding without patents, such as the work of the Open Source Seed Initiative, while opposing further seed company mergers and patents that prevent seed saving. Our future ability to produce the food we need in the face of climate change depends upon it.