Even as science works to prove the safety, or lack thereof, of GMOs when it comes to human health, there are other issues at stake with biotechnology.

1. GMO Contamination --
Currently, GMO and non-GMO crops coexist side-by-side. But due to cross-pollination from insects, wind, and farmer error, some non-GMO and organic crops are being contaminated with GMOs. Such contamination can be a disaster for farmers, especially those who need to meet minimum standards to sell their products abroad or to Non-GMO Project certified sources.

George Naylor, an Iowa farmer, says he receives a much-needed premium for his non GMO corn and soy from European buyers, which helps him make ends meet. The shadow of being rejected for GMO contamination hangs over him each growing season. “If I’m going to continue to market products as non-GMO, I definitely have to worry about contamination from my neighbors,” he says. “I know farmers who have had their crops rejected by the people who buy my crops.”

Naylor says that contamination has made it difficult to even gain access to enough non-GMO seeds for the growing season.

“One year, I was going to raise non-GMO soy for a processor that sends to Japan for food products,” he says. “I had picked a variety I knew would do well. When I was supposed to get my seed delivered, the company said it couldn’t find enough seed that wasn’t already contaminated with Roundup Ready. I had to pick another, and my yield that year was terrible.”

Although USDA organic certifiers don’t test for the presence of GMOs, cross contamination does threaten the integrity of organic foods. And as more buyers start requiring a minimum threshold for GMOs, the results could be disastrous for organic farmers.

Even food processors are worrying about contamination from certain types of GMOs. In 2011, the USDA approved Syngenta’s Enogen corn, which is engineered to contain a gene from a bacteria that produces alpha amylase, an enzyme that breaks corn down into sugar. This enzyme makes the process of converting the corn to ethanol easier and cheaper.

News of the approval was met with objections from various corn processors, the Pet Food Institute, and the Snack Food Association, which issued a joint statement expressing “deep disappointment” with the decision. The trade groups worried that if food corn becomes contaminated with Enogen corn, it could result in “significant adverse impacts” to their corn products, including soggy, crumbling food items.

2. Corporate Control of Seeds --
Fifty-three percent of the global commercial seed supply is owned by three biotech companies: Monsanto, DuPont, and Syngenta. This corporate control has led to a dramatic rise in seed prices, putting a huge strain on farmers. “From 1995- 2011, the average cost to plant one acre of soybeans has risen 325 percent; for cotton, prices spiked 516 percent, and corn seed prices are up by 259 percent,” says a 2013 report from the Center for Food Safety, Seed Giants vs. US Farmers.

It’s led to lawsuits that pit farmers against biotech “seed police,” who sue when patented GMO traits are detected on fields, even through accidental contamination.

And it’s led to a reduction in seed diversity as well, particularly when it comes to GMOs. For centuries, humans have cultivated thousands of varieties of crops—fostering enough genetic diversity to forge crops that are resistant to weather conditions and diseases. However, we’re losing this heritage and replacing it with crops that are hybrids of a few limited genetic lines—many of which are now patented GM hybrids.

A mere handful of GM strains made up 90 percent of USgrown corn, 93 percent of soy, and 90 percent of cotton.

“The quality of our food and clothing depend on the quality of our seeds—and right now, most of the seeds being developed are optimized for chemically intensive agriculture,” says Matthew Dillon of Seed Matters, a nonprofit founded by the Clif Bar Foundation that works to conserve seed diversity.

“This is problematic because of the toll that this method of farming takes on our water quality, soil health, genetic diversity, and the health of farm workers and consumers.”

And now, what pure, heirloom seeds that remain are further endangered by cross pollination from GM plants.

“GMOs are part of an increasingly industrialized food system, with increasingly centralized control and profits,” says Nicole McCann, Green America food campaigns director. “This is the opposite direction we need to be taking.”

The 2011 film Bitter Seeds details how farmers in India have seen their costs rise in part due to GM seeds. See Green America’s review of the film here.

3. The Pesticide Treadmill --
GMO proponents like to note that thanks to Bt crops, “we’re running the pesticide treadmill in reverse.” A closer look reveals that not only is this not true, but GMOs are responsible for increased use of pesticides—and the water pollution, soil contamination, and risks to farmworker health associated with them.

Data from the USDA annual pesticide use surveys from 1996 to 2008, analyzed by the Organic Center, show that Bt corn and cotton did reduce insecticide use by 64.2 million pounds over that time. However, crops engineered to be glyphosate-resistant or Roundup Ready increased herbicide use by 382.6 million pounds in that same period. All told, GM crops resulted in a 318.4-million-pound increase in overall US pesticide use.

The reason? “When you use a product to control pests, either an herbicide or Bt crops that produce their own toxin, inevitably you’ll get resistance,” says Dr. Doug Gurian- Sherman, a molecular biologist with the Union of Concerned Scientists. “The response in our current industrialized agriculture system is to use more pesticides.”

Indeed, a January 2014 press release from Dow noted that “an astonishing 86 percent of corn, soybean, and cotton growers in the South have herbicide-resistant or hard tocontrol weeds on their farms.”

In response, Dow is seeking USDA approval of Enlist corn and soybeans, which are engineered to withstand a combination of glyphosate and 2, 4-D herbicide. 2, 4-D, the “less-toxic” half of Agent Orange, has been linked to non-Hodgkin’s lymphoma and Parkinson’s, says Gurian-Sherman. And the World Health Organization classifies it as a “possible human carcinogen.”

“2, 4-D is also known to travel considerable distances from the fields on which it is applied, making it one of the most destructive herbicides of neighboring vegetation,” says Gurian-Sherman. If dicamba- and 2, 4-D-resistant crops are approved, “weed scientists have predicted that herbicide use will more than double or even triple,” he says.

Also, studies indicate GM pesticides could be harming pollinators: A 2012 study by the Royal Society, for example, found that herbicide sprayed on herbicide-tolerant GM canola may have cut butterfly populations in the fields by two-thirds and bee numbers in half.

4. Failure to Feed the World --
Are GMOs necessary to feed the world? A comprehensive 2009 report, “Agriculture at a Crossroads,” examined that question, as part of a larger study into what kinds of agricultural systems can best meet future world needs, which was conducted by the United Nations’ International Assessment of Agricultural Knowledge, Science and Technology for Development (IAASTD). The report found that modern biotechnologies are far more likely to harm rather than help subsistence farmers in developing countries. In short, they are not helping to feed the hungry.

“Modern biotechnology has a poor track record of relevance to the poor and subsistence farmer, and its control by a relatively small number of large multinational companies means that adopting modern biotechnologies could also require accepting significant social changes and adopting agricultural models that may not result in poverty reduction or sustainable practices, while also increasing the dependency of local farmers on technological exports from the wealthy countries,” states the report.

In India, 90 percent of soy and 95 percent of cotton is controlled by Monsanto, which owns both Roundup-ready and Bt seed technology. Monsanto prevents even the poorest farmers from saving seed, so farmers must buy more seed from the company each year, in addition to Roundup herbicide for the glyphosate-resistant GM seeds.

Other GM seeds, like the Bt cotton commonly farmed in India, need more water and fertilizer than conventional seeds, applied according to precise timetables. But India’s subsistence farmers have no irrigation systems and are rain-dependent, and they have no extra money for increased fertilizer. As the Bt plants have succumbed to other pests that have moved in to replace those killed by the Bt toxin, and the Roundup-ready plants to superweeds, these farmers are losing entire fields.

The IAASTD report states that the use of biotech seed patents “may drive up costs ... while also potentially undermining local practices that enhance food security and economic sustainability.”

To actually feed the world, the report recommends an emphasis on agroecology farming techniques and a reliance on traditional knowledge combined with modern techniques, as well as a precautionary approach when it comes to GMOs and other new technologies.

“If we do persist with business as usual, the world’s people cannot be fed over the next half-century,” said Dr. Robert T. Watson, IAASTD director and the report’s chief scientist. “It will mean more environmental degradation, and the gap between the haves and havenots will expand.”