The short answer to this question is no, there are no 30-plus year studies done on GM crops. The first plant transformation to produce a GM plant was reported in 1982. Before a GM plant can be approved by the USDA, its potential ecological impact must be fully evaluated. The question appears to be asking if full-spectrum ecological studies are done for every organism, and, by implication, every conceivable situation. It is simply impossible to test all organisms in all situations. Accordingly, scientists select key nontarget species and indicator organisms that serve as surrogates for different classes of environmental organisms, from microbes to whole animals, and typically at a minimum evaluate ecological effects in at least six agro-ecosystems on three continents for at least three growing seasons—sometimes more.
Field tests are always performed with and without the normally used pesticides and herbicides, since that’s just good experimental design. Scientists and regulators have concluded that this provides a clear enough view of how a crop will impact the environment. As an additional safeguard, a plan for postmarket agro-ecological monitoring is also put in place to ensure that any unexpected adverse effects are detected. If any postmarket adverse effect is detected, systems for management and mitigation can be put in place, or the crop can be withdrawn from the market. Fear-mongers who are opposed to GM crops always forecast ecological doom from some unforeseen impact, when in fact crops are grown season by season, and if an adverse impact occurs, the use of the crop can be discontinued. This is a peculiar concern, since irreversible ecological disasters caused by domesticated crops have not been scientifically documented to date. The resilience of natural ecosystems would most likely allow affected ecosystems to quickly return to their prior state. That said, GM crops have been planted on more than 2 billion hectares by more than 17 million farmers over 17 years in about 30 countries, with no adverse ecological impacts observed. Fair to say, that’s a pretty robust long-term study!
The use of the term "monoculture" has become quite polemical, and there’s no point replowing that ground here. Suffice it to say that in today’s world, almost all agriculture is a monoculture; organic farmers, conventional farmers and GM farmers all seek to have a single kind of plant growing in their fields, no matter how big or small an area they cover. And that’s not necessarily a bad thing. Each crop (and each associated soil) has different requirements for water, nutrients, disease and pest management, and those requirements make anything but monocultural farming very difficult. Our ancestors sensed this when they first began farming monocultures over 10,000 years ago. They were perhaps inspired by seeing natural monocultures larger than 8,000 hectacres of wild wheat in what is now Turkey. The history of agriculture is a fascinating story but one for another day. It’s simply worth noting that “monoculture” should not be used as a pejorative adjective. None of us would be alive today without monocultures—or we would all be hunter-gatherers.
The question asks if science can predict the future. The answer to that question is no and yes. Science is the best system available for making extrapolations about what is most probable in the future. Climate-change science is a good example. No, the world hasn’t gotten as warm as it is going to get in 50 years, but scientists are confident that if current trends continue, it will get much warmer. That’s using science to predict the future. Can science predict with 100 percent certainty? Absolutely not! We all have different personalities. To some of us, a glass is half full; to others, it is half empty. When we think about change—as, for example, adopting GM crops—some of us see risks, and other of us see benefits. That’s just human nature, and we are fortunate that the risk-averse among us help us to look before we leap into a bad situation. It is, however, worth pointing out that for all the claimed failures like DDT and thalidomide, there are literally thousands, if not millions, of new products and technological innovations that bring benefits without serious unwanted side-effects. There’s no point resurrecting the controversy about DDT here. Below are a few useful resources on this topic.
- The Story of DDT
- DDT in NYT: The Unfinished Agenda
- Health Costs and Benefits of DDT Use in Malaria Control and Prevention
There is overwhelming evidence that limited and controlled use of DDT could save millions of lives each year through prevention of malaria. More importantly, in the hypothetical case of a GM crop that caused an adverse effect, a simple solution is available: stop planting it!
In summary, we don’t test anything for 30 years—asking for 30 years of testing may sound like a reasonable precaution, and it may be a good way to block the introduction of a competitor’s product or a product that you just don't like—but it can actually do more harm than good. The under-lying reason is fundamental to understanding why new products are developed in the first place. They are usually developed because there is a market need for the product. For instance, farmers lose a significant percentage of their crops even though they use pesticides and herbicides. Those pesticides and herbicides are expensive and consume time and labor. A product that can reduce environmental impact, increase production and lower costs provides clear benefits to the consumer, the farmer and the environment. Those benefits would be lost during 30 years of testing, and during those 30 years far more harm would be done by the use of present-day methods. Considering the evidence that GM crops are more precisely constructed, contain fewer compositional and other unintended changes than those produced by other methods of breeding and have been used around the world by millions of farmers on billions of acres without harm and with significant economic and environmental benefits, it can be argued that having waited for the completion of 30 years of testing before deploying a new GM crops would often have been a serious error in judgment.
I can’t resist pointing out that long-term tests have never been required for any new seed variety or crop. GM crops are the only crops to be subjected to premarket safety assessments, in spite of the fact that crops produced, using other methods of genetic modification and having identical new traits, are not tested before their use. It makes absolutely no scientific sense to single out GM crops for premarket testing while ignoring others that are made using older less exact methods. Of course, we don’t require premarket testing of crops because crop breeding has, over many years and thousands of new varieties introduced, proven to be a safe science. And there’s no scientific reason to believe that GM crops are any different with regard to safety, in spite of the well-financed and professionally orchestrated global campaign aimed at making consumers believe that GM crops are inherently different, inherently unsafe.