20 points of broad scientific consensus on GE crops

coverBy Pamela Ronald and Karl Haro von Mogel
Just as many on the political right discount the broad scientific consensus that human activities contribute to global warning, many progressive advocacy groups disregard, reject, or ignore the decades of scientific studies demonstrating the safety and wide-reaching benefits of GE crops.  Is political identity more important than science and the environment?
Review your knowledge of food, farming and plant genetics by reviewing this list. It represents specific points of broad scientific consensus: that is, the conclusions of the scientific community based on analysis of thousands of experimental results over the past 10-20 years. For each point, we have provided links to appropriate references. Please let us know which ones we missed.

  1. GE crops currently on the market are safe to eat. (See the European Commission Joint Research Centre, European Food Safety Authority, The American Medical Association, the National Academy of Sciences, and the World Health Organization)
  2. The processes of genetic engineering and conventional genetic modification pose similar risks of unintended consequences.
  3. The risks and benefits of new traits in crops depend upon the traits themselves and not the means of their introduction, whether through GE or conventional means.
  4. The planting of Bt cotton has reduced the use of sprayed insecticides.
  5. The planting of Bt corn in the US has benefited growers of non-GE corn.
  6. Planting of Bt cotton has enhanced yields in China and India.
  7. Planting of Bt cotton has reduced insecticide poisonings of farmers and their families. 
  8. Adoption of Bt cotton enhances insect biodiversity. 
  9. If not properly managed, overuse of Bt spray or Bt crops will lead to Bt resistant insects.
  10. Farmers need to deploy a crop diversity strategy and crop rotation to reduce the evolution of insect resistance.
  11. US farmers that plant BT crops are required to deploy a “refuge strategy”: creating refuges of crop plants that do not make Bt toxins. This promotes survival of susceptible insects and has helped to delay evolution of pest resistance to Bt crops.
  12. Global pest-monitoring data suggest that Bt crops have remained effective against most pests for more than a decade.
  13. Failure to provide adequate refuges appears to have hastened resistance of pink bollworm in India and western corn rootworm in the US to Bt.
  14. Effective methods for slowing the spread of insect resistance include crop rotation, intercropping and planting refuges of non-BT cotton and non-crop species.
  15. Planting of herbicide tolerant (HT) crops has reduced the environmental impact of herbicide use. This is because the reduced tillage associated with planting of HT crops has led to reduced soil erosion and reduced greenhouse gas emissions.
  16. The liberal use of glyphosate without proper management has spurred the evolution of weeds resistant to that herbicide.
  17. The evolution of herbicide resistant weeds is a problem for farmers who rely on a single herbicide.
  18. GE crops are just one of the many tools that can be used to enhance the sustainability of farms.
  19. Papaya genetically engineered for resistance to papaya ringspot virus has protected yields against significant losses from the virus and saved the Hawaiian papaya industry.
  20. Consumption of Golden Rice, within the normal diet of rice-dependent poor populations, could provide sufficient vitamin A to substantially reduce the 6,000 deaths caused every day by vitamin A deficiency and save the sight of several hundred thousand people per year in a cost efficient manner.

In the last few weeks, on various blogs and forums, representatives of the Union of Concerned Scientists have variously supported, rejected or ignored many of these 20 points of scientific consensus. Most often they simply avoid stating their position.
Consider point #1. “GE crops currently on the market are safe to eat.”
Margaret Mellon of UCS recently stated that they “agree that GE products currently on the market–overwhelmingly herbicide tolerant (HT) and BT crops–are unlikely to be allergenic or toxic and on that basis are likely safe to consume. “
That sounds pretty clear right? Mellon, a scientist herself, agrees with the scientific consensus. But a statement on the UCS Web site appears to reject this scientific consensus and instead does some fear mongering: “GE crops do have the potential to cause a variety of health problems and environmental impacts. For instance, they may produce new allergens and toxins, spread harmful traits to weeds and non-GE crops, or harm animals that consume them.” While it is technically true that any new crop, whether it was developed by genetic engineering or conventional plant breeding, poses risks, by excluding conventional methods in their statement (which are the only crops that have so far caused allergies), and by not mentioning the scientific consensus about the safety of GE crops, the UCS is misleading their followers.
This is just one of the many striking examples of why it is difficult to discern whether UCS rejects or accepts the scientific consensus on GE crops. It is not possible to know the reason for their inadequate communication on key points, but what we do know is that the result contributes to the spread of misinformation about plant genetics, which can impair policy-making.
We extend an open invitation to UCS and other advocacy groups to state clearly whether they accept or reject the scientific consensus on these 20 points. We would like to see these groups become a more credible source of scientific information about GE crops to the public. For science-based policy to be effective, policy makers need accurate information.  
In a subsequent post we will address policy implications of the scientific consensus.


  1. I’d like to see the UCS issue addressed in a separate post. I think it’s important and they need to be called out on the way they are ducking the issue and clouding the waters.
    But I wish it had been left out of this post because it is such a great resource, it’s going to be bookmarked and used to send folks here for some clear information. The insider baseball politics are a bit of a distraction and will surely give some people the permission they need to ignore the evidence and focus on the debate and the players.
    Just a thought.

  2. Allow online shops for example for Golden Rice and fair cotton.
    I would buy Golden Rice. Not because I need more carotene, but to show that I eat this. To make the peoples trust in Golden Rice, which saves the lives of young children. An other project in poor countries could be the use of sweet potatoes, which naturally have much carotene. This online shops could offer cotton products like shirts and towels produced by good social working conditions and fair wages. Perhaps coffee ,tea, tropical nuts, cacao same way… But I dont wanna eat insecticides sprayed ones nor such expressed by genes…

  3. Good points. Perhaps with a little more info and refinement of these points, we can graduate it to a Page on the site which will be about that – and only that. 🙂

  4. Re: #15: Planting of herbicide tolerant (HT) crops has reduced the environmental impact of herbicide use. This is because the reduced tillage associated with planting of HT crops has led to reduced soil erosion and reduced greenhouse gas emissions.
    The second link points to file:///1.%09http/::www.agbioforum.org:v9n3:v9n3a02-brookes.htm when I think it should be http://www.agbioforum.org/v9n3/v9n3a02-brookes.htm (note all the slashes were converted to : characters so best to verify and repaste the whole thing).
    But more, I have trouble parsing this sentence “Planting of herbicide tolerant (HT) crops has reduced the environmental impact of herbicide use.” It seems like it reduces the impact of farming overall, not jut impact of herbicide use. If that’s really what is meant, I want evidence that is more directly related to the impacts of herbicide use you mean.

  5. To Mike Lewinski:
    Planting herbicide tolerant crops has reduced the environmental impact of herbicides. Glyphosate is a pretty mild herbicide to the environment. If it was not available to use, Atrazine would have to be used in a much larger scale to have the same effect. Atrazine is much more harmful to the environment.
    In years past, farmers had to cultivate and spray to keep fields clean. Cultivating and tillage led to soil erosion on land with slopes greater than 5%. Now that we have a few herbicide choices that are environmentally friendly, we reduce the environment contamination by using these. It’s a win-win. Hope this answers your question.

  6. First Officer, I think that’s a great article to keep handy to show people, too!

  7. Hi guys: Pam, I’m teaching your book (Tomorrow’s Table) in a science literacy oriented advanced composition course focusing on food health and food sustainability, urban agriculture, etc.
    In the second chapter, R. Adamchuk notes that Bt toxins(applied organically) don’t work well with the corn earworm.
    Is this true for Bt corn?
    Thanks for all your work.

  8. I think when it comes to GMOs, you can’t talk about the scientific consensus in the same way you do with global warming. We don’t have an independent board assessing the value and meaning of the research. And we have an industry that’s profiting from the technology.
    I don’t see that the graph you link to in #2
    supports the conclusion that:
    “The processes of genetic engineering and conventional genetic modification pose similar risks of unintended consequences.”
    It looks like transgenics are inherently more risky, right?
    Also, the data seem to show that bt cotton in India has reduced yields, not increased them.
    Bt Cotton, Remarkable Success, and Four Ugly Facts
    the graph on pg 68 of the following paper illustrates the relationship between yield and bt cotton very simply, and the paper talks about why it may be that we see erroneous data so often:
    Constructing facts, Bt Cotton Narratives in India
    #12 in your list:
    Global pest-monitoring data suggest that Bt crops have remained effective against most pests for more than a decade.
    may have a conflict of interest
    I’ve just sort of picked out the above links to look at, and I find that I’m now tempted to look at every single one to see if there’s something more substantial behind this list of pro-industry statements.
    As far as crop diversity and rotation, aren’t these tools that wise farmers have used for a long time in the attempt to thwart unwanted species? Unfortunately, they aren’t tools that are encouraged by the US Farm Bill, which supports corn and soy over every other crop, thereby indirectly moving taxpayer money to Monsanto, and encouraging monocropping and the further development of transgenic crops – the very method we’re discouraging with the advise to diversify and rotate.
    By pulling Margaret Mellon’s quote out of context, you’ve misrepresented her view on GE products. And in my opinion, the Union of Concerned Scientists site you link to:
    doesn’t sound like fear-mongering at all, but rather an even-handed assessment of the current state of the science, and a well-reasoned position on GE, stated at the bottom of the page.
    “We see that the technology has potential benefits, but we are critics of its commercial application and regulation to date. GE has proved valuable in some areas (as in the contained use of engineered bacteria in pharmaceutical development), and some GE applications could turn out to play a useful role in food production.
    However, its applications in agriculture so far have fallen short of expectations, and in some cases have caused serious problems. Rather than supporting a more sustainable agriculture and food system with broad societal benefits, the technology has been employed in ways that reinforce problematic industrial approaches to agriculture. Policy decisions about the use of GE have too often been driven by biotech industry PR campaigns, rather than by what science tells us about the most cost-effective ways to produce abundant food and preserve the health of our farmland.”
    They proceed to offer suggestions.
    Also, now that it’s starting to look like the class of artificial recombinant DNA sequences used in genetic engineering is likely contributing to anti-biotic resistance.

  9. correct —the problem with applied Bts is that there is only short time for the Bt to be applied, not ashes off by rain and available to kill the larvae. Bt in the plant through Gm technology kills the ear worm more effectively but it also depends on the specific Bt used. The second generation Monsanto Bt is better than the first.

  10. Was there ever a reply to Mlema? I would like to see it! It may not be coming across on my phone view….

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