1.) There is no evidence of GMOs impacting human (or animal) health1)Like with organics , health claims are what drives virtually all the active anger. I refuse to waste more verbiage discussing this non-issue with GMOs .
2.) The problems with GMOs are really just existing problems with our industrial agriculture system
- Corporate Takeover: Sure, Monsanto and pals are not so great but agriculture in the USA (and elsewhere) has been dominated by corporate interests  long before GMOs appeared and would still be so if they were banned. I have mixed feelings about how harmful corporate consolidation is to Sustainability. But GMOs themselves don't inherently have to be so corporate. With better patent laws and more of the research done at public labs, the dynamic would be very different.2)I could not figure out who actually made this image, would love to properly credit them!
- Monoculture etc.: Many of the other problems attributed to GMOs are really just offshoots of intensive monocultures focused on grains and oils. Whether GMO or not, these require high uses of pesticide and fertilizer and create loads of environmental externalities. In some cases GMOs are worsening (herbicide resistance) the existing situation and in others they may help (BT cotton).
- Poorly Regulated: Our food system is a regulatory mess . GMOs are probably under-tested and under-regulated but so are food processing facilities like slaughterhouses  and the impact from that has actually killed people (unlike GMOs). The whole food regulatory system needs an overhaul (here's one proposal ).
3.) So what's good about GMOsFirstly, we should not accept something today just because of claimed potential sometime down the road, especially if there are reasons to suspect it might never bear fruit (eg fusion power plant). The first claim is that GMOs will increase productivity. We have already practically maxed out crops like corn's possible productivity  and conventional means continue to be responsible for virtually all recent yield gains . The other that deserves skepticism is that GMOs will yield varieties that will help us adapt to climate change, such as resistance to extreme droughts. So far no significant improvements have been affected in the real world . With our changing climate we'll definitely need new varieties whether conventionally breed or GMO, so let's keep the research going, but no credit is yet deserved for this. There are however a couple areas where GMOs have demonstrated clear benefits:
Photo by World Bank Photo Collection  
- BT Cotton: Cotton is one of the crops that uses the most pesticide and BT is a highly effective natural pesticide. Bringing the two together has driven down the need for chemical insecticides . Cotton is an important crop for poor farmers in many regions and the weight of evidence is that it is improving their lives . BT in other crops, like corn, has similar benefits but considering that BT is by far the most effective natural pesticide, I don't foresee other possible pest fighting GMOs, the BT revolution may have been a one off improvement which has pretty much run it's course.
- Specific Diseases: GMOs have a demonstrated potential to combat specific crop diseases. In the 90s Hawaiian Papaya were on the verge of being wiped out by the ringspot virus when a GMO variety was perfected  by a local researcher which so far has defeated the disease completely. In Florida farmers are desperately hoping that a GMO variety  will save them from unstoppable "citrus greening". Without these GMO varieties farmers' only option was to dump endless chemicals on their fields and even that was insufficient. There are other crop-specific diseases out there which may prove vulnerable to GMOs and GMO science could provide a way to rapidly respond to new diseases which may pop up in the future.
- Improved nutrition: This attribute of GMOs is another which has been much promised but so far success has been very limited. The famous golden rice (which seeks to tackle beta carotene deficiency) still has not made it to the farmers' fields .3)In general technologists over estimate the ease of getting people, particularly the rural poor, to adopt a new technology, especially one so wrapped up in culture and tradition like Rice and for an invisible benefit. This is the most successful case of improving crop nutrition that I know of. Nutrition is still a very promising area for NGOs and researchers who for example are seeking to make the staple of poor Africans, Cassava, more nutritious and less poisonous . Unfortunately in a country (like the US, where the money is for GMOs) where a "perfect tomato" can't even penetrate the market , I see little likelihood that GMO companies will focus much beyond PR efforts on making crops more nutritious (or taste better for that matter).
4.) Some real worries about GMOsSo far we don't have clear evidence that GMOs generate unique problems such as genes mixing with wild plants or as previously emphasized any health issues such as allergies. Instead GMOs principally are exacerbating currently existing problems with our food system. There are three particular excaerbations which I am very concerned about:
- Worsening the arms race: Since farmers began applying chemicals to kill weeds and pests, those weeds and pests have been evolving to survive them. This creates an arms race where as the pests adapt we invent new weapons to defeat them. So far the impact on chemical use has been mixed . BT crops have in general reduced insecticide use while herbicide resistant varieties have increased herbicide use. Weeds resistant to herbicides  are now becoming common while some pests may be developing immunity to BT. There is much debate in this area but my instinct is that GMOs are accelerating the arms race with agricultural pests.4)This of course is great for the companies that can keep selling new solutions as their patents expire--another reason to move this type of research into the public domain.
- Focused on Grains and Oils: Globally, but particularly in the USA, we produce a crazy amount of grains and oils and GMO companies are mostly focused on these crops (eg corn, soybeans, & canola). We've got more than enough corn ! (and oil too) Producing more grains and oils more cheaply is not going to improve our food system. The cheapness and ubiquity of these basic ingredients is the foundation for the terrible diets we have developed in the US and exported around the world (cheap, abundant corn is also why meat is so cheap and we eat too much of that too !). We need to eat a lot more vegetables  and I believe that GMOs are functionally doing the opposite.
- Tail Risks: In a recent NY Times editorial  Taleb and Spitznagel compared defenders of GMOs with defenders of the pre-2008 recession economy. This was a follow-up on an argument against GMOs Taleb made much more completely (though still unconvincingly) in a paper last fall . Having read Taleb's books I can help you cut through all the insults and zingers  to get to the useful meat of his argument. GMOs could potentially have big tail risks. Taleb's central argument (on this an other topics) is that we systematically underestimate the probability of rare but devastating events. A crop disease is not a problem on one farm but when nearly 100% of the corn planted in the US is genetically identical it could be a massive problem. And that is the key point. GMOs (as they are being currently deployed)5)An easy solution, as with the other problems, is not necessarily getting rid of GMOs. Most of the tail risks could be minimized by encouraging more diverse varieties of crops whether GMO or not and some improved regulation are greatly increasing (though these risks existed previously--see Irish Potato famine) the potential severity and likelihood of low probability catastrophes.
5.) Conclusion: Achieving Sustainability in our food systems can happen with OR without GMOs
Footnotes [ +  ]
|1.||↑||Like with organics , health claims are what drives virtually all the active anger. I refuse to waste more verbiage discussing this non-issue with GMOs .|
|2.||↑||I could not figure out who actually made this image, would love to properly credit them!|
|3.||↑||In general technologists over estimate the ease of getting people, particularly the rural poor, to adopt a new technology, especially one so wrapped up in culture and tradition like Rice and for an invisible benefit.|
|4.||↑||This of course is great for the companies that can keep selling new solutions as their patents expire--another reason to move this type of research into the public domain.|
|5.||↑||An easy solution, as with the other problems, is not necessarily getting rid of GMOs. Most of the tail risks could be minimized by encouraging more diverse varieties of crops whether GMO or not and some improved regulation|