Because Genetically modified crops risk widespread ruin, they should not be permitted without far greater scientific knowledge, for which the burden of proof falls on those proposing GMOs, not those opposing, say experts in risk and ruin.
if an action or policy has a suspected risk of causing severe harm to the public domain (such as general health or the environment), and in the absence of scientific near-certainty about the safety of the action, the burden of proof about absence of harm falls on those proposing the action.
A paper by Nassim Nicholas Taleb and co-authors lays out a formal statisticial and risk-analyis theory of what is sufficient risk of ruin to apply the precautionary principle, using GMOs as their prime example.
In contrast to nuclear energy (which, as discussed in section 10.1 above, may or may not fall under the PP, depending on how and where (how widely) it is implemented), Genetically Modified Organisms, GMOs, fall squarely under the PP because of their systemic risk. The understanding of the risks is very limited and the scope of the impacts are global both due to engineering approach replacing an evolutionary approach, and due to the use of monoculture.
If you don’t know the risk of ruin of monoculture, read up on the boll weevil, for example in this 2003 USDA writeup: We Don’t Cotton to Boll Weevil ‘Round Here Anymore,
The year before boll weevils marched into Georgia in 1915, the state produced 2.8 million bales of cotton. Less than 10 years later, Georgia’s annual cotton production had fallen to 600,000 bales. By 1983, Georgia cotton production was down to 112,000 bales harvested from 115,000 acres.
Farther west, cotton monoculture and the weevil led to the dust bowl and sped on the Great Depression.
Unfortunately, eventual eradication of the boll weevil opened fields for Monsanto’s GMO cotton seeds, which are another monoculture, already breeding disaster in mutant glyphosate-resistant weeds such as pigweed.
Taleb’s paper continues:
Labeling the GMO approach “scientific” betrays a very poor—indeed warped—understanding of probabilistic payoffs and risk management. A lack of observations of explicit harm does not show absence of hidden risks. Current models of complex systems only contain the subset of reality that is accessible to the scientist. Nature is much richer than any model of it. To expose an entire system to something whose potential harm is not understood because extant models do not predict a negative outcome is not justifiable; the relevant variables may not have been adequately identified.
This is the same point made in Cosmos Episode 11 that Neil deGrasse Tyson read but apparently didn’t understand, of short-term profit misusing technical know-how beyond understanding of nature.
Back to the Taleb paper:
Given the limited oversight that is taking place on GMO introductions in the US, and the global impact of those introductions, we are precisely in the regime of the ruin problem. A rational consumer should say: We do not wish to pay—or have our descendants pay— for errors made by executives of Monsanto, who are financially incentivized to focus on quarterly profits rather than long term global impacts. We should exert the precautionary principle—our non-naive version— simply because we otherwise will discover errors with large impacts only after considerable damage.
Large effects such as irrigation-residue salt poisoning ancient Mesopotamian agriculture, as mentioned in that Cosmos episode. Or the global effects of lead poisoning from leaded gasoline described in Cosmos Episode 7.
The paper is “The Precautionary Principle (with Applications to the Genetic Modification of Organisms),” by Nassim Nicholas Taleb, Rupert Read, Raphael Douady, Joseph Norman, and Yaneer Bar-Yam. Working Paper, September, NYU School of Engineering Working Paper Series, 4 September 2014.
Lest anyone think nukes are off the hook:
In large quantities, we should worry about an unseen risk from nuclear energy and invoke the PP. In small quantities, it may be OK—how small we should determine by direct analysis, making sure threats never cease to be local.
In addition to the risks from nuclear energy use itself, we must keep in mind the longer term risks associated with the storage of nuclear waste, which are compounded by the extended length of time they remain hazardous. The problems of such longer term “lifecycle” effects is present in many different industries. It arises not just for nuclear energy but also for fossil fuels and other sources of pollution, though the sheer duration of toxicity effects for nuclear waste, enduring for hundreds of thousands of years in some cases, makes this problem particularly intense for nuclear power.
Fossil-fuel-burning-induced climate change could also have extreme duration, as in which “the consequences can involve total irreversible ruin, such as the extinction of human beings or all life on the planet.” This is the type of extreme situation for which the precautionary principle should be invoked, according to the first page of the paper. The obvious solution is to stop burning fossil fuels. Fortunately, we can do that, by switching to sun, wind, and solar power.
As we saw earlier we need to remain careful in limiting nuclear exposure —as other sources of pollution — to sources that owing to their quantity do not allow for systemic effects.
Seems to me deliberately dumping radioactive Fukushima cooling water into the Pacific Ocean has already turned nukes into a systemic problem. But indeed Taleb’s point is good that GMOs are a more obvious risk of systemic ruin.
The paper also includes this gem:
Invoking the risk of famine as an alternative to GMOs is a deceitful strategy, no different from urging people to play Russian roulette in order to get out of poverty.
The evocation of famine also prevents clear thinking about not just GMOs but also about global hunger. The idea that GMO crops will help avert famine ignores evidence that the problem of global hunger is due to poor economic and agricultural policies. Those who care about the supply of food should advocate for an immediate impact on the problem by reducing the amount of corn used for ethanol in the US, which burns food for fuel consuming over 40% of the US crop that could provide enough food to feed 2/3 of a billion people 
The widespread dissemination of that deceitful strategy illustrates another risk of GMOs. The oligarchy of a handful of companies that produce them and their related agrochemicals has sufficiently corrupted the mass media (which in turn is almost completely owned by a handful of companies) that big lies such as that are parrotted without scrutiny. Then there is the systemic risk of ruin to our political system, which is similarly influenced by GMO and agrochemical money.
The precautionary principle indicates that the only way to avoid ruin from GMOs is to stop using them. Fortunately, we know how to do that: winter cover crops plowed under before planting rotated diverse crops, with weeds controlled through cultivating, with resulting yields just as high and more profit.