A reasonable summary of selected arguments around genetic modification of living organisms.
And, a couple crucial points I think were missed here. They apply generally but I'll frame them in terms of permaculture perspectives.
1) a core permaculture principle is "thoughtful and protracted observation" (usually in contrast to "thoughtless and protracted labor," but with other applications). As with all principles, this is relative to context. For working somewhat wisely with a small area of land, a few years may be sufficient, as long as one is constantly accepting and acting on feedback. For climate, as we are learning, hundreds, thousands, tens of thousands, even millions of years are needed to see and begin to understand patterns.
For consequences of directly altering genetic material in complex organisms, I propose that 20 years - or even 50 or 100 years - is far too little observation to be relevant. We have made this mistake many times before but still have not learned from it.
In the shorter term, consider DDT, and PCBs, and any other now mostly banned (in the minority world anyhow) chemicals produced since WWII. How long were they considered 'harmless' - including while their dangers were covered up for the sake of profits - before being recognized as systemically harmful? Far longer than 20 years.
In the domain of activities rather than substances, consider that we still do not, as a society, acknowledge the destruction of fertility, biodiversity, and nutritional value arising from mass monoculture commodity agribusiness, after more than 70 years of its expansion. Add to this the fact that most GM research is intended to be used primarily or exclusively in mass monoculture agribusiness applications. Further, the "green revolution" model which originally destroyed fertility, local diverse land ownership, biodiversity, and families as well as entire communities in India is over 50 years old and is still being propagated as a 'solution' by minority world corporate and government actors in majority world nations - now including GM organisms in the mix.
In summary, a well established pattern of inadequate observation combined with denial of relevant feedback is now being repeated with GM organisms. Any idea that 20 or 30 years is adequate observation time to determine consequences of GM products being released into the biosphere ought to be both laughable and terrifying - especially to permaculture practitioners.
2) Permaculture practitioners are (in theory) well aware of systems complexity, and the impossibility of humans being able to understand, in their wholeness, complex systems such as we are often interacting with. In other words, there is a great deal we don't know. More crucial even than these "known unknowns" is what we don't know we don't know - our "unknown unknowns." Considerable humility is an essential element of quality design practice.
In scientific domains, there is a persistent refusal by too many scientists working with direct genetic modifications to acknowledge how little is truly known and understood about consequences. Our form of science relies heavily on deterministic cause-and-effect models which are not well suited to the outrageously complex systems we are now meddling with. Meanwhile the many and diverse experimental results to date - well over 20 years' worth - that demonstrate how unpredictable these consequences are, are buried well away from public exposure, because they threaten ego-systems, belief systems, research funding, and profits. This confirmation bias behavior at a societal scale is another consistent pattern that is ignored in most conversations about direct genetic modification.
In summary - merely from awareness of system complexity and "unknown unknowns," any GM research ought to proceed far more slowly and carefully (back to "thoughtful and protracted observation!") than it has been and is.
3) At its core permaculture shows us that there is no systemic need for taking risks like direct genetic manipulation of organisms. Solutions already exist that do not require such risk-taking, are in the public domain, and are applicable at diverse scales and with relatively low technology requirements.
Unfortunately, applying those solutions broadly would require cultural change that is shown in most past cases to be functionally impossible. Empirical evidence shows that we humans seldom respond proactively and by design to 'approaching' crises. We wait until they are acute emergencies, at which point, it is generally too late for intentional cultural change.
GM is a 'solution' steeped in, and inseparable from, a culture of biosphere-destroying 'high' technology. We believe that more of our forms of technology can solve the problems created by our forms of technology. This fits that working definition of insanity described as "doing the same things and expecting different results." This seems an obvious pattern, but one that some permaculturalists at least are failing to recognize and call out.
As always, we will get the systemic consequences of what we do whether we know about or consider them, or not. In the biggest picture, any stupidity of human activity is ultimately self-correcting.
It is the "collateral damage" we generate that concerns me. Would that we could be a more graceful species than we are proving to be.