There are lots of creative ideas regarding future farming. Unfortunately, almost all of them seem to ignore basic economics - both fiscal and physical energy budgets. The world is facing a major food shortage as the biomass of those currently being born - go from 7 lbs. to 150+lb. humans. What isn't being discussed adequately is that 85% of current human food stocks are dependent on petro-chemical fertilizers, 95% of human foods rely on petroleum fuels to get from field to consumer, and that 85% of food relying on petro-chemical fertilizers - is also 100% reliant on non-renewable phosphate fertilizer additives. According to recent scientific estimates, phosphates will peak in less than 30 years and be effectively gone in 50 years. Farm production levels as we know them now will also disappear with the phosphates. Many of the food and energy production systems that we are currently investing in developing today assume that there will always be petroleum, phosphates and food aplenty - just like now. Those developers ignore basic economics and the finite nature of key critical non-renewable resources.

While we can certainly do a better job at recycling our wastes, we have to recognize that scientific estimates say that only about 3% of human wastes are currently logistically, economically and technically practical to recycle. That isn't enough to make a dent in the coming food shortages associated with current human population growth. The time necessary to re-engineer our society(s) and it's infrastructure to a point where we could effectively recycle our wastes - appears to be longer than the time we have before the non-renewable resource shortages and the resulting chaos make them impossible to implement.

While it's clear that no one is accurately predicting the exact crisis points of peak oil, or peak phosphate - it is clear that the concept of the finite and non-sustainable nature of critical high production human food/ fertilizer components - is not debatable. Scientist and government leaders have their work cut out for them trying to prepare global populations not just for declining energy, for declining food supplies, developing a workable economic system for declining populations (our current economic concepts require growth), but convincing our species that there is simply too many of us for the planet to feed and the responsibility that we all have in changing this fact. The latter may prove to far more difficult than any technological challenges we have.

By ignoring the economics of life cycle analysis in things like bio-fuel development - which necessarily competes with foods for non-sustainable petro-chemical fertilizers at the large commercial scales required by growing human populations, we are putting the next generation at serious risk of food shortages and the civilization killing chaos that will come with those food shortages. Without a comprehensive integrated plan to reduce human population growth and a focus on applying our declining resources on technologies based on more renewable energy resources such as solar, wind, tide, and wave - the handwriting is on the wall for our species... and it's an obituary. Sadly, many will view these comments as "philosophical" rather than the basic math they are based on.

Thierry, fortunately other maritime sectors are the trail blazers in this arena of autonomous operation at sea. The protocols are in place, along with the rules of the road, the lighting and EIS requirements, etc. However, we all know that a level of lawlessness occurs at sea, and not just in distant international waters. It is this concern that will dictate the scale of a fish farming operation - the need for security on top of the more obvious logistical support.

As we both know, the effluent from fish farms are anything but pollution when they are properly sited in a location prepared to absorb and thrive on the nutrients. Only in an ecosystem already challenged by excess nutrients do fish farms exacerbate the situation. In doing so, the questionable record of poorly sited operations has brought underdeserved criticisms of those more thoughtfully located. A mobile farm in uncompromised oceanic waters seems to be a good solution. Regards, Cliff

You touched on the issue of maintenance and feeding with the system promoted by Cliff Goudey and that is a key thing to address. Another point which needs to be addressed is to whom these self-propelled/drifting farms belong in international waters? The present international law of the sea is not that comforting for privately owned equipment (farms in this case) found at sea!!! The vagueness of territorial jurisdictional competence in the Exclusive Economic Zone (EEZ) in different countries, and certainly in international waters, has been a major impediment to progress of the so-called offshore aquaculture.
The debate at the end is interesting, despite the fact that one person should not need to swear and get nasty to make his point (I think he is, in fact, losing his efficiency!). But what surprises me (or, in fact, does not surprise me!) is that these two guys are debating about the evolution of agriculture on land as the only solution. We have to put the water (seawater, brackish or freshwater) in the equation if we want to progress and it is about time we talk about Marine Agronomy. One guy is swearing by science and technology to solve everything and the other is swearing by traditional/organic practices to solve everything. In fact, I firmly believe that it is the combination science and traditional knowledge that will help us to find solutions. IMTA is exactly at this interface, modernizing traditional practices: bay management area, fallowing, combining ecosystem complementary crops is nothing new, but revisited and updated, based on what we have learn from past experience (which includes a lot of mistakes over the centuries, but not assimilated by the characteristically short-term memory of humans!).