There seems to be a growing idea that zero input, zero carbon footprint food systems are possible. The latest incarnation is a revamp of old technology that raises fish in tanks and then circulates the nutrient rich water (fish poo) around containers used to grow fruit and veg. It is generally known as aquaponics.
The claimed advantages range from less use of water to a magical zero input food system input based on the premise that no fertilizers are needed. What is often ignored, or glossed over, is that fish need food and that the system needs a constant supply of energy.
Energy can come from renewable sources so that is not a huge problem for small systems but the capital investment and embedded energy used to create large renewable electricity generation plants for large scale aquaponics systems is often totally over looked by enthusiasts.
One of the latest ideas that is generating some publicity and getting support from those who see it as a quick techno fix is detailed in an article with the strap line “Why aquaponics may be the future of urban farming, and one solution to our local food problem.”
The idea looks relatively simple; raise fish in tanks, circulate the faces laden water around other tanks which are used to grow food. If only it were that simple. The experiences of fish farming are that confining fish to tanks and cages in sea water drastically increases problems from pests and diseases which leads to the reliance of pesticides. Are the aquaponic enthusiasts saying there are no such problems with their systems or do they just ignore the potential problems?
The authors are very enthusiastic and use eco speak to support their arguments.
According to Food & Water Watch, 80 percent of that energy is spent on “processing, packaging, selling, and storing food after it leaves the farm.” Some estimates “predict that 120 million tons of CO2 emissions are directly attributable to domestic food transport each year.” The U.S. food system is so inefficient that it “uses 10 nonrenewable fossil fuel calories to produce only one food calorie.”
There is no disputing any that and it shows just how dependent we have become on converting oil calories to food calories.
What bothers me is that there is a growing rush to find a techno fix for every problem we now face. Maybe it is because we do not want to give up our comfortable life styles. Maybe it is because we have become accustomed to leaving the tricky stuff to others. Maybe we rely on the centralised power of government and big companies too much. Who knows what drives people to find the seemingly easiest solution to everything without looking further than their dinner fork.
One thing is certain, we do need a change in the food is produced and distributed and I am equally sure that sustainable urban farms have a crucial part to play. To be really sustainable they need the absolute minimum of inputs and to make the maximum use of space, the overall design guidelines: should be keep it simple, use what we have, use the least possible amount of energy for creating and running the farm.
Maybe there is a hybrid media based growing system out there that uses manure or compost to produce plant food and uses a renewably sourced growing media. I would dearly love to hear about it as that really would be revolution. Until then lets make the best use of the biggest resource we have i.e. soil by growing intensively and organically.