News of food price escalation is bringing global carrying capacity for human beings 'front and center'- with food riots all over the world. 

This is being precipitated now by food-to-ethanol programs, although with constantly rising populations fed by the increased food produced by various agricultural revolutions (the Green Revolution being the latest), these riots would have eventually happened. However the speed of these developments is awe inspiring.

On April 14 2008 we heard Robert Zoellick, head of the World Bank, calling for a crash program of food production increases to stave off the approach of famine. How many times does he think we can pull new ‘productivity rabbits’ out of the hat when soil resources of the planet continue to be degraded to produce more food for the irresponsibly breeding horde?

At the core of our problems today has been our unwillingness to see the relationship between the population numbers that we have built up since the advent of cultivation agriculture, and the sustainability problems that we have been side stepping for 10,000 years.

Many keen thinkers have understood that the driver enabling our numbers to shoot so far over long-term carrying capacity has been the one-time gift of fossil fuels, and that this overshoot has resulted in our rampant destruction of the biosphere. The global human population, before the start of the Fossil-Fuel Revolution, was about 1 billion, while it is now about 6.7 billion and rising. These holistic thinkers suggest that without oil, the earth will only support about 2-3 billion people.

Their forward thinking has not yet included an understanding of the thesis that the other major factor that has enabled our numbers to shoot so far over long-term carrying capacity has been the one-time gift of erodible soils and the vast store of nutrients they contained until we began to irreversibly mine them about 10,000 years ago with cultivation agriculture.

The global imbalance between humans and their supporting environments is much more serious than most people on Earth realize.

I suggest that without petroleum, and after we stop mining arable soils, the Earth will only support the 100-300 million people it did before the advent of cultivation agriculture.

Recent prognostications about the possibility of sustainable development in the context of further population and economic growth, are in direct opposition to a growing understanding among ecological economists that all economic and population growth since the advent of agriculture 10,000 years ago has effectively lowered the basic long-term carrying capacity (food productivity potential) of the soil resources on the planet.

William Rees and Mathis Wackernagel who developed the Ecological Footprint analysis appear to believe that humanity overshot global carrying capacity sometime in the 20th century. I have been circulating the thesis that the human family has been in overshoot mode for the last 10,000 years and it is long past time to address this issue.

Most of us agree that the human experiment, which is now the size of the Earth, has gone terribly wrong. At issue is the point at which humanity took the unsustainable fork in the road -and- what we must do to get back on track. There is a growing realization that human numbers will decrease, either by planned contraction or by the development of various scarcities.

My recommendation for the necessary decrease of the global human footprint includes allowing the functional integrity of terrestrial (and aquatic) communities to begin to re-establish by ceasing to stage-manage ecosystems. A reliance on self-organizing/self managing systems, that evolution has already created, would feed a very small number of humans sustainably. This sustainability would be predicated on the ability of this small population to regulate their exploitation/harvesting activities to fall within the (now better understood) capacity of their supporting ecosystems to maintain critical breeding populations, species and structural diversity, to replace soil lost by erosion and to replace soluble plant nutrients lost by harvest export or leaching.

For fisheries, because they represent such a small fraction of the global human diet, a return to sustainably harvesting restored wild populations would not cause widespread starvation.

In forestry a shift to alternate harvesting systems that accommodate the time requirement for full species and structural restoration, and that approximate natural disturbance dynamics - as opposed to creating ecosystem-simplifying, product-driven species assemblages - could be initiated very quickly.

The abandonment of agriculture in favour of the re-establishment of self-managing, native, nutrient-conservative forest and grassland/prairie ecosystems would require much more time because these unmanaged systems cannot produce enough food for human needs until population numbers have fallen to a fraction of present levels.

For the sustainable future of the global human experiment, cultivation agriculture must be relied upon to feed us until we have reduced our numbers to a level that can be supported by carefully regulated exploitation/harvesting activities that fall within the (now better understood) capacity of supporting ecosystems to maintain diversity, to restore soil mass lost by erosion and to replace soluble plant nutrients lost by harvest export or leaching.

This e-mail address is being protected from spam bots, you need JavaScript enabled to view it  is a Research Scientist at the Canadian Wood Fibre Centre Natural Resources Canada, Canadian Forest Service.