Peak Soil: Are We Taking More Than the Earth Can Give?

There is a tendency for humans to perceive ill occurrences as unconnected events, rather as the Biblical plagues of Egypt: water into blood, frogs, lice, wild animals or flies, deceased livestock, boils, storms of fire, locusts, darkness and death of the firstborn. Scientists now believe that these events really happened, but they were in fact all results of a single cause: not the wrath of a punitive God, but climate change. Modern humans are aware of contemporary global menaces: a changing climate, peak oil, a dodgy economy that could collapse at any moment, and the extinction of honey bees, but relatively few of us know that the world’s productive soils are also under threat. What has been most noticeable is that the price of food and fuel has increased markedly over the past decade, during when we have also experienced an economic crash. We fear another such shock, even amid whispers of “growth”, which can only be expected to be of a slow stuttering kind, since we cannot significantly grow our rate of production of resources. Thus, the price of a barrel of crude oil has more than trebled since 2004, while global production has practically flat-lined at around 75 million barrels a day over that same period, leading to the view that we have reached the ceiling of our oil supply.

Given that all components of human civilization are inextricably linked to petroleum, either as a chemical feedstock or a fuel, if we cannot elevate our production rate of oil, nor can we grow the global economy. The troubles of the human condition, however, are more fundamental, since we are steadily using-up Mother Earth’s bestowal to us of fertile soil. This has been dubbed “peak soil” in analogy with “peak oil”, and while the two phenomena are not of the same kind, they are connected, as indeed are all the elements listed in the title of this article: soil, land, water, climate (change), honeybees, oil and food. Alice Friedmann wrote, in the context of the unsustainable nature of growing land-based crops and producing biofuels from them.

“Iowa has some of the best topsoil in the world, yet in the past century it’s eroded from an average of 18 inches to less than 10 inches (Pate 2004, Klee 1991). When topsoil reaches 6 inches or less (the average depth of the root zone in crops), productivity drops off sharply (Sundquist 2005). Soil erodes geologically at a rate of about 400 pounds of soil per acre per year (Troeh 2005). But on over half of America’s best crop land, the erosion rate is 11,000 pounds per acre, 27 times the natural rate, and double that on the worst 7% of cropland (NCRS 2006), partly because farmers aren’t paid to conserve their land, and partly because hired farmers wrench every penny of profit they can on behalf of short-sighted owners.”

This is deeply disturbing, all the more so because rates of erosion that are in excess of the natural rate of soil formation are not restricted to Iowa, but are a global feature. According to a report by the World Resources Institute (WRI) some 20% of the world’s cultivated areas are afflicted by land degradation, and in order to feed Humankind over the next 40 years, food production must be increased by 60%. This conclusion is drawn, in part, from the expectation that another 2.5 billion people will be added to the current number of just over 7 billion of us, and that a rising middle class will have greater expectations of their diet, particularly in wanting to eat more meat. The amount of food that is wasted is another consideration, and combining this factor with population increase suggests a daily gap between the demand for food and what is likely to be available by 2050 of 900 calories (kilocalories) per capita.

Many of the limitations to meeting such a testing challenge are those of the modern industrialised agricultural system per se. The factors involved are complex and inseparable, in short providing a nexus. The impact of climate change adds further weight to the problem, and seven clear courses of action have been identified, by which we might adapt to ensure food security into the future. 24% of anthropogenic greenhouse gas emissions are from agricultural activities, including methane from livestock, nitrous oxide from fertilizers, carbon dioxide from running tractors and combine harvesters etc. and from changes in land use. Furthermore, 70% of all human water consumption is claimed by agriculture. In the last 40 years, 20 million square kilometers of land have suffered degradation, which accounts for around 15% of the total land area of the Earth, while 30% of the originally available cropland is now unproductive. As noted for Iowa, the degradation of topsoil is occurring many times faster than the rate at which soil is generated by Nature, which can take longer than 500 years to form just an inch of it.

There is an increasing pressure on water supplies too, which may begin to struggle in meeting demand in the food basket regions of the Americas, west and east Africa, central and eastern Europe, Russia, the Middle East and south and south-east Asia, within only 12 years. As alluded earlier, the costs of both fuel and food have risen markedly over the past decade: food prices follow oil prices because oil and gas are involved at all principal stages in the food production and distribution chain. The World Bank has proposed restricting oil prices as a means to mitigating food price increases. There appears little doubt that oil prices will remain high, and most likely rise considerably, since the global oil supply will increasingly be provided from unconventional sources, e.g. producing shale oil by fracking, tar sands and (ultra) deepwater drilling, all of which have poorer net energy returns than does conventional crude oil. Indeed, were the price of oil not as high as it is currently, no one would bother to produce it from such expensive and demanding sources. There is also the critical question of how high an oil price the economy can bear, before it falls into recession and finally collapses.

According to the U.S. National Agriculture Statistics there has been a decline from about 6 million bee-hives in 1947 to 2.4 million in 2008, representing a reduction by 60%. Over the past 10 years, beekeepers in both the U.S. and Europe have reported annual hive losses of 30%, and last winter losses of 50% in the U.S. were not uncommon, with worst case examples of 80-90%. Since one third of all food crops rely on bees to pollinate them, if this “bee-collapse” continues, the effect on world food production could be calamitous. Various causes have been brought culpable for killing the bees, including pesticides, parasitic mites, intensive monoculture farming methods and urban development. The nexus of components that we have identified is totally at odds with providing sufficient food for a population of 9.5 billion by 2050 and maybe 11 billion by 2100.

The various ills we have described are outcomes of the industrial nature of monoculture farming, which frets the ecology and does not restore it, including the soil itself. Alternatively, methods of regenerative agriculture and permaculture have been advanced. These help to rebuild the soil, making it more fertile through increasing its soil organic matter content (SOM), including establishing a healthy network of microbes and other creatures to live in it (the soil food web), thus securing fertility and crop productivity. Such methods of ecological food production can be done on a more local scale, and the food consumed closer to where it is grown, largely obviating the necessity for an extensive transportation/distribution system powered by oil-refined fuels. They are further less intensive in their demand for other inputs, such as water, fertilizers, pesticides and herbicides. By keeping the soil covered throughout the year, it is protected from erosion, and the SOM improves its structure so that it can absorb water more effectively and allow aquifers to recharge, thus mitigating both water shortages and flooding. It is likely that a reduced use of pesticides, through reintroducing biodiversity, might help to bring the bees back too.

By Chris Rhodes

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