We do not know just when farming in Michigan will be seriously impacted by climate change, but we do know that other places are already suffering droughts or flooding attributed to global warming. We also know that greenhouse gases, mainly carbon dioxide, methane, and nitrous oxide, are accumulating in our atmosphere and as they help to trap the warmth of the sun, global temperatures are slowly rising. These greenhouse gases are emitted when fossil fuels, such as coal, oil, and gas, are burned, but emissions began much earlier from deforestation and soil erosion. The warming this causes is very slow, and the danger lies in the fact that global temperatures are rising so slowly that the prospect of global warming has lost its urgency. In 2007, 71% of Americans believed that burning fossil fuels caused global warming, but two years later this percentage was down to 51%. People in this country are not inclined to change their energy-intensive lifestyle and so carbon dioxide, the main greenhouse gas, has increased from 280 parts per million before the Industrial era to about 400 ppm today. Eventually, of course, emissions of carbon dioxide must be reduced by using more renewable sources of energy, and less energy, but that is not a likely possibility to solve the problem of climate change for the time being.
The other possibility, getting carbon dioxide out of the atmosphere through the natural process of photosynthesis, is rejected by many scientific writers in our urban society even as it is affirmed by many others who know more about farming. It is this possibility that is explored in this essay. We do know that before the industrial era, organic matter, which is 58% carbon, had accumulated quite naturally in soils and plants and did not concentrate in the atmosphere. Prairie soils in our Great Plains had 10 to 20% of organic matter before they were plowed. Since farming began soils have lost 30 to 80% of their organic matter. Although carbon has always circulated through the atmosphere, the soil, and the oceans, the current excess in the atmosphere and in the oceans (which are being acidified as a result) and the loss of carbon from the soil, is caused by both destructive farming practices and the burning of fossil fuels.
These destructive practices included deforestation and the loss of organic matter as plowing for annual grain crops caused the oxidation of carbon in the soil and its escape as carbon dioxide. The loss of organic matter was much greater as chemicals for fertilizers and pest control were adopted. The use of fossil fuels for the manufacture of agricultural inputs and for mechanization added to the carbon emissions from agriculture. Rattan Lal, a soil scientist from Ohio State University who has written much on this topic, has suggested that “more carbon may have been emitted into the atmosphere from deforestation and land use conversion than from fossil fuel combustion until the end of the twentieth century.” (Lal, Preface to Geotherapy edited by Thomas Goreau, p. xvi.)
Can this carbon dioxide be returned to the soil as organic matter by better farming practices? This is what organic farmers have always tried to do, and they have recently been joined by soil scientists such as Lal, mentioned above, and many others. Some of them make extravagant claims, as when Allan Yeomans, in his book Priority One, says (p. 101) we could beat global warming “in well under ten years.” This may be possible, but it assumes that the world’s farmers will all become organic farmers immediately. And even Yeomans complains about the lobbying power of the fossil fuel industries as they resist a transition to organic farming.
In a special paper published a couple of years ago, the Rodale Institute provided a more carefully-reasoned statement of carbon sequestration through regenerative organic agricultural practices. It lends some support to Yeoman’s claims, and, recognizing that not all farms will shift to organic methods, it states that “if we extrapolate to half rather than all of global pasture and cropland, transition to regenerative modes of production may sequester 55% (29GtCO2) of 2012 annual emissions.” This is a bit over half of the total global emissions of greenhouse gases in 2012, so it is possible to sequester greenhouse gases in soils and plants.
Getting the excess greenhouse gases out of the atmosphere is more urgent than the reduction of the rate of burning fossil fuels because it helps to postpone the warming of the planet immediately even as it builds up soil fertility, which is the aim of organic farmers. And it is necessary for all of us as eaters if we remember that chemical fertilizers, which came into use to maintain yields after chemical farming methods had destroyed soil fertility, may not be as easily available and widely used in the future. Organic methods are the alternative. Also, it is urgent to reduce greenhouse gases in the atmosphere because the warming they cause in turn causes the melting of methane hydrates in tundra and in the oceans, and these emissions of methane can add more warming very rapidly.
What the Rodale Institute calls “regenerative organic farming” includes some specific emphases that add up to a reformed method of organic farming. They are not proposing a simple return to the good old days of organic farming even though they still emphasize feeding the organisms in the soil rather than the plants. It is farming and gardening without any or very reduced tillage, along with temporary cover crops planted between the main crops to cover the soil and help to control weeds and erosion. It also depends on crop rotation, retention of crop residue on the soil, and the use of compost for fertilizer which helps to fix carbon in the soil as humus. All this adds up to a more management-intensive system which has to be adapted to different soil types and climate conditions.
Some critics have rejected the possibility of carbon sequestration in soil because they argue that the carbon would escape sooner rather than later. According to the Rodale paper, arbuscular mycorrhizal fungi secrete a protein called glomalin which remains in the soil for decades as a stable form of organic carbon. Mycorrhizal fungi can also be added in the soil to seedlings through inoculations especially in places where heavy tillage had destroyed the native population of fungi.
The Rodale paper mentions both cropland and global pasture, or grasslands, which include 40% of global land surface area. Efforts have been made recently, informed especially by the work of Allen Savory’s Holistic Management System, to develop grazing methods that can restore these grasslands. These depend on the intensive grazing of ruminants in relatively small paddocks where large herds are pressured as by the presence of predators. Their hoofs help to mix their manure and dead grasses into the soil to replenish its organic matter. This process is described by Adam D. Sacks and colleagues in a long article entitled “Reestablishing the Evolutionary Grassland-Grazer Relationship to Restore Atmospheric Carbon Dioxide to Preindustrial Levels” which is included in Geotherapy edited by Thomas Goreau et. al.
Another way to sequester carbon includes greater reliance of perennial crops as emphasized in Permaculture. This has been advocated by Eric Toensmeier in his recent book, The Carbon Farming Solution: A Global Toolkit of Perennial Crops and Regenerative Agricultural Practices for Climate Change Mitigation and Food Security. Because of their extensive roots and reduced need for tillage, perennial plants and trees can sequester more carbon in the soil than annual crops. This is also true of the perennial grains under development at the Land Institute co-founded by Wes Jackson. Tree crops can also be competitive with annuals in net productivity, as argued by J. Russell Smith in his book of 1950, Tree Crops. The shift to more perennials will happen, but it is a long-term process. In the meantime annual crops can be produced with regenerative organic methods.
The most comprehensive book on strategies for restoring carbon from the atmosphere to the soil is Geotherapy, published in 2015 and edited by Thomas J. Goreau, Ronal Larson and Joanna Campe. The first 100 pages of this 600 page book consists of introductory essays by the editors, and the following pages include about ten chapters on biochar and another ten chapters on techniques for the remineralization of soils and organic additives. Biochar is essentially charcoal which has been “energized” with organic matter and helps plants grow. The charcoal embodies carbon in a form that stays in the soil. Any organic matter can be burned in the absence of oxygen to form biochar. Certainly it should be a vital component in the effort to sequester carbon.
Remineralization of soils may be questioned by some critics who remember the apocalyptic tone of a book in 1982 by John D. Hamaker entitled The Survival of Civilization. That book does include a section on the problem of increased carbon dioxide in the atmosphere, but relates it to the author’s perceived need for a new glaciation to remineralize soils. In Geotherapy the issue of remineralization is presented as the addition of rock minerals much as organic farmers use rock minerals to restore minerals that have been depleted by intensive cropping.
Although Goreau was present as a Senior Scientific Affairs Officer in 1989 when the United Nations Framework Convention on Climate Change took on the challenge of climate change, he failed to convince the UN FCCC to include soil as a sink for carbon even though it has four times more carbon than the atmosphere. This helps to explain why soil as a sink for excess carbon is not on the climate change agenda. He argues, and Geotherapy provides the evidence, that “if managed responsibly pastures alone, agriculture alone, or reforestation alone could absorb much of the carbon dioxide increase” (p. 37).
There will definitely be organic farming in our future. It is one of the essential strategies that can assure that we have a future, both because it can restore carbon from the atmosphere, where it is a pollutant, back into the soil, where it is a necessary nutrient that helps plants grow. Best of all, it thereby enriches the soil so that food can be grown without the chemicals that add to greenhouse gases in the atmosphere.
Maynard Kaufman was a founding member of both Organic Growers of Michigan and MOFFA. He was an organic farmer from 1971 to 2003, when he sold most of his land to three young organic farmers. This article is a preliminary version of the final chapter in the book he is editing on the organic movement in Michigan.
Source: MOFFA