The Carbon Connection

The Rodale Institute: Worldwatch Institute authors join Rodale Institute in answering the climate question with smart food production

Terrestrial carbon sequestration is the best way to buy time in a warming world. Cutting emissions will help, but not as immediately as sequestration. Making sequestration a priority matters, given critical policy choices that must be made as evidence of current, specific climate-change impacts to agriculture and wildlife mounts.

The Rodale Institute’s vigorous call for land-based biological sequestration dovetails with contentions found in a recently published Worldwatch Institute report on climate change: 2009 State of the World: Into a Warming World. A chapter entitled “Farming and Land Use to Cool the Planet” by Sara J. Scherr and Sajal Sthapit examines ways to reverse the trend of environmentally destructive agriculture and use carbon sequestration to mitigate climate change.

They argue that food production must be fundamentally restructured to simultaneously preempt and react to the devastating effects of climate change. They confirm the Rodale Institute’s contention that reexamining the role of carbon in agriculture is a vital first step in this restructuring process.

The Institute posits that organic agriculture presents an untapped solution, an underutilized carbon sink at the ready. A conservative extrapolation of carbon sequestration data drawn from our own long-term research indicates that, if the world’s 3.5 billion tillable acres could be transitioned to organic agriculture now, land could sequester almost 40 percent of our current carbon emissions. No other proposed carbon mitigation solution comes close to that potential impact, particularly using existing and readily available technology.

The Worldwatch authors argue that a food-centric approach might catalyze a climate-saving revolution. «A worldwide, networked movement for climate-friendly food, forest, and other land-based production is needed. This calls for forging unusual political coalitions that link consumers, producers, industry, investors, environmentalists, and communicators. Food, in particular, is something that the public understands.» (p 49)

Scherr and Sthapit illustrate the interconnection of carbon and other current environmental issues: «Land uses and management systems that are accelerating greenhouse gas emissions (GHG) are also undermining the ecosystem services upon which long-term food and fiber production depend—healthy watersheds, pollination, and soil fertility.»

They recommend multiple strategies for carbon sequestration, including organic farming, reduced tillage, use of biochar to aid in revegetation of degraded soils, retaining forests and grasslands as carbon sinks, agroforestry and perennial cropping to retain more biomass, rotational grazing, and biogas digestion to convert manure into energy and organic fertilizer. They include several good suggestions in ramping up the quest for better perennials, such as looking at more tree crops for food production and finding suitable perennial biodiesel crops.

The authors cite the Institute’s research documenting soil organic matter increases of 15 to 28 percent over a 22-year period, but say more research is needed “to understand the potentials and limitations of biologically based soil nutrient management systems across the range of soil types and climatic conditions.” (p. 35)

The chapter also recognizes the importance of geographical context when considering these improvements: “The actual net impacts on greenhouse gases of reduced emissions and increased carbon storage from reduced tillage depend significantly on associated practices, such as the level of vegetative soil cover and the impact of tillage on crop root development, which depends on the specific soils type.” (p. 36) Carbon material binds more easily to clay or loamy soil particles than to sand, making already good quality soil readily improvable.

We welcome more organic research in more places, incorporating timeless farmer wisdom with advanced science to adapt organic principles to local conditions. Let’s also:

* Rethink the value of soil carbon, elevating it to the position it deserves. This means reprioritizing our land use patterns, moving preservation of prime farmland to a high priority for national ecological security.

* Focus on building biologically active soil organic matter that leads, by default, to more sustainable and environmentally sound agriculture.

* Credit the added benefits of fertilizer reduction and water management. Since organic systems can use compost, manure and cover crops for fertility, they gradually eliminate the need for chemical fertilizers due to increases in naturally cycling fertility. At the same time, the soil water-holding capacity improves to better maintain crop growth and production in drier and wetter years. Keeping diverse and nearly year-round vegetative cover growing on the soil surface has the benefit of holding soil in the field (rather than losing it to erosion) and improving rainwater infiltration through the soil profile to recharge groundwater.

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