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...
February 1, 2009 | Source: The Rodale Institute | by
OCA Editors’ Note: CLICK HERE TO TAKE ACTION! Tell Congress: Don’t Leave Organic Out of Climate Change Legislation!
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
- 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
- Recognize that even annual crop systems can
transition away from greenhouse gas emission to carbon sequestration in
the form of carbon compounds.
The Institute’s 29-year-long Farming Systems Trial (FST) has shown
that, after the initial transition phase, organic annual systems
produce a competitive yield and often do better than conventional
systems in drought years. This may be due to a relatively high rate of
moisture-absorbent carbon content in organic rotations, as Institute
trials also show accumulation of 500 lb/C/a/yr (legume) to 2,000
lb/C/a/yr (compost) in various long-term observations.
Scherr and Sthapit target these agricultural solutions:
“In terms of climate change, landscape and farming
systems should actively absorb and store carbon in vegetation and
soils, reduce emissions of methane from rice production, livestock, and
burning, and reduce nitrous oxide emissions from inorganic fertilizers.
At the same time, it is important to increase the resilience of
production systems and ecosystem services to climate change.” (p 33)
The Institute’s work shows that organic practices have the power to
work toward these solutions. We know, for example, that mycorrhizal
fungi—microorganisms that work in symbiosis with plant roots and help
supply them with nutrients—are more prevalent in the carbon-rich soils
of organically managed systems. Mycorrhizae secrete glomalin, a
glue-like substance, that actually conserves organic matter by
aggregating it with clay and mineral soil particles. While mycorrhizae
have been the focus of our research on soil microbial life over the
past few decades (conducted in conjunction with USDA researcher David
Douds), they are part of a vast community of organisms found just below
the soil surface that deliver diverse but comparable benefits to the
crop ecosystem when soil is managed for health and biodiversity.
Minimal tillage, advocated in the report, has many benefits as well,
and is most effective when used in concert with a diverse rotation.
Reducing tillage also presents an effective way to cycle nutrients and
store carbon. As Scherr and Sthapit point out, tillage can disrupt
critical microbial functions by exposing anaerobic microbes to oxygen
and suffocating aerobic microbes by working them deeper into the soil.
Minimal tillage encourages a more biologically rich soil environment
than does no-till, with less carbon loss than conventional tillage.
The authors suggest, finally, the use of the FAO Global Carbon Gap Map
which helps identify areas where soil carbon storage is greatest and
targets geographic regions where it is lacking. This map could
pin-point the most promising regions to start using organic methods to
restore degraded land.
The individual practices recommended by the authors are already used
in various locations throughout the world. These carbon-building
techniques, when they are coordinated into a dynamic system, constitute
what the Rodale Institute calls regenerative organic agriculture.
Scientific examination and practical application of each individual
component is vital to understand their roles in a complete organic
system. With this understanding, we can then work effectively with
farmers to implement as many practices as quickly as possible to affect
real carbon sequestration benefits.
Research and outreach provide the practice guidelines that allow
food producers to make meaningful changes to their field and rangeland
management. Policy makers and consumers are critical, however, in
providing the economic support that allows farmers to transform
agriculture into a climate-saving force around the world.
See Scherr and Sthapit’s chapter, “Farming and Land Use to Cool the Planet” .
Thanks to communications intern Genevieve Slocum for her research and writing on this post.