Estimates of potential impact of organic farming in sequestering CO2
KEY POINTS: - Soils are the second biggest carbon sink, after the ocean - Over 2700 Gt of carbon is stored in the soil -- about twice the carbon combined in the atmosphere and biosphere - 780 Gt of carbon is stored in the atmosphere and 575 Gt is stored in the biosphere = 1355 Gt combined [AH math] - The oceans cannot absorb anymore CO2 without causing serious environmental damage - Agriculture is responsible for 14% of global GHG emissions (FAO) - 70% of mitigation potential could come from developing countries (FAO) - Soils managed organically hold 40% more soil organic carbon compared to non-organically managed soils. [AH math] - Average organic farming practices remove 2200 kg CO2 ha-1 yr-1 - Widespread global adoption of current organic practices could potentially sequester 10 Gt CO2, or 20% of world's GHG emissions - 10 year study revealed organic systems sequestered 2000 lbs carbon/acre/yr while standard tillage lost 300 lbs carbon/acre/yr - Case Studies results projected on global scale: - Sekem (oldest biodynamic farm in Egypt) (desert climates): Their methods adopted globally could potentially sequester 16 Gt CO2 per yr which is 30% of current GHG emissions (2007) - Royal Thai Organic Project (tropical systems): Their methods adopted globally could potentially sequester 114 Gt CO2 per yr, which is more than double the world's current GHG emissions (2007) - Pasture cropping and holistic stock management in Australia (arable and pasture systems): Their methods adopted globally could potentially sequester 82 Gt of CO2/yr --- significantly more than world's 49 Gt yearly emissions and could help reverse climate change!! - Composting is a good way to avoid methane emissions from waste - Carbon sequestration can alleviate farmer poverty: If farmers were paid $20 per ha per ton of CO2 sequestered, then 5 billion ha sequestering 2 tons each could potentially "redistribute $200 billion from CO2-polluting industries to rural communities" (29)
CORRESPONDING DIRECT QUOTES - "Soils are the greatest carbon sink after the oceans" (23) - "According to Professor Rattan Lal of Ohio State University, over 2,700 Gt of carbon is stored in soils worldwide" (23) - "This is considerably more than the combined total of 780 Gt in the atmosphere and the 575 Gt in biomass" (23) - "The world's oceans, like the atmosphere, cannot absorb any more CO2 without causing potentially serious environmental damage to many aquatic ecosystems" (23) - "'Agriculture not only suffers the impacts of climate change, it is also responsible for 14 percent of global greenhouse gas emissions...Some 70 percent of this mitigation potential could be realized in developing countries.'" (23) - "'In soils under organic management, the SOC...stocks averaged 37.4 tonnes C ha-1, in comparison to 26.7 tonnes C ha-1 under non-organic management'" (23) - "Study by the United Kingdom Soil Association found that average organic farming practices removed about 2,200 kg of CO2 per hectare per year" (23) - "the widespread adoption of current organic practices globally has the potential to sequester 10 Gt of CO2, which is around 20 percent of the world's current GHG emissions" (23) - "a 10 year study comparing the use of composts, manures and synthetic chemical fertilizer - show that the use of composted manure with crop rotations in organic systems can result in carbon sequestration of up to 2,000 lbs/ac/year. By contrast, fields under standard tillage relying on chemical fertilizers lost almost 300 pounds of carbon per acre per year" (24) - "the widespread adoption of Sekem's practices globally has the potential to sequester 16 Gt of CO2, which is around 30 percent of the world's current GHG emissions, into soils" (24) - "Royal Thai Organic Project...If this was applied globally, it would sequester 114 Gt CO2/ha/yr - more than double the world's current GHG emissions (4,883,697,000 ha x 23.4 tons of CO2/ha/yr = 114 Gt CO2/yr - "Australia...This system can be, and is being, successfully used in both arable and pasture systems, including in horticulture. If this was applied around the world, it could potentially sequester 82 Gt of CO2/yr...This is significantly more than the world's GHG emissions of 49 Gt and would help reverse climate change. The increase in soil carbon would also significantly improve the production and adaptation capacities of global grazing systems." (25) - "Composting the organic wastes in cities and transporting them to the farm brings multiple benefits in closing the nutrient cycle by returning the nutrients that are exported from the farm, avoiding methane emissions and increasing the rate of soil carbon sequestration." (28)
United Nations Conference on Trade and Development, Andre Leu, "Commentary V: Mitigating Climate Change with Soil Organic Matter in Organic Production Systems," in Wake Up Before It Is Too Late: Make Agriculture Truly Sustainable Now for Food Security in a Changing Climate, United Nations, Trade and Development Review, 2013, 22-33, accessed June 5, 2014, http://unctad.org/en/PublicationsLibrary/ditcted2012d3_en.pdf.