Replicable climate change approach for China
By Dr. D. Michael Shafer
China confronts three national challenges: reversing climate change; reducing the public health cost of smoke and smog pollution; and ending rural poverty. Policy has treated these as separate, intractable problems requiring large, ongoing State expenditures. This memo proposes a sustainable, low-cost, integrated approach to all three that can be replicated in every rural county of China.
Solving these problems requires implementing a business model that gives farmers incentives to convert China’s 400,000,000 metric tons of crop waste into biochar, thus raising yields and incomes, reducing particulate and smog precursor emissions, cutting GHG emissions and sequestering CO2.
Biochar is “super charcoal” made by heating biomass (corn stalk, wheat, rice straw, etc.) without oxygen. Low-cost, low-tech biochar equipment is available that farmers can make themselves. Converting biomass such as crop waste to biochar has big environmental and public health benefits. Each ton of biochar sequesters three tons of CO2 and averts the emission of 4.3 tons of eCO2. It also averts the emission of 0.03 tons of PM2.5 and 0.25 tons of smog precursors. Plowed into fields, biochar renders heavy metals, industrial chemicals and pesticides bio-unavailable, protecting the food chain and water supply.
Conservatively, China burns 100,000,000 tons of crop waste annually, producing 107,303,000 tons of eCO2 (more than Belgium), 626,000 tons of PM2.5, 17,000,000 tons of smog precursors, and no economic benefit. Crop fires alone account for 50% of Beijing’s smoke and smog in the summer months, and more in many other cities. The government has banned burning, but to no effect. Government and entrepreneurs have invested in schemes to collect field waste, take it to central processing points and convert it to biofuel. These efforts have proved uneconomical and have a carbon footprint larger than the carbon savings of not field burning.
If just 10 percent of Chinese small farmers charred instead of burning their crop waste, the benefits to China and world would be immense. They would remove 30,000,000 tons of CO2 from the atmosphere annually, making China the only country in the world to contribute meaningfully to reversing climate change. They would avert the emission of 10,700,000 tons of eCO2 (more than Luxemburg). They would save thousands of lives otherwise lost to smoke and smog related illnesses.
China’s problem is that it is a nation of small farmers farming just 1 to 3 Chinese acres each (600 – 1,800 m2). This distributes crop waste widely and makes its collection for feedstock infeasible. The only solution is for farmers to convert crop waste into biochar on the farm and carry the much-reduced volume and weight of value-added biochar to market with their crops.
In villages, there is no feedstock collection cost. Farm-scale technology permits farmers to convert waste to biochar in the field. Mixed with manure and potter’s clay, the biochar offers a soil amendment that increases yields, restores soil, improves plant health, binds contaminants, and retains water, mitigating climate change risk.
Implementing this proposal requires confronting challenges. Farmers do not burn their fields for fun, especially not in the face of stiff penalties; they burn because they have no alternatives. The challenges all involve demonstrating to farmers that biochar will work for them. This means, first, proving that biochar delivers the promised yield and soil improvements. Second, farmers often cannot sell the crops they are producing now; such a program must also improve their access to markets. Why bother to produce biochar in order to increase yields if there is no place to sell the new produce? Third, because there is so much crop waste, most farmers will be able to produce more biochar than they can use on their farms. Most of the public benefits are lost, however, if they char just a small portion of their crop waste and burn the rest. To avoid this, the challenge is to establish a market for biochar or local industries that need it: animal feed, cosmetics, decontaminants, fertilizer, filter, fruit packing, and natural pharmaceuticals companies all use lots.
Overcoming these challenges makes biochar into an engine for rural development. It converts slowing climate change, improving public health and reducing rural poverty from costly government programs into self-sustaining rural businesses that also happen to clear the air. The beauty of the scheme is that no one must spend money on the environment, public health or poverty reduction. Farmers and biochar-using businesses solve these social problems as the incidental benefits of pursuing their own profits.
1 These calculations use emission factors from S. Akagi, et al., “Emission factors for open and domestic biomass burning for use in atmospheric models,” Atmospheric Chemistry and Physics, 11, 2011: 4039-72, which are more conservative than those in published Chinese sources. This seems to be because the Chinese sources report EFs for specific crop wastes whereas the Akagi EFs are more general. These figures assume a crop waste to biochar conversion ratio of 4 to 1, measure eCO2 in terms only of methane and NOx emissions (GWPs of 25 and 298), estimates PM2.5 emissions at 6.26 kg/ton of biomass, and refers to only CO, CH4, NOx, NH3, SO2 and NMOCs as smog precursors. The calculation of eCO2 assumes that CO and CO2 emissions are carbon neutral.
2 Estimates range from 17% to 25.6% of total crop waste or 120 to 157.5 Tgr (120,000,000 to 157,500,000 tons). Assuming 25% of a lower base figure, 100,000,000 tons offers a round, conservative figure. See Xinghua Li, et al., “Particulates and Trace Gas Emissions from Open Burning of Wheat Straw and Corn Stover in China,” Environmental Science and Technology, 41, 2007, p.6052 and Xin Huang, et al., “Harvest season, high polluted season in East China.” Environmental Research Letters, 2012, p. 1.
3 Farmers are not interested in climate change or smoke. They view these as far beyond their sphere of influence. Programs that emphasize educating farmers about these things do not work. What works is showing farmers that biochar-based fertilizer increases yields and plant health and that there are now markets for all that (s)he produces/