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Methane Digesters (Small)

Electricity Generation

At backyard- and farmyard-scale, anaerobic digesters are used to manage organic waste. They control methane emissions, while producing biogas (an energy source) and digestate (nutrient-rich fertilizer).

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Rank and results by 2050 #64

Methane Digesters (Small)

Reduced CO2: 2 gigatons
Net cost (Billions US$): $15.50
Net operational savings: $13.90 billion
What do these numbers mean?

TOTAL CO2-EQ REDUCTION (GT)

Total CO2-equivalent reduction in atmospheric greenhouse gases by 2050 (gigatons)

NET COST (billions US $)

Net cost to implement

SAVINGS (billions US $)

Net savings by 2050

Impact:

We project that by 2050, small digesters can replace 57.5 million inefficient cookstoves in low-income economies, resulting in 1.9 gigatons of carbon dioxide emissions avoided at a cost of $15.5 billion. If you couple this impact with that of large methane digesters, the cumulative result is 10.3 gigatons of carbon dioxide emissions avoided.

Methane Digesters (Small)

Electricity Generation

At backyard- and farmyard-scale, anaerobic digesters are used to manage organic waste. They control methane emissions, while producing biogas (an energy source) and digestate (nutrient-rich fertilizer).

Agricultural, industrial, and human digestion processes create an ongoing (and growing) stream of organic refuse. Without thoughtful management, organic wastes can emit fugitive methane gases as they decompose. Methane creates a warming effect 34 times stronger than carbon dioxide over one hundred years.

One option is to control decomposition of organic waste in sealed tanks called anaerobic digesters. They harness the power of microbes to transform scraps and sludge and produce two main products: biogas, an energy source, and solids called digestate, a nutrient-rich fertilizer. The digestion process unfolds continuously, so long as feedstock supplies are sustained and the microorganisms remain happy.

Anaerobic digestion is used in backyards and farmyards around the world, and that use is on the rise. Small-scale digesters dominate in Asia. More than 100 million people in rural China have access to digester gas, which is used for cooking, lighting, and heating. In fact, during his years in ancient China, Marco Polo encountered covered sewage tanks that produced cooking fuel.

Biogas can reduce demand for wood, charcoal, and dung as fuel sources and therefore their noxious fumes, which impact both planetary and human health. Digestate enriches home gardens and small agricultural plots.

Vs

Conservation Agriculture

Food

Conservation agriculture avoids tilling and employs cover crops and crop rotation. By protecting the soil, it makes land more resilient and sequesters carbon.

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Rank and results by 2050 #16

Conservation Agriculture

Reduced CO2: 17 gigatons
Net cost (Billions US$): $37.53
Net operational savings: $2,119.07 billion
What do these numbers mean?

TOTAL CO2-EQ REDUCTION (GT)

Total CO2-equivalent reduction in atmospheric greenhouse gases by 2050 (gigatons)

NET COST (billions US $)

Net cost to implement

SAVINGS (billions US $)

Net savings by 2050

Impact:

Based on historic growth on large farming operations, our analysis projects the total area under conservation agriculture will continue growing from 177 million acres to peak at 1 billion acres by 2035. We assume that as regenerative agriculture becomes more widely used, farms that have already adopted conservation agriculture will convert to these more effective soil fertility practices in response to consumer demand for fewer harmful herbicides. The benefits of that conversion are counted by the regenerative agriculture solution. Nonetheless, conservation agriculture offers significant benefits in the interim, reducing carbon dioxide emissions by 17.4 gigatons based on average carbon sequestration rates of .15 to .25 tons of carbon per acre per year, depending on region. Implementation costs are low at $38 billion with a return of $2.1 trillion.

Conservation Agriculture

Food

Conservation agriculture avoids tilling and employs cover crops and crop rotation. By protecting the soil, it makes land more resilient and sequesters carbon.

Plows are absent on farms practicing conservation agriculture, and for good reason. When farmers till their fields to destroy weeds and fold in fertilizer, water in the freshly turned soil evaporates. Soil itself can be blown or washed away and carbon held within it released into the atmosphere. Tilling can make a field nutrient poor and less life-giving.

Conservation agriculture was developed in Brazil and Argentina in the 1970s, and adheres to three core principles:

1. Minimize soil disturbance: absent tilling, farmers seed directly into the soil.
2. Maintain soil cover: farmers leave crop residues after harvesting or grow cover crops.
3. Manage crop rotation: farmers change what is grown and where.

The Latin root of conserve means “to keep together.” Conservation agriculture abides by these principles to keep the soil together as a living ecosystem that enables food production and helps redress climate change.

Conservation agriculture sequesters a relatively small amount of carbon—an average of half a ton per acre. But given the prevalence of annual cropping around the world, those tons add up. Because conservation agriculture makes land more resilient to climate-related events such as long droughts and heavy downpours, it is doubly valuable in a warming world.

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