Capture Carbon with Agriculture

Mixed farming

Carbon farming is growing a selection of crops that is designed to capture carbon while meeting human needs at the same time. According to Eric Toensmeier (Yale University),  "If widely implemented, these practices have the capacity to sequester hundreds of billions of tons of carbon from the atmosphere in the coming decades. Unlike high-tech geoengineering strategies, these practices can also feed people, build more fertile soils and contribute to ecosystem health." In a twist of technology, these techniques harken back to traditional agricultural practices. Carbon farming varies according to where the farm is located, but the principles are all the same: Emphasize no-till practices, cover crops, multilayered crops and crop rotation, with a percentage of perennial crops to trap the carbon in the soil. Even carefully managed livestock using fodder banks and silvo-pasture (mixing trees with pastureland) can capture and store carbon in greater amounts than the methane release from the cattle.

As Eric sums up: "At present, the tropics have stronger carbon farming options than colder climates; many of the agroforestry techniques that have the highest sequestration rates are largely confined to the tropics, and most of the best perennial crops available today are also native to, or grown best in, the tropics. The head start the tropics have on carbon farming provides an excellent opportunity for wealthy countries to repay climate debt by bankrolling mitigation, adaptation and development projects in the Global South and to take lessons from the endeavors already under way there.

Carbon farming alone is not enough to avoid catastrophic climate change, even if it were practiced on every square meter of farmland. But it does belong at the center of our transformation as a civilization.

Growing grass for biomass

Plant material is used to create biomass available for a wide array of energy purposes from simply burning it to create heat or electricity: using a digester to create methane, or even convert it into ethanol or biodiesel for fuel.

Although many biomass converters use corn, it takes a lot of energy to produce corn so that is not efficient. Instead, the use of grasses or fast growing tress, such as switchgrass, fountain grasses, silver grass, poplar, willow, eucalyptus, and locust can reduce emissions by 85 percent compared to corn ethanol. Replacing annuals with perennials also raises carbon sequestration in soil increases the stability of the soil, and generates more predictable yields.

Biochar

Biochar or terra preta has been used for thousands of years. Researchers have fond that almost 10% of the Amazonian forest floor has biochar as the waste disposal method of choice. Wastes were buried and then burned in the soil.

Biochar is created using pyrolysis. This can be tweaked to produce more syngas and oil or less. The process requires little or no oxygen and if it is done as a slow process, the yield in biochar is maximized; done quickly (seconds) it maximizes the yield of combustibles that can be used directly in a standard diesel type engine. This latter however does not sequester carbon. Used as a global scale operation, biochar has the potential (derived from a small percentage of our annual organic waste) to sequester about 15% of the annual carbon emissions. Biochar lasts for centuries in the soil and theoretically, could sequester billions of tons of carbon dioxide every year, making it a significant technique for reducing our excess emissions. Once excess emissions are at zero, the use of biochar could continue tosequester carbon out of the atmosphere until we were down to a reasonable level to maintain a stable climate.

There is already a growing industry in biochar, so there is money to made here. This is a positive socioeconomic idea - just like no-till agriculture.

The only risk is to ensure that the biochar is made from waste so as not to displace food production - avoiding the corn/ethanol problem.

Capture Carbon with Trees

New Forests

Plant new forests where pasture and agricultural lands have been abandoned or in old strip mine sites to create biomass. This becomes a carbon sink, taking in carbon and depositing it in the tree and eventually in the soil.

Plantations don't work very well because they do not have enough diversity to create a real forest. Japanese botanist Akira Miyawaki figured out a better way. He uses fast-growing, dense plots of native species that support lots of biodiversity while at the same time generating food and medicine, and also ensuring ecosystem services such as flood and drought protection.

Reforestation

Another similar approach (Thomas Goreau - The Down-to-Earth Solution to Global Warming: How Soil Carbon Sequestration Works ) is to use soil restoration and planting trees, restoring wetlands, and improving agricultural techniques to rapidly improve the natural carbon sinks. Put them all together and you have an easy winner.

Bamboo

Some trees are better than others. Bamboo is especially good at sequestering carbon in biomass and soil. It also can handle poor soil so marginal locations are great for bamboo if the weather is warm enough. Bamboo has the compressive strength of concrete and the tensile strength of steel, it grows fast and can be harvested in 4 years or less. Not only that but after being cut, bamboo re-sprouts and grows again.

Hemp helps defeat Global Warming

Hemp fiber is amazing. It is used to make everything from rope to clothing. Hemp grows much faster than even the fastest trees so can about 90 times to produce fibre. Hemp is also global warming solution because it can replace: cotton. Cotton demands huge applications of chemical and is depends heavily on fossil fuel. A simplewhite cotton shirt produces about 80 pounds of carbon once it is grown and turned into a shirt. In some countries hemp is also used as a component of "hempcrete" a construction material for houses.

In the United States, unfortunately, cultivation of hemp has not been approved by the federal Drug Enforcement Agency for cultivation because it has trace amounts of cannabinoids associated with marijuana. In fact, of course the concentration is too low to be of interest as a amrijuana substitute.