Author: David Wolfe
Now that 195 nations, including the U.S., have agreed to ambitious greenhouse gas emission reductions to slow the pace of climate change, the question everyone is asking is: How will we actually meet our targets set for 2035?
Given past performance, many don’t think we will get there without so-called “geoengineering” solutions, such as blasting sulfur dioxide or other particles into the atmosphere to shade the planet and compensate for the warming effect of greenhouse gases. Clever, eh? Maybe not. Some recent modeling studies show these seemingly easy fixes could backfire in catastrophic ways, such as disrupting the Indian monsoon season and completely drying out the Sahel of Africa. Another risk is atmospheric chemical reactions that deplete the ozone layer. Do we really want to run global-scale experiments for 20 or 30 years and see what happens?
There is another way, one that is zero-risk and builds on something farmers around the world are already motivated to do: manage soils so that a maximum amount of the carbon dioxide plants pull out of the air via photosynthesis remains on the farm as carbon-rich soil organic matter. “Carbon farming,” as it is sometimes called, is Mother Nature’s own geoengineering, relying on fundamental biological processes to capture carbon and sequester it in the soil, carbon that would otherwise be in the air as the greenhouse gas, carbon dioxide.
Over the past century soils worldwide have been degraded due to expansion of agriculture and poor soil management. Today, there is a revolution in agriculture that recognizes the importance of building “healthy” soils by replacing the organic matter that has been lost over time. One way to do this is to use carbon- and nutrient-rich organic sources of fertilizers such as manure or compost rather than synthetic chemical fertilizers. Another is to include carbon- and nutrient-rich crops like legumes (e.g., peas, beans) in rotations, and plant winter cover crops that contribute additional organic matter in the off-season. We’ve also discovered that reducing the amount of plowing and tilling of the soil (“conservation tillage”) slows the microbial breakdown of organic matter that leads to carbon dioxide emissions from soils.