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Digging into Soil Carbon

Climate change is all around us. Greenhouse gases like carbon dioxide account for a greater share of our atmosphere than ever in the last million years, and cause heat to stay trapped in earth’s atmosphere. Droughts, rising sea-levels, and precarious food systems all come downstream from the slow rise in global temperatures. Those effects bring about a serious human toll, from displacement to hunger. 

There is strong evidence that temperatures rising more than 1.5 degrees celsius will greatly exacerbate climate migration, food insecurity and water shortages around the world, and bring about greater suffering by people and planet. This calls for a wholesale rethinking of how we as people live our lives--no doubt, it’s an injunction on all humanity to stop emitting greenhouse gases. However, as we can easily visualize from this Carbon Brief graph, stopping emissions is only half the battle. Each coming year our path to emissions reductions gets less and less realistic, especially as humanity is showing no sign of letting up. Reaching zero emissions by 2050 (as we need to do to limit warming to the already harmful 1.5 degrees C), will necessarily involve some serious negative emission strategies.  

Negative emission strategies, or carbon storage techniques, have started to move into the limelight recently as futuristic technological advances that could mitigate the worst effects of climate change and cushion the world’s transition away from emitting carbon. While big pieces of equipment that suck carbon out of thin air are cool, the Intergovernmental Panel on Climate Change (IPCC) makes it quite clear that the technology that holds the most promise in terms of impact, also happens to be the cheapest way to pull carbon out of the atmosphere--soil carbon sequestration. Soil carbon sequestration is the use of plants to pull carbon out of the atmosphere and put it into soil in the form of organic matter, which is 58% carbon. Each individual plant only sequesters a small amount, but with improved practices at a landscape scale, soil carbon sequestration could pull from the atmosphere more than an eighth of current global carbon emissions each year, based on the IPCC’s conservative estimates.

The landscape used to serve as a huge carbon sink, but as humans required more and more resources to survive, deep rooted grasslands and forests around the world were repurposed to grow corn and wheat. Industrialized food systems streamlined production without regard for the greenhouse gas emissions of transportation, fertilizer and chemical synthesis, nor regard for the land use itself. Today, the emissions from agriculture account for 24% of global greenhouse gas emissions. Food production has accommodated a burgeoning human population, but now, in furthering climate change, it stands to inflict harm on those very same people. We must shift our food production to resemble a landscape that can sequester carbon to its fullest potential and still yield food for humanity to survive.   

Nothing is a more hopeful example today than Kernza® Perennial Grain. Kernza is just like wheat--it can be milled and eaten in breads and cakes or it can be cooked whole and eaten in a grain salad. However, it comes along with a whole host of ecosystem services including incredible soil carbon sequestration potential. Kernza is a domestication of a prairie forage grass known as intermediate wheatgrass, a plant known to have deep and highly developed root systems that can sequester outsized amounts of carbon from the atmosphere. Kernza grows it’s root system so thick because instead of putting all its energy into one growing season and then needing to be uprooted every year like its annual cousin wheat, Kernza is a perennial, so it can be planted once and yield food for multiple years to come. Scientists at The Land Institute have spent years breeding intermediate wheatgrass, selecting for the greatest food attributes and highest yields. Once you understand how a developed root system is responsible for sequestering carbon in the earth, this image courtesy of The Land Institute speaks for itself. How much CO2 Kernza sequesters exactly is still out for conclusive findings, but past studies of similar prairie grasses (such as switchgrass) show that a field of prairie grasses could store something in the ballpark of 1.89 metric tons of CO2 per acre. In the US alone, wheat accounts for 50 million acres of cropland. Taken together, those datapoints support the compelling case for Kernza, and the adoption of perennial agriculture more broadly.

What’s more, not only do those highly developed root systems provide that carbon sink we so dearly need, but also the production of Kernza requires less greenhouse gas emissions to pull off. Erik Engellant, a Montana-based organic Kernza grower, found that over the course of three years, there was an average fuel burn of 1.8 gallons per acre per year for his Kernza production and an average fuel burn of 4.89 gallons per acre per year for the on the annual production field. Perenniality requires less field work, and is a more efficient method of farming.

Kernza is especially hopeful because it is bred to substitute for wheat, which accounts for 18% of the calories consumed by the world. 18% of global calories is the type of serious landscape scale change that we need to be envisioning. Not only is Kernza itself exciting, but it’s part of a whole perennial foodscape that offers perennial alternatives for most major crops, and allows us to imagine impacting all of grains, which account for 70% of global calories 

As we take stock of our world this earth week, we see Kernza as a leading soil champion, an incredibly promising climate solution, and one that enriches peoples’ lives with nourishment and flavor.  Perennial agriculture is our future, and we all need to build this better future together.