Deep soil burying of woody debris as the most effective, least expensive, and most sustainable carbon dioxide removal strategy

It becomes hopeful to limit climate warming to 1.5 °C if woody debris produced in managed forests, metropolitan areas, orchards, and fire-prone forest lands over the globe is buried in deep soil. We have recently estimated that deep soil burying of woody debris produced in managed forests has the capacity to remove 10.1-12.3 Gt CO₂ yr^-1 from the atmosphere and slow down climate warming by 0.35 - 0.42°C by the end of this century. Similarly, waste wood materials from metropolitan areas, pruned woody materials from orchards, and woody materials from forest thinning or dead wood salvaged from forestry in fire-prone regions can be buried in deep soil for carbon dioxide removal (CDR) from the atmosphere. Globally, wildfire burning releases 7.7 ± 0.7 Gt CO₂ yr^-1 to the atmosphere. Urban woody waste is produced from pruned branches and fallen trees from streets and public areas, possibly in a range of 1-2 Gt CO₂ yr^-1. Taking all together, burying woody debris has the potential to remove substantially more than 12 Gt CO₂ yr^-1, which is approximately 10 times more effective than almost any of the other CDR methods that have been explored by the scientific community. For example, CDR methods, such as cover cropping, soil carbon sequestration, and enhanced rock weathering, have potentials to remove 1 Gt CO₂ yr^-1 or less.  Forestation, which has been considered to have the largest CDR potential, may remove 1.54 Gt CO₂ yr^-1 according to a recent study. Even so, CDR via reforestation may no longer be effective once the past disturbed ecosystems have mostly been restored whereas burying woody debris can keep removing CO₂ as woody debris can be sustainably delivered year after year. Moreover, burying woody debris costs the least in comparison with other CDR methods. Overall, deep soil burying of woody debris not only makes it hopeful to limit climate warming to 1.5 °C but also create markets for low-value timber common, reduce forest wildfire risks, and offer alternative practices for waste wood management in urban areas.