Carbon Capture and Storage.
I have figured this out pretty much.
This is going to take energy to start but has to have a building impact over time. The energy needs to be solar or at least renewable.
The impact has to be global and low tech and mult-pronged.
The idea is to transform housing construction and agriculture and the answer is hemp lime construction or hempcrete construction.
Hemp is a low resource agricultural crop with multiple uses from food to fiber and the waste is called hemp hurds and it is the key to carbon sequestration. Combining hemp hurds with lime and water in a simple ratio and easily mixed, yields a building material that is carbon negative. It absorbs carbon from the air for about 100 years as the lime returns to a state of a kind of limestone entombing the hemp hurds for potentially centuries. Hempcrete is nearly pest proof, fire proof, high R value, sound dampening, mold resistant and is typically utilized in form-based construction (easy).
Using this building material displaces a large portion (not all) of the need for forest harvesting of wood for construction so not great for loggers but wonderful for farmers.
There is a chemical process called the lime cycle.
Lime Cycle - an overview | ScienceDirect Topics
Creating lime releases CO2 (but it is absorbed back later) and is energy intensive but the energy source can be mostly electrical and solar sourced. The raw material required is limestone and is widely available so transportation is reduced.
Hempcrete homes are healthy, efficient, safe and potentially cheaper. Lime production is industrial but the hemp part is local and generally low tech.
Hemp has been held back by legality but much of that has been removed.
The trick with hemp lime or hempcrete is that hemp hurds contain silica and lime has an affinity for silica creating more stable substance that one using straw or sawdust. Together the lime stabilizes the hemp hurds such that they do not rot nor do they support molds. The lime allows the slow movement of moisture without restriction such that moisture problems do not happen. Formed construction techniques create a very tight envelope without creating moisture problems (think a 12 inch wall poured into forms of infinite shapes).
The US has somewhere between 60-90 million acres of GMO corn and a LOT of this corn (not being used for ICE fuels) could become hemp used for housing, food and fiber.
I view this as a relatively low tech solution but it is also broadly applicable and is in harmony with solar energy, recycling, high efficiency, labor friendly and healthful. There are many wins and few challenges.
Barriers that do exist are related more to zoning where hempcrete is curiously viewed as insulation in many cases. These are challenges to architecture. There are challenges to construction timing since hempcrete has a longer setting process. Decorticators need to be expanded to support the fiber industry but these are known technologies.
This is a solution that has many harmonies and could be well on its way globally in 5 years with a few modest governmental incentives IMO.
