Do we need NETs? The short answer is yes. A recent report by the UN shows that updated national pledges since COP26 still place the world far from the Paris Agreement goal of limiting global warming to 1.5 degrees. Policies currently in place point to a 2.8°C temperature rise by the end of the century.
Strategies like tree planting can remove carbon from the atmosphere, but there simply isn't enough space on earth to plant enough trees to remove the CO₂ that needs to be removed. Tree planting needs to be paired with emission reduction and NETs to solve the climate crisis.
Some of the main negative emission technologies include:
- Enhanced weathering
- BECCS (bioenergy carbon capture and storage)
- DAC (direct air capture)
Rocks in nature are continuously weathering - in addition to mechanical weathering by wind, rain and frost, they react with CO₂ in the air to form carbonates. This weathering process progresses very slowly in nature. To enhance the weathering process we can crush the rock to increase its surface area, and spread the crushed rock in areas that are known to weather rocks quickly.
This process is very efficient at permanently removing CO2 from the atmosphere, even after accounting for the rock being mined, crushed and transported to farms - all of which need diesel and electricity. The good news is that for every 1 tonne of CO2 produced in mining and transport, over 10 tonnes of atmospheric CO₂ is permanently sequestered. This is calculated in a detailed Life Cycle Analysis we have prepared.
Any technology that tries to make an appreciable difference needs to be able to scale to remove billions of tonnes of CO₂ from the atmosphere per year. Carbonaught believes that enhanced weathering, which involves crushing and spreading of appropriate rocks, fits that bill since humanity already digs up billions of tonnes of rock per year.
Carbonaught speeds up this process by crushing the rocks to increase surface area and spreading it in soils. As well as absorbing CO₂ from the atmosphere, this has numerous co-benefits like remineralising and improving degraded soils. This means it can easily be paired with afforestation and BECCs, and regular farming, by providing nutrients that are removed.