Cheaply sequesters, billions of tons of emissions.
Carbon Brief 16, specializes in clear, data-driven articles and graphics, both in terms of the science and the policy response, includes explainers, interviews, analysis and factchecks, as well as a range of popular email newsletters, Explainer: 10 ways 'negative emissions' could slow climate change, 04-16-2016, https://www.carbonbrief.org/explainer-10-ways-negative-emissions-could-slow-climate-change/, yao
Enhanced weathering ramps up this process. Pulverising rocks bypasses the slow weathering action, and spreading the resulting powder on large areas of agricultural land makes use of microbes in the soil to speed up the chemical reactions. At the same time, adding minerals to the soil boosts nutrient levels in the soil, providing a benefit for crops. The powder can also be spread directly onto the ocean surface.
One of the by-products of this process is to make water more alkaline, thus enhanced weathering has an additional benefit of partially counteracting ocean acidification.
According to one paper, enhanced weathering could be used to sequester up to 3.7bn tonnes of CO2eq per year globally. Closer to home, another paper says the UK has “substantial” resources of rock that are suitable for enhanced weathering, and calculates that the UK could capture a total of 430bn tonnes of CO2 at a cost of between £15 and £361 per tonne.