Assessing the risk for alkalinity loss due to carbonate precipitation on particles after an ocean alkalinity enhancement operation

Climate change continues to pose a significant threat to humanity and the planet, especially with net anthropogenic CO₂ emission peaking at 59 (+/- 6.6) gigatons in 2019, which was 54% high than the previous decade. Fossil fuel Emissions cumulated between 1850 to 2020 reached 455+- 25GtC of which 42% occurred from 1990 to 2019 and 17% from 2010 to 2019. The budget imbalance during this time amounted to 25GtC (Friedlingstein et al. 2022, Working Group III to the IPCC Sixth Assessment Report et al. 2022). Based on global current trends (from 2015 to 2100), it is projected that the Earth’s average temperature will increase by 2.8^oC by the year 2100 (Liu & Raftery 2021). There is wide agreement among scholars that achieving net zero emissions is unlikely without significant and rapid changes in our approach to mitigation. According to Liu & Raftery (2021) achieving net-zero emissions by 2030 is considered unattainable at the current levels. However, to meet this target by 2050, it has been proposed that 0.4GtC needs to be removed every year (Friedlingstein et al. 2022). Estimates show that global CO₂ emissions are likely to lead to a temperature rise of over 1.5^oC (Working Group III to the IPCC Sixth Assessment Report et al. 2022). Achieving the target of limiting the temperature increase to 1.5^oC or 2oC after 2030 remains increasingly urgent. To compensate for the necessary reduction in emissions, carbon dioxide removal mitigation will be required to compensate for necessary reduction emissions (Rogelj, Shindell, et al. 2018).