The role of enhanced rock weathering deployment with agriculture in limiting future warming and protecting coral reefs

• Published in: Environmental Research Letters
• Main Authors: Vakilifard, Negar, Kantzas, Euripides P., Edwards, Neil R., Holden, Philip B., Beerling, David J.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2021
• Subjects: Ocean acidification
• Online Access: https://oro.open.ac.uk/78577/; https://oro.open.ac.uk/78577/1/2021_Vakilifard_ERW_ERL.pdf; https://doi.org/10.1088/1748-9326/ac1818

Meeting the net-zero carbon emissions commitments of major economies by mid-century requires large-scale deployment of negative emission technologies (NETs). Terrestrial enhanced rock weathering on croplands (ERW) is a NET with co-benefits for agriculture, soils and ocean acidification that creates opportunities for generating income unaffected by diminishing carbon taxes as emissions approach net-zero. Here we show that ERW deployment with croplands to deliver net 2 Gt CO 2 yr −1 removal approximately doubles the probability of meeting the Paris 1.5 °C target at 2100 from 23% to 42% in a high mitigation Representative Concentration Pathway 2.6 baseline climate. Carbon removal via carbon capture and storage (CCS) at the same rate had an equivalent effect. Co-deployment of ERW and CCS tripled the chances of meeting a 1.5 °C target (from 23% to 67%), and may be sufficient to reverse about one third of the surface ocean acidification effect caused by increases in atmospheric CO 2 over the past 200 years. ERW increased the percentage of coral reefs above an aragonite saturation threshold of 3.5 from 16% to 39% at 2100, higher than CCS, highlighting a co-benefit for marine calcifying ecosystems. However, the degree of ocean state recovery in our simulations is highly uncertain and ERW deployment cannot substitute for near-term rapid CO 2 emissions reductions.