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

• Published in: Environmental Research Letters
• Main Authors: Negar Vakilifard, Euripides P Kantzas, Neil R Edwards, Philip B Holden, David J Beerling
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2021
• Subjects: coral reefs; enhanced rock weathering; Earth system model; ocean acidification; Paris agreement temperature targets; RCP2.6; Environmental technology. Sanitary engineering; TD1-1066; Environmental sciences; GE1-350; Science; Q; Physics; QC1-999; Ocean acidification
• Online Access: https://doi.org/10.1088/1748-9326/ac1818; https://doaj.org/article/f78f7540081a4c24801b57e228f1065d

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.