CC BY 3.0 UnportedFuss, SabineLamb, William F.Callaghan, Max W.Hilaire, JérômeCreutzig, FelixAmann, ThorbenBeringer, Timde Oliveira Garcia, WagnerHartmann, JensKhanna, TarunLuderer, GunnarNemet, Gregory F.Rogelj, JoeriSmith, PeteVicente Vicente, José LuisWilcox, Jenniferdel Mar Zamora Dominguez, MariaMinx, Jan C.2023-01-162023-01-162018https://oa.tib.eu/renate/handle/123456789/10890http://dx.doi.org/10.34657/9916The most recent IPCC assessment has shown an important role for negative emissions technologies (NETs) in limiting global warming to 2 °C cost-effectively. However, a bottom-up, systematic, reproducible, and transparent literature assessment of the different options to remove CO2 from the atmosphere is currently missing. In part 1 of this three-part review on NETs, we assemble a comprehensive set of the relevant literature so far published, focusing on seven technologies: bioenergy with carbon capture and storage (BECCS), afforestation and reforestation, direct air carbon capture and storage (DACCS), enhanced weathering, ocean fertilisation, biochar, and soil carbon sequestration. In this part, part 2 of the review, we present estimates of costs, potentials, and side-effects for these technologies, and qualify them with the authors' assessment. Part 3 reviews the innovation and scaling challenges that must be addressed to realise NETs deployment as a viable climate mitigation strategy. Based on a systematic review of the literature, our best estimates for sustainable global NET potentials in 2050 are 0.5–3.6 GtCO2 yr−1 for afforestation and reforestation, 0.5–5 GtCO2 yr−1 for BECCS, 0.5–2 GtCO2 yr−1 for biochar, 2–4 GtCO2 yr−1 for enhanced weathering, 0.5–5 GtCO2 yr−1 for DACCS, and up to 5 GtCO2 yr−1 for soil carbon sequestration. Costs vary widely across the technologies, as do their permanency and cumulative potentials beyond 2050. It is unlikely that a single NET will be able to sustainably meet the rates of carbon uptake described in integrated assessment pathways consistent with 1.5 °C of global warming.enghttps://creativecommons.org/licenses/by/3.0690carbon dioxide removalclimate change mitigationnegative emission technologiesscenariosArticle