The study does include the assumption that some agricultural land can be freed up for reforestation, providing “natural” carbon dioxide removal.

See Carbon Brief [7]’s coverage of the research here [8].

Abstract

Mitigation scenarios that achieve the ambitious targets included in the Paris Agreement typically rely on greenhouse gas emission reductions combined with net carbon dioxide removal (CDR) from the atmosphere, mostly accomplished through large-scale application of bioenergy with carbon capture and storage, and afforestation. However, CDR strategies face several difficulties such as reliance on underground CO₂ storage and competition for land with food production and biodiversity protection. The question arises whether alternative deep mitigation pathways exist. Here, using an integrated assessment model, we explore the impact of alternative pathways that include lifestyle change, additional reduction of non-CO₂ greenhouse gases and more rapid electrification of energy demand based on renewable energy. Although these alternatives also face specific difficulties, they are found to significantly reduce the need for CDR, but not fully eliminate it. The alternatives offer a means to diversify transition pathways to meet the Paris Agreement targets, while simultaneously benefiting other sustainability goals.

Reference

van Vuuren, D.P., Stehfest, E., Gernaat, D.E., Berg, M., Bijl, D.L., Boer, H.S., Daioglou, V., Doelman, J.C., Edelenbosch, O.Y., Harmsen, M. and Hof, A.F., (2018). Alternative pathways to the 1.5° C target reduce the need for negative emission technologies. Nature Climate Change, p.1.

Read the full paper here [9]. See also the Foodsource chapter Food systems and greenhouse gas emissions [10].