Negative Emissions Technologies for Climate Change Mitigation  - Chapter 2 - Overview of Negative Emissions Technologies

Early discussion of negative emissions technologies (NETs) was confined to quiet conversations “in the corridors of scientific meetings”, due to concerns that the promise of technical solutions to climate change would discourage essential decarbonization of the global economy. Improving understanding of the climate challenge, documented in successive IPCC assessment reports, coupled with the lack of international progress in curtailing emissions growth, led to the recognition in the IPCC Special Report on 1.5°C that gigatonne-scale deployment of NETs would be required to keep within the Paris 1.5°C target. This chapter describes this emergence, and introduces the broad range of NETs under development, including approaches to defining the optimum NET portfolio, and high-level deployment potentials and costs. The technology innovation process is introduced, and the chapter concludes with a summary of overarching knowledge gaps and research priorities for the NET portfolio.