The European pulp and paper sector has an estimated potential for large-scale, permanent Carbon Dioxide Removal (CDR) of 50 Mtpa, through the implementation of CO2 capture and storage (CCS). CCS has been explored for this sector in literature, but results are limited compared to many other sectors and show substantial variability in costs and performance across mill types, operating conditions and locations. Several assessments highlight large kraft pulp mills in Northern Europe as among the most cost-effective opportunities. However, the characteristics of pulp mill black liquor recovery boiler flue gases raise concerns regarding the interaction with CO2 capture, due to elevated levels of alkali species, sulfur compounds, chlorides, trace metals and other constituents. Potential challenges include solvent degradation, foaming, fouling, corrosion and operational instability. Supported by results from pilot testing on two black liquor recovery boiler flue gases at a Swedish kraft pulp mill, this Perspective argues that more research is required in the public domain to understand the physico-chemical mechanisms involved in alkaline solvent CO2 capture from black liquor flue gases. Unleashing the CDR potential in the pulp and paper sector also requires a supportive regulatory framework and beneficial financial conditions, including buyers of CDR certificates on an megatonne scale. In view of the long investment cycles (up to 40 years) this Perspective calls for the development of scenarios for a stable, sustainable, climate-neutral economy well beyond 2050.