Carbon capture and sequestration (CCS) has emerged as a viable technique to mitigate climate change, reduce greenhouse gases and ocean acidification, and to enhance oil or gas recovery. An important part of the CCS chain is pipeline transport of dense-phase carbon dioxide (CO2) from large point sources to suitable storage sites. Since CO2 is an asphyxiating gas, deliberate or accidental leaks from pipelines represent a serious hazard, and realistic consequence modelling of such scenarios is of paramount importance for safety. This paper presents results from numerical simulations of an industrial-scale pipeline release and the subsequent dispersion of CO2 in the atmosphere. The experiment and flow model development was part of the CO2PipeHaz project in the European Commission's Seventh Framework Programme for Research and Technological Development (FP7). The length and internal diameter of the pipeline used in the experimental setup was 260 m and 0.233 m, respectively. Pure CO2 was discharged through a 0.05 m diameter orifice located 0.5 m above ground at the end section of the pipeline. The initial temperature was 20 °C and the initial pressure 53 bar. The measurements included wind speed, wind direction and temperature of the CO2 plume. Comparison between experimental results and numerical simulations with the computational fluid dynamics (CFD) software FLACS shows good agreement. The numerical study provides useful insight into the dispersion behaviour of the CO2 plume, and highlights the sensitivity towards the use of various turbulence models, surface roughness and wind conditions. The paper represents a significant contribution to the understanding of hazards associated with pipeline transport of carbon dioxide.