The instrumental use of technical doubts: Technological controversies, investment decisions and air pollution controls in the global shipping industry

In principle, the installation of emissions abatement technology (otherwise known as scrubbers) on ships would reduce air pollution and premature deaths from disease and allow vessels to save costs by continuing to burn cheap high-sulphur residual fuel oil. But very few scrubbers have been installed. A recent House of Commons Select Committee Inquiry was unable to decide between the competing technical claims of scrubber manufacturers and ship operators, over whether scrubber technology was sufficiently 'mature' for present installation. From the perspective of science and technology studies, this paper draws on interviews with stakeholders and written and oral evidence to the committee to argue that this was a dispute, which foregrounded technical arguments for investment decisions that were actually being taken on economic grounds. Where scientific/technical closure is a matter of communal understanding rather than technical demonstration, technical doubt can be used instrumentally for economic reasons to delay closure.