The emerging climate engineering (CE) debate will be fed by scientific information–and likely by misinformation as well. The first intense, international studies of any type of CE began in the early 1990s with ocean iron fertilisation, a method associated with the carbon dioxide removal branch of CE techniques. The ocean fertilisation experiments and analyses led to discussions by scientists and stakeholders about not only the environmental advantages and disadvantages but also political and ethical concerns. While a major part of the future evolution of CE research will extend on some of the trajectories outlined above, especially the expansion of community-wide multi-model studies, a highly uncertain direction of development involves future field testing of CE. Many CE studies have already been published in the separate disciplines, with only a few interdisciplinary studies so far, and even less trans-disciplinary work.