As scientists in a sustainable-development research institute, our experience has demonstrated two further principles that are crucial for successful interdisciplinary research (see R. R. Brown et al. Nature 525, 315–317; 2015).
First, solving real-world problems requires integration of the social and biophysical realms. Key to this is the explicit consideration of differences in scale. For example, water governance has a typical time horizon of years, yet hydrological processes operate on timescales from seconds to millennia.
Second, a critical mass of interdisciplinary scholars is necessary to become a credible counterpart for disciplinary researchers and to catalyse progress. Our institute employs 150 interdisciplinary researchers, who engage much greater numbers of single-discipline researchers in interdisciplinary projects.