This paper is an outcome of the International Space Science Institute (ISSI) Forum on “Monitoring the evolution of coastal zones under various forcing factors using space-based observing systems” (http://www.issibern.ch/forum/costzoneevo/) held at ISSI, Bern, Switzerland on 11-12 October 2016 (convened by J. Benveniste, A. Cazenave, N. Champollion, G. Le Cozannet and P. Woodworth)