For generations, humankind has been focused on its terrestrial environment; shaping it through agriculture, urbanisation and conservation. Our aquatic environment, meanwhile, has been a comparatively unmanaged source of food, enabled transport, and is a location for leisure. It has also absorbed much of our CO2 production and been a repository of our waste from land. In recent years, we’ve demanded even more of it: a place for low carbon energy generation, a mine of rare minerals, and a site for commercial development. The cost of that use – over-use – is increasingly clear when we consider the loss of biodiversity, reduced fish catches, degraded environments and increased pollution, particularly plastics. We also see the impact of climate change gases in the form of ocean acidification, reduced oxygen and rising temperatures.