The many established uses of the global ocean include commercial shipping, fishing, and scientific research. Others are emerging, or may emerge in years to come: mining of minerals from the seabed, bio-prospecting for novel organisms or novel genes, generating electricity, and geoengineering to increase the absorption of carbon dioxide.

Some of these activities, such as industrial fishing, have already had major impacts on ocean ecology; others have the potential to increase pressures on the global ocean. With some uses, the concern is not ecological damage, but equity in the way that resources are allocated. Others, such as illegal fishing raise additional issues, including human rights abuses, national security and piracy. Environmental factors such as climate change, meanwhile, are compromising the health of the global ocean in a variety of ways.

Solutions that have been proposed include reforming fishing subsidies, expanding marine protected areas, and tightening rules on fishing vessel movements.

Swordfish caught on longline (Kydd Pollock/Marine Photobank)