The oceans
Scientific certainties and uncertainties
The oceans cover almost three-quarters of the Earth's surface and comprise over nine-tenths of our total water resources. We use and exploit the oceans extensively for food, energy and materials, and they have a major role in controlling our climate.
Most people are familiar with coastal waters, because of their proximity to us and the varied uses we make of them. But the deep oceans are much more inaccessible and aspects remain unexplored. We have better maps of the moon's surface than of most of the seafloor.
Concern about the health of the oceans' centres on the diversity of marine plants, animals and microbes, and how resilient they are to human impacts, such as pollution and fishing. We also need to know how natural and human induced climate change can alter the internal movements and total volume of the oceans. Changes in their massive currents not only affect ocean productivity but may also alter rainfall, temperature and atmospheric composition for the planet as a whole. A key question is their role in climate.
Conservation of marine biodiversity lags well behind that of the land. The UK Biodiversity Action Plan has identified habitats in British waters that are most in need of protection. But these sites are few in number and are only coastal and estuarine.
The key to sustainable development of the oceans lies in scientific knowledge and understanding of the marine environment. Here we spell out what we see as the main threats to the oceans, what we know with a reasonable level of certainty, and what we need to find out.