An essay for International Earth Day by Dorrik Stow, professor of ocean and earth science at the University of Southampton, UK, and the author of Oceans: An Illustrated Reference.

Sustainability is neither a fashionable trend that will go away once its media exposure has played out, nor is it an option we can lightly dismiss. Sustainability is every bit as essential to the future of human existence as are the food and water we consume and the air we breathe. April 22 has been designated International Earth Day, a time to focus across the world on planet Earth—her natural resources, environment and future.
Despite being endowed with enormous richness and diversity of natural resources, the United States can only sustain itself at present rates of consumption for about six months of each year. For the remaining half year it is totally reliant on imports. Furthermore, if the global population consumed at the same rate as the American people, the world would require more than five times the total global resource base to survive. The sums simply do not add up. But we are no better here in the UK, so I am not simply pointing an accusing finger from across the Atlantic. Yes, our rates of consumption are somewhat lower, as is the population, but our more limited natural resource base means that we run out of self-sufficiency after only 3½ months in any one year. Collectively, the world is on a fast track to nowhere—resources will simply run out, that is if the environmental havoc we wreak does not first choke us. So, is there a solution?

From time immemorial humankind has looked to the oceans, both for their bountiful resources as well as for timeless inspiration. The oceans are vast indeed and, although science has barely dipped its toes into the shoreline of this final frontier, we know already that the marine world holds an important key to sustainable development on planet earth. To the energy sector, the oceans represent oil and gas in abundance, and a scramble for new-found reservoirs beneath the deep sea floor that will ensure global reserves last well into the third millennium. More importantly, there is a plethora of renewable energies awaiting technological advance and a commitment to develop them. To the metals industry, there are untouched fields of polymetallic nodules and black smokers, as well as beach sands of gold, diamonds and precious gems. Second only to the hydrocarbon sector, sand and gravel extraction amounts to over 8 billion tons annually—progressively more each year coming from offshore aggregate sites.
The fisheries sector already lands a catch of over 100 million tons a year, and now looks towards new rich harvests of krill and myriad other small planktonic species. Mariculture produces a further 18 million tones from coastal waters and looks set to develop gigantic farms spread out across the continental shelves. The list of potential resources goes on… from salt farms to desalination plants, from microbes to new medicines, from acres of frozen methane trapped just below the seafloor to heavy hydrogen for use in fusion power of the future.
But to an ever burgeoning global population, even these seemingly limitless resources are ultimately finite. World population now exceeds 6 billion people, and is set to top the 10 billion mark well before the middle of the century. Developing countries and their rightful development aspirations can only place further strain on both resources and the environment.
We use and abuse the oceans in other ways too. The sheer scale of waste generated by humankind is staggering. Collectively we produce 6 billion tons of domestic waste each year, unevenly distributed between the profligate developed and frugal developing worlds, and some 10 billion tons of sewage sludge. Industry and agriculture together yield equally enormous volumes of waste products. Although disposal and treatment on land consumes a large proportion, marine dumping takes an increasing share, particularly along coastal zones in highly populated regions, or where golden sands and warm sunshine make for a booming tourist industry.
It is not only the absolute volume of waste product that is important in determining its effect on pollution, but also the length of time that it remains in the marine environment. Whereas much organic waste can be readily dealt with by natural processes of bio-degradation and marine recycling, certain pesticides, detergents and synthetic organo-halogens are less easily degraded. As much as 150,000 tons of plastic nets and other fishing gear are lost at sea annually, while plastic refuse washes ashore on the most remote Pacific islands and along the once pristine Arctic shoreline.
History is littered with the excesses of human activity. Natural resources have been pillaged from our land, while the environment is trampled underfoot with an abandon dictated solely by political and economic imperatives. Such gross mismanagement resulting in blatant unsustainability is fast being transferred into ocean space. This cannot be allowed to happen. Although the oceans are vast and their potential remains enormous, responsible global management of their rich resources and finely balanced environment is the only means to a sustainable future.