The bounty of the sea
From ocean threat to ocean under threatFor millennia the sea seemed infinitely vast. Coastal dwellers, fishers and seafarers perceived it as overpowering and even threatening although it was the basis of their livelihoods. Myths of sea monsters and sea gods grew up around its unfathomable depths. In most countries and regions, the sea has long been demystified, and it is becoming apparent that the oceans are by no means as invulnerable as our forebears believed – on the contrary: today humans are influencing and harming the ocean. We are discharging toxic substances and excessive nutrients into the sea and plundering fish stocks. Due to emissions of the greenhouse gas carbon di-oxide, large volumes of which dissolve in seawater, humans are even beginning to alter the chemistry of the water masses. Many climate researchers believe that as the atmosphere and the ocean undergo warming, ocean currents will shift in future, resulting in changing weather conditions on land. The human-induced – anthropogenic – changes taking place in the sea, the atmosphere and on land are so far-reaching that in the year 2000, scientists working with the meteorologist Paul Crutzen suggested considering the era since the beginning of the Industrial Revolution as a human-influenced geological epoch in its own right. Crutzen, one of the researchers who discovered the hole in the ozone layer, aptly names this epoch the age of humans, or the Anthropocene (from the Greek word ánthrõpos: human).
Rising resource consumptionAlthough the various kinds of damage caused by humans have been known for some time, efforts to bring the global economy onto a sustainable course have had very little success, if any. Instead, theconsumption of natural gas, petroleum and coal as well as metals and other resources continues to rise. Since the beginning of the 1970s, worldwide energy consumption has doubled. By the year 2035 it will increase again by more than one third, according to data from the International Energy Agency (IEA) in Paris. In the quest for new resource supplies, humans are also encroaching ever further into the sea. Today around one third ofFurther information on this topic is available here:crude oil is drilled at sea– and the trend is rising. At the same time the mineral oil industry is conquer- ing the last bastion of the marine environment: the deep-water and ultra-deep-water zones at depths of 400 and 1500 metres respectively. Around 10 per cent of the petroleum drilled worldwide is currently recovered from such great depths. The sums invested by mineral oil corporations for offshore oil extraction are correspondingly high.Further information on this topic is available here:
- 2.2 > The deep-water docks of Chinese company CIMC Raffles in Shandong Province. Up to nine drilling rigs at a time can dock at this pier, showing the vast scale on which deep-sea drilling of natural gas and petroleum now operates.
- Furthermore, experts anticipate that the extraction of ores at sea could also begin in the year 2016. For instance, the Canadian mining group Nautilus Minerals definitively intends to start extracting ores off Papua New Guinea in 2016, after a dispute over financing between the corporate group and the island state was settled in the autumn of 2014. Nautilus Minerals wants to extract “massive sulphides”: deposits which formed around hot volcanic vents on the sea floor and are rich in precious metals.Further information on this topic is available here:Manganese nodulesorFurther information on this topic is available here:cobalt crusts, some of which are high in metal content and even contain larger quan-tities of certain metals overall than equivalent mineral deposits on land, are further attractions of the deep sea. The first heavy underwater vehicles are currently being built for ocean mining.Further information on this topic is available here:
The sea – the main trading routeThe sea is of great economic significance to humans in other respects as well. For instance, it is themost important trading route. Ships move more commodities than any other means of transportation. And unlike land-based roads where tolls are often payable, the trading routes across the open ocean are available for free. Ships carry petroleum, coal, ores and grain around the world. Container-loads of electrical appliances, clothing and foods are sent from Asia to North America and Europe. Crude oil from the Persian Gulf or South America is shipped in oil tankers. Apart from a decline in the cargo statistics during the economic crisis in 2008 and 2009, the quantity of goods transported by ships since the mid-1980s has constantly grown – from around 3.3 billion tonnes in 1985 to around 9.6 billion tonnes in 2013. Some 620 000 ships’ officers are employed in sea travel alone. Added to these are many millions of people who work as sailors or dockers. Above all, the sea coasts exert a special appeal to human beings. It is not by chance that many major cities, like Hong Kong, New York or Singapore, are in coastal locations. Numerous industrial plants have been and are being constructed by the sea, because raw materials and goods can be delivered and dispatched rapidly across the water. Experts estimate that today 41 per cent of the global population lives no more than 100 kilometres from the sea. The United Nations believes that this figure is likely to rise further in future. In many regions, it is also boosted by the millions of domestic tourists who seek out the coasts for bathing and recreation.Further information on this topic is available here:
- 2.3 > The oceans are the world’s most important transportation routes. The volume of seaborne cargoes continues to rise since the 1980s.
- The sea’s most important living resource, from the human viewpoint, is fish. According to estimates by the Food and Agriculture Organization of the United Nations (FAO), today the livelihoods of 600 to 820 million people worldwide depend directly or indirectly upon fisheries. These people include fishers’ families and suppliers – the makers of fishing equipment, for instance. Moreover, fish is the principal component of food in many places and a very important source of protein. Overall, about 20 per cent of humankind’s nutritional needs are met from the sea. Apart from fish, crustaceans and bivalves, people also consume algae and jellyfish.
Critical issues go unseen in the seaAs pressure on the sea continues to grow, the question arises of how any sustainable use of the oceans could be achieved under these circumstances. Normally sustainabil- ity theories refer to the situation on land, where critical issues quickly become evident. If the effluent from a mine contaminates rivers and soils for a long period, for exam-ple, then there are people directly affected whose usage or property rights are infringed. Damage is normally directly visible or at least measurable. It is also obvious right away who the beneficiary is. This means that interest groups can be clearly defined, conflicts aired and negotiations conducted about a sustainable use of natural resources. Processes in the sea remain invisible to most people, however, and are difficult to bring to light. For example, at the mouth of the Mississippi in the Gulf of Mexico, a 20 000-square-kilometre dead zone has formed in recent years which is almost devoid of oxygen. It has been caused by large quantities of nutrients discharged by agriculture into the river and then carried into the coastal region. In the sea, nutrients lead to rampant algal growth. When the algae die, they sink into the deeper water layers and are broken down by bacteria in a process which consumes oxygen. When the algae multiply especially quickly, the microbial degradation gradually exhausts all the oxygen. For higher organisms such as fish, crustaceans, bivalves and molluscs, this is disastrous: either they flee, or they die of oxygen starvation. Humans living on land barely notice any of this – with the exception of a few fishers whose fishing grounds have shrunk or shifted due to the expansion of the dead zone. The second major difference from land is that continuous sea areas extend beyond national borders or are even – like the high seas – international areas. Ocean sustainability can therefore only be achieved if numerous nations pull together. So today it is necessary to find new approaches for sustainable ocean use which are interna-tionally applicable above all else.
Critical limits in sightAn accessible approach that is currently inspiring the international sustainability debate, and which combines the terrestrial and marine realms, is the concept of planetary boundaries. To develop this concept, which was first published in 2009 in the scientific journal Nature and updated in 2015 in Science magazine, an international Swedish-led research team asked itself how potentially catastrophic environmental changes could be avoided in future. For this purpose they defined nine essential environmental dimensions, or Earth system processes, such as climate change, freshwater consumption or ocean acidification. For seven of these dimensions – based on existing and to some extent provisional calculations – the researchers were able to quantify critical limits. If these were exceeded, they say, it could result in grave global or regional environmental changes – with unforeseeable consequences for life on Earth. In the scientists’ view, this applies particularly to climate change and bio-diversity loss. In order to illustrate the potential hazards of crossing the thresholds, for every dimension three levels of risk are specified: the first is a zone of safety; the second is a zone of uncertainty or danger which indicates that the risk of grave effects is rising; and the third zone signals a high risk of grave effects or that such effects have already occurred. Large-scale extinction of different organisms, for example, is already taking place and is clearly irreversible.
2.4 > The planetary boundaries model makes it clear how excessively humankind is overusing resources. The different colours indicate the status of the individual environmental dimensions.
- Currently, according to researchers, the planetary boundaries or critical environmental limits are already being exceeded on four of the nine dimensions: biodiversity, the global phosphorus and nitrogen cycles, climate change and land use. If the situation is considered from a regional rather than a global perspective, limits are also being exceeded on other dimensions such as water consumption, e.g. in dry regions like the western USA, parts of Southern Europe, Asia and the Middle East. According to estimates by the International Union for Conservation of Nature and Natural Resources (IUCN), the persistent destruction of species-rich and near-natural habitats is accelerating the speed at which species – along with their genetic information – are being irretrievably lost. Compared with the fossil record, the extinction rate today is substantially higher. Historically, only one mammal species died out per millennium, for example. In the period from the 1970s until today, the rate was 100 to 1000 times higher. By the year 2050 it is likely to have risen once more by a factor of 10. A key reason for bio-diversity loss is the progression of land use. Forests con-tinue to be cleared to create farmland, e.g. in South America or in China and South East Asia. More intensive land use is likely to cause the worldwide area of forest and grassland to shrink by a further 10 to 20 per cent by 2050 – affecting many near-natural habitats along with the species they host. >