A holistic vision for our future deep ocean

Healthy oceans are essential to maintain a healthy planet, but the ocean is facing many challenges that need urgent attention. Robust scientific data and innovative technological, policy, and industrial solutions are essential to support sound management of the deep-ocean natural capital, both within and beyond national jurisdiction, to ensure future healthy and productive oceans. As with many systems on Earth, there is a delicate ecological balance in the deep ocean that must be maintained. Understanding the interactions of the different components of natural capital in the deep sea is complex, as many of the variables are interlinked and many have cumulative and synergistic effects on the ecosystem. Add to this the global and changing effects of climate change and ocean acidification, and legislators and managers have a tough job ahead to account for all of these issues when designing appropriate conservation measures. It is important that scientists work hand in hand with multiple stakeholders to identify issues and research needs that contribute to enhancing knowledge and the science needed for decision-making to help towards securing a healthy future for our deep-ocean ecosystems and their long-term natural capital.

Climate change cumulative impacts on deep-sea ecosystems

Climate models report that the environmental changes resulting from excess CO2 and heat absorption by the ocean already reach many deep-ocean margins, basins, and seas. Decadal monitoring programmes have confirmed significant warming and deoxygenation trends down to the abyss, which combine with CO2-enriched, more corrosive conditions. Although the resolution of current models does not account for the typical mesoscale seafloor heterogeneity, cumulative impacts on biodiversity and productivity hotpots are anticipated. The growing interest in deep-sea resource exploitation has shed light on the lack of knowledge about current climate-driven disturbance and potential cumulative threats at great depth. Assessing the sensitivity of deep-sea ecosystems to temperature increase combined with oxygen and resource decline is emerging as a growing challenge. The natural patchiness of deep-seafloor habitats and associated deep-sea diversity patterns inform about environmental constraints over space, but the temporal dynamics of these systems is not well known. Experimental studies are required to assess the physiological limits and explore the adaptation and acclimation potential of foundation species exposed to various forms of abiotic stress. The case of cold-water corals is particularly illustrative of the potential synergistic effects of climate stressors, including warming, acidification, deoxygation, and reduced food availability. Addressing ecosystem vulnerability also requires dedicated monitoring efforts to identify the current and future drivers of climate-change impacts on deep-sea habitats. United Nations policy objectives for protected high-sea biodiversity and healthy oceans and seas drive the momentum towards better climate-change forecasting over the ocean-depth range and related integrated observing strategies.

The deep ocean’s link to culture and global processes

The ocean covers a vast region of the planet and is often thought of as remote and poorly known. However, more than a century of research has made it clear that the ocean provides many beneficial and critical services to society, including a diversity of society–ocean interactions beyond what humans extract (or may extract) from it. The deep sea is no different; it provides a wealth of societal benefits that span the spectrum from inspiring art and captivating the mind to mitigating the rate of climate change through its connectedness with the Earth’s ecosystems. These processes and societal impacts fall within the broad category of ‘nonuse’ ecosystem services, or societal benefits that occur in addition to, or instead of, the services realised through resource extraction. Much like the surface ocean, while there is much more to discover, there is a significant body of information about the deep sea that has resolutely identified this environment as an important resource for nonuse benefits. In this chapter we give an overview of the nonuse services that are provided by the deep ocean, identify some of the advances to date on incorporating these values into the discussion of the natural capital of the deep, and highlight the challenges and opportunities that face incorporation of nonuse values into management-decision processes.

Space, the final resource

The greater than 109 km3 volume of the deep-sea water column and greater than 300 × 106 km2 area of the deep-sea floor represent a major natural capital asset. Global society has been utilising space in the deep ocean as a reservoir for solid, liquid, and hazardous waste produced by terrestrial-based societies, as a buffer that absorbs nonsolid, nonliquid industrial waste streams, specifically CO2 from fossil fuel and biomass burning, heat from a warming atmosphere, and as freely available and convenient space. High-value uses such as the deployment of transoceanic telecommunications cables provide substantial, near-term economic and societal returns with minimal environmental impact. Low-value uses of this natural capital as empty space to absorb waste have arguably enabled industrialisation to continue further along an unsustainable trajectory than would have occurred had there been no such waste buffer available.

The legal framework for resource management in the deep sea

The deep oceans and their protection, management, research, and resources are governed by a range of legal instruments. This chapter sets out the relevant legal framework for the deep oceans and discusses the role of scientists in ocean governance. The chapter introduces the law’s spatial zoning approach to marine governance and considers the role of coastal states in managing marine spaces and resources through domestic law. The chapter then offers a discussion of the international legal framework for deep-sea fishing, marine pollution, deep-sea mining, and marine scientific research, before analysing current gaps in the law relating to marine biodiversity in areas beyond national jurisdiction, as well as ocean fertilisation.

A primer on the economics of natural capital and its relevance to deep-sea exploitation and conservation

Marine science is now moving quickly to reveal the biophysical, geochemical, and ecological properties of the deep sea. As this understanding grows, deep-sea resources will begin to be exploited more extensively, embodying the hopes of many for a Blue Economy. Institutions to govern this exploitation are only just finding their strides or even just emerging, but there are many cases already of resource overuse and degradation, including overfishing and the impacts beginning to be wrought by a changing climate. Progress towards the sustainable development of the deep sea requires useful indicators that point to changes in human well-being as the deep sea is exploited, such as measures of inclusive wealth. Accounting prices for the natural capital of the deep sea would be useful indicators, and several examples are explored to illustrate current understanding and research gaps. A future economic research agenda would involve refining estimates of accounting prices for the most important types of deep-sea natural capital, locating these within linked classifications of ecosystem services and natural capital, and the design and implementation of a system of economic and environmental accounts for the deep sea comprising the high seas, which lies beyond the purview of individual states.

The exploitation of deep-sea biodiversity

Humans have been harnessing the natural properties of marine organisms for millennia—initially in their unprocessed form for sustenance, and more recently via extracted products as biomaterials, functional food ingredients, and medicines. As accelerating scientific and technological advances open up the deep ocean, potential avenues to exploit components and characteristics of marine biodiversity are revealed. To keep pace with such innovations and to promote equitable and sustainable activities, the international legal framework has evolved over recent decades to address the conservation and sustainable use of biodiversity, together with the sharing of benefits arising from the utilisation of genetic resources. Gaps remain, however, particularly for the deep, remote and technologically demanding ocean areas beyond national jurisdiction (ABNJ) that account for more than 60 per cent of the global ocean. The question of how to share benefits from marine genetic resources is one of the most contentious issues in ongoing negotiations for the development of a new international legally binding instrument for the conservation and sustainable use of marine biodiversity in ABNJ under the 1982 United Nations Convention on the Law of the Sea (UNCLOS). In this chapter, the potential exploitation of deep-sea biodiversity is considered, and the governance challenges associated with the sharing of benefits are discussed. Associated opportunities and challenges for the conservation and sustainable use of deep-sea biodiversity are discussed. The development of a new legal instrument under UNCLOS provides a central focus for the discussion in this chapter.

The natural capital of offshore oil, gas, and methane hydrates in the World Ocean

Over half of the global energy consumption is based on fossil fuels that are now mainly extracted from ocean depths below 150 m. These hydrocarbon reserves are thus a significant natural capital from deep oceans that support human well-being. Technological advances have guided the offshore deep-sea explorations to virtually all major ocean basins with thousands of wells being drilled on the deep seafloor to reach reserves that now support a significant part of the global markets. However, the environmental footprint of the oil and gas industry is significant and arises from regional impacts of regular operations on deep-sea ecosystems, from major disasters, or day-to-day accidents that spill millions of gallons of oil into the oceans each year, and from a significant contribution to greenhouse gas emissions and its climate effects globally. This is despite the general compliance with a wide array of environmental and political regulatory frameworks globally. The contrast from energy and market demand for fossil fuels against a background of environmental costs and impacts into the deep sea as exploration advances has not previously been examined. Here we apply the natural capital concepts of stock value of hydrocarbon reserves and contrast their financial and human value to the social and economic costs of their exploration and social costs from impacts on ecosystem services. We suggest that the economic value of hydrocarbon resources is very limited when compared to its vast environmental costs, supporting the global transition to a green energy strategy.

Deep-sea mining

Mining the extensive accumulations of minerals on the seafloor of the deep ocean might provide important resources, but it also has the potential to lead to widespread environmental impacts. Some of these impacts are unknown, and some may differ for the three main resource types: polymetallic nodules, seafloor massive sulphides, and polymetallic (cobalt-rich) crusts. Here, we detail the mining processes and describe the ecosystems associated with the minerals of interest. We then explain the expected impacts of mining, and discuss their potential effects on deep-ocean ecosystems. We also highlight the missing evidence needed to underpin effective environmental management and regulation of the nascent deep-sea mining industry.

Exploitation of deep-sea fishery resources

Deep-sea fisheries occur at depths between 200 and 1800 m, using bottom trawls, long lines, and occasionally pots and gillnets. These fisheries were of minor interest and value until the mid-1980s when large stocks of fish were discovered, mostly on high-seas seamounts. However, because of the life-history characteristics of deep-dwelling fish, most seamount fish stocks were soon overfished, and few have recovered. Total deep-sea fish catch since 1950 represents about 3 per cent of the global catch, yet the environmental harm caused to deep-sea bottom communities by bottom trawling is extensive and long lasting, far exceeding the value of the fishery. In response, the United Nations has passed several resolutions since 2004 requiring the establishment of regional fisheries management organisations (RFMOs) who would be responsible for setting catch limits for the target species and requiring actions that would limit the damage to the habitat by fishing gear. To date, the latter of these two requirements, at least, has not been successfully met.