When Arvid Pardo, a Maltese diplomat, took the floor at the United Nations General Assembly in New York in 1967 and began speaking at length on international law, the room was sparsely populated. Pardo was undeterred.

The deep, dark ocean, he said, is the womb of life. “We still bear in our bodies—in our blood, in the salty bitterness of our tears—the marks of this remote past.” With technology fast progressing, “man, the present dominator of the emerged earth, is now returning to the ocean depths. His penetration of the deep could mark the beginning of the end for man, and indeed for life as we know it on this Earth; it could also be a unique opportunity to lay solid foundations for a peaceful and increasingly prosperous future for all peoples.”

Pardo argued that the deep seafloor falls outside the territory of any state. As humanity raced to exploit the “immeasurable wealth” already known to be hiding there, Pardo said that wealth should be viewed as the common heritage of humankind.

At a time when countries around the world were grappling with the Cold War along with the lingering consequences of colonization and exploitative resource extraction, Pardo’s treatise struck a nerve. After all, who should have access to the deep? Who should benefit from its wealth?

His speech—later characterized by historians as a “you should have been there” moment—set the stage for nearly a decade of negotiations. Eventually, those discussions resulted in the United Nations Convention on the Law of the Sea (UNCLOS) containing this language: that any industrial activity on the international seafloor must “be carried out for the benefit of mankind as a whole.”

Today, with deep-sea mining companies closing in on mineral-rich rocks called polymetallic nodules, policymakers at the International Seabed Authority (ISA)—the intergovernmental body that governs activities on the seafloor in international waters—are still grappling with the challenge passed down by Pardo. If the resources on the international seafloor are the common heritage of humankind, as UNCLOS states they are, then what, exactly, does that mean? With little to no precedent to rely on, and with the reality of deep-sea mining inching ever closer, the ISA and its member states are in the process of figuring out how to make deep-sea mining work for all of humanity.

At a practical level, this huge responsibility is in the hands of just 15 people—the state representatives who make up a working group at the ISA, uninspiringly called the Finance Committee. The Finance Committee meets in private, with limited public reporting of its deliberations. Observers have called for the Finance Committee to have greater transparency.

According to an ISA technical study, the Finance Committee is currently exploring two main options for sharing financial benefits. One involves distributing any leftover proceeds from deep-sea mining to world governments, with countries that have large populations and low incomes getting more money than smaller, wealthier ones.

Crucially, the money being disbursed would be what’s left after the mining company and its sponsoring state have made their profits, after the administrative costs of running the ISA have been accounted for, and after any compensation is paid out to countries negatively affected by mining.

In its own analyses, the ISA uses US $500-million as a benchmark for discussing how to equitably share benefits among nations. But one independent economic forecast estimates that the actual amount available for benefit sharing could fall between $14-million and $228-million each year. That study found that countries like India could receive about $1-million annually, while Pacific Island nations, such as Kiribati, might receive as little as $7,500.

The ISA’s second option to make deep-sea mining benefit all of humanity involves channeling the leftover proceeds into a fund that could be used to pay for scientific research and address the environmental harms caused by seabed mining.

The risk with this approach, says Aline Jaeckel, an expert in deep-sea mining regulations at the University of Wollongong in Australia, is ensuring the money genuinely benefits humanity, rather than being used to clean up the problems created by deep-sea mining itself.

But both approaches, says Jaeckel, miss the bigger picture. The deep sea is home to an incredible amount of life—much of which has yet to be discovered by scientists, let alone fully understood.

Recently, a treatment for brain cancer was sourced from microbes living on the ocean floor, while enzymes found in bacteria near hydrothermal vents were used to develop tests for COVID-19. Even polymetallic nodules—the very objects deep-sea miners covet—may play a role in oxygenating the deep ocean. Narrowly focusing on the financial benefits of deep-sea mining, says Jaeckel, misses what else the deep sea already provides, or could provide in the future.

The ISA’s approaches to interpreting the deep seafloor as the common heritage of humanity also fail to leave room for Indigenous rights to the deep sea. In some countries, terrestrial mining operations are required to financially benefit local Indigenous communities. But the benefit-sharing mechanisms currently under discussion at the ISA do not specifically account for the people who might be most directly affected by seabed mining, such as those from Pacific Island nations. Instead, it’s up to states to compensate people who might be particularly affected by mining.

Neil Craik, an expert in international environmental law at the University of Waterloo in Ontario, says that with so much uncertainty around the environmental consequences of seabed mining, and limited information on the economic benefits, “one of the big questions states must ask themselves is if [seabed mining] is worth it.”

Earlier this year, Leticia Carvalho, a Brazilian oceanographer and environmental policy expert, took the helm of the International Seabed Authority (ISA) as secretary general. The ISA, an intergovernmental body that governs what happens on the seafloor in international waters, is responsible for an area that spans more than half the planet.

One of the agency’s key roles is in deciding the future of deep-sea mining, a nascent industry targeting tennis ball–sized rocks called polymetallic nodules. Rich in cobalt, nickel, and other valuable metals, polymetallic nodules can be found in some areas of the seafloor, most notably in the Clarion-Clipperton Zone, a vast tract between Hawai‘i and Mexico.

In a landslide victory, Carvalho unseated Michael Lodge, an English lawyer who had served as the ISA’s secretary general since 2016. Lodge’s tenure at the international body—which is tasked with the contradictory goals of both helping deep-sea mining get off the ground and keeping it in check—was marred by allegations of bribery, corruption, and of Lodge having an undue bias toward the mining companies the ISA oversees, all of which Lodge has vehemently denied. Many environmentalists and scientists welcomed the news of Lodge’s displacement.

In the wake of her win, Carvalho told Mongabay that she aims to rebuild trust in the ISA, and in Politico she said she planned to investigate the corruption and mismanagement allegations. But Carvalho’s term does not seem set to bring about the kinds of sweeping changes that would satisfy the 32 countries that have called for a pause on the development of deep-sea mining—including Canada, New Zealand, and Costa Rica—or those, like France, pushing for an outright ban.

For years after the ISA’s inception in 1996, environmentalists, mining industry representatives, and government delegates gathered at the agency’s seaside headquarters in Kingston, Jamaica, to develop the Mining Code—the set of rules and regulations that will govern everything about deep-sea mining from who is allowed to mine to how they will mine, and even the way the industry’s proceeds will be disbursed to, somehow, benefit all of humanity. For 25 years, deep-sea mining was a distant reality. Negotiations were easygoing, and those gathered in Jamaica would mingle at weekend retreats and dance parties.

All that changed in 2021 when representatives from Nauru, a Pacific Island nation, triggered a clause in the United Nations Convention on the Law of the Sea (UNCLOS) known as the “two-year rule.” The move meant that, suddenly, the ISA had only two years to either finish the Mining Code or consider a company’s application to exploit the seafloor with whatever unfinished rules it happened to have in place.

Three years later, no company has yet applied for an exploitation permit. But the triggering of the two-year rule sparked a flurry of contentious debates over the legal and environmental implications of deep-sea mining. With so much still under discussion, Julian Jackson, an ocean governance expert from the nonprofit Pew Charitable Trusts who has closely followed the negotiations, says the Mining Code is still months—or even years—from being finished.

“The ISA needs to be upfront with itself about where we are in this process,” he says.

Despite this, Carvalho says she expects member states to finalize the Mining Code by 2025.

Doing so will not be easy. To finish the Mining Code, negotiators must agree on—and draft into legalese—decisions that will have widespread consequences for sensitive deep-sea ecosystems, such as those in the Clarion-Clipperton Zone. They’ll also have to develop a system to ensure that the profits from deep-sea mining are distributed in a way that benefits all of humanity, as required by UNCLOS. Figuring out what that means and how it will work is just one of the daunting decisions facing negotiators.

Throughout 2024, the ISA worked overtime grappling with unanswered questions around the environmental impacts of mining. For instance, countries have not fully resolved what counts as “serious harm” to the marine environment, much less what level of harm regulators are willing to permit.

To finish the Mining Code, “a lot of compromises need to be made,” says Pradeep Singh, a legal expert on the law of the sea at the Research Institute for Sustainability in Potsdam, Germany.

Yet with negotiations nowhere near an end, the question becomes: what happens if a company submits an application to mine the deep?

The two-year rule requires the ISA to consider mining permits using its current draft regulations. Under normal circumstances, the Legal and Technical Commission, a closed-door body within the ISA, holds significant power to decide whether to approve or reject a mining application. But the ISA’s council, which represents 36 of the ISA’s 169 member states, recently implemented new safeguard measures. The council decided that if a mining application comes in before the regulations are finalized, the council will determine what procedures to put in place to review the application, rather than the Legal and Technical Commission.

The most likely candidate to test this unresolved process is the Metals Company (TMC), a mining company based in Vancouver, British Columbia. Despite initially triggering the two-year rule, TMC—along with its sponsoring state, Nauru—have so far held off on submitting a mining application. That will likely change in June 2025.

Aquaculture is big business in Canada. In 2023, open-net-pen salmon farming in British Columbia alone produced 50,000 tonnes of fish worth just over US $350-million. But on June 30, 2029, the federal government’s long-looming ban on open-net-pen salmon farming is set to take effect. On that day, 63 operations will be forced to shut down.

For decades, BC’s open-net-pen salmon farmers have faced criticism that their activities are harming the environment by promoting the spread of disease and fostering parasitic sea lice that can infect wild salmon. But closing a salmon or other kind of marine farm isn’t as simple as letting a field lie fallow.

Whether degraded by poor maintenance, battered by heavy storms, or beset by financial woes, aquaculture operations have gone under before—sometimes literally. And when they do, derelict equipment can find its way to the seafloor or become suspended in the water column.

“It’s pretty devastating,” says Ben Boulton, the program manager of British Columbia’s Rugged Coast Research Society, a charity that works with the provincial government and First Nations to clean up marine debris specifically from shellfish farms. These efforts have often involved smaller mom-and-pop oyster operations that lost gear to the ocean floor years or decades ago.

“You come upon a mound of gear that is seemingly infinite—a huge mess everywhere you look,” he says. Abandoned nets, ropes, buoys, concrete blocks, plastic buckets and trays, PVC pipes, generators, steel anchors, iron rebar, floats, gangways, docks, drums, tires, and polystyrene foam can all linger, threatening the marine environment.

During one disturbing stint at a derelict operation on northern Vancouver Island, for instance, workers with the nonprofit Ocean Legacy Foundation found that a group of river otters had started building dens inside the polystyrene foam from decaying floats and were eating the marine life growing on it.

The federal government is more optimistic that open net-pen salmon farmers in 2029 won’t leave an environmental mess.

Multinational companies dominate salmon farming in British Columbia and are “quite professionalized and generally highly compliant” with regulations, says Brenda McCorquodale, the senior director of the Aquaculture Management Division at Fisheries and Oceans Canada (DFO) on the West Coast. “We’re not anticipating there’d be some sort of abandonment of infrastructure.”

Boulton’s experience with shellfish aquaculture, however, emphasizes the importance of vigilance. “There’s a need for oversight—a third party, for sure—on sites to supervise the decommissioning,” he says.

Cleaning up an abandoned or derelict aquaculture facility is dirty, dangerous, expensive work. Photo by Deep Search Diving

Nico Prins, the executive director of the British Columbia Shellfish Growers Association, says government oversight of marine debris issues at shellfish facilities has historically been lax. “I’ll be honest with you,” he says, “the level of enforcement probably hasn’t been what was required or what has been needed.”

“I know there are plenty of shellfish farms that are in a pretty bad state of repair,” Prins adds. “There’s a lack of … government regulators to achieve enforcement of the conditions.”

In recent years, the government has been trying to make a dent in the problem, working to clean up sites and prevent more farm owners across British Columbia from cutting their losses and walking away from nets, floats, and other equipment. But cleaning up ocean debris requires money—and lots of it.

British Columbia government regulations require licensed aquaculture operations, including salmon farms, to outline their future debris management plans and post a security deposit to cover cleanup. But the amount set aside, Prins says, can fall short of what’s required. In the past, some purchasers of farm sites have also inherited the costs of removing the accumulated mess. Otherwise, taxpayers can wind up paying the price.

In 2020, the province launched Clean Coast, Clean Waters, an initiative that has so far spent roughly $35-million to remove more than 2,100 tonnes of marine debris and 215 derelict vessels from the province’s coast. The program tackled the first two derelict aquaculture sites in 2024.

The Rugged Coast Research Society, says Boulton, specializes in cleaning up remote and hard-to-reach parts of the coast. The organization’s process of trash removal starts with using a remotely operated vehicle—equipped with a camera and grabber claw—to survey the site. Often, they’ll complement this visual search with side-scan sonar to identify hotspots of trash and map out targets. From there, four commercial divers work in limited visibility and at risk of entanglement to rig up gear for removal. Then, they’ll use a hydraulic crane to haul the material to the surface to be cleaned, sorted by type, and brought to shore. Typically, about half the haul is repurposed or recycled, with the rest going to landfill. Depending on the depth of the water, the weather, and the tides, divers may have only a few minutes to work.

“It’s a very challenging industry,” says Dylan Smith, the owner of BC-based Deep Search Diving.

Since 2020, Smith’s company has been contracted by governments or private operators to survey 92 shellfish farms, half of which he’s already cleaned up. Typically, the company’s services cost between $7,000 and $35,000—but they can climb as high as $70,000 if a lot of gear has drifted beyond the reach of divers.

The work is taxing but rewarding, says Boulton. “It takes months to get these projects going, then you end up in the field. It’s a lot of labor, very dirty. But seeing a barge fully loaded up with debris from a site—our crews feel a sense of relief and accomplishment.”

Tossing money at debris cleanup is one thing, but changing future behavior is another.

Over the past five years, DFO has launched several initiatives targeting marine debris, including a mandatory tagging program to more easily identify who owns aquaculture equipment that goes rogue, and containment measures to prevent foam flotation from breaking free.

One of the big game changers occurred in 2022 when federal regulations began forcing aquaculture operators to hire divers or use remotely operated vehicles to survey the seafloor for old gear within their operating areas and document its removal. The goal, says McCorquodale, is to make license holders “responsible for knowing what’s going on underneath their sites and keeping the area clean and free of debris.”

As the world increasingly turns its attention to the environmental woes caused by ghost nets, microplastics, and other forms of marine debris, increased scrutiny of the hidden costs of aquaculture on the ocean environment couldn’t come at a better time.

One of the biggest mistakes novice children’s book writers make is to assume that a story must teach something. An overt message—share, don’t be a bully, eat your veggies—can make for a boring book. There can, of course, be a lot to learn in children’s books, but it takes a deft hand to avoid being didactic. Several of this season’s marine-themed books tackle big subjects—death, extinction, fear, even a lost toy (a monumental disaster for some). But in the hands of these skilled writers and illustrators, any takeaway messages are secondary to a good story well told. First and foremost, these creators offer rich language, characters and places to care about, and beguiling adventures. Along the way, they help us learn something, too.

Dive, Dive into the Night Sea
Text and illustrations by Thea Lu
32 pp. Candlewick Studio

Life After Whale: The Amazing Ecosystem of a Whale Fall
Text by Lynn Brunelle
Illustrations by Jason Chin
48 pp. Neal Porter Books

It Bears Repeating
Text by Tanya Tagaq
Illustrations by Cee Pootoogook
24 pp. Tundra Books

Pau: The Last Song of the Kaua‘i ‘Ō‘Ō
Text and illustrations by Tony Piedra and Mackenzie Joy
40 pp. Candlewick Press

Have You Ever Heard a Whale Exhale?
Text by Caroline Woodward
Illustrations by Claire Victoria Watson
32 pp. Pownal Street Press

Sea Snooze
Text by Sarabeth Holden
Illustrations by Emma Pedersen
32 pp. Inhabit Media

Super Ocean Weekend: The Ultimate Underwater Adventure
Text and illustrations by Gaëlle Alméras
172 pp. Greystone Books

My Bunny Lies Over the Ocean
Text by Bill Richardson
Illustrations by Bill Pechet
36 pp. Running the Goat Books

As humanity works to slash greenhouse gas emissions and stem the pace of planetary warming, scientists, governments, and industry leaders are looking for low-carbon alternatives to fuel the future. Alongside renewables such as solar and wind energy, hydrogen gas is bubbling to the forefront as a fuel of choice—especially for energy-intensive processes like forging steel.

However, the carbon footprint of hydrogen gas is not necessarily as tiny as proponents argue. According to new research led by Kiane de Kleijne, who studies the environmental impacts of new technologies at Eindhoven University of Technology in the Netherlands, hydrogen’s climate friendliness ultimately depends on many factors, not least of which are where and how the hydrogen is produced.

Today, most hydrogen gas is made from natural gas using a chemical process called steam reforming. This hydrogen—known as “grey hydrogen”—is highly polluting; for every kilogram of usable hydrogen gas produced, the process spits out emissions equivalent to 13.7 kilograms of carbon dioxide. A slightly better option is “blue hydrogen,” for which hydrogen gas production is coupled with a carbon capture and storage system. This can theoretically bring emissions down to around six kilograms of carbon dioxide per kilogram of hydrogen gas. However, carbon capture technology is expensive and largely unproven; it rarely reaches even modest levels of capture.

What’s really got experts’ attention is “green hydrogen,” which results when renewable energy—think solar or wind—is used to electrically split water into hydrogen and oxygen gases through a process known as electrolysis. The International Energy Agency, an intergovernmental organization, and many national governments claim that projects powered by green hydrogen produce no greenhouse gas emissions. This has spurred a flurry of subsidies from governments around the world designed to get the green hydrogen industry off the ground.

But green hydrogen isn’t free of carbon emissions just because electrolyzing water produces little planet-warming pollution. To get a true take on the environmental footprint of hydrogen gas, it’s important to consider the toll of everything else that goes into making and using it, such as building renewable energy and electrolysis infrastructure, storing the hydrogen, and shipping it around the world. These factors are collectively known as embodied emissions.

Government “policies are not designed with embodied emissions in mind,” says de Kleijne. But “if we don’t count them, we don’t see them.”

To get a better sense of the future footprint of the budding green hydrogen industry, de Kleijne and her colleagues estimated the embodied emissions that will likely result from the more than 1,000 green hydrogen projects planned to be built worldwide by 2030. The scientists analyzed each plant’s proposed design and electricity source and the emissions stemming from different methods of transporting hydrogen gas. Many projects, for instance, plan to ship their hydrogen gas by first converting it to liquid ammonia and then converting it back to hydrogen gas on the other end. But this conversion is energy intensive, and up to 30 percent of the hydrogen is lost in the process.

At best, de Kleijne and her team find that green hydrogen production creates around 2.9 kilograms of carbon dioxide–equivalent pollution for each kilogram of hydrogen gas produced. Then, depending on whether the gas is transported by pipeline or ship, add on another 1.5 or 1.8 kilograms of carbon pollution.

If these embodied emissions were included in official calculations, de Kleijne says, it would be difficult for many proposed green hydrogen projects to meet climate-related targets, such as the European Union’s renewable fuel threshold, which requires hydrogen fuels to produce less than 3.4 kilograms of carbon dioxide per kilogram of hydrogen to qualify as a clean fuel.

Mark Winfield, who studies sustainable energy and climate change at York University in Ontario, says the study reinforces the warning already being sounded by many scientists and environmentalists about green hydrogen. “Emissions can pile up through the life cycle, so we might not end up as far ahead as we thought,” Winfield says.

In general, de Kleijne says, green hydrogen will always be cleaner than grey and blue hydrogen, which also face the same challenges around embodied emissions. However, even within green hydrogen production, the analysis shows that some approaches are much greener than others.

The scientists find that the biggest differences between green hydrogen plants stem from the type of renewable energy used to power the electrolysis and how the plant is configured. Wind power is generally better than solar because building wind turbines has a lower carbon cost than deploying solar panels. And a green hydrogen plant connected to the wider electricity grid—meaning it can send any extra electricity it produces back to the grid—is better than a stand-alone facility.

Another big factor in determining the climate-friendliness of a particular facility is how far the plant is from the end user and how the hydrogen gets to them. Pipelines have the lowest emissions over short distances, while shipping is better over longer distances. “Avoiding transport is one of the most important conditions,” de Kleijne says, so building the plant near where the hydrogen will be used is key.

Zane McDonald, executive director of the industry-associated Open Hydrogen Initiative, says the hydrogen production industry is acutely aware of the need to account for embodied emissions; that’s why his group is developing a standardized method for estimating a project’s emissions. The goal, says McDonald, is to offer project leaders ways to reduce embodied emissions. There’s a strong financial incentive to do so. McDonald notes that in the United States the 45V tax credit, which supports the development of green hydrogen projects, gives more credit to cleaner projects.

“Having a policy that benefits you for investing in decarbonization measures—and erodes the competitive advantage of organizations that do not—is how we can ensure that organizations will start to make these investments,” McDonald says.

Winfield says de Kleijne’s work underlines the need to look at hydrogen production on a project-specific basis rather than making blanket assumptions about its green credentials. There will be times and places where renewable energy–powered hydrogen gas production will be a good option. But often, Winfield says, using renewable electricity to make hydrogen that will then be transported around the world just introduces extra unnecessary steps.

“We should do direct electrification where we can and only bother with hydrogen if there is a good use case that makes sense,” he says.

De Kleijne agrees. “If you can electrify something with renewable energy directly, just do that.”