The Ocean’s Potential to Combat Climate Change

Harnessing the ocean’s potential to combat climate change will help limit global warming to 1.5°C.
Reading Time: 8 minutes

Harnessing the ocean’s potential to combat climate change will help limit global warming to 1.5°C. Image Unsplash.

Reading Time: 8 minutes

Harnessing the ocean’s potential to combat climate change will help limit global warming to 1.5°C.

Research published by the UN IPCC in its Climate Change 2022: Mitigation of Climate Change report reveals the ocean’s potential to combat climate change. Findings show scalable ocean-focused initiatives could deliver over one-third (35%) of the annual emissions reductions required by 2050 to restrict global warming to 1.5°C.

The report underscores seven key opportunities to exploit the ocean’s potential to combat climate change. Not surprisingly, these are the same sectors where we must focus on land to make gains against climate change.

Renewable Energy

Expanding offshore renewable power from wind, waves, tidal, thermal, and algae offers the sizable potential to displace carbon-intensive fossil fuel electricity generation. The wind blows more consistently and stronger over the open ocean than over land, making offshore wind farms up to 60% more efficient than their onshore counterparts. Installing floating wind turbines further offshore allows access to even better wind resources. The UK and EU have led initial offshore wind development, and capacity is growing in China, the US, and across Asia.

Further growth in emerging ocean renewables can provide low-carbon energy to coastal populations. Wave power uses the motion of surface waves to generate electricity through buoys, pivots, or oscillating water columns built into coastal structures or seawalls. Tidal stream generators are underwater turbines spun by tidal currents, while ocean thermal energy uses heat differences between surface and deep waters to produce clean power through closed-cycle systems. Floating solar photovoltaics mounted on the sea surface avoid land-use changes while accessing reflected light from the water. Cultivating marine algae and seaweed can generate biomass for bioenergy and biofuel production with modest inputs and space requirements compared to land-based agriculture.

While most projects remain in pilot stages, industry experts suggest emerging ocean renewable technologies could expand from a few gigawatts today to provide up to 500 additional gigawatts by mid-century as projects scale up. Powering expanded electrification with offshore renewables avoids significant carbon emissions from equivalent fossil fuel generation. Locating projects near demand centers also reduces transmission losses, while synergies exist with offshore hydrogen production and hybrid wind-wave systems.

Public concerns over visual, acoustic, or ecological impacts must be addressed through careful siting, monitoring requirements, and community engagement. However, the sheer size of the potential resource and urgency of climate targets provide compelling incentives to develop this new industry.

Reduced Emissions from Shipping

International shipping transports over 80% of global trade and is responsible for nearly 3% of total greenhouse gas emissions – nearly equivalent to the total emissions of Germany. Heavy fuel oil burned in massive marine engines powers an estimated fleet of 95,000 cargo ships trading goods worldwide. Beyond CO2, sulfur-rich petroleum produces black carbon, nitrogen oxides, and heavy metals that degrade air quality. Growing shipping activity could see emissions climb 90-130% by 2050 under business-as-usual scenarios.

But technology and policy advances are transitioning seaborne trade to run on low or zero-emission fuels. Battery power is suitable for short routes, while hydrogen fuel cells, ammonia combustion, and methanol reformers can eliminate operational emissions from oceangoing freight on longer transoceanic shipping. Onshore power hookups allow vessels to plug into electricity grids while docked in port. Wind power can supplement propulsion needs through rotors, wing sails, and kites. The International Maritime Organization aims to halve greenhouse gas emissions from shipping by 2050, with ambitious proposals to achieve zero-emission transoceanic shipping as early as 2030.

While alternatives cost two to seven times more than regular fuels, tightening regulations on sulfur and carbon emissions improves relative competitiveness. Major ports like Los Angeles, Singapore, and Rotterdam now offer shore power connections and cleaner fuel supplies as standard practice. Companies like Amazon, IKEA, and Unilever are specifying low-carbon shipping for procurement contracts, while challenge programs aim to accelerate technology through competition.

Implementing known technical and operational efficiencies provide immediate opportunities to cut emissions. Simple measures like reducing speeds, optimizing routing, and autopilot upgrades can significantly reduce fuel consumption. Larger slow-steaming container ships, though counterintuitive, emit up to 40% less CO2 per container than smaller ships run at faster speeds. Retrofitting vessels with air lubrication, wind power, and waste heat recovery now have payback periods as short as 2-4 years from fuel savings. Digitizing fleet optimization and port operations through automation and real-time data also shows great promise.

Combined aggressively, these solutions can feasibly achieve zero or near-zero emission shipping by 2050, according to think tanks like the Getting to Zero Coalition. With over $2 trillion in new vessels expected in coming decades, decisions made today by ship financiers and charterers will lock in emissions trajectories for years to come. The societal payoffs are also huge – eliminating this sizable slice of emissions will be a major milestone in reaching carbon neutrality.

Sustainable Food Production

Wild capture fisheries and marine aquaculture supplied over 179 million tons of food in 2021 – a new record high. Seafood provides 17 percent of the global animal protein supply, feeding billions through both subsistence and commercial markets. However, overfishing diminishes carbon and nutrient cycling by removing fish biomass that would otherwise be recycled naturally through feeding or decomposition. Meanwhile, aquaculture production, which now exceeds wild fisheries, requires energy-intensive feed inputs, which drive deforestation from crop and oilseed demand. Feed production paired with direct energy use makes mariculture responsible for roughly 20% of emissions within the broader agriculture sector.

Shifting both wild and farmed seafood sectors toward sustainable production is critical for climate mitigation as well as long-term food security. Preventing overexploitation in capture fisheries preserves blue carbon stored in undisturbed vegetated coastal habitats while maintaining fish populations that regulate carbon cycling through respiration and nutrient releases. Transitioning one-third of current fisheries toward maximum sustainable yield could increase retained catch by over 15 million tons, according to fisheries experts, feeding more people while enhancing resource sustainability and carbon retention.

In aquaculture, improving feed conversion, farm management, and genetics can significantly curb emissions intensities. Fed species groups like salmon and shrimp emit nearly six times the emissions per edible gram raised versus unfed groups like bivalves and seaweeds, largely due to agricultural inputs like soy and fishmeal for high protein diets. Switching carnivorous species production to lower trophic level species, paired with partial substitutions of fishmeal and oils for algal meals, insect frass, and single-cell proteins, can reduce both land and ocean footprints. Optimizing energy use, feeding, oxygenation, and polyculture could cut mariculture energy usage and waste discharges. Selective breeding for fast growth and disease resistance also reduces required inputs.

Combined, fishery and aquaculture improvements provide important nutrition with lowered emissions intensities compared to meat proteins. Sustainably managed, local, small-scale fisheries contribute to poverty alleviation and climate resilience for vulnerable coastal populations most at risk of environmental change. Several countries now integrate climate and biodiversity goals within ocean food production planning.

Decarbonizing Tourism

Tourism linked to ocean and coastal environments has boomed in recent decades with continued rising demand. Island vacations, cruise ship travel, recreational boating, and nature tours attract visitors while driving economic growth valued at over $400 billion annually. However, this rising affinity for getaways centered around beaches, charismatic megafauna, and underwater adventures drives significant carbon footprints. Transportation emissions alone have doubled since 2000 as affordable air travel and cruise ship expansions opened access for growing middle-class consumer segments across Asia and South America.

Cruise ships, in particular, emit carbon dioxide at nearly double the rate per passenger mile compared to flights, according to sustainability analysts. An average cruise ship carrying 5000 people, including crew, generates over 10 tons of carbon dioxide daily – equivalent to 800 compact cars. Expanding capacity has seen emissions triple since 1990. The “all-inclusive” cruising model also promotes overconsumption with lavish buffets and entertainment. Port communities face infrastructure demands and waste management impacts at terminals. Underwater noise pollution, reef damage from anchors, and tide turbulence disturb fragile marine habitats already threatened by warming and acidification.

However, the cruise industry has lagged behind other tourism sectors in embracing environmental standards and transparency. Major lines only recently began assessing and reporting even basic fuel usage and waste generation benchmarks for their fleets. Criticism over “floating cities” dumping pollution has spurred marginal emission reductions, but systemic changes are needed to achieve low-impact, zero-emission models. Transitioning to renewable hybrid engines using biofuels, fuel cells, or batteries paired with solar, wind, and other innovations offers potential pathways for meeting climate goals. Size reductions, optimized design, and automation can further improve efficiencies. Portside wastewater treatment, incentive fees, and raised environmental criteria for permitting also help curb impacts at origin.

Ecotourism built around experiences fostering education and conservation offers regenerative alternatives aligned with climate goals. Visitor fees directly support habitat protections while linking inland communities to resources supporting resilience. Interpretive programs cultivate connections, sparking behavior shifts back home. Non-intrusive wildlife encounters, green boating practices, and low-impact diving reinforce sustainability.

Voluntary carbon labeling schemes like those from the Cruise Lines International Association also allow consumers to support operators investing more in sustainability. However, regulation and access to finance may ultimately be needed to force the higher upfront costs of deep decarbonization. Companies worldwide face major asset stranding if unable to meet climate policy requirements. Transforming ocean leisure travel to run cleanly before Mid-century is critical both for operators’ licenses to grow and for reducing tourism’s rising climate burden.

Reducing Offshore Oil and Gas Extraction

Burning fossil fuels from offshore oil and gas production releases both carbon dioxide during combustion and fugitive methane emissions from leaks in production and transit infrastructure. These emissions warm the climate at many times the rate of carbon dioxide, according to the latest climate science. Petrostates like Saudi Arabia, Russia, and Qatar also depend heavily on hydrocarbon revenues – linking continued offshore production to geopolitical conflicts that slow progress on climate cooperation.

While onshore fields provide over two-thirds of the global oil supply, offshore sources generate growing shares as new major discoveries shift production offshore over past decades. Brazil’s pre-salt basins, U.S. shale wells in the Gulf of Mexico, mega-projects off Australia, and Canada’s region of the North Atlantic account for where most new drilling investments target.

Avoiding additional offshore production aligned with energy transition roadmaps has become a priority for groups like the International Energy Agency. Analysis shows no need for new oil and gas fields – whether onshore or offshore – if we are to stay within carbon budgets limiting warming to 1.5°C. Existing wells paired with efficiency and renewables can meet declining demand. Demonstration projects testing plugging, repurposing, and remediating decommissioned platforms also showcase how oil and gas infrastructure can aid or convert to renewable energy in some cases.

The magnitudes of emissions clearly depend on where and how offshore production occurs. For example, shallow wells in sensitive Arctic regions like Alaska’s Cook Inlet pose higher ecological risks from spills while facing extraction challenges from pack ice and extreme weather. The carbon intensity of offshore production also depends heavily on whether fuels used to power offshore rigs and operations come from zero-emission sources like renewables or directly from extracted gas and crude. However, when including total life cycle emissions from downstream combustion, avoiding new offshore development delivers substantial climate progress.

A a managed slowdown of offshore oil and gas is feasible without severe market disruptions or job losses if paired with major investments in offshore wind, carbon capture, and hydrogen, but the pace of transition must align workforce transfer programs providing retraining, early retirement provisions, and mobility support for impacted communities. For example, Norway’s offshore sector agreements struck between government, companies, and unions provide templates for balancing sustainable blue economies with energy transitions.

Getting climate strategies right requires addressing all emissions – even seemingly essential offshore industries. Well-designed policies and strategic economic diversification of regional economies can ease shifts that benefit society and workers. Keeping offshore oil and gas in the ground avoids additional climate damage while spurring innovations in specialist vessels and infrastructure needed for accelerating offshore renewables and new energy carriers like hydrogen. These and other steps curb emissions at their source while offering realistic pathways for managed drawdowns – buying time and options for nascent carbon removal technologies to scale up.


The IPCC report highlights key areas across ocean systems that combined offer over 35% of needed annual emission reductions by 2050 to meet 1.5°C climate targets. Offshore renewables, sustainable fishing and shipping, and managed offshore oil and gas phase-outs all play major roles in achieving net zero. While projections always have uncertainty, the magnitude of solutions warrants prioritizing collaborative efforts between governments, industry, and civil society stakeholders in advancing an ocean climate agenda.

Maintaining the ocean’s crucial mitigation role requires coupling emission reductions with the conservation of blue carbon stocks like mangroves, salt marshes, and seagrass that sequester and store atmospheric carbon. Networks of climate-smart Marine Protected Areas enhance ecosystem and evolutionary resilience to withstand mounting climate impacts. Vulnerable developing island and coastal countries also need support through adaptation finance and technology transfers to reinforce both natural and societal adaptive capacities.

While no singular solution can address the climate emergency alone, the findings spotlight the ocean’s pivotal and still untapped role needed within a broader whole-of-society strategy. Offshore renewables, sustainable fisheries and shipping, constrained oil and gas alongside blue carbon, resilient coasts, and marine conservation provide a toolkit. With ambition, investment, and cross-sectoral collaboration, the report outlines an optimistic path where healthy ocean systems can meaningfully support worldwide decarbonization efforts. The ultimate takeaway is clear – the ocean is part of the cure.

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