The Ocean Can Play a Bigger Role in Fighting Climate Change than Previously Thought

With climate extremes dominating the global news cycle in 2023, from record heat both on land and at sea to devastating wildfires and floods around the world, the need to address climate change is more apparent and urgent than ever.

But one of the most promising areas for climate action has been largely overlooked and underinvested to date: the ocean.

New research commissioned by the High Level Panel for a Sustainable Ocean Economy (Ocean Panel) shows that ocean-based climate solutions can deliver up to 35% of the annual greenhouse gas emission cuts needed in 2050 to limit global temperature rise to 1.5 degrees C (2.7 degrees F) — the threshold scientists say is necessary to avert the worst outcomes from climate change. This represents a significant increase from previous estimates, which put the ocean’s potential emissions reductions at around 21% of the total needed by 2050.

This research is based on solutions that are ready to implement and economically viable today. But while investments in a sustainable ocean economy are seen to be profitable — with data showing that investing $1 in key ocean actions can yield at least $5 in global benefits, often more, over the next 30 years — finance for these solutions has largely been lacking to date. Countries must substantially increase investments in the necessary technology and infrastructure if we are to take full advantage of the ocean’s ability to help tackle the climate crisis.

Here are seven key opportunities for ocean-based climate action that can deliver substantial emissions cuts alongside social, economic and environmental benefits for coastal communities:

1) Scaling Ocean-based Renewable Energy

Ocean-based renewable energy is a major area of opportunity with ready-to-implement solutions — including offshore wind as well as floating solar and tidal power — which could slash greenhouse gas emissions by up to 3.60 gigatonnes per year in 2050. That’s more than the total combined emissions for all 27 EU member states in 2021. Increasing deployment of renewables will also be critical to meeting global energy demand as the world works to phase out coal and other fossil-based energy sources.

This potential is more than theoretical, with investment in ocean-based renewables already ramping up significantly. Global pledges in offshore wind have approximately doubled in the last four years, bringing targeted deployment to up to 2000 GW (enough to power approximately 1.5 billion homes annually) by 2050. And certain countries are leading by example: Norway, for instance, is home to the world’s largest fully operational floating offshore wind park, Hywind Tampen. It has also allocated areas for 30 GW of offshore wind power production by 2040 and announced a competition for offshore wind production in two areas on the Norwegian continental shelf: Sørlige Nordsjø II (3000 MW) and Utsira Nord (1500 MW).

To accelerate this transition at a global scale, countries must set ambitious national targets in their upcoming 2025 climate commitments (NDCs) to increase the share of renewable power in the energy mix. They must also provide a stable economic and regulatory framework to stimulate investments in supporting infrastructure for ocean-based energy systems. This includes reducing barriers in scaling up offshore wind turbines (both fixed and floating) as well as investing in new, innovative ocean-based energy sources, such as floating solar photovoltaics, wave power and tidal power, that can help meet the world’s energy needs while minimizing harm to surrounding marine environments.

2) Reducing Emissions from Ocean-based Transport

Currently, the international shipping industry carries about 80% of the world’s trade between nations; if counted as a country, it would be among the world’s top-10 largest emitters. In a bid to align more closely with global climate goals, the International Maritime Organization (IMO) recently revised its emissions-reduction strategy, setting a target to reach net zero “by or around” 2050 according to “national circumstances.”

While some progress has been made toward decarbonizing ocean-based transport over the last decade — primarily through energy efficiency measures such as redesigning and refurbishing ships to reduce fuel use and lower emissions — meeting the sector’s net-zero goals will require much more investment in both existing and emerging low-carbon shipping solutions.

Shipping companies must enhance efforts to increase operational and logistical efficiencies, such as reducing the speed of vessels and taking weather conditions into account when planning routes. At the same time, companies and governments will also need to step up investments in new zero-emission fuel technologies, such as those made from hydrogen and ammonia, as well as supporting infrastructure, including  fuel storage and processing facilities. Taken together, these solutions could lower shipping emissions by up to 2 gigatonnes per year in 2050 — equivalent to taking over 400 million cars off the road every year.

3) Conserving and Restoring Coastal and Marine Ecosystems

Healthy “blue carbon” ecosystems such as mangrove forests, seagrass meadows and tidal marshes are powerful carbon sinks that can store up to 5 times more carbon per area than tropical forests and absorb it from the atmosphere about 3 times as quickly. This makes them an important — though often overlooked — ally in tackling the climate crisis.

Beyond their ability to remove and store carbon from the atmosphere, these ecosystems also offer myriad co-benefits that can support sustainable development and climate resilience, particularly in vulnerable coastal areas. They sustain economies through fisheries and tourism, provide crucial habitat for diverse marine species and help enhance freshwater quality, all while buffering coastal communities from the impacts of increasingly extreme weather events like cyclones.

However, blue carbon ecosystems are disappearing at a rapid pace, driven by the “coastal squeeze” between climate-driven impacts (including sea level rise and extreme weather events) and development of coastal areas. Action to address and reverse this degradation has been woefully inadequate to date.

Enhanced efforts to conserve, restore and sustainably manage blue carbon ecosystems can contribute significantly to global climate targets — removing greenhouse gas emissions equivalent to 76 coal-fired power plants per year in 2050 — while also helping achieve the goals of the Convention on Biological Diversity (including 30 by 30) and the UN’s Sustainable Development Goals.

4) Expanding Sustainable, Ocean-based Food Production

As the global population rises, so, too, will the need food and protein sources. The ocean can play a key role in meeting this need with a wide range of sustainable seafoods — such as algae, fish and invertebrates like shellfish — which are less land intensive and require fewer resources to produce than options like beef and lamb. Incorporating these “blue” foods into global diets not only diversifies protein choices but could also reduce global emissions by up to 1.47 gigatonnes per year in 2050, comparable to removing 393 coal fired power plants annually.

However, while these foods are common in some cultures, awareness and use of them remains limited at a global scale and prices are sometimes prohibitively high for consumers. More must be done by governments and industry to raise awareness, send clear policy signals (such as subsidizing these foods) and invest in an enabling environment to take advantage of this opportunity.

Some countries are starting to do this. Australia, for example, is investing AUD $70 million (US $45 million) in the Blue Economy Cooperative Research Centre to bring together expertise in aquaculture, marine renewable energy and marine engineering as part of a collaborative effort between industry, researchers and the community. It aims to develop innovative and sustainable offshore industries to increase Australian seafood and marine renewable energy production.

5) Leveraging the Ocean’s Potential for Carbon Removal and Storage

The latest climate science recognizes that, in addition to deep emissions cuts across all sectors, meeting global climate goals will require removing some of the carbon that’s already been emitted into the atmosphere. Alongside restoring blue carbon ecosystems which absorb CO2 naturally, ocean-based carbon removal approaches, including marine carbon dioxide removal and carbon capture and storage in the seabed, have sparked interest globally in recent years.

Carbon capture and storage involves harvesting carbon from the atmosphere through direct air capture or waste combustion and pumping the liquified carbon into chambers below the seabed, where it can be stored permanently. These methods are currently more mature than marine carbon dioxide removal techniques and could provide up to 1 gigatonne of emission reduction potential in 2050 if current deployment trajectories continue.

Marine carbon dioxide removal includes a range of techniques such as ocean alkalinity enhancement, where alkaline minerals are added into the ocean to alter its chemistry and increase carbon uptake, and ocean nutrient fertilization, which spurs massive algal blooms that take up huge amounts of carbon. These strategies show promise, but are currently only at concept, prototype or early demonstration stages of development. Prior to scaling marine carbon dioxide removal, thorough research on the ecological and socio-economic impacts of these techniques must be conducted in addition to addressing policy and governance questions.

While research into ocean-based carbon removal technologies should be accelerated, it should not be a reason to delay solutions that are already viable and ready to implement today — such as offshore wind, marine ecosystem restoration and conservation and increasing low-carbon food from the sea.

6) Decarbonizing Ocean-based Tourism

Coastal and marine tourism represents at least 50% of total global tourism. It also constitutes the largest economic sector for most small island developing nations and many coastal ones. But, while critical to these countries’ economies, cruise tourism is also a considerable polluter: One recent study found that a large cruise ship can have a carbon footprint greater than 12,000 cars. Cruise ships also emit other pollutants besides carbon dioxide — such as sulfur oxides, nitrous oxides and particulate carbon — that can harm marine ecosystems as well as human health.

In the near term, efforts to reduce emissions from ocean tourism should start with improving the efficiency of ships, such as through investing in net-zero fuels and decreasing ship resistance in the water. Policies promoting fuel efficiency and the use of alternative fuels (such as liquefied natural gas and other bio and synthetic hydrogen-derived fuels) are also needed to drive investment and development at the global, regional and national levels and enable long-term emissions reductions throughout the sector. Successfully decarbonizing ocean-based tourism could deliver 0.1 gigatonne of emissions reduction potential in 2050 — equivalent to the annual emissions of 251 natural gas-fired power plants.

7) Reducing Offshore Oil and Gas

The world cannot tackle the climate crisis without drastically reducing fossil fuel production and consumption. Phasing down offshore oil and gas offers the largest opportunity for ocean-based climate action, with the potential to eliminate up to 5.30 gigatonnes of greenhouse gases annually in 2050, equivalent to taking about 1.1 billion fossil-fuel cars off the road each year. This assumes that energy demand formerly supplied by fossil fuel generation can be met by a parallel increase in zero-emission energy sources (such as ocean-based renewables).

To help accelerate this transition, governments can withdraw fossil fuel subsidies in countries which currently provide them; enact legislation and/or regulations to ban routine flaring (a method and current practice for disposing of large unwanted amounts of associated petroleum gas); stop new licensing for offshore oil and gas extraction; and invest public finance in energy security and access for the most economically vulnerable communities.

Investing in the Ocean as a Climate Change Solution

These ocean-based climate solutions could potentially exceed one-third of the total emissions reductions needed to meet global climate goals — but that’s not all. They can also contribute to the development of a sustainable ocean economy and may come with a wide range of co-benefits, including protecting coastal communities from storms, providing jobs, protecting biodiversity and improving food security.

However, these benefits can only be realized if investments are made in developing the technology and infrastructure needed for full implementation. Fulfilling the ocean’s potential in emissions reductions will require at least $1 trillion of additional finance between now and 2030, increasing toward $2 trillion between 2030 and 2050.

These investments must be applied intelligently across each sector to maximize impact. Where finance is already available (for example with offshore renewable energy), it needs to be fully directed toward strategies that align with net-zero pathways. Where funding is scarce, such as is the case for blue carbon solutions, de-risking, guarantees and blended finance can help by making investing in these solutions more attractive.