ocean-climate nexus

oceans aware: inform, inspire, involve

the more you know about the ocean the more you can do to protect and restore it

The Earth’s temperature is rising steadily as a direct result of anthropogenic, or human, activity. Since the beginning of industrialization in the mid-18th century, humans have emitted more than 2,200 gigatons of carbon dioxide (CO2), not to mention the other greenhouse gases such as methane or nitrous oxide, and the world is on track to warm by about 2.5 °C by the end of the century. Only recently has the role of the ocean and the impact of climate change upon it been recognized: we now know that the ocean has absorbed about 25% of CO2 emissions and 93% of the excess heat, saving us from an average estimated rise in temperature on land of 36 °C (see the Grantham Institute Briefing paper No 14). But not without cost: the physical and chemical balance of the ocean changes as it takes on both additional CO2 and heat, causing marine habitats to suffer, particularly the fragile ecosystems of the polar, tropical and coastal zones, and slowing the great ocean conveyor belt.

See NASA’s time machine to see how climate indicators are changing

From the excess heat, we see

warming oceans;
melting sea-ice and icebergs;
rising sea levels;
increasing storm intensity; and
growing areas of deoxygenation.

From the excess carbon, we see:

higher levels of ocean acidification.

Scientists have recently raised concerns that climate change is slowing the thermohaline circulation (the great ocean conveyor belt that takes about 1,000 years to move a drop of water arond the planet): as CO2 emissions increase, the ocean temperature rises and sea-ice melts, with more freshwater entering the ocean the salinity and therefore density of the water is reduced, meaning that the downwellings at the poles are also reduced. This slows the thermohaline circulation and reduces the ocean’s capacity to absorb more CO2, meaning that more CO2 will enter the atmosphere, causing ocean temperatures to rise faster, sea-ice to melt faster, thermohaline circulation to slow further, and the ocean’s capacity to absorb carbon dioxide to diminish further. A vicious circle if ever there was one.

Data on the meridional overturning circulation has been collected by the RAPID/MOCHA/WBTS team using arrays of mooring to measure its variability over more than 20 years. The Atlantic meridional overturning circulation (AMOC) carries 1.2PW (a petaWatt is a million-billion Watts) of heat northwards in the ocean – a quarter of the combined global atmosphere-ocean poleward transport and equivalent to the power output from 1.2 million power plants.

Figure illustrating the horizontal (gyre) and vertical (AMOC) circulations in the Atlantic today (left) and in a warmer world (right). The Gulf Stream is a warm current composed of both circulations. Source: IPCC (2021) FAQ 9.3, Figure 1.

On the one hand, the ocean is suffering as a result of climate change. On the other it could be our strongest ally in fighting climate change, indeed, the ocean’s capacity to take up greenhouse gas emissions and heat from the atmosphere means that ocean-based climate solutions could reduce the emissions gap by as much as 35% by the year 2050. The Ocean Breakthroughs were launched by the Marrakech Partnership for Global Climate Action with the support of the UN Climate Change High-Level Champions in 2023. These are transformative pathways covering five key ocean sectors (marine conservation, ocean renewable energy, shipping, aquatic food, and coastal tourism) where accelerated action and investments could help unlock the potential of the ocean as a source of solutions to the challenges posed by climate change and biodiversity loss, contributing to a resilient, nature-positive and net zero future by 2050.

Matt Curnock/Coral Reef Image Bank
More than 80% of the global ocean experienced a marine heatwave at some time in 2020. 2023 saw the highest ocean temperatures since record keeping began in the 1880s. 60% of coral reefs are currently under threat. According to the World Resources Institute, at the current rate of ocean temperature rise coral reefs will no longer exist by 2050.

Rolf Gelpke/Unsplash
According to NASA, ocean levels are currently rising at the rate of 3.4 mm a year. and are expected to have risen by between 26 and 98 cm by 2100.
The Arctic is regarded one of the fastest-warming regions worldwide and is said to be heating at three times the global average. Antarctica has been losing an estimated 150 billion metric tonnes of ice every year since 2002.

Danijel Durkovic/Unsplash
The United Nation’s ‘The Climate Crisis – A Race We Can Win’ states that 90% of disasters are now classed as weather and climate-related, costing the world economy €430 billion each year.
The United Nations High Commissioner for Refugees (UNHCR) reports that since 2008, an annual average of 21.5 million people have been forcibly displaced by weather-related hazards such as floods, storms, wildfires or extreme temperatures each year.

UNFCCC and the ocean

L.Filipe C.Sousa/Unsplash

Back in 1972, when the United Nations Conference on the Human Environment was held in Stockholm, climate change was certainly not on the political agenda. Over the years this has slowly changed: the Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) to provide policymakers with regular assessments of scientific papers related to climate change from all over the world, aiming to provide a comprehensive summary of what is known about the drivers of climate change, its impacts and future risks, and how adaptation and mitigation can reduce those risks. The IPCC now has 195 members and representatives of their governments meet at least once a year. The IPCC secretariat is based at the WMO in Geneva.

In 1994, the United Nations Framework Convention on Climate Change (UNFCCC) (the parent treaty of the Kyoto Protocol (1997) and the Paris Agreement (2015)) was adopted with the goal of preventing dangerous interference of humans with the climate system. With regular meetings of its 197 parties (so-called COPs or conferences of the parties), much progress has been made on the international level:

there is now a global recognition of the need to restrict temperature rise to less than 2 °C (and preferably 1.5 °C);
net-zero emissions (where a State emits less carbon than it captures, usually by both reducing fossil fuel consumption and offsetting carbon emissions by planting trees or developing areas which are natural carbon sinks, such as wetlands, mangroves or seagrass beds) has become a goal for many States; and
civil society, inspired in particular by the younger generations, has started to hold governments and companies to account for policies which do not support these goals.

Nevertheless, fossil fuel consumption is still rising - and with it emissions and temperatures. We currently emit around 40 billion tons of CO2 a year. Policies currently in place point to a 2.8 °C temperature rise by the end of the century. To stay within the 1.5 °C goal, a 55% reduction in emissions is needed before 2030. The International Energy Agency estimates that we also need to capture 350 million metric tons of CO2 per year by 2030, for example by using traps at the end of industrial smokestacks or directly from the air. We captured just 35 million tons in 2019—less than 1% of what we emit annually. Much more needs to be done if we are to combat climate change and turn its devastating effect on our planet around.

The role of the ocean was largely absent in the climate conversation for many years, making its formal debut in the preamble to the Paris Agreement, which recognizes the importance of ensuring the integrity of ocean ecosystems, in only 2015. While failing to embed the ocean in the main text of the agreement, the 21st Conference of Parties to the UNFCCC (COP21) did however issue the first Because the Ocean declaration, proposing three major steps with relation to the ocean:

that the IPCC prepare a Special Report on the Ocean and Cryosphere;
that a high-level UN Ocean conference be convened in support of the implementation of SDG14; and
that an Ocean Action Plan be created within the UNFCCC.

At COP22 in Marrakech in 2016, the Strategic Action Roadmap on Oceans and Climate: 2016-2021 was published on Oceans Action Day and the Roadmap to Oceans and Climate Action (ROCA) set up to advance the oceans and climate agenda in particular at the UNFCCC but also at the national level in all countries. In 2017, the Ocean & Climate Platform (a French coalition of research institutes, NGOs, higher education institutions, aquariums, representatives of the private sector and French and international institutions) launched the Ocean and Climate Initiatives Alliance (OCIA) to consolidate and coordinate actions linking ocean and climate, and to ensure a connection between the UNFCCC and voluntary actions globally. The OCIA presented its first report, Measuring Progress on Ocean and Climate Initiatives: An Action-Oriented Report, at COP23 in Fiji in 2017. The Ocean Pathway, also launched during COP23, called attention to the critical links between the ocean and climate change.

The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate was released in 2019 at the 51st Session of the IPCC in Monaco. More than 100 authors from 36 countries assessed the latest scientific literature related to the ocean and cryosphere (those parts of the Earth which are frozen) for the report, referencing about 7,000 scientific publications. With this report the role of the ocean in climate change was finally fully recognized, establishing it on the IPCC agenda as an important tool in CO2 capture, finding that:

“strongly reducing greenhouse gas emissions, protecting and restoring ecosystems, and carefully managing the use of natural resources would make it possible to preserve the ocean and cryosphere as a source of opportunities that support adaptation to future changes, limit risks to livelihoods and offer multiple additional societal benefits.”

Later in 2019, the Because the Ocean Initiative released its report Ocean For Climate: Ocean-Related Measures in Climate Strategies ahead of COP25 (originally organized in Santiago de Chile but held in Madrid). The results of what was heralded as the ‘Blue COP’ did not meet expectations. However, united under the umbrella of the Ocean Pathway, delegates did manage to include the ocean in the final decision of COP25, with a call for the UNFCCC Subsidiary Body for Scientific and Technological Advice (SBSTA) to include ocean science issues on its official research agenda.

In December 2020, the first Ocean and Climate Change Dialogue took place organized by SBSTA. In April 2021, the Chair of the Subsidiary Body for Scientific and Technological Advice of the UNFCCC released a summary report on ‘Ocean and climate change dialogue to consider how to strengthen adaptation and mitigation action’, concluding that:

“the ocean provides multiple untapped and powerful opportunities to mitigate and adapt to climate change. The tools are available to generate multiple benefits that go beyond climate benefits. Collaborative action is needed to move forward with the work of leveraging those tools in a sustainable and environmentally and socially sound manner… The broader context remains the connectivity between the existential crises of declining ocean health, nature loss and climate change that we face today. Urgent integrated action is needed to respond to climate change and protect and restore nature, and with that, to secure our health, our ocean’s health and our planet’s health.”

COP26 and the ocean

Stephen O’Donnell/Unsplash

COP26, held in Glasgow, UK, in November 2021, was not the success many were hoping for but it was certainly bluer than all previous conferences of the UNFCCC Parties. The recognition of the impact of climate change on the ocean and the role that ocean-based solutions can play in addressing the crisis was an important and welcome step but the inability of conference participants to make substantial progress in meeting the 1.5 °C target of the Paris Agreement was disappointing. According to The Times, before the Paris Agreement the world was on track for 6 °C of warming, this came down to 4 °C after Paris. In the run-up to Glasgow, the pledges submitted took it down further to 2.7 °C and over the course of the two-week summit this fell again to 2.4 °C. There is a ray of hope: if all the net-zero pledges made in 2021 are enacted we could be on track for 1.8 °C.

Some significant steps were taken at the conference. With its thematic approach and one day of the conference dedicated to the ocean (Ocean Action Day), the meeting clearly established the link between ocean action and climate action. Neglected in the past in the final texts of the conferences, the ocean was included in both the preamble to the Glasgow Pact as well as in the main body of the text. The pact recognizes the importance of the role of the ocean in mitigation. It emphasizes the importance of:

“protecting, conserving and restoring nature and ecosystems, including forests and other terrestrial and marine ecosystems, to achieve the long-term global goal of the Convention by acting as sinks and reservoirs of greenhouse gases and protecting biodiversity, while ensuring social and environmental safeguards;”

invites the relevant work programmes and constituted bodies under the UNFCCC to:

“consider how to integrate and strengthen ocean-based action in their existing mandates and workplans and to report on these activities within the existing reporting processes”

and calls on the Chair of the Subsidiary Body for Scientific and Technological Advice to hold:

“an annual dialogue, starting at the fifty-sixth session of the Subsidiary Body for Scientific and Technological Advice (June 2022), to strengthen ocean-based action and to prepare an informal summary report thereon and make it available to the Conference of the Parties at its subsequent session”.

It can be safely said that COP26 ensured that the ocean-climate nexus is included in the main agenda of future UNFCCC COPs rather than being dealt with on the sidelines.

Other important developments and funding initiatives were announced during the conference were:

20 countries signed the third instalment of the Because the Ocean Declaration, which called on states to integrate ocean, climate and biodiversity linkages in their plans to implement the Paris Agreement.
100 signatories from civil society organizations, the private sector and academia called for governments to include ocean conservation initiatives within their formal commitments to reduce emissions in the Ocean for Climate Declaration.
US$145 million in funding was announced for the Global Funds for Coral Reefs.
$20 million was committed towards supporting nature-based solutions and vulnerable communities at the Ocean Risk and Resilience Action Alliance roundtable.
Western Indian Ocean States and partners including the IUCN launched the Great Blue Wall initiative to establish a network of marine and coastal conserved areas to benefit biodiversity and local livelihoods, empowering communities to become stewards of the ocean.
A new MPA in the Eastern Tropical Pacific involving Colombia, Costa Rica, Ecuador and Panama was announced.
Fiji announced its plan to issue a sovereign blue bond in 2022.
Belize pledged to develop a pioneering “project finance for permanence” scheme for marine protected areas (MPAs), conservation and coastal ecosystems.

COP27 and the ocean

Matthew TenBruggencate/Unsplash

COP27 was held in Sharm El-Sheikh, Egypt, and attended by nearly 33,500 people. While the decision to establish a fund for loss and damage made the headlines, much criticism was levied at negotiators’ attempts to go back on agreements made in Glasgow. A push to agree on text setting 2025 as the peak for emissions was far from acceptable to all and the pulse of 1.5 °C, already described as weak in Glasgow, was weakened further. The final decision of COP27 retained the Glasgow Climate Pact’s call to phase down unabated coal power and phase out inefficient fossil fuel subsidies but failed to go further.

Building on the momentum of COP26, the ocean‘s role as a key player in the climate conversation was confirmed, with a pavillion dedicated to it in the blue zone and multiple ocean-related side events.

The outcome document, the Sharm el-Sheikh Implementation Plan, includes the following, in particular the fact that States were encouraged to consider appropriate ocean-based action in their national climate goals:

“XIII. Ocean

45. Welcomes the outcomes of and key messages from the ocean and climate change dialogue in 2022 and decides that future dialogues will, from 2023, be facilitated by two co-facilitators, selected by Parties biennially, who will be responsible for deciding the topics for and conducting the dialogue, in consultation with Parties and observers, and preparing an informal summary report to be presented in conjunction with the subsequent session of the Conference of the Parties;

46. Encourages Parties to consider, as appropriate, ocean-based action in their national climate goals and in the implementation of these goals, including but not limited to nationally determined contributions, long-term strategies and adaptation communications;”

Additional outcomes from the meeting were as follows:

ten shipping organizations and green hydrogen producers committed to produce and deploy at least five million tons of green hydrogen by 2030;
Belgium, Colombia, Germany, Ireland, Japan, the Netherlands, Norway, the UK and the US joined the Global Offshore Wind Alliance (GOWA), founded at COP26;
the Mangrove Breakthrough was launched, with an investment target of $4 billion to support conservation of 15 million hectares of mangroves by 2030;
the Netherlands introduced the Champions Group for Deltas and Coastal Zones, aiming to harmonize action between countries and small island states to realize sustainable management of deltas and coastal zones in the short and medium-term;
the Egyptian presidency, Germany and IUCN launched the ENACT initiative (Enhancing Nature-based Solutions for an Accelerated Climate Transformation);
the Great Blue Wall initiative was supported by East African countries to create a transboundary marine protected area and blue economy collaboration;
the government of Egypt declared a 2,000 square km marine protected area, thereby protecting all Red Sea coral reefs;
the High Quality Blue Carbon Principles and Guidance were also announced.

COP28 and the ocean

Adam Schulz/Unsplash

Generally the ocean fared well at COP28, held in Dubai, UAE, from 30 November – 12 December 2023. The launch of the Ocean Breakthroughs ahead of COP28, provided the ocean community with a rallying point for pushing for ocean action and investments to deliver on climate goals, key to success at the next climate conferences. During the meeting numerous ocean-related pledges were made (such as the Bezos Earth Fund pledging $100 million to support Pacific islands to restore and protect their coastal ecosystems, and to strengthen community-based fisheries management and conservation, or the establishment of the Coral Reef Breakthrough by the International Coral Reef Initiative with an investment of $12 billion to help protect at least 125,000 square kilometres of shallow-water tropical coral reefs) and the outcome text of the meeting, the Global Stocktake, makes several references to the importance of protecting and preserving the ocean and coastal ecosystems and calls for a “strengthening of ocean-based action.”

Ocean Panel: Top Ocean Moments at COP28

Back to blue initiative: COP28: Mainstreaming the ocean agenda

COP29 will be held in Azerbaijan in 2024 and COP30 in Brazil in 2025.

The capacity of the deep ocean to store carbon - and the enourmous impact that mining or dredging the seabed will have - are discussed in this informative webinar, Policy Perspectives on the Deep Ocean under Climate Change, organized by the Deep Ocean Stewardship Initiative as part of their anniversary series. It is well worth a watch!