UNFCCC COP25 Briefing

Date: 1st December 2019

In December 2019, government leaders and states will gather for the UNFCCC COP 25. This COP follows hard on the heels of the IPCC* Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC) and has been described as the ‘Blue’ COP by Sebastián Piñera, the President of Chile.

As yet, the interaction between the ocean and climate has not been officially recognised within global processes such as the UNFCCC.  Policies, targets and assessments which should recognise the ocean do not do so, in relation to:

  • climate mitigation, e.g. carbon sequestration;
  • ocean impact, e.g. acidification and heating;
  • exacerbation, e.g. re-release of carbon.

The ocean and climate work together as part of the Earth System of our planet. Because of the close links between the two, the ocean has borne the brunt of the climate crisis, standing between humanity and its worst impacts. It has absorbed most of the excessive heat and much of the excessive carbon dioxide but at a cost which is detrimental to its health and our survival. It is time these essential services were reflected at the global level and with an acute awareness of solutions necessary to preserve the role of the ocean in mitigation and other services.

Holding heating to 1.5o C is crucial for the ocean and this target can only be achieved through states committing to more ambitious Nationally Determined Contributions (NDCs) in 2020.

At present, however, the level of ambition shown by countries in their domestic climate change plans (NDCs) are taking us towards 3oC. All states will need to raise the level of ambition significantly.


The Madrid Climate Change Conference runs from 2nd – 13th December and will include the 25th session of the Conference of the Parties (COP 25) to the UNFCCC and meetings of the UNFCCC subsidiary bodies.

When in Santiago, Heads of State were scheduled to attend on 2nd December with the High-Level Segment (Ministers) attending on 10-11th. The schedule for Madrid is pending confirmation.

The pre-sessional period will be from 26th November to 1st December 2019.

The formal agenda for COP25 has already been set and does not include the ocean. It is as yet unclear how the COP will be ‘Blue’ as conceived by the Chilean government, which retains the Presidency of the event, despite the change of location.

The PreCOP was held in Costa Rica in October and was attended by approximately 2000 people, including civil society representatives, negotiators, government officials and environmental ministers from 30 states. Some 90 states sent official delegations.

Although the importance of the ocean was raised at the PreCOP, it remains unlikely that it will find an official platform at COP 25.

The PreCOP side events were grouped under three categories: (i) nature-based solutions; (ii) sustainable cities; and (iii) the ocean. The ocean events were focused on the role of the ocean in mitigating climate change.

The main conclusions from the ocean events were:

  • the need to take ocean science into account for climate action;
  • the need for capacity building in developing countries;
  • the importance of coordination among the different available legal instruments to ensure proper climate action and protection of key ecosystems (i.e. High Seas Treaty and MPA targets);
  • better recognition for the role of the ocean as a climate solution.

In relation to the last point, it should be noted that only a healthy ocean can provide this service and that the impact of climate breakdown on the ocean remains a key concern which needs far greater focus. In addition to its climate mitigation function, we need a healthy ocean for its many other services to humankind and it is important that these are not overlooked.

* The IPCC is a scientific body. It reviews and assesses, at regular intervals, the most recent scientific, technical and socioeconomic information produced worldwide, relevant to the understanding of climate change. The UN Climate change process receives the outputs of the IPCC and uses IPCC data and information as a baseline on the state of knowledge on climate change in making science-based decisions. 


Prof. Alex Rogers – University of Oxford

“Climate breakdown is impacting the entire ocean through heating, acidification and deoxygenation. The changes are unpredictable and there are continuous surprises for scientists, including the recent increase in marine heatwaves. Unless CO2 emissions are limited to prevent heating of more than 1.5C, we will see increasingly extreme and less predictable consequences for the ocean as tipping points are passed.”

Dr. Lucy Woodall – University of Oxford

“The impacts of climate breakdown such as sea level rise, acidification and ocean heating are causing massive transformations in the ocean. From the shallow coastal reefs to the deepest ocean, as scientists we witness and document these effects on all parts of the planet. The ocean controls many of our planetary processes, so the consequences of climate breakdown on the ocean must be considered when we debate the health of the planet. They are one and the same.”

Prof. Jason Hall-Spencer- University of Plymouth

“Human carbon dioxide emissions are speeding up the sixth mass extinction of life on this planet by causing sea level rise and coastal habitat loss. Surface seawater warming and acidification are killing tropical coral reefs and hypoxic events are causing ecosystem collapse.”

Rémi Parmentier, Secretary of The Because the Ocean Initiative.

“Action has to be taken to hold warming at 1.5 degrees Celsius. We need to see all states commit to more ambitious NDCs and go further to prevent the climate crisis from deepening and irreparably damaging the ocean upon which all life depends. Climate breakdown has brought the ocean to a crisis. Undermined by multiple stressors from overfishing to pollution, the effect of CO2 absorption and heating have had a life-threatening impact on the blue heart of our planet. Words are not enough at COP25; we need life-saving action.”


Three factors have been found in every mass extinction event in Earth’s history, heating, acidification and deoxygenation. Climate breakdown is creating all these factors in the ocean now:




Prof. Dan LaffoleyIUCN Global Marine and Polar Programme

“The IPCC report showed us all that the ocean is critical to life on Earth. It helps regulate our climate and provides conditions for life – if it gets too warm species die, if it gets too cold species also die. The ocean keeps conditions just right for life on Earth. What the IPCC report shows is that we are pushing that ocean – our ocean – to dangerous limits, and that matters, not just to us, but to all life on Earth.”


The ocean has absorbed 93% of the excess heat trapped by human-emitted greenhouse gases since the 1970s. This has tempered global heating but has caused the temperature of the ocean to rise, with multiple knock-on effects including deoxygenation.

Since the 1970s the average global sea surface temperature has risen at a rate of 0.11˚C per decade and a total rise of approximately 1˚C since pre-industrial levels. Long-term effects have been detected at a depth of 700m.

Even incremental heat changes can have a profound effect on ocean chemistry, ecosystems and sea levels. If all the heat absorbed by the ocean since the 1950s was suddenly added to the atmosphere, air temperatures would soar by around 36oC.

The rate of ocean warming has more than doubled since 1993.

By 2100 the ocean will have absorbed 2 to 4 times more heat than between 1970 and the present if global temperature rise is limited to 2˚C, and 5 to 7 times at higher emission scenarios.

Ocean heating impacts include:


Accelerated sea level rise

Sea level rise is projected to continue beyond 2100, even if greenhouse gas emissions are significantly reduced.

During the 20th century sea levels rose globally by approximately 15 cm.

Sea levels are currently rising more than twice as fast as during the 20th century at a rate of 3.6 mm/year.

Reduced ocean mixing

As the ocean heats, there is increased stratification (layering of water of different salinity and density) in the upper layers, resulting in reduced movement of nutrients from deeper layers.

Reduced biodiversity

Heating and associated deoxygenation are driving the extinction of vulnerable species and causing non-native species from different biogeographic regions to spread beyond their range and become established across the ocean.

Weather changes

Warmer waters are bringing more frequent marine heatwaves – periods of extreme warm sea surface temperature that persist for days to months. There is also evidence of a recent increase in global wave power as a consequence of oceanic heating.

Increases in tropical cyclone winds and rainfall, and increases in extreme waves, combined with rising sea levels, will exacerbate extreme sea level events and coastal hazards.

El Niño and El Niña events are projected to become more frequent, bringing more extreme weather events.

Marine heatwaves are projected to increase in frequency, extent, duration and intensity and since 1982 have doubled in frequency.

Acceleration of polar ice melt

Redistribution of important ocean species

Ocean heating has already begun to cause a change in distribution of many marine species including invertebrates, fish and marine mammals. This will lead to local extinctions and cause permanent changes.

Impacts on coral reefs

Since the 1980s, rising sea surface temperatures due to global heating have triggered unprecedented mass bleaching of corals, including three pan-tropical events in 1998, 2010 and 2015/16.



Prof. Jason Hall-Spencer- University of Plymouth

“Human carbon dioxide emissions are speeding up the sixth mass extinction of life on this planet by causing sea level rise and coastal habitat loss. Surface seawater warming and acidification are killing tropical coral reefs and hypoxic events are causing the ecosystem collapse.”


Today, the ocean absorbs over one million tonnes/1 billion kg of CO2 from the atmosphere every hour and as the CO2 dissolves in seawater, it forms carbonic acid and decreases the pH of the ocean, driving the water towards acidity.

Between 20% and 30% of human-induced emissions have been absorbed by the ocean since the 1980s, causing ocean acidification.

The massive increase in our carbon emissions means that this chemical process is happening on an unprecedented scale, causing what is collectively known as ocean acidification.

Ocean acidification is now occurring about 10 times faster than anything experienced over the last 300 million years. It is expected to increase by 170% by 2100 if things continue as they are, causing sweeping changes to the chemistry of seawater and threatening marine life.

Without the ocean absorbing CO2 , the rate and severity of climate change would be far greater.

Many sea creatures – including mussels, clams, coral, oysters and certain phytoplankton and zooplankton species – require calcium carbonate to build their shells and skeletons, a process disrupted by acidification.

As these species are at the bottom of marine food-webs, the effects ripple up to fish, seabirds and marine mammals. Declining harvests attributed to ocean acidification are already being reported, for example in the US Pacific Northwest’s oyster industry.

The world’s coral reefs, already under existential threat from ocean heating, are also severely impacted by ocean acidification, with many corals and calcifying algae unable to adapt to changing.

Ocean acidification will accelerate as long as concentrations of atmospheric CO2 continue to rise. The long-time lags of the marine carbon cycle make urgent action to cut CO2 emissions even more imperative if we are to avert the worst, most destabilising consequences.



Mirella von Lindenfels – Director, International Programme on the State of the Ocean

“How will we breathe if the ocean cannot? Half our oxygen comes from the ocean and it is running out of breath. A robust High Seas treaty in 2020 is an essential step towards protecting the ocean and increasing its resilience to climate breakdown.”


Oxygen is vital to life in the ocean. As the sea temperature rises, oxygen becomes less soluble via a process known as deoxygenation.

Reduced oxygen levels in coastal areas are associated with the run-off of nutrients from fertilisers and sewage and this is being exacerbated by global heating and is now affecting the open ocean.

Between 1970 and 2010 the open ocean lost 0.5 to 3.3% of oxygen overall from the ocean surface to 1000 m.

Low oxygen waters are described as hypoxic. Hypoxic water has oxygen concentrations below 2mg per litre – a level so low that it is detrimental to most organisms and very few species can survive. Since 1950, more than 500 coastal sites have reported oxygen concentrations below this level.

In the open ocean, oxygen-minimum zones have expanded by 4.5 million km2 – about the same size as the European Union.

Between 1970 and 2010 oxygen minimum zones in the open ocean increased by 3-8%.

Impacts of deoxygenation on the ocean include:

  • reduced growth and reproduction, altered behaviour, and increased disease and mortality in marine animals;
  • increased mortality of corals and associated fauna;
  • amplification of ocean acidification because increased respiration by marine organisms increases CO2, and
  • a contribution to global heating (due to the microbes that proliferate at very low oxygen levels producing more nitrous oxide – a powerful greenhouse gas).

Global heating driven by rising greenhouse gas emissions is having a pervasive and accelerating effect on the ocean. The most direct impact is the heating of the ocean itself, which recent studies show is occurring faster and deeper than previously thought.


Climate breakdown is profoundly damaging the ocean, attacking numerous aspects of marine life and function, and fundamentally eroding the health and resilience of the ocean and the services it provides to us all.

We cannot currently prevent the ocean impacts caused by climate breakdown – the heating, acidification, sea-level rise and deoxygenation – but we can take measures to protect the ocean from the stressors we can control, and to boost its resilience, health and immune system:


30 X 30

State parties to the legally binding Convention on Biological Diversity will negotiate new targets to protect biodiversity at a meeting in 2020. The target for marine biodiversity should be to protect at least 30% of the ocean through implemented highly and fully protected areas, with the remaining 70% of the ocean sustainably managed.

Prof. Callum Roberts – University of York

“Current conservation ambitions fall far short of what is needed to keep our planetary life support network functioning. Expanding full protection from extraction and harm to at least 30% of the ocean by 2030 will help recover endangered marine life, rebuild healthy ecosystem function and resilience, mitigate the effects of climate change and help wildlife and people adapt to change. It’s time for a shift from a losing battle to save nature, to using nature to help save ourselves.”

Linda Nowlan – Marine Project Lead, West Coast Environmental Law

“The recent IPCC report makes it crystal clear that the time for ocean action is now – and success will depend on political will and strong legal tools implemented around the world. The proposed new global goal of protecting at least 30% of the ocean by 2030 is well within reach. The world is on the right track with recent progress on both the quantity of new marine protected areas (MPAs) as well as a new focus on the quality of protection. Legal innovation will accelerate the adoption of solutions that are close at hand – from international climate rules to high seas treaty negotiations that will influence national, provincial and local ocean laws. Let’s turn the tide!”

Lance Morgan, President of Marine Conservation Institute.

“Healthy, functioning ocean ecosystems are a critical and neglected part of the solution to climate change; we need to dramatically accelerate creation of fully protected areas from the meager 2.2% in existence today to the 30% that scientists recommend.”

High Seas

The High Seas – the area beyond the national jurisdiction of any state, which makes up half the planet and two-thirds of the whole ocean – should be protected under international law. A new treaty is being negotiated at the United Nations and states should complete this in 2020 in line with a UN General Assembly resolution.

A robust treaty will provide a strong legal process for the designation, effective management and enforcement of a network of protected areas and measures to ensure that proper environmental impact assessments are carried out, as well as ensuring that the treaty is supported by a global decision-making body, an independent scientific committee and adequate financing.

Peggy Kalas – Coordinator, High Seas Alliance

“The importance of protecting the biodiversity of the whole ocean cannot be overstated, it is essential in combatting climate breakdown and maintaining the life support system that makes our planet habitable. Currently two thirds of the ocean, almost half the planet, falls outside the protection of law and that’s why it is so important that we secure a new, robust high seas treaty in 2020.”

Ocean Resilience

We are taxing the health and immune system of the ocean through multiple stressors. Bringing an end to overfishing and pollution in all its forms and preventing further biodiversity, ecosystem and habitat loss are essential measures within our reach.

Tony Long – CEO, Global Fishing Watch

“We know that overfishing, one of many pressures, has severely weakened our ocean’s immune system, diminishing its ability to withstand the impacts of the climate crisis. We also know that ending overfishing will contribute to mitigating these impacts. Stamping out illegal fishing, in particular, is one of the most immediate and do-able actions the world can take to strengthen the ocean, making it more capable of withstanding climate breakdown.” 

Dr. Craig Downs – Haereticus Environmental Laboratory

“Where deoxygenation is occurring, it is creating dead zones in our ocean. There are things we can do immediately to reduce the impact of deoxygenation such as reducing pollution and such approaches are vital we if are going to help the ocean maintain its life-giving functions.”

Dr. Miriam Goldstein – Director of Ocean Policy, Center for American Progress

“For too long, we’ve tried to fight oceanic plastic pollution by trying to change consumer behaviors. But it’s become increasingly clear that, like climate change, the real driver of ocean pollution is the petrochemical industry. The solution for our climate and our ocean is the same – a rapid investment in a 100% clean energy future that creates good jobs, ends toxic contamination of impoverished communities, and protects the habitats we live in.” 

Monica Verbeek – Executive Director, Seas At Risk

“The IPCC special report on the ocean highlighted how much the climate crisis has already impacted the ocean. A healthy ocean with abundant wildlife is capable of slowing the rate of climate breakdown substantially. The biggest impact on the marine environment so far has come from overfishing.  Ending overfishing is a quick, deliverable action which will restore fish populations, create more resilient ocean ecosystems, decrease CO2 pollution and increase carbon capture, and deliver more profitable fisheries and thriving coastal communities. A real no-brainer.”

Climate Breakdown

Tackling climate breakdown and holding warming at or as close to 1.5 degrees Celsius as possible is essential if the ecosystem services of the ocean are to survive. All states need to commit to new and more ambitious plans (NDCs) in 2020 to achieve this.

Dr. Miriam Goldstein – Director of Ocean Policy, Center for American Progress

“We cannot ignore the 71 percent of our planet that is underwater. To protect the ocean’s natural ability to store carbon, to feed billions of people across the world, and to save ocean ecosystems, we must substantially reduce climate pollution as quickly as possible. We must also preserve the ocean’s ability to adapt to the changes already underway by strongly protecting at least 30 percent of the ocean. We must act now to create a better, healthier future for our ocean  – and ourselves.”

Torsten Thiele – Global Ocean Trust

“Innovative Finance mechanisms that address climate and ocean health aspects comprehensively need to be a key outcome of UNFCCC COP25.”

Aimee David, Monterey Bay Aquarium

“The ocean does so much for humanity: it provides food, generates jobs and modulates our weather. Climate change threatens all of these vital services. We must quickly reduce our emissions and transition to renewable energy sources like solar and wind. We also must stop overfishing, polluting and destroying habitats, which diminish the ocean’s resilience to the impacts of climate change. And we must redouble our efforts to conserve important marine ecosystems. Though we are moving in the right direction, climate change is still outpacing our attempts to address its consequences. We must move faster—for our ocean, and for ourselves.”

Jay Ritchlin, David Suzuki Foundation, Western Canada director-general

“The oceans are taking a serious beating as they continue to protect our atmosphere from drastic temperature rises. Science shows that we need a double-pronged approach to climate and ocean issues. Countries around the world must bring forward more ambitious climate plans to curb emissions and prevent our atmosphere from heating by more than 1.5 degrees. In parallel, we must increase ocean protection measures and reduce the negative impact of human activities on oceans, or risk irreparably damaging this natural ecosystem upon which all life depends.”

Taehyun Park, Climate and Oceans Political Advisor, Greenpeace

“The climate crisis that scientists have been warning us about is already a reality, and it is affecting the ocean as much as anywhere else. Cities are flooding, extreme weather events are becoming the new normal and ecosystems are dying. Human exploitation and our dependence of burning fossil fuels has pushed our blue planet to the verge of collapse. The climate crisis is an ocean crisis, we need to see governments stepping up and raise their ambitions to protect our oceans by halving carbon emissions as if our life depended on it, because it does.”

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