“The ocean will either be the driver of climate change, or the pillar of our resilience.”
.
On 25 September, in Monaco, the Intergovernmental Panel on Climate Change (IPCC) has launched its Special Report on the Ocean and Cryosphere in a Changing Climate. This unprecedented event in IPCC’s history finally marks the recognition of the ocean as a major challenge of climate change, and the Ocean and Climate Platform is thrilled with this victory. The Platform, along with Monaco, France and Chile, had been actively calling on the IPCC, since COP21, for the necessity to produce this Special Report during its 6th Assessment Cycle.
“Talking about climate change without the ocean, it’s forgetting the heart of the climate machine” – Françoise Gaill, CNRS, Vice-President of the Ocean and Climate Platform.
This is because the ocean is at the very heart of the planet’s climate system. It absorbs more than 25% of the anthropogenic CO2 produced every year in the atmosphere and provides 50% of the oxygen produced on Earth. It also absorbs more than 90% of the heat resulting from greenhouse gas emissions, therefore limiting the warming of the air we breathe and playing an essential part in climate regulation. More than 3 billion people depend on food resources and proteins produced by the ocean, and more than a quarter lives less than 100 km away from the coast.
For the Ocean and Climate Platform – a 70-member coalition bringing together scientists, NGOs, members of the private sector and public entities – this report is an unprecedented victory. It represents a crucial milestone: ocean and climate interactions are finally subject to a detailed review of scientific knowledge. This new report clearly highlights marine biodiversity as a major component of the world climate system, and acknowledges the services provided by coastal and marine ecosystems to humans, but also their vulnerability in the face of climate change.
“Taking into account marine biodiversity is innovative in such a climate report, the health of the ocean is finally acknowledged as one of the main challenges for fighting climate change” – Romain Troublé, President of the Ocean and Climate Platform and Executive Director of the Tara Ocean Foundation.
.
.
The IPCC alerts on the acceleration of phenomena, their irreversibility and their impacts on populations
According to the IPCC:
The pace of global changes is accelerating
The ocean is warming faster: if the ocean has absorbed more than 90% of the excessive heat produced by anthropogenic activities since the 1970s, it could still absorb 5 to 7 times more heat by 2100. For example, between 2013 and 2015, the temperature of the North-West Pacific has risen by 6°C. This phenomenon leads to the occurrence of oceanic heat waves, which constitute a new research subject with major impacts on marine biodiversity.
The sea level is rising faster than according to projections, because of global warming and the melting of ice sheets and glaciers. In the last decade, the sea level has risen by 3.6 mm per year but, by the end of the century, it could rise by up to 1.5 cm per year. By 2100, the global sea level rise could be of 110 cm.
The ocean is losing oxygen, a phenomenon finally highlighted in the report. The oxygen consumption in some areas is becoming superior than the oxygen produced by the ocean. During the last decades, the ocean has probably lost between 0.5 to 3.3% of its oxygen, between the surface and 1000 m of depth. Over the same period, minimum oxygen zones have expanded by 3 to 8%. In these areas, many species cannot survive and deoxygenation could lead to the loss of 15% of the global biomass of marine animals by 2100.
Irremediable and irreversible phenomena
Each observed phenomenon in both the ocean and cryosphere results from sudden changes which, once they reach a tipping point, become irremediable and irreversible. For example, although carbon absorption by the ocean has resulted in the acidification of 95% of surface water, stopping greenhouse gas emissions will not reverse the process.
Moreover, the melting of ice sheets and glaciers, as well as increasing temperatures, are altering the functioning of marine currents, whose cycle extends over a lengthy time period. Among other things, the North Atlantic current deceleration is reducing marine productivity, causing winter storms in Europe and reducing rainfalls in the Sahel and South Asia.
A report firmly focused on the impacts on human societies
The human factor now appears as essential. If the particularity of this report is to observe climate change consequences on marine and coastal ecosystems, the report also offers for the first time a global vision of the diverse changes that will be impacting human societies the most.
Overall, more than a quarter of the planet’s inhabitants is directly threatened by climate change consequences on the ocean and cryosphere. Coastal areas are home to 28% of the world population, 11% of which live at less than 10 m above sea level, and almost 10% of our planet’s inhabitants live in arctic regions or high mountains.
.
Concrete policy measures, based on the scientific evidence emphasized by this IPCC report, are urgently needed, starting at COP25
Considering the urgency of the climate crisis and the threats to human societies, many challenges remain. The Ocean and Climate Platform is calling for immediate and ambitious political action, taking into account on all the scientific information highlighted in this report.
In this perspective, the Ocean and Climate Platform and its 70 members will continue to join and mobilize forces, acting at the interface of science and policy.
The Platform is publishing a booklet entitled “Ocean and Climate Change: new challenges” (available in French only), in which 5 of the topics addressed by the Special Report are explained with a didactic approach. With these factsheets, our scientific mediators decrypt the main issues and mechanisms regarding ocean and climate: the role of the ocean in the global climate regulation; ocean warming; climate change and the Southern ocean; rising sea levels; extreme events; and deoxygenation.
Along with this booklet, the Platform is also publishing 13 scientific factsheets (available in French only) which provide very recent scientific information that is not included in the IPCC report.
.
Towards COP25
Building on the strong scientific consensus within the UNFCCC negotiations, the Ocean and Climate Platform will use COP25 in Chile as the opportunity to present its policy recommendations on the ocean and climate – regarding mitigation, adaptation, research and finance – compiled in a document entitled “A healthy ocean, a protected climate”.
This upcoming event must no longer be overlooked and must enable States and all stakeholders to take concrete and rapid actions to preserve marine biodiversity, the most vulnerable populations, and the climate through ocean protection.