What Ocean for Tomorrow? Marine Ecosystems in a Changing Climate: Insights from the IPCC’s Sixth Assessment Report

Ocean & Climate Platform
Posted on: 6/06/2023 - Updated on: 6/21/2023

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Drawing from the IPCC Sixth Assessment Report, this new publication provides a synthesis on current knowledge about the linkages between marine ecosystems, climate change, and sustainable development.

The ocean and its ecosystems are essential to sustain life on Earth and meet human needs. Covering over two thirds of the planet’s surface, the ocean plays a crucial role in the climate system by regulating heat transfers, water and carbon cycles, among others. Since the beginning of the Industrial Revolution the ocean has absorbed close to a third of all greenhouse gases emissions and 90% of the heat produced by human activities.

The ocean is a reservoir of biodiversity and the world’s largest habitable zone by volume. It is home to a wide variety of ecosystems which include coral reefs, mangroves, salt marshes, as well as kelp forests and seagrass meadows. These environments play an essential role in maintaining species diversity. They have a cultural value for many communities and provide food, minerals, energy and jobs for human populations.

Climate change is exposing marine ecosystems to conditions that have not been experienced for millennia. Its impacts on life in the ocean are considerable and compounded by human activities such as fishing, oil exploitation, shipping and coastal development.

In consequence, marine ecosystems are becoming increasingly less capable of maintaining the essential services they provide, including in terms of climate regulation. All life, whether in the sea or on land, is greatly affected. As the impacts of climate change accelerate and intensify, the conservation of marine ecosystems becomes even more critical. To ensure the proper understanding of these phenomena by the greatest number of people, and to improve the inclusion of marine ecosystems in climate and environmental policies, the Ocean & Climate Platform and its members are publishing “What ocean for tomorrow? Marine Ecosystems in a Changing Climate: Insights from the IPCC’s Sixth Assessment Report”, a summary of the key issues on marine ecosystems explored in the IPCC’s Sixth Assessment Report (AR6).

The purpose of this publication is to provide answers to the following questions:

  1. What services do marine ecosystems provide?
  2. What are the consequences of deteriorating marine ecosystems?
  3. How can the protection of marine ecosystems help us achieve a sustainable future?

Key Takeaways:

  • The ocean is central to the regulation of the climate system.
  • It is home to a great diversity of ecosystems present at all depths and throughout the world.
  • These ecosystems convene a multitude of different species and provide numerous services to human societies.
  • As climate change accelerates and intensifies, and human-induced pressures increase, certain marine ecosystems are reaching their tipping points.
  • Ecosystem degradation in turn accelerates climate change and increases the vulnerability of human populations.
  • In contrast, protected and healthy ecosystems are more resilient and provide solutions to the challenges of climate change.
  • Nature-based Solutions can generate multiple co-benefits in terms of mitigation and adaptation, and contribute to achieving the Sustainable Development Goals.
  • Their effectiveness depends on reducing greenhouse gases emissions and mitigating the impacts of human activities. Institutional, political and financial resolve is a precondition to the deployment and sustainability of Nature-based Solutions.


Ocean & Climate Platform (2023). What ocean for tomorrow? Marine ecosystems in a changing climate. Insights from the IPCC’s Sixth Assessment Report, 36 pages.

Affiliated Organizations

The Ocean & Climate Platform (OCP) aims to provide civil society and decision-makers with new knowledge and insights on the issues, challenges and solutions at the interfaces between biodiversity, the ocean and climate. 

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