ocean-climate.org OCEAN & CLIMATE PLATFORM SCIENTIFIC FACT SHEETS FOR MORE INFORMATION, PLEASE CONTACT: The secretariat of the Ocean & Climate Platform: [email protected] Coordination: Françoise Gaill Animation and production: Anaïs Deprez, Gauthier Carle Graphic design: Elsa Godet CITATION OCEAN AND CLIMATE, 2019 – Scientific Fact Sheets. www.ocean-climate.org, 130 pages. December 2019 ocean-climate.org The “Ocean & Climate” Platform Covering 71% of the Earth’s surface, the world The Ocean & Climate Platform (OCP) was formed ocean is a complex ecosystem that provides ser- out of an alliance between non-governmental orga- vices essential to sustaining life on the planet. The nizations and research institutes. It brings together ocean absorbs more than 30% of the anthropogenic more than 70 organizations, scientific institutions, CO2 emitted annually into the atmosphere. It is also universities, etc., whose objective is to enhance the world’s largest net oxygen supplier, being as im- scientific expertise and advocate on ocean-climate portant as forests. The ocean is therefore the Earth’s issues with policy makers and the general public. main lung and is at the center of the global climate machine. Relying on its strong expertise, the OCP supports decision makers by providing them with scientific Even though the ocean continues to limit global war- information and guidance to implement public po- ming, human pressure has degraded marine eco- licies. The OCP also responds to a need expressed systems over the past few decades, mainly through by both the scientific community and representa- CO2 emissions, resource overexploitation and pollu- tives of the private sector and civil society by crea- tion. The ocean’s role as a climate regulator is thus ting a space dedicated to meetings, exchanges and disrupted. There is an urgent need to maintain the reflection where ocean and climate stakeholders can health of marine ecosystems and to restore those build an effective and holistic approach to address that are deteriorating. the challenges of protecting marine ecosystems and combating climate change. 3 4 ocean-climate.org Table of contents Foreword Françoise Gaill ......................................................................... 06 1• The ocean, a heat reservoir Sabrina Speich .......................................................................... 08 2• The ocean, a carbon pump Laurent Bopp, Chris Bowler, Lionel Guidi ....................................................... 23 3• The deep ocean in a changing climate Nadine Le Bris ........................................................................... 29 4• Coral and climate change Denis Allemand ......................................................................... 36 5• Coral bleaching, an imminent threat to biodiversity Leïla Ezzat . ............................................................................ 50 6• Ocean, biodiversity and climate Gilles Bœuf . ............................................................................ 59 7• Exploited marine biodiversity and climate change Philippe Cury . .......................................................................... 64 8• Overfishing and sustainable fishing: the challenges for today and tomorrow? Didier Gascuel . ......................................................................... 68 9• Aquaculture and global changes Marc Metian . ........................................................................... 75 10• The Arctic: Opportunities, Concerns and Challenges Emmanuelle Quillérou, Mathilde Jacquot, Annie Cudennec, Denis Bailly, Anne Choquet, Laure Zakrewski . .... 81 11• Small islands, ocean and climate Virginie Duvat, Alexandre Magnan, Jean-Pierre Gattuso . .......................................... 98 12• Ocean, climate change and migration Guigone Camus, Christine Causse, Daria Mokhnacheva . .......................................... 112 13• The International Laws for Ocean and Climate Bleuenn Guilloux . ...................................................................... 118 5 ocean-climate.org Foreword Françoise Gaill The ocean is an essential component of our planet's mentioned the ocean in its preamble. In addition, the climate. Scientists know this and have proven it time and Intergovernmental Panel on Climate Change (IPCC) again: without the ocean, human-induced greenhouse published a Special Report entitled “The Ocean and gas emissions would have destabilized the climate Cryosphere in a Changing Climate” in September 2019. machine much more. It is therefore a crucial regulator, It was the first IPCC report on the ocean. but is constantly threatened by human activities and the impacts of global climate change. The ocean is now an integral part of the climate negotiations. These achievements are the result of years The numbers speak for themselves: the ocean covers of advocacy work by the Ocean & Climate Platform and 71% of the planet’s surface, accounts for 97% of its its members. habitable volume, contains 97% of the water on Earth, absorbs 90% of the excess heat and 30% of the However, the battle for the ocean does not stop there. anthropogenic CO2, provides livelihoods for a large It is no longer simply a matter of mobilizing diplomatic part of the world's population, and produces many processes (which still need to do more to include the pharmacological substances. Its ecosystems are ocean); marine civil society must also take part in the worth more than the U.S. GDP! The threats it faces (as Agenda for Action, propose alternatives, set up and well as the communities depending on it) are just as support initiatives, disseminate best practices, and share colossal and alarming: acidification, global warming, knowledge. The Platform is already part of this process. deoxygenation, rising sea levels, etc. First of all, however, we need to gain a better Yet despite all the stress factors impacting the ocean understanding of the ocean. This vast, diverse and its crucial role in climate inertia, international efforts environment contains unexplored and abundant to mitigate and adapt to climate change have neglected biodiversity. The ocean floor remains the last terra it. For more than 20 years, the ocean has not even been incognita. Many physical, chemical and biological mentioned in the additional texts of the United Nations mechanisms are still unexplained and poorly Framework Convention on Climate Change (UNFCCC). understood. Scientists and public policy makers must Alarmed by this situation, the 70 or so members of the work to fill the knowledge gaps on the ocean-climate Ocean & Climate Platform (public institutions, NGOs, relationship. Last year, building on its scientific expertise, universities, etc.) have decided to give the ocean a the Platform had already published 17 scientific fact voice during the COP21 climate negotiations. sheets. Maintaining its momentum, it now offers you this second volume. According to them, the Paris Agreement marked an important step, a major success in taking “ocean and This booklet seeks to be more inclusive and open. climate” themes into account. Human science is the second fundamental pillar to understand the ocean and the related socio-economic For the first time since the UNFCCC, the Paris issues. This publication is therefore a mix of “hard” Agreement, held in December 2015, explicitly and “soft” sciences, intended to stimulate international 6 ocean-climate.org reflection on adaptation strategies, persistent gaps and The potential for investigation is immense, but individual behavior, as well as provide a sound basis absolutely necessary. The ocean is our “comprehensive for understanding human challenges and adapted insurance” and the time is long overdue to protect it! solutions. We call for a greater integration of “hard” and “soft” sciences. In keeping with the OCP publications relating to the COP21, this set of articles revisits a number of key In order to find solutions to global issues (climate aspects of the IPCC Special Report on “The Ocean and change), research must be interdisciplinary and holistic. Cryosphere in a Changing Climate (September 2019), and includes new data published since the report came A scientific approach focusing on ocean-climate out. The present document provides an overview of interactions is currently being developed and faces the latest ocean-climate developments in order to considerable challenges: collecting sufficiently highlight the key challenges of our time and contribute numerous and diversified data, reducing scales, to taking action. understanding local and global phenomena, studying surface, intermediate and deep water, from the high seas to the coasts, as well as biodiversity and humans. 7 ocean-climate.org The ocean, Sabrina Speich a heat reservoir The ocean’s ability to store heat (uptake of 94% of the excess energy resulting from increased atmospheric concentration of greenhouse gases due to human activities) is much more efficient than that of the continents (2%), ice (2%) or the atmosphere (2%) (Figure 1; Bindoff et al., 2007; Rhein et al., 2013; Cheng et al., 2019). It thus has a moderating effect on climate and climate change. However, ocean uptake of the excess heat generated by an increase in atmospheric greenhouse gas concentrations causes marine waters to warm up, which, in turn, affects the ocean's properties, dynamics, volume, and exchanges with the atmosphere (including rainfall cycle and extreme events) and marine ecosystem habitats. For a long time, discussions on climate