Climate change Impacts on Global Oceanic Ecosystems & Fisheries. – CIGOEF

Oceanic ecosystems cover more than 70% of the Earth surface and provide major ecosystem services. They are responsible for most of the carbon transfer to the deep ocean, thus having a major influence on atmospheric CO2 and climate. They host a rich biodiversity with emblematic large predatory fishes whose exploitation supports livelihood and supplies animal protein for hundreds of millions of people worldwide. Amongst them, tunas are the major part with annual catches reaching more than 7.7 million tons and an economical value around 40 billion US$.
But climate change is threatening these ecosystems and precious ecological services. Climate change impacts ocean temperature, stratification and circulation. It may trigger the expansion of anoxic “dead zones” over vast regions of the global ocean and the absorption of anthropogenic carbon leads to a marked seawater acidification. It has negative consequences on primary production, which fuels food chains and biodiversity, and potentially important effects on the structure of ecosystems. Climate change pushes oceanic ecosystems toward new states, with unknown consequences for essential services such as fisheries and associated economies, and potential feedbacks to the climate system through alteration of the biological carbon pump. Achieving sustainability of oceanic ecosystems in this context is a fundamental issue, and there is an urgent need for clear political strategies toward this aim.
In this perspective, an inclusive socio-ecological analysis is urgently needed to anticipate climate-change threats and opportunities, and integrate complex processes into policy-relevant scenarios, in support of sustainable governance of oceanic resources and adaptation to climate change. The purpose of this project is to address these urgent challenges from a scientific perspective, analyzing and projecting the global oceanic socio-ecological system each step of the way from climate to fish markets. To advance toward the achievement of such an ambitious goal, CIGOEF will build on recent developments in coupled numerical modeling (ANR project MACROES) to simulate and analyze the cumulative effects of multiple climatic and non-climatic stressors on oceanic socio-ecosystems. MACROES initiated the incorporation of a marine ecosystem component into one of the French Earth System Models. The resulting global model presently couples climate and related atmospheric and oceanic processes, marine biogeochemistry, marine ecosystem, and fishing effort distribution components. It doesn’t have any equivalent worldwide. CIGOEF will explicit bacteria and gelatinous organisms in the system, two components of critical functional importance that were previously overlooked. It will also improve and integrate components that were developed but not coupled in the system for representing exploited oceanic tuna populations, fishing fleet bio-economy and global tuna markets. The coupled models will be used for both process studies and scenarios development. First CIGOEF will study the effects of climate change on the bacterial loop and jellyfish populations at the global scale, and quantify their feedbacks to the carbon cycle and the climate system. Second it will study the impacts of climate change on tuna resources, fisheries and markets, quantify their vulnerability and study alternative adaptation strategies through the development of integrated model-based scenarios, jointly with the CLIOTOP Scenario Task Team. To ensure their wide availability, simulated scenarios will be provided online. This would constitute a major contribution to IPCC and IPBES endeavors.