Advancing Ocean Monitoring and Knowledge for Societal Benefit: The Urgency to Expand Argo to OneArgo by 2030

Virginie Thierry^1*Hervé Claustre²Orens Pasqueron de Fommervault³Nathalie Zilberman⁴Kenneth S Johnson⁵Brian A King⁶Susan Elizabeth Anne Wijffels⁷Udaya TVS Bhaskar⁸Magdalena Alonso Balmaseda⁹Mathieu Belbeoch¹⁰Marine Bollard¹¹Jacqueline Boutin¹²Philip Boyd¹³Romain Cancouët¹¹Fei Chai¹⁴Stefano Ciavatta¹⁵Richard Crane¹⁶Sophie E CRAVATTE¹⁷Giorgio Dall'Olmo¹⁸Damien Desbruyères¹Paul James Durack¹⁹Andrea J Fassbender²⁰Katja Fennel²¹Yosuke Fujii²²Florent Gasparin¹⁷Alberto González-Santana²³Claire Gourcuff¹¹Alison Gray²⁴Helene Theresa Hewitt²⁵Steven Robert Jayne⁷Gregory C Johnson²⁰Nicolas Kolodziejczyk¹Arnaud Le Boyer⁴Pierre Yves Le Traon^15,26William LLOVEL¹M. Susan Lozier²⁷John Miller Lyman^20,28Elaine L. McDonagh^29,6Adrian Peter Martin⁶Benoit Meyssignac¹⁷Kristian Mogensen⁹Tamaryn Morris³⁰Peter R. Oke³¹Walker Smith³²Breck Owens⁷Noe Poffa²⁶Joanna Post³³Ryan Rykaczewski³⁴Dean Roemmich⁴Shubha Sathyendranath³⁵Megan Scanderbeg⁴Carolyn Scheurle³⁶Oscar Schofield³⁷Karina von Schuckmann¹⁵James Scourse³⁸Janet Sprintall⁴Toshio Suga^39,40Marina Tonani¹⁵Esmee van Wijk³¹Xiaogang Xing⁴¹Hao Zuo⁹

• ¹Univ Brest, CNRS, Ifremer, IRD, Laboratoire d'Océanographie Physique et Spatiale (LOPS), IUEM, Plouzané, France
• ²Sorbonne University, CNRS, Laboratoire d’Océanographie de Villefranche (LOV), Villefranche-sur-Mer, France
• ³OceanOPS, World Meteorological Organization / Intergovernmental Oceanographic Commission (IOC) of UNESCO,, Monaco, Monaco
• ⁴Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, United States
• ⁵Monterey Bay Aquarium Research Institute (MBARI), Moss Landing, California, United States
• ⁶National Oceanography Centre, Southampton, United Kingdom
• ⁷Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States
• ⁸Indian National Centre for Ocean Information Services, Hyderabad, Andhra Pradesh, India
• ⁹Research Department, European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom
• ¹⁰OceanOPS, Plouzané, France
• ¹¹Euro-Argo ERIC office, Plouzané, France
• ¹²Sorbonne University, CNRS, IRD, MNHM, LOCEAN-IPSL Laboratory, Paris, France
• ¹³Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia
• ¹⁴State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, Fujian Province, China
• ¹⁵Mercator Ocean International, Ramonville-Saint-Agne, France
• ¹⁶Camborne School of Mines, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, England, United Kingdom
• ¹⁷Université de Toulouse, LEGOS (IRD/UT3/CNES/CNRS), Toulouse, France
• ¹⁸Instituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS, Sezione di Oceanografia,, Trieste, Italy
• ¹⁹Program for Climate Model Diagnosis and Intercomparison (PCMDI), Lawrence Livermore National Laboratory, Livermore, United States
• ²⁰Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration (NOAA), Seattle, Washington, United States
• ²¹Department of Oceanography, Dalhousie University, Halifax, Canada
• ²²Meteorological Research Institute, Japan Meteorological Agency, Tsukuba, Ibaraki, Japan
• ²³Centro Oceanográfico de Canarias, Instituto Español de Oceanografia (IEO), CSIC, Santa Cruz de Tenerife, Spain
• ²⁴School of Oceanography, University of Washington, Seattle, United States
• ²⁵Met Office, Exeter, Devon, United Kingdom
• ²⁶Centre de Bretagne, Institut Français de Recherche pour l'Exploitation de la Mer, Plouzane, France
• ²⁷Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, United States
• ²⁸Cooperative Institute for Marine and Atmospheric Research, University of Hawaii at Manoa, Honolulu, Hawaii, United States
• ²⁹Norwegian Research Institute (NORCE), Bergen, Hordaland, Norway
• ³⁰Egagasini Node, South African Environmental Observation Network, Cape Town, South Africa
• ³¹CSIRO Environment, Hobart, Australia
• ³²School of Oceanography, Shanghai Jiao Tong University, Shanghai, China
• ³³Intergovernmental Oceanographic Commission of UNESCO (IOC-UNESCO), Paris, France
• ³⁴Ecosystem Sciences Division, NOAA Pacific Islands Fisheries Science Center, Honolulu, United States
• ³⁵Plymouth Marine Laboratory, Plymouth, England, United Kingdom
• ³⁶Sorbonne University, CNRS, Institut de la Mer de Villefranche (IMEV), Villefranche-sur-Mer, France
• ³⁷Center for Ocean Observing Leadership, Rutgers University, New Brunswick, United States
• ³⁸Centre for Geography and Environmental Science, College of Life and Environmental Sciences, University of Exeter, Penryn, Cornwall, United Kingdom
• ³⁹Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kagawa, Japan
• ⁴⁰Advanced Institute for Marine Ecosystem Change (WPI-AIMEC), Tohoku University, Sendai, Japan
• ⁴¹State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Hangzhou, China

The ocean plays an essential role in regulating Earth's climate, influencing weather conditions, providing sustenance for large populations, moderating anthropogenic climate change, encompassing massive biodiversity, and sustaining the global economy. Human activities are changing the oceans, stressing ocean health, threatening the critical services the ocean provides to society, with significant consequences for human well-being and safety, and economic prosperity. Effective and sustainable monitoring of the physical, biogeochemical state and ecosystem structure of the ocean, to enable climate adaptation, carbon management and sustainable marine resource management is urgently needed. The Argo program, a cornerstone of the Global Ocean Observing System (GOOS), has revolutionized ocean observation by providing real-time, freely accessible global temperature and salinity data of the upper 2,000m of the ocean (Core Argo) using cost-effective simple robotics. For the past 25 years, Argo data have underpinned many ocean, climate and weather forecasting services, playing a fundamental role in safeguarding goods and lives. Argo data have enabled clearer assessments of ocean warming, sea level change and underlying driving processes, as well as scientific breakthroughs while supporting public awareness and education. Building on Argo’s success, OneArgo aims to greatly expand Argo’s capabilities by 2030, expanding to full-ocean depth, collecting biogeochemical parameters, and observing the rapidly changing polar regions. Providing a synergistic subsurface and global extension to several key space-based Earth Observation missions and GOOS components, OneArgo will enable biogeochemical and ecosystem forecasting and new long-term climate predictions for which the deep ocean is a key component. Driving forward a revolution in our understanding of marine ecosystems and the poorly-measured polar and deep oceans, OneArgo will be instrumental to assess sea level change, ocean carbon fluxes, acidification and deoxygenation. Emerging OneArgo applications include new views of ocean mixing, ocean bathymetry and sediment transport, and ecosystem resilience assessment. Implementing OneArgo requires about $100 million annually, a significant increase compared to present Argo funding. OneArgo is a strategic and cost-effective investment which will provide decision-makers, in both government and industry, with the critical knowledge needed to navigate the present and future environmental challenges, and safeguard both the ocean and human wellbeing for generations to come.