A healthy, sustainably managed ocean is vital to all life on Earth. It regulates the climate, sustains biodiversity, and provides transport, renewable energy, food security and livelihoods to billions of people. But the ocean faces mounting pressures, from climate change and pollution to biodiversity loss, pushing ecosystems toward critical tipping points. While science holds powerful potential for transformative solutions, ocean science remains fragmented and siloed.
We asked two ocean experts from the International Science Council (ISC) network what must change to ensure ocean science can drive a just, resilient, and sustainable future.
Tipping points mark thresholds at which incremental changes may trigger abrupt, irreversible shifts in ecosystem function and stability. They highlight the complexity and interdependence of marine systems and reinforce the urgency of effective ocean action.
As explained by Jean-Pierre Gattuso, tipping points in ocean systems can be elusive. For instance, his research on ocean acidification shows that changes often unfold gradually, without a sudden or dramatic shift, making it challenging to pinpoint a clear threshold. But other ocean systems behave differently. Coral reefs, for example, show distinct thresholds – just a 1-1.5°C increase in sea temperature can cause coral bleaching, and if the heat stress persists for more than a week or two, it can cause mass coral mortality, threatening the collapse of the entire ecosystem. In 2024, the ocean experienced its fourth global coral bleaching event since 1998 – a stark reminder of how close we are to potential ecosystem collapse. But because not all ecosystems exhibit clear tipping points, precautionary, science-based and timely ocean action is essential to avoid unintended and potentially irreversible damage.
Beyond biophysical systems, tipping points can also occur in social-ecological systems, emerging from the interplay of environmental, economic and social pressures. Laura Pereira refers to these changes as “regime shifts” – disruptions that may not be fully irreversible, but where recovery is often slow, difficult, or unlikely within policy-relevant timeframes. The demise of the Atlantic cod fishery in the North Sea illustrates such a shift – overexploitation and climatic changes have pushed the system into a depleted state where cod populations have struggled to recover. However, if properly anticipated, these dynamics can sometimes also provide a window of opportunity for action. This is exemplified by the transformational governance of Chilean fisheries following political turbulence and resource stock collapse.
Recognising and responding to these tipping points – whether ecological or social – is critical. As Gattuso reminds us, the stakes are high: the ocean supports ecosystems, economies, and billions of lives. If it were a country, its economy would rank fifth in the world.
Whether or not you care about nature’s beauty, you should care about the countless services it provides. The ocean economy is estimated to be worth $2.6 trillion per year. If the ocean were a country, it would be the world’s fifth-largest economy.
The complexity and interconnectedness of ocean systems render fragmented and siloed approaches to ocean science ineffective in addressing ocean challenges. When disciplines and institutions operate in isolation, it weakens our ability to develop comprehensive solutions – and it can even inadvertently contribute to ocean degradation rather than prevent it. Given the accelerating pressures on marine ecosystems, the shift from fragmented to integrated approaches in ocean science and governance has never been more urgent.
Jean-Pierre Gattuso points to the fragmented global governance landscape where ocean issues are addressed in isolation: climate under the UNFCCC, biodiversity under the CBD, shipping through the IMO, and fisheries under the WTO. But the ocean is one vast, interconnected system. UNOC-3, he argues, offers a rare and vital platform for countries to tackle interconnected challenges in a holistic and coordinated way, bridging institutions, sectors, and disciplines for more integrated and effective solutions.
This fragmentation is paralleled in ocean science itself. While studying food systems in South Africa’s Western Cape, Pereira found it impossible to separate terrestrial and marine dynamics given how deeply ocean processes shape coastal livelihoods, ecosystems, and food security. Yet many scientific models and policies still treat these systems separately. This weakens our ability to foster resilience and drive just, sustainable transformations.
Sustainability science starts from the question, not the discipline. The solutions to global challenges are messy, value-laden, and require different knowledge systems.
Pereira urges scientists to ask what expertise is needed to solve the problem rather than which field it belongs to. Embracing diverse narratives as integral to science is essential for navigating the complexity of ocean challenges. That is why science must engage with values, power, and complexity, and support platforms for non-linear, transformative thinking. It also requires reflection on where we are transforming to – and the value systems that underpin those imagined futures.
Importantly, good science can still be rigorous while being impactful. Pereira calls for greater transparency about the assumptions behind scientific questions and a more reflexive practice that builds public trust and invites diverse perspectives.
However, traditional science and funding systems might not yet be designed to support this kind of transdisciplinary, solutions-oriented work. Yet, the ocean is an ideal space to experiment with this model, precisely because of its interconnectedness with social and ecological systems.
Overcoming ocean challenges requires breaking down silos within science and governance, and bridging the gap between knowledge and policy.
As scientists, we must honestly describe the problems ecosystems face, but we also have a responsibility to explore solutions and provide options and advice to policy-makers. Science, while not political, is a foundation of truth. It must be used in policy to serve the people. – Jean-Pierre Gattuso.
Gattuso reinforces the need for science to guide solutions and inform decision-making. He points to the early 2000s when red tuna populations in the Mediterranean were collapsing due to overfishing. Scientific evidence informed quotas imposed by the EU and regional fisheries bodies, and today, red tuna stocks have recovered, contributing to regional food security.
Similarly, humpback whales have rebounded in the Pacific following a hunting ban in 1986 by the International Whaling Commission, and in Vietnam’s Mekong Delta, mangroves destroyed during the war were restored by local communities, now storing carbon on par with intact forests while providing natural defence against storms and tsunamis.
Yet too often, scientists overemphasise uncertainty which, among other factors, poses a barrier to effective science-policy integration. Gattuso stresses that policy-makers seek certainty and actionable information when making decisions. Therefore, he urges scientists to communicate findings more confidently and focus on tangible benefits, especially the short-term ones, to capture the interest of policy-makers.
For urgent, large-scale challenges, waiting for perfect certainty can mean a dangerous delay. We already know enough to act. Especially on issues central to UNOC-3 – like biodiversity, climate, marine resources and plastic pollution – even 70% certainty should be enough for policy decisions. – Jean-Pierre Gattuso
As Gattuso remains sceptical about the extent to which policy-makers can or will meaningfully engage with scientific complexity, he advocates for a two-step process: scientists engage with technical advisors and trusted intermediaries who can then relay the key insights to decision-makers in more digestible formats.
He points to COP25, where he and other scientists presented the Intergovernmental Panel on Climate Change (IPCC) Special Report on the Ocean and Cryosphere to an audience of 300 delegates who listened intently for hours. It was proof that science can resonate when shared through credible platforms. Gattuso also stresses the need for a global ocean science-policy panel, similar to the IPCC, but focused on solutions. He emphasises that there is no better mechanism than multilateral cooperation to ensure that ocean benefits are protected and shared equitably.
Organisations like the IPCC and IPBES have credibility and are effective in communicating to policy-makers. The key is not to dilute the science, but to communicate it through trusted, well-established platforms that bridge the technical, scientific and political worlds. – Jean-Pierre Gattuso
Pereira agrees – scientific knowledge must be communicated better to be accessible and actionable for policy-makers, but without stripping it of its nuance. She warns against the urge to reduce scientific complexity to a soundbite, emphasising that complex challenges demand nuanced, place-based approaches.
Stop asking us to simplify the complex. Learn to work with messy, value-based decisions. Science is evolving. Now it is time for policy-makers to meet us halfway. – Laura Pereira
Pereira and Gattuso are clear: transforming ocean science to meet today’s challenges means embracing interdisciplinarity, inclusivity, and bold, confident engagement. The ocean’s complexity should not be perceived as a barrier to action but rather as a call to rethink how we do and use ocean science. That is why UNOC-3 can be a true turning point, driving integrated, transdisciplinary science and strengthening the multilateral cooperation we need to avoid crossing the tipping points threatening the ocean ecosystems.
Photo de Paul Flatten sur Unsplash
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