Every element of the causal chain that produced the five largest mass extinctions of the last half-billion years is presently active in the Earth system. The rate of the modern perturbation exceeds every peer-reviewed paleoclimate reference case. A six-intervention portfolio, deployed together at wartime industrial scale beginning now, is the physically necessary and sufficient response. The window in which that portfolio remains fully effective closes between 2028 and 2040. The anthropogenic-versus-feedback tipping point is expected between 2035 and 2040; corrected for the at-least-order-of-magnitude higher rate of contemporary carbon release, loss of agency — the point at which coordinated intervention can no longer arrest the cascade — arrives 200 to 400 years after feedback engagement under sustained portfolio deployment, and collapses onto the tipping point itself under any scenario in which the portfolio is not deployed within the 2028–2040 window.
Continue reading ‘Inside the Extinction Envelope: a systemic review and meta-analysis of paleoclimate extinction markers with comments on the necessary array of last-threshold interventions’Posts Tagged 'policy'
Inside the Extinction Envelope: a systemic review and meta-analysis of paleoclimate extinction markers with comments on the necessary array of last-threshold interventions
Published 21 October 2026 Science Leave a CommentTags: mitigation, paleo, policy, review
Microplastics in a warming ocean with coupled climate change interactions and implications for marine ecosystem functioning
Published 9 October 2026 Science Leave a CommentTags: mitigation, multiple factors, plastics, policy, review
Highlights
- Climate driven processes intensify microplastic fragmentation and redistribution.
- Microplastics disrupt carbon cycling and climate sensitive ocean processes.
- Warming acidification and ice melt amplify microplastic impacts on marine biota.
- Polar ice acts as a major reservoir and emerging source of legacy microplastics.
- Integrating microplastics into climate policy is critical for ocean resilience.
Abstract
Microplastics (MPs) pollution and climate change are now recognized as two pervasive and interacting stressors reshaping marine ecosystems, yet their combined effects remain insufficiently integrated within marine pollution research. This review synthesizes current global evidence on how climate-driven processes modulate the sources, transport, fate, and ecological impacts of MPs, and how MPs in turn influence climate-linked ocean processes. A systematic literature review was conducted following PRISMA principles, drawing on peer-reviewed studies retrieved from major scientific databases without temporal restriction. A total of 205 publications included for qualitative synthesis. The results demonstrate that ocean warming, acidification, sea-ice melt, extreme weather events, and altered circulation patterns intensify MP fragmentation, redistribution, and bioavailability across marine environments. Warming accelerates polymer degradation and enhances biological interactions, acidification alters surface chemistry and toxicity, and polar ice melt releases large reservoirs of legacy MPs into vulnerable ecosystems. Evidence further shows that MPs disrupt key climate-related processes, including primary productivity, nutrient cycling, and the biological carbon pump, thereby creating feedbacks that may weaken oceanic climate regulation. Combined exposure to MPs and climate stressors amplifies physiological stress, reduces growth and reproductive performance, and compromises resilience across multiple trophic levels. These findings highlight that MPs are not passive contaminants but active modifiers of climate-sensitive marine systems. Integrating MP dynamics into climate research, monitoring frameworks, and policy instruments is therefore essential. Addressing plastic pollution alongside climate mitigation and adaptation strategies will be critical to safeguarding marine ecosystem functioning under future global change.
Continue reading ‘Microplastics in a warming ocean with coupled climate change interactions and implications for marine ecosystem functioning’A solution mitigating ocean acidification and hypoxia (OAH) in coastal marine ecosystems
Published 1 October 2026 Science ClosedTags: mitigation, multiple factors, North Pacific, oxygen, policy
Globally, oceans are becoming increasingly acidic and hypoxic due to anthropogenic carbon emissions increasing atmospheric CO2, much of which is absorbed by the ocean. Recent research demonstrates that wastewater discharges, particularly in densely populated regions with large wastewater treatment plants, exacerbate ocean acidification and hypoxia (OAH). Excess nutrients contained in treated wastewater amplify OAH processes, negatively impacting marine life. In the United States, state and federal agencies have the authority to manage nutrient levels in treated sewage in order to protect marine ecosystems. This study includes a compilation of data on OAH and wastewater inputs across key areas—biological thresholds, wastewater plant data, treatment technology options, and policy recommendations—to provide guidance to regulators in reducing excess nutrients that contribute to OAH. A series of steps provided to coastal managers focuses on wastewater discharge as a concrete example of how to translate an emerging scientific understanding into a concrete policy and regulatory recommendation. Wastewater discharges that cause or contribute to OAH conditions in ocean-receiving waters have infrequently been regulated to reduce or eliminate impacts despite the efficacy of increasingly common treatment technologies. With a focus on the California Current Ecosystem (CCE), this study recommends implementing more stringent wastewater treatment plant regulations by moving to technology-based standards to limit nitrogen concentrations in treated sewage discharged off the coast. If implemented, these limitations would minimize wastewater contributions to OAH and reduce its harmful impacts, safeguarding coastal ecosystems and economies. The nutrient management framework outlined here can be replicated nationally using the Clean Water Act framework, or internationally using a similar regulatory framework. Sewage effluent discharges and overflows to the ocean occur in all coastal states and territories, and mitigating these nutrient contributions is a management issue for all coastal managers. In this study, we present a nutrient management framework that can be integrated into regional and national strategies to help coastal regions mitigate OAH impacts on marine ecosystems.
Continue reading ‘A solution mitigating ocean acidification and hypoxia (OAH) in coastal marine ecosystems’The future of aquatic food systems: climate change adaptation and resilience strategies – a narrative review
Published 30 September 2026 Science ClosedTags: biological response, fish, fisheries, mitigation, multiple factors, oxygen, physiology, policy, review, socio-economy, temperature
Across the world’s oceans, lakes, and rivers, climate change is reshaping fisheries and aquaculture systems on which billions of people depend for food and millions rely for their livelihoods. This narrative review summarizes peer-reviewed and selected literature published between 2008 and 2026 on climate impacts, adaptation options, and critical knowledge gaps in marine and freshwater fisheries, with a particular focus on tropical and African inland fisheries. This review shows that warming, acidification, deoxygenation, and altered hydrology are disrupting fish physiology; shifting the distribution of marine species poleward by over 70 km per decade, at rates that vary greatly by taxon, depth, and area; and destroying critical habitats. Although this rapid poleward shift is well documented in open marine environments, it contrasts sharply with landlocked or fragmented freshwater systems, where horizontal migration is physically constrained, a contrast central to the concept of climate entrapment developed in this review. In scenarios characterized by high emissions, tropical fisheries may see a reduction of up to 40% in their maximum catch potential, a statistic relevant to specific tropical Exclusive Economic Zones based on bioclimate-envelope forecasts, which should not be interpreted as a global or universal result. This figure is a model-derived projection under a bioclimate-envelope framework rather than an observed trend, and the realized outcome will depend on future emission pathways. These biophysical changes compound already serious pressures, overfishing, habitat loss, and pollution, and the burden falls heaviest on those least responsible: small-scale fishers, women, and indigenous communities. We introduce the concept of climate entrapment to describe the distinct vulnerability of freshwater fisheries: trapped by fragmented habitats and hydrological barriers, fish stocks cannot migrate to more secure waters as conditions deteriorate. While there are promising adaptation strategies, major gaps remain in understanding what works, for whom, and under what conditions. We conclude with priority recommendations for research, policy, and practice.
Coastal and marine ecosystems under climate change ecological and socio-environmental impacts
Published 15 September 2026 Science ClosedTags: corals, paleo, phanerogams, policy, review, socio-economy
Coastal and marine systems are some of the most biologically productive and economically important systems on Earth, yet they are being compromised at an accelerating pace by climate change. Ocean warming, marine heatwaves, sea-level rise, ocean acidification and deoxygenation along with increasing extreme events are interacting to change the structure, function and resilience of ecosystems among coral reefs, mangroves seagrass meadows and salt marshes. Although effort has been devoted to understanding individual ecosystem effects of climatic change, we know less about comparative mechanistic synthesis and cross-ecosystem vulnerability trajectories. This synthesis explores recent understanding of the biophysical determinants of ecosystem decline, with particular reference to thresholds, regime shifts and feedbacks that limit capacity to adapt. We explore different sensitivities among these biogenic coastal systems, and explain why coral reefs are confronted with sharp thermal and carbonate chemistry thresholds, while mangroves and tidal wetlands have threshold-based resilience contingent on sediment supply and geomorphologic setting. Beyond ecological effects, we compile social–environmental responses including fishery reduction, coastal defense loss and blue carbon release, and rising human vulnerability especially in small island and developing coastal regions. The review also examines ecosystem-based adaptation and nature-based solutions, considering their co-benefits and implementation challenges in a high-emission world. By synthesizing climate drivers, ecosystem thresholds, and social–ecological tipping points within a unified conceptual framework, this review integrates mechanisms of change and alternative stable-state transitions to improve understanding of coastal ecosystem resilience under accelerating climate change.
Continue reading ‘Coastal and marine ecosystems under climate change ecological and socio-environmental impacts’Uncovering hidden and cumulative impacts of construction life cycle processes on planetary boundaries through Forgotten Effects Theory
Published 11 September 2026 Science ClosedTags: modeling, policy
This study applies the Forgotten Effects Theory (FET), a fuzzy-logic-based modelling framework, to analyse how construction life cycle processes generate direct and indirect pressures on multiple planetary boundaries. The approach captures multistage and nonlinear causal relationships derived from expert-based incidence matrices. Results show that mineral extraction, material distribution, and waste disposal strongly influence ocean acidification; construction operations and building use affect biosphere integrity; material production drives land-use change; and demolition contributes to climate change. The analysis revealed substantial hidden effects: the influence of mineral extraction on ocean acidification increased from 0.4 to 0.9 when material production was included as a mediator; the relationship between building use and biosphere integrity increased from 0 to 0.8 through indirect pathways; and the influence of demolition on climate change increased from 0 to 0.8 through waste-disposal mediation. A ±10% sensitivity analysis confirmed the stability of the main incidence hierarchy, with changes below 0.05 for the most relevant coefficients. These findings demonstrate that indirect (“forgotten”) effects can be as influential as direct impacts, significantly intensifying pressures across planetary boundaries. The construction sector is therefore characterised as a cumulative and interconnected system in which impacts propagate and reinforce each other across life cycle stages. These results highlight the limitations of silo-based environmental assessments and underscore the need for integrated, life cycle-oriented sustainability strategies. Policies prioritising upstream interventions, material efficiency and reduced demolition can generate broader systemic benefits. The study demonstrates the potential of FET as a transparent and reproducible modelling approach for linking local construction decisions with global environmental processes, supporting more integrated circular economy strategies and contributing to the achievement of Sustainable Development Goals 11, 12 and 13.
Continue reading ‘Uncovering hidden and cumulative impacts of construction life cycle processes on planetary boundaries through Forgotten Effects Theory’Chapter 22 – Environmental ethics and the case of ocean acidification
Published 2 September 2026 Science ClosedTags: policy, socio-economy
Ocean acidification (OA) is a paradigm case of an encroaching long-term environmental problem that is mainly caused by CO2-emissions and will have diverse and often uncertain impacts on marine organisms and ecosystems. SDG 14 (‘Life below water’) demands to halt or slow down OA. Since occurrence of OA is remote to our daily terrestrial life, it has not been in the focus of moral attention so far. This chapter emerged from the BIOACID research programme at Kiel University. It examines five sources of normativity in environmental ethics, addresses problems of uncertainty and framing, and interprets the metaphor of ‘ocean health’ with recurrence to an updated version of Aldo Leopold’s principle. The chapter argues that basic non-anthropocentric approaches, such as biocentrism, ecocentrism, and holism, face severe problems with respect to marine environments and can’t serve as solid groundings for an ocean ethics. The chapter proposes that a deep anthropocentric environmental ethics can provide an appropriate grounding for ambitious marine stewardship policies, including ocean acidification. Finally, the chapter proposes to define a critical threshold for OA which should not be passed.
22.1 Introduction
This chapter addresses ocean acidification (OA) from an environmental ethics perspective. Ocean acidification is seen as a paradigm case for post-normal science. At its core, the chapter adopts and substantiates several ethical building blocks from a discourse-pragmatic approach, as (a) common heritage of humankind, (b) strong sustainability, (c) Aldo Leopold’s principle, and (d) ecosystem services, with a special eye on cultural services. The idea to attribute inherent moral value to marine organisms and ecological systems is seen critically.
This chapter emerged from the research programme BIOACID (Biological Impacts of Ocean Acidification) being conducted at Kiel University. Within the final period of the BIOACID research programme, a work package on environmental ethics was included to address the underlying normative issues. This project resulted in a monograph: Frederike Böhm and Konrad Ott, Impacts of Ocean Acidification: An Analysis from an Environmental Ethics Perspective (Böhm & Ott, 2019).1 The following chapter presents the essential lines of reasoning of this book and adds new thoughts. It is organized as follows: Section 22.2 gives a brief overview of the scientific dimension. Section 22.3 presents a post-normal-science framing of OA. Section 22.4 deals with interrelated sources of normativity which stem from environmental ethics. Section 22.5 addresses the problem of defining a planetary boundary for OA.
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Continue reading ‘Chapter 22 – Environmental ethics and the case of ocean acidification’Chapter 21 – How can we curb ocean acidification in a time of multiple competing crises?
Published 2 September 2026 Science ClosedTags: policy, socio-economy
Since the 1972 Stockholm Conference, many global environmental agreements have been struck for climate, biodiversity, and sustainable development goals. Still, the planets environment has continued to decline, including on the ocean. One result has been ocean acidification, caused by the uptake of 30–40 per cent of all carbon dioxide from the atmosphere. On its face, this ocean CO2 uptake sounds positive. However, with a continuous increase of CO2 in the atmosphere, this also means an increase in the ocean, which alters its chemistry in ways that may disrupt oceanic biodiversity through making waters more acidic. When coupling this with other major global crisis, we see that we have only adopted global environmental agreements that protect humans from our own nature-induced change – and not ensured that we take our ethical obligation to nature itself by protecting it from human use. This chapter looks at the risk perception literature and considers how the science–policy interface can be exploited to convey the importance of ocean acidification, and whether the anthropogenic lens is what will always be necessary to ensure action to protect something from ourselves.
21.1 Introduction
Around the end of the eighteenth century, with the design of the steam engine by James Watt, the geological age of the Anthropocene started (Crutzen 2006). This has led to unprecedented changes in the natural environment, the most serious of which is climate change. We have tried to change our paths since then though. In fact, more than 50 years have now passed since the 1972 Stockholm Conference (Rockström et al. 2021) – the United Nations Conference on the Human Environment. This was when global leaders for the first time made the environment and the triple planetary crisis of climate, nature, and pollution a focus issue. At that time, in 1972, they warned – and this still holds true today – that ‘Through ignorance or indifference we can do massive and irreversible harm to the earthly environment on which our life and well-being depend’ (United Nations 1973).
Since then, state leaders have created the United Nations Environment Programme (UNEP) entered into force both a climate and biodiversity agreement (United Nations Framework Convention on Climate Change (UNFCCC) and the Convention on Biological Diversity (CBD)) with many iterations; signed the UN 17 Sustainable Development Goals (SDGs) in 2015 with corresponding targets, as part of the realization of Agenda 2030; and in 2022 and 2023, state leaders also signed the Kunming-Montreal Global Biodiversity Framework (GBF) and the Agreement under the United Nations Convention on the Law of the Sea on the conservation and sustainable use of marine biological diversity in areas beyond national jurisdiction (BBNJ). Still, we have continued to saturate Earth’s capacity to support future generations (Intergovernmental Panel on Climate Change 2018). The planet is more polluted than earlier, there are fewer fish in the ocean, the temperature is increasing, methane levels are at their highest in 800,000 years, polar regions are melting, plastics are ubiquitous, and the ocean is more acidic than ever (Barnes & Kaiser 2009; Hönisch et al. 2012; Worm & Branch 2012; MacLeod et al. 2021; Intergovernmental Panel on Climate Change 2022).
In fact, six of nine planetary boundaries that are needed for humans to be able to develop and thrive for generations to come have been breached already (Richardson et al. 2023). Then, in 2025, the ocean acidification boundary was crossed (Findlay et al. 2025). This is a boundary that is also specifically mentioned in the SDGs, with target 3 of SDG14 Life below water specifying the need to ‘Minimize and address the impacts of ocean acidification, including through enhanced scientific cooperation at all levels’. It was in fact the only by-product of climate change and greenhouse gas emission that was singled out to be included under this goal (United Nations Department of Economic and Social Affairs 2022). Still, there is a lack of concrete knowledge of how breaching this boundary will impact either non-human populations or the corresponding human population that depends on these (Buckley et al. 2017).
In light of this, the current chapter considers ocean acidification within the planetary boundaries framework and assesses the lack of responses that led to, and may further exacerbate, the breaching of this boundary. We argue that this in part can be explained by the human-centric perspective of global environmental governance, where effective governance is linked to risk perception within a human context. In terms of ocean acidification, we argue that humans still have a low personal risk perception, coupled with a lack of knowledge (or interest) about it, which directly hinders its agenda setting and implementation of effective governance. We conclude with considering whether the increased saliency of biodiversity challenges, as brought to the surface with the signing of the GBF in 2022, can bring more attention to the role of stressors such as ocean acidification on sustainability and the consequences the breach of this planetary boundary can have on not only humans but also non-human populations.
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Continue reading ‘Chapter 21 – How can we curb ocean acidification in a time of multiple competing crises?’Chapter 20 – Introduction to the ocean acidification boundary
Published 2 September 2026 Science ClosedTags: policy, socio-economy
The oceans mirror many of the environmental problems described in the planetary boundaries framework and reported widely in the media, such as overfishing and deep-sea mining (biosphere integrity), plastic islands or microplastics (novel entities), shipping (atmospheric aerosol loading), or dead zones lacking oxygen (biogeochemical flows). Less present in the media is the problem of ocean acidification addressed by the planetary boundary. Like the atmosphere, the oceans are sinks for CO2 produced by the burning of fossil fuels.
CO2 absorption changes the chemistry of the oceans, lowering their pH. The resulting acidification also leads to fewer of the calcium carbonate shells produced by numerous creatures sinking carbon to the ocean floor before they dissolve back into the water. The boundary’s control variable relates to this by describing the ‘carbonate ion concentration in surface seawater’ and, more specifically, the ‘average global surface ocean saturation state with respect to aragonite’ (Richardson et al. 2023). Aragonite is one of the most abundant forms of calcium carbonate. The boundary is at more than 80 per cent of the pre-industrial aragonite concentration, defined as 3.44. In 2023, the level was 81 per cent, meaning the ocean boundary was, at that time, still one of the few that had not been crossed. Thus, Pelejero et al. (2010: 332) describe ocean acidification as the ‘“evil twin” of global warming’ – it is a moot question, though, as to which is of the two is more evil. This also means that reducing greenhouse gas emissions will reduce the pressure on ocean acidification.
Acidification of the oceans and declining concentrations of calcium carbonate are becoming a problem for marine life. Many creatures depend on the presence of these calcium compounds in the water to build their shells or skeletons. Lower pH not only erodes the existing structures of these creatures, but they also find less calcium to rebuild them. These include plankton, corals, crustaceans, and molluscs, which are vital to marine biodiversity, marine food chains, and, ultimately, human food security (Rockström et al. 2009). So, the control variable of the ocean boundary is the global average saturation state of calcium carbonate in surface water. The framework sets the preindustrial Holocene base value at 3.44 and the boundary value at 2.75. Since 2009, the actual values have fluctuated between 2.8 and 2.9 (Richardson et al. 2023). In 2025, the ocean acidification boundary was first recognized as having been crossed (Findlay et al. 2025).
Both chapters on ocean acidification take the problem structure of the ocean acidification boundary as the starting point of their ethical reflections. Konrad Ott describes it as post-normal, that is, a situation when problem-solving has to cope with uncertain facts, disputed values, high-stakes, and urgent decisions (Funtowicz & Ravetz 1993). Ott explores the issue of ocean acidification from an environmental ethics perspective. He discusses different ways of justifying why ocean acidification is an ethical problem and what follows from this. In doing so, he aims to show how well the most common environmental ethical approaches can address the issue. They mostly differ in their scope of the moral community, that is, to whom we have direct moral obligations: to humans only, or also to individual animals, species, or ecosystems? Depending on the answer one gives, the reasons for protecting oceans will change. Ultimately, Ott intends to specify the normative building blocks of deep anthropocentrism as his preferred approach to the issue.
Rachel Haug Fossbakk, too, addresses the issue of decision-making relating to uncertainty and risk perception. She argues that the human response to ocean acidification is inadequate. This is despite the fact that there is already enough knowledge to act. Her hypothesis is that action requires an adequate perception of risk, which many people do not have when it comes to ocean acidification. She concludes by asking who has a responsibility to act, and on what ethical basis. Rachel Haug Fossbakk then advocates an ecocentric perspective by which she understands a situation ‘where humans are part of nature and need to live sustainably as part of it on the same term as other species’.
Continue reading ‘Chapter 20 – Introduction to the ocean acidification boundary’ISO 18191:2026 – Water quality — Determination of pHT in seawater — Method using the purple indicator of m-cresol
Published 24 August 2026 Science ClosedTags: chemistry, methods, policy
This document specifies a spectrophotometric determination of the pHT of seawater on the total hydrogen ion concentration pH scale. The total hydrogen ion concentration, [H+]T, is expressed as moles per kilogram of seawater. The method is suitable for assaying oceanic levels of pHT from 7.4 to 8.2 for normal seawater of practical salinity ranging from 20 to 40.
Continue reading ‘ISO 18191:2026 – Water quality — Determination of pHT in seawater — Method using the purple indicator of m-cresol’From climate data to regulatory decisions: integrating climate AI into marine EIAs
Published 13 August 2026 Science ClosedTags: policy
Climate change is increasingly reshaping the sustainable development of the ocean through ocean warming, deoxygenation, acidification, and other compounding stressors. Against this backdrop, environmental impact assessment (EIA) has become a pivotal governance instrument for anticipating and reducing the climate-related impacts of human activities at sea. From the United Nations Convention on the Law of the Sea (UNCLOS) to the Agreement on Biodiversity Beyond National Jurisdiction (the BBNJ Agreement), regulatory expectations for marine EIAs are moving toward more structured thresholds, procedural workflows, and reporting obligations. At the same time, rapid advances in climate artificial intelligence (climate AI), such as machine-learning forecasting, deep-learning nowcasting, and agentic AI workflows, are expanding the ability to produce timely, high-resolution, and probabilistic climate information from heterogeneous climate data streams. These capabilities can strengthen climate-related EIAs by combining short-term forecasting and nowcasting for early warning, long-term observation and monitoring for dynamic baselines, and scenario-based climate modelling for impact estimation and decision support. Climate AI can therefore be integrated throughout the EIA workflow rather than appended as an auxiliary layer, translating climate data into regulatory evidence under changing marine-climate conditions. To ensure regulatory robustness and accountability, implementation should be grounded in evidence standards and quality assurance, transparent and auditable documentation, human oversight, responsibility allocation, and formal mechanisms for cross-institutional data sharing. We argue that a standards-driven, AI-enabled EIA framework can improve the relevance, reviewability, and robustness of marine EIA decisions, supporting long-term ocean sustainability under accelerating climate risks.
Continue reading ‘From climate data to regulatory decisions: integrating climate AI into marine EIAs’The Third World Ocean Assessment
Published 20 July 2026 Newsletters and reports , Science ClosedTags: policy, resource, socio-economy
Share the knowledge on the ocean
The ocean is the foundation of life on Earth. But its health is at grave risk as ecosystems and habitats approach or surpass critical tipping points. In the search for solutions, ocean science is indispensable. The third World Ocean Assessment offers the most comprehensive evaluation to date, providing Governments, institutions and the public with the evidence needed to shape coordinated, effective action.
Five years ago, the previous Assessment found persistent degradation of marine ecosystems. This third Assessment documents a deepening crisis, as climate change, pollution, overfishing and biodiversity loss put ocean systems under severe strain. Its findings demand urgent action, through stronger multilateral cooperation, greater ambition and decisions grounded in the best available science.
This Assessment comes midway through the United Nations Decade of Ocean Science for Sustainable Development and the United Nations Decade on Ecosystem Restoration. It takes stock of what we have learned, how far we have come and what more is needed to secure a healthy, resilient ocean for current and future generations.
The entry into force of the Agreement under the United Nations Convention on the Law of the Sea on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction in January 2026 marks a historic milestone for ocean stewardship and multilateral cooperation. Now we must translate that momentum, and the latest science, into decisive action for a healthy and resilient ocean.
May this Assessment strengthen our resolve to protect the ocean and, in doing so, help safeguard our climate, our food systems, our prosperity and our future.
António Guterres, Secretary-General of the United Nations
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Continue reading ‘The Third World Ocean Assessment’Policy brief: ocean acidification & food security
Published 15 July 2026 Science ClosedTags: policy
Key insights
Policymakers and researchers can better understand, mitigate, and adapt to the impact of ocean acidification on food security, ensuring a more sustainable future for blue foods and the communities that depend on them if they:
- Ensure baseline measurements of acidification are taken across different ocean basins.
- Research the impact of ocean acidification on fisheries, shellfish, coral and plankton and priortize seafood
species of local importance. - Explore knowledge gaps in ocean acidification science and research through a food security lens.
- Align and integrate ocean acidification and food security research with regional and national policy objectives.
- Leverage international frameworks to direct research, policy and financing support to more adequately assist
nations in prolonged responses to the impacts of ocean acidification on food security
Key takeaways:
By implementing these recommendations, policymakers and researchers can better understand, mitigate, and adapt to the impact of ocean acidification on food security, ensuring a more sustainable future for blue foods and the communities that depend on them:
- Ensure baseline measurements of acidification are taken across different ocean basins.
- Research the impact of ocean acidification on fisheries, shellfish, coral and plankton and prioritize seafood species of local importance.
- Explore knowledge gaps in ocean acidification science and research through a food security lens.
- Align and integrate ocean acidification and food security research with regional and national policy objectives.
- Leverage international frameworks to direct research, policy and financing support to more adequately assist nations in prolonged responses to the impacts of ocean acidification on food security.
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Continue reading ‘Policy brief: ocean acidification & food security’Dialogue, inclusion, and adaptation in a remote marine sanctuary: evidence from Flower Garden Banks
Published 10 June 2026 Science ClosedTags: modeling, policy, review
Interdisciplinary, stakeholder-engaged research is increasingly being used for managing climate change in social-ecological systems. We apply a Collaborative Adaptive Experimental Governance lens to the Flower Garden Banks National Marine Sanctuary, a remote, relatively pristine coral reef system ~130–190 km offshore in the Gulf of Mexico, where biodiversity protection coexists with recreation and offshore energy. We coupled participatory social science with climate and ecosystem modeling to inform dialogue with decision-makers and users. First, we generated scenarios using Community Earth System Model2-LE ocean temperature and aragonite saturation state to characterize warming and acidification; translated heat stress into a variability-based coral bleaching index; and projected demersal and pelagic fish biomass. We then conducted 37 semi-structured interviews (managers, oil and gas, commercial and recreational fisheries, dive operators, Non-governmental organizations, and science/education), employed multi-coder reliability, and triangulated findings with policy and legal documents. Results highlight the centrality of the Sanctuary Advisory Council in structuring inclusive dialogue, co-producing recommendations, and supporting outreach in distant coastal communities. Multi-level coordination among NOAA, the Gulf of Mexico Fishery Management Council, and the Bureau of Ocean Energy Management enabled boundary expansion and reconciled conservation with industry and fishing interests. Key barriers to adaptive responses include offshore remoteness and logistics, limited public awareness, funding constraints, trust deficits, and procedural delays; pressures that intersect with warming, acidification, and episodic hypoxia. Our study shows that remote marine protected areas can operationalize inclusive, experimental governance to align science and management, but sustained investment in monitoring, restoration capacity, boundary-spanning outreach, and cross-agency coordination is needed.
Continue reading ‘Dialogue, inclusion, and adaptation in a remote marine sanctuary: evidence from Flower Garden Banks’Climate change impact on the socioeconomic conditions and well-being of the South Asian small-scale fishermen: a review
Published 5 June 2026 Science ClosedTags: policy, review, socio-economy
Climate change is a major threat to the small-scale fishing communities, particularly in South Asia, a region characterized by widespread coastlines, extreme population density, and high dependence on marine resources for food, income, and employment. This review synthesizes findings from peer-reviewed articles published between 2000 and 2025 to analyse the climate change impact on socioeconomic conditions and well-being of the small-scale fishermen. The review identifies a range of climatic stressors, such as rising sea surface temperatures, ocean acidification, sea level rise, and extreme weather events, that are severely disrupting marine ecosystems and fish availability. These ecological shifts directly affect the livelihoods, income stability, and food security of fishing communities, escalating existing vulnerabilities like poverty, indebtedness, and limited occupational mobility. The study categorizes the impacts into physical, economic, and social dimensions, highlighting issues such as declining catch volumes, increased operational costs, infrastructure destruction, and disruptions in food supply and nutrition. It also examines local and regional adaptation responses, ranging from ecosystem-based solutions, such as mangrove restoration and cage aquaculture, to institutional and behavioural shifts, including migration, livelihood diversification, and early warning systems. While some adaptations enhance resilience, others pose sustainability challenges. This review highlights the pressing need for targeted policy interventions that support sustainable adaptation, enhance institutional frameworks, and prioritize vulnerable fishing communities in climate resilience planning.
Continue reading ‘Climate change impact on the socioeconomic conditions and well-being of the South Asian small-scale fishermen: a review’Navigating the souring seas: the global experimentalist governance of ocean acidification
Published 2 June 2026 Science ClosedTags: policy
Navigating the Souring Seas explores how ocean acidification (OA)-a significant yet under-governed environmental threat-is being addressed on the global stage. Bridging science, law, and international policy, this interdisciplinary book introduces global experimentalist governance as an innovative and adaptable framework for tackling complex and uncertain issues like OA. It provides a clear overview of the scientific background of OA and maps the international governance landscape, identifying it as a regime complex. Through detailed interview-based case studies of the Ocean Acidification Alliance and the International Maritime Organization, the book evaluates real-world efforts to govern OA and highlights how experimentalist features, such as flexibility, learning, and multilevel collaboration, can enhance their effectiveness. Accessible and timely, this book is essential reading for scholars, students, policymakers, and environmental practitioners seeking practical, forward-looking governance strategies for ocean and climate challenges. It offers both theoretical insight and concrete recommendations for improving global environmental governance.
Continue reading ‘Navigating the souring seas: the global experimentalist governance of ocean acidification’HELCOM strategic approach to ocean acidification
Published 16 April 2026 Newsletters and reports ClosedTags: Baltic, policy
Acidification of the global oceans is a major trend. In the past, a well-documented trend of increasing alkalinity has partly counter acted drivers of acidification in the Baltic Sea. However, decrease in pH has been observed in areas of intense respiration of organic matter and hypoxia. General long-term projection indicates intensified acidification of the Baltic Sea.
There is uncertainty in how ocean acidification may impact the Baltic Sea ecosystem in the future. Developing a shared view of the current evidence base would be a first step in HELCOM. This could inform future work on adapting policies or developing new measures. In order to understand ocean acidification of the Baltic Sea, there is a need to better understand the carbon-cycle. Monitoring and measurements of carbon parameters are central to the assessment of eutrophication, a topic which has been a focus area of HELCOM for decades. Alkalinity of the Baltic Sea waters is a key element to be addressed and is a focus area for this strategic approach. There could be differences in alkalinity between surface- and deep-waters that would need to be better understood, and there are knowledge gaps in how the Baltic Sea functions in terms of alkalinity sources and sinks.
The HELCOM Baltic Sea Action Plan 2021 sets the scene for this HELCOM strategic approach to ocean acidification; “Although acidification is currently not a major trend in the Baltic Sea ecosystem, it is an advancing and significant trend in the world’s oceans, directly connected to carbon dioxide emissions. The long-term forecast for the Baltic Sea also projects an increased acidification, but neither the carbon chemistry of the Baltic Sea nor possible impacts of acidification on biota are fully understood yet, and mitigation measures have not been considered so far. “
The role of HELCOM is to facilitate a science-policy dialogue on how ocean acidification affects the Baltic Sea ecosystem and related services, and to explore options for adaptation to this pressure and encourage actions to reduce CO2 emissions by taking action on climate change.
HELCOM also has a role in coordinating environmental monitoring in the Baltic Sea. An overarching aim of this strategic approach is to develop a future monitoring programme that is optimised on the regional scale in terms of spatial and temporal scope.
This strategic approach describes how HELCOM will use its existing structures to assess and address the emerging pressure of ocean acidification. HELCOM will collaborate with other organisations and institutions to create an evidence base to inform policy actions and measures. HELCOM will coordinate work between its subsidiary bodies to ensure best available scientific knowledge is used to create a coherent response to ocean acidification.
Continue reading ‘HELCOM strategic approach to ocean acidification’Ocean acidification: the silent threat to marine biodiversity
Published 8 April 2026 Science ClosedTags: Indian, policy, review
Ocean acidification (OA) is one of the quietest yet most profound changes unfolding in our seas. Caused mainly by the ocean’s absorption of excess carbon dioxide from the atmosphere, it steadily lowers seawater pH and depletes carbonate ions — the essential building blocks for shells, skeletons, and coral reefs. These chemical shifts ripple through marine ecosystems, weakening coral structures, slowing the growth of shellfish, disrupting plankton communities, and ultimately destabilising the food webs that sustain biodiversity and human livelihoods. Although OA is recognised as a global problem, its effects are not uniform. Some regions, particularly the Indian Ocean and other tropical waters, remain poorly studied despite being home to rich biodiversity and millions of people whose lives depend on healthy coastal ecosystems. This paper focuses on OA as a “silent” driver of biodiversity loss and addresses two major gaps: the lack of strong policy and governance integration, and the scarcity of regional data for Indian and tropical waters. To explore how OA is framed in global agreements such as the United Nations Convention on the Law of the Sea (UNCLOS) and the Paris Agreement, and examine its treatment in India’s environmental laws, including the Environment (Protection) Act, Coastal Regulation Zone rules, and the Biological Diversity Act. While these frameworks provide important protections, none directly target OA or mandate systematic monitoring. The shortage of long-term, high-resolution data on pH and carbonate chemistry in Indian waters makes it difficult to gauge the scale of the threat or design locally relevant solutions. The lack of species-specific studies in this region adds further uncertainty to impact predictions. This is mainly upon doctrinal studies. This study calls for integrating OA into national marine policies, creating dedicated monitoring networks in the Indian Ocean, and fostering interdisciplinary research that links chemical changes to ecological shifts and community livelihoods. Closing these gaps is vital not only for protecting marine biodiversity but also for ensuring food security and economic stability for coastal populations.
Continue reading ‘Ocean acidification: the silent threat to marine biodiversity’California’s 2026 Coast and Ocean Assessment
Published 1 April 2026 Science ClosedTags: North Pacific, policy, review
Key Messages
- California’s coastal ocean moderates our climate, holds potential solutions to climate change, and is directly impacted by a changing climate. California’s coast and ocean are also critical natural resources and economic assets, generating $51.3 billion in gross domestic product and supporting more than 500,000 jobs.
- The public and policymakers can get a broad, state-level understanding of the overall status of the coast and ocean through this synthesis of complex data into single statewide metrics and subsequent aggregation of those evaluations in this report. At the same time, some categories are better understood through downscaled or local evaluations.
- This coast and ocean assessment is the result of the work of more than 120 scientific experts from academic institutions, state and federal agencies, NGOs, and Tribes. The widespread support that it has garnered exemplifies the value of leveraging buy-in from a broad scientific community that stands poised to continue to support in delivering the best available science to policymakers.
- State-federal partnerships provide essential infrastructure: evaluations for 13 of the 19 categories leveraged federal data, and the evaluations of five categories were fully reliant on the specialized expertise and in-kind time of federal scientists.
- Distilling data into single metrics for each category enabled us to flexibly incorporate multiple data types, retain geographic information while providing statewide coverage, and present findings that are both accurate and easily understood. This approach also ensures forward compatibility to incorporate new data as they become available and repeat this
analysis in the future. - The 2014-2015 marine heatwave was a seminal event that disrupted California’s ocean ecosystems, including loss of species and ecosystem services, declining populations, and geographic range shifts. We can expect more warm years like this in the future.
- The state has a valuable role to play in strengthening the ocean monitoring and evaluation enterprise, such as expanding monitoring in Northern California, coordinating networks and standardizing methods, supporting innovative monitoring technologies to better track cryptic species, and identifying where strategic investments can fill data gaps.
See summary of ocean acidification findings.
Continue reading ‘California’s 2026 Coast and Ocean Assessment’State of the global climate 2025
Published 30 March 2026 Newsletters and reports ClosedTags: chemistry, policy, review
The temperature of the Earth changes in response to the rate at which energy enters and leaves the Earth system. Increasing concentrations of greenhouse gases in the atmosphere such as carbon dioxide, methane and nitrous oxide, all of which reached their highest level in 800 000 years in 2024 (the last year for which we have consolidated global figures), reduce the rate at which energy leaves the Earth system. This imbalance – the Earth’s energy imbalance, a new indicator in this year’s report – leads to an accumulation of excess energy.
One of the longest observational records of climate change is that of global mean near-surface temperature. The past three years are the three warmest years in the 176-year combined land and ocean observational record. The year 2025 is the second or third warmest year, depending on the dataset used, slightly cooler than the record warmth of 2024, due in part to the transition from El Niño at the start of 2024 to La Niña in 2025. The warming seen at the surface and throughout the troposphere represents just 1% of the excess energy trapped by greenhouse gases.
The vast majority of the excess energy – around 91% – has been absorbed by the ocean in the form of heat. Ocean heat content reached a new record high in 2025, reflecting the continued increase in energy.
Another 3% of the excess energy warms and melts ice. In a global set of reference glaciers with long-term measurements, eight of the ten most negative annual glacier mass balances since 1950 have occurred since 2016. The ice sheets on Antarctica and Greenland have both lost significant mass since satellite records began.
The extent of sea ice in the Arctic has decreased in all seasons since satellite measurements began in 1979, and the annual maximum extent in 2025 was the lowest or second lowest in the observed records. Sea-ice extent around Antarctica showed a small long-term increase until 2015, but since then, extents throughout the annual cycle have dropped considerably, and the past four years have seen the four lowest Antarctic sea-ice minima on record.
The warming ocean and melting of ice on land from glaciers and ice sheets have both contributed to the long-term rise in global mean sea level. The rate of global sea-level rise has increased since satellite measurements began in 1993.
The remaining ~5% of the excess energy is stored in the continents, increasing the temperature of the land mass and thereby affecting terrestrial processes.
As well as absorbing the majority of the energy trapped by increasing concentrations of greenhouse gases, the ocean has also absorbed around 29% of the anthropogenic emissions of carbon dioxide in the past decade. While this helps to buffer the effects of climate change, it also alters the chemical composition of the ocean water, reducing the pH in a process known as ocean acidification.
These rapid large-scale changes in the Earth system have cascading impacts on human and natural systems, contributing to food insecurity and displacement where hazards intersect with high vulnerability and limited adaptive capacity.
Continue reading ‘State of the global climate 2025’
