Ocean in Peril: Understanding the Escalating Threat of Marine Heatwaves and Acidification



Ocean sea life and coral reef. Credit: Francesco Ungaro, Unsplash.


As the planet grapples with climate change, our oceans are experiencing unprecedented shifts. Recent research by Joel Wong, Matthias Münnich, and Nicolas Gruber, Column‐Compound Extremes in the Global Ocean published in the Journal of Oceanic Studies into the increasing frequency, intensity, and spatial extent of compound marine extremes—particularly marine heatwaves combined with ocean acidification—highlights a looming crisis for global marine ecosystems. The study, conducted over nearly six decades, offers important insights into these phenomena and underscores the urgent need for global environmental strategies.

The Escalating Intensity of Marine Extremes

The study analyzes data from 1961 to 2020, revealing a concerning trend in the behavior of oceanic compound extremes, referred to as Column-Compound Extreme Events (CCX). These events, characterized by simultaneous occurrences of extreme heat and acidity, have become more intense and longer-lasting over the years. Such changes are primarily driven by global warming and increased carbon dioxide emissions, which not only warm but also acidify ocean waters at alarming rates.

Impact on Marine Life

The effects of these compound extremes are profound. Marine ecosystems, particularly coral reefs, kelp forests, and the myriad species dependent on them, face severe threats from prolonged exposure to extreme conditions. The study estimates that the habitable space within the water column has potentially reduced by up to 75%, a stark indication of the dire conditions many marine organisms now endure. This habitat compression threatens biodiversity, disrupts fishing industries, and jeopardizes the livelihoods of communities dependent on these ecosystems.

Geographic and Vertical Spread

The research identifies that these extremes are not uniformly distributed. Tropical and high latitude regions, known for their rich biodiversity, are the most affected. The impacts extend beyond the surface, complicating the survival conditions for species that cannot migrate to more hospitable waters.

Role of Climate Phenomena

El Niño and other climate phenomena play a significant role in modulating these compound events. The study highlights specific patterns and regional variations in CCX occurrences, linking them to broader climatic shifts that influence ocean currents and temperature distribution.

Need for Advanced Modeling Techniques

A key contribution of this research is the development of advanced models that enhance our understanding of CCX characteristics and drivers. These models are crucial for predicting future changes and implementing effective conservation strategies. They also serve as a vital tool for policymakers and environmental planners as they prepare to mitigate the effects of these changes.

Summing Up

The findings from the study serve as a clarion call for immediate action. Protecting our oceans from compound extremes requires global cooperation and innovative solutions aimed at reducing greenhouse gas emissions and enhancing marine conservation efforts. This research provides a foundation for understanding the scale of the problem and outlines the critical areas for needed interventions.

The preservation of marine biodiversity and the sustainability of our global ocean ecosystems depend on our ability to respond effectively to the challenges posed by climate change. Through informed policy-making and collaborative international efforts, there is hope for mitigating the impact of these profound marine disturbances.


Source: Wong, J., Münnich, M., & Gruber, N. (2024). Column‐Compound Extremes in the Global Ocean. Journal of Oceanic Studies, 5(3). https://doi.org/10.1029/2023AV001059.

A new deal for nature?

Lake Forest. Image by Alain Audet from Pixabay
Lake Forest. Image by Alain Audet from Pixabay

Feeling out the new framework for biodiversity protection with the Kunming-Montreal pact

By Robert Nasi, Forests News

Well, they got there. After years-long delays due to the COVID-19 pandemic, a relocation from Kunming, China to Montreal, Canada, and following weeks of late-night negotiations peppered with walkouts and protests, a ‘new deal’ for biodiversity has been struck: on 19 December 2022, the Kunming-Montreal Global Biodiversity Framework (GBF) was adopted as the outcome of the 15th meeting of the Conference of the Parties (COP15) to the UN Convention on Biological Diversity (UNCBD).

The failure of the framework’s predecessor – none of the biodiversity targets set at Aichi in 2010 were reached by the 2020 deadline – added to the fraught tenure of the negotiations. The new framework isn’t perfect, as I’ll explain, but there are some important elements that, if implemented effectively and equitably, can make genuine impact.

Perhaps most notable is the target of protecting 30 percent of Earth’s land and sea by 2030. The global nature of the target means that the focus will be on the most biodiverse countries protecting key areas such as the tropical forests of the Amazon, the Congo Basin, and Indonesia – all areas where the Center for International Forestry Research and World Agroforestry (CIFOR-ICRAF) has a strong presence and strong partnerships.

Given it took the global community almost six decades to protect 17% of the planet, this is a lofty goal that will require coordinated – and careful – action. Much protected area creation in the past has been propelled by colonialist ‘fortress conservation’ approaches that fail to take the rights, territories, and contributions of Indigenous Peoples and local communities into account. Such restrictive approaches have had dire consequences for people and nature, with both biodiversity and livelihoods crumbling as a result.

As such, the strong language on these issues in the new framework – which reaffirms the protection of Indigenous rights and territories throughout its 23 targets and four goals, and purports to ensure their voice in decision-making – is to be commended, though as always it will be crucial to pay careful attention to how and if this plays out on the ground. As much of CIFOR-ICRAF’s work highlights, it’s critically important to recognize human agency in the shaping of sustainable landscapes. As a global community, we need to become more skillful at differentiating between human activity that has been harmful and natural resource use that has been, is, or can be sustainable.

On that note, the agreement to develop a multilateral benefit-sharing and funding mechanism, to help put sovereignty over digital genetic code in the hands of those in whose land and sea-scapes it resides (rather than those of biopirates and corporations) is also significant. It was heartening, too, to see a new standalone target on gender equality and women and girls’ empowerment, and the inclusion of the term ‘gender-responsive’ in place of the weaker ‘gender-sensitive’. Also welcome is the (long overdue) target of reducing harmful subsidies for fisheries, agriculture and fossil fuels by at least USD 500 billion annually by 2030: right now, at least USD 1.8 trillion of such subsidies are financing the destruction of biodiversity each year.

Among these victories, it was disappointing to see the watering-down of language promoting and centering agroecology in the framework’s sustainable agriculture target. The final text reads, “The application of biodiversity-friendly practices, such as sustainable intensification, agroecological and other innovative approaches”; sustainable intensification, however, causes significant biodiversity loss and has been shown not to stop agricultural expansion. Another concern is that over-emphasis on protected areas through the 30×30 target could take away from necessary attention on developing biodiverse, inclusive, and resilient food systems – a subject on which CIFOR-ICRAF has a combined 70 years of international experience. Agroforestry and trees on farms, for instance, can play a significant role in restoring and enhancing ecosystems while producing critical food and nutrition.

Discussions on who will foot the bill for biodiversity conservation were also fraught, and wealthier countries’ reluctance to front up prompted the walk-out of delegates from over 70 countries in the Global South at one stage. In the end, the financial target of USD 200 billion a year for conservation initiatives – a sum determined to be critical for the framework’s success – was reached, through some developing countries such as the Democratic Republic of the Congo (DRC), Brazil and Malaysia expressed disappointment that richer ones did not offer up a larger amount, and that a new fund for biodiversity was not established.

So, now that we have an agreed path towards halting the loss of species and protecting the world’s remaining biodiversity, what lies ahead? By addressing the current polycrisis  – biodiversity loss, climate crisis, growing inequalities, broken food systems, unsustainable supply chains – simultaneously through transdisciplinary science, CIFOR-ICRAF is delivering holistic solutions at scale in priority areas with the greatest potential for positive impact: sustainably managing multiple-use landscapes, promoting conservation in productive landscapes through agroecological approaches, and preserving local and global livelihoods. We will continue working to reverse negative environmental trends by generating evidence of the enormous value of trees – in forests, on farms, and across landscapes.


Robert Nasi is the Director General of the Center for International Forestry Research (CIFOR)