Tag: Marine Ecosystems

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

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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.

Ocean warming study so distressing, some scientists didn’t even want to talk about it

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Ship in the ocean, Hamburg, Germany. Photo by Martin Damboldt from Pexels.
Ship in the ocean, Hamburg, Germany. Photo by Martin Damboldt from Pexels.

“This is one of those ‘sit up and read very carefully’ moments,” said one science journalist.

By Julia Conley, Common Dreams

Scientists are so alarmed by a new study on ocean warming that some declined to speak about it on the record, the BBC reported Tuesday.

“One spoke of being ‘extremely worried and completely stressed,'” the outlet reported regarding a scientist who was approached about research published in the journal Earth System Science Data on April 17, as the study warned that the ocean is heating up more rapidly than experts previously realized—posing a greater risk for sea-level rise, extreme weather, and the loss of marine ecosystems.

Scientists from institutions including Mercator Ocean International in France, Scripps Institution of Oceanography in the United States, and Royal Netherlands Institute for Sea Research collaborated to discover that as the planet has accumulated as much heat in the past 15 years as it did in the previous 45 years, the majority of the excess heat has been absorbed by the oceans.

In March, researchers examining the ocean off the east coast of North America found that the water’s surface was 13.8°C, or 24.8°F, hotter than the average temperature between 1981 and 2011.

The study notes that a rapid drop in shipping-related pollution could be behind some of the most recent warming, since fuel regulations introduced in 2020 by the International Maritime Organization reduced the heat-reflecting aerosol particles in the atmosphere and caused the ocean to absorb more energy.

But that doesn’t account for the average global ocean surface temperature rising by 0.9°C from preindustrial levels, with 0.6°C taking place in the last four decades.

The study represents “one of those ‘sit up and read very carefully’ moments,” said former BBC science editor David Shukman.

Lead study author Karina Von Schuckmann of Mercator Ocean International told the BBC that “it’s not yet well established, why such a rapid change, and such a huge change is happening.”

“We have doubled the heat in the climate system the last 15 years, I don’t want to say this is climate change, or natural variability or a mixture of both, we don’t know yet,” she said. “But we do see this change.”

Scientists have consistently warned that the continued burning of fossil fuels by humans is heating the planet, including the oceans. Hotter oceans could lead to further glacial melting—in turn weakening ocean currents that carry warm water across the globe and support the global food chain—as well as intensified hurricanes and tropical storms, ocean acidification, and rising sea levels due to thermal expansion.

A study published earlier this year also found that rising ocean temperatures combined with high levels of salinity lead to the “stratification” of the oceans, and in turn, a loss of oxygen in the water.

“Deoxygenation itself is a nightmare for not only marine life and ecosystems but also for humans and our terrestrial ecosystems,” researchers from the Chinese Academy of Sciences, the National Center for Atmospheric Research, and the National Oceanic and Atmospheric Administration said in January. “Reducing oceanic diversity and displacing important species can wreak havoc on fishing-dependent communities and their economies, and this can have a ripple effect on the way most people are able to interact with their environment.”

The unusual warming trend over recent years has been detected as a strong El Niño Southern Oscillation (ENSO) is expected to form in the coming months—a naturally occurring phenomenon that warms oceans and will reverse the cooling impact of La Niña, which has been in effect for the past three years.

“If a new El Niño comes on top of it, we will probably have additional global warming of 0.2-0.25°C,” Dr. Josef Ludescher of the Potsdam Institute for Climate Research told the BBC.

The world’s oceans are a crucial tool in moderating the climate, as they absorb heat trapped in the atmosphere by greenhouse gases.

Too much warming has led to concerns among scientists that “as more heat goes into the ocean, the waters may be less able to store excess energy,” the BBC reported.

The anxiety of climate experts regarding the new findings, said the global climate action movement Extinction Rebellion, drives home the point that “scientists are just people with lives and families who’ve learnt to understand the implications of data better.”

Red List calls out ‘perfect storm of unsustainable human activity decimating marine life’

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Turtle at Sea. Photo by Jeremy Bishop

“As the world looks to the ongoing U.N. Biodiversity Conference to set the course for nature recovery, we simply cannot afford to fail,” said the head of the International Union for Conservation of Nature.

By Jessica Corbett, Common Dreams

During the United Nations biodiversity summit in Montreal, an international conversation group on Friday highlighted how humanity is dangerously failing marine life with illegal and unsustainable fishing, pollution from agricultural and industrial runoff, and activities that drive up global temperatures.

The International Union for Conservation of Nature (IUCN) Red List of Threatened Species now features 150,388 species, 42,108 of which face possible extinction. Of the 17,903 marine animals and plants on the list, more than 1,550 are at risk.

“Today’s IUCN Red List update reveals a perfect storm of unsustainable human activity decimating marine life around the globe. As the world looks to the ongoing U.N. Biodiversity Conference to set the course for nature recovery, we simply cannot afford to fail,” Bruno Oberle, the group’s director general, warned Friday. “We urgently need to address the linked climate and biodiversity crises, with profound changes to our economic systems, or we risk losing the crucial benefits the oceans provide us with.”

The primary aim of the 15th Conference of the Parties (COP15) of the Convention on Biological Diversity (CBD)—which is hosted by China but kicked off earlier in Canada this week due to Covid-19 restrictions—is the development of post-2020 global biodiversity framework (GBF).

A top priority for many parties to the treaty—along with the United States, which has failed to ratify the CBD over the past three decades but is still participating in the summit—is to protect 30% of lands and waters by 2030. However, as activists and Indigenous leaders from around the world have noted, there are serious human rights concerns regarding implementation of the 30×30 goal.

COP15 comes after the fifth round of discussions about establishing a U.N. treaty for the high seas, or the two-thirds of oceans outside territorial waters. Those August talks failed to produce an agreement—which, as Laura Meller of Greenpeace’s Protect the Oceans campaign warned at the time, “jeopardizes the livelihoods and food security of billions of people around the world.”

“While progress has been made, particularly on ocean sanctuaries, members of the High Ambition Coalition and countries like the USA have moved too slowly to find compromises, despite their commitments,” Meller continued. “Time has run out. Further delay means ocean destruction. We are sad and disappointed. While countries continue to talk, the oceans and all those who rely on them will suffer.”

Similarly, urgent warnings came with the update Friday. Ashleigh McGovern, vice president of the Center for Oceans at Conservation International, said that “with this devastating IUCN Red List update on the status of marine species, it is clear that business as usual is no longer an option.”

“Human activity has had devastating effects on marine ecosystems and biodiversity, but it can also be harnessed to drive action as a matter of survival, equity, and climate justice,” she added. “If we are to secure a new future for the world’s oceans and the essential biodiversity they harbor, we must act now.”

Jon Paul Rodríguez, chair of the IUCN Species Survival Commission (SSC), pointed out that “most of the Earth’s biosphere, 99% of all livable space on our planet, is underwater.”

“Humanity acts as if oceans were inexhaustible, capable of sustaining infinite harvest of algae, animals, and plants for food and other products, able to transform vast quantities of sewage and other pollutants that we pour in coastal areas, and absorb the CO2 generated by land-use change and burning fossil fuel,” he said. “This Red List update brings to light new evidence of the multiple interacting threats to declining life in the sea.”

According to the IUCN Red List, 20 of the 54 abalone species—some of the world’s most expensive seafood—are threatened with extinction.

“Abalones reflect humanity’s disastrous guardianship of our oceans in microcosm: overfishing, pollution, disease, habitat loss, algal blooms, warming, and acidification, to name but a few threats. They really are the canary in the coal mine,” said Howard Peters, a member of the IUCN SSC Mollusc Specialist Group and research associate at the U.K.’s University of York who led the abalone assessment.

“The most immediate action people can take is to eat only farmed or sustainably sourced abalones. Enforcing fishery quotas and anti-poaching measures is also critical,” Peters noted. “However, we need to halt the changes to ocean chemistry and temperature to preserve marine life including abalone species over the long term.”

The update also raised the alarm about dugongs, particularly in East Africa and New Caledonia. Populations of the large herbivorous marine mammals are threatened by fishing gear, oil and gas exploration and production, chemical pollution, and the destruction of seagrasses they rely on for food.

“Strengthening community-led fisheries governance and expanding work opportunities beyond fishing are key in East Africa, where marine ecosystems are fundamental to people’s food security and livelihoods,” said Evan Trotzuk, who led the region’s assessment.

Another focus of the list is the pillar coral in the Caribbean, given that its population has shrunk by more than 80% across most of its range over the past three decades.

Noting that it is just one of 26 corals now listed as critically endangered in the Atlantic Ocean, Arizona State University associate professor Beth Polidoro, Red List coordinator for the IUCN SSC Coral Specialist Group, said that “these alarming results emphasize the urgency of global cooperation and action to address climate change impacts on ocean ecosystems.”

Amanda Vincent, chair of the IUCN SSC Marine Conservation Committee, declared that “the awful status of these species should shock us and engage us for urgent action.”

“These magical marine species are treasured wildlife, from the wonderful abalone to the charismatic dugong and the glorious pillar coral, and we should safeguard them accordingly,” she added. “It is vital that we manage fisheries properly, constrain climate change, and reverse habitat degradation.”

Nodding to the conference, Jane Smart, director of IUCN’s Science and Data Center, said the update reinforces her group’s “urgent call for a post-2020 global biodiversity framework that will be ambitious enough to cease destruction of our life support system and catalyze the necessary action and change to secure life on this planet.”