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Within the ocean’s vast expanse lie immense reservoirs of carbon – surpassing those found in either the atmosphere or the land.

The ocean actively captures and incorporates carbon through various natural mechanisms, locking in a significant portion that would otherwise circulate within the Earth’s systems, thereby functioning as a continuous carbon sink.

This crucial role mitigates climate change by reducing the amount of carbon which ends up in the atmosphere. If the ocean remains as a net carbon sink, it can aid in offsetting ongoing emissions and slowing global warming.

Unfortunately, a longstanding misconception persists that the ocean has an infinite resilience to human exploitation and negligence – likely stemming from the fact that the consequences of our actions are obscured beneath the surface.

Unsustainable use of the ocean’s resources – such as through overfishing – coupled with warming and acidification progressively erode the ocean’s capacity to regulate carbon and heat and its ability to sustain essential resources and services. 

Consequently, rates of carbon sequestration are weakening and the vast carbon reserves held within marine ecosystems are increasingly susceptible to release. 

This guest post lays out the climate opportunities presented by “blue carbon” and the challenges these ecosystems face.

Blue carbon is a term that refers to carbon captured by the world’s ocean and coastal ecosystems that has potential to be conserved or enhanced. Blue carbon is stored in vegetated coastal and marine ecosystems such as seagrass, mangroves and salt marshes.

The opportunity of coastal ecosystems

Coastal ecosystems – particularly vegetated ones, such as mangroves, seagrasses and salt marshes – are among the most crucial marine systems for storing carbon. Like plants on land, marine vegetation absorbs CO2 through photosynthesis. Because their waterlogged soils are low in oxygen, the carbon stored there can be locked away for centuries.

Despite only occupying approximately 0.5% of the ocean, these ecosystems boast remarkable carbon sequestration capabilities, contributing more than 50% of total carbon buried in marine sediments.

However, these vital ecosystems also face relentless human-caused pressures, from runoff of nutrients and sediments to urban expansion. They are being destroyed at an alarming pace – an average of 2% loss per year for mangroves – and are among the most threatened ecosystems on the planet. 

Nevertheless, amidst this threat lies an opportunity: by reversing the conditions that are causing their decline, we can restore lost ecosystems and harness their potential as carbon sequestration hotspots once more.

The chart below shows the annual carbon storage potential of coastal ecosystems around the world, with yellow and light green indicating low storage potential and darker blues indicating high storage potential. The US, Mexico, Australia, Indonesia and Mexico stand out as countries with particularly high storage potential.    

Map of global blue carbon stocks (in millions of tonnes of carbon), with yellow and green colours representing lower amounts of blue carbon storage potential and blues indicating higher amounts of storage potential. Source: Bertram et al. (2021).
Map of global blue carbon stocks (in millions of tonnes of carbon), with yellow and green colours representing lower amounts of blue carbon storage potential and blues indicating higher amounts of storage potential. Source: Bertram et al. (2021)

Managing coastal vegetated ecosystems to enhance carbon sequestration, often referred to as “blue carbon”, represents a valuable nature-based strategy for mitigating climate change. 

While the amount of carbon that is offset through these methods is estimated to be at least an order of magnitude below other mitigation approaches – such as ocean alkalinisation and direct carbon capture and storage – they have additional benefits. 

These ecosystems also enhance adaptation by stabilising coastlines, safeguarding against erosion and storms, enhancing water quality and nurturing marine life – thus promoting biodiversity through the provision of shelter, food and nursery grounds.

Climate and biodiversity

Blue carbon is a prime example of how climate change and the alarming decline in global biodiversity are connected

Initiatives focused on blue carbon restoration – such as the “Mangroves for Coastal Resilience” project in Indonesia, the largest such initiative in the world – not only enhance carbon sequestration, but also reverse habitat loss and bolster biodiversity. Safeguarding marine biodiversity can also help secure the long-term well-being and prosperity of people whose lives and livelihoods are tightly linked to the oceans. 

For example, declines in marine biodiversity undermine ecosystem resilience, heightening vulnerability to environmental disturbances and impacting economies reliant on marine resources. Loss of species degrades the food webs underpinning fisheries, jeopardising food security and livelihoods.

Furthermore, biodiversity loss directly compromises human health by fostering the emergence of zoonotic diseases that pass from animals to humans, diminishing water quality and impeding the exploration of new pharmaceuticals and treatments. 

Protecting communities

Coastal restoration projects are already being carried out around the world, from small, local projects to larger initiatives.

They also encompass a range of activities, from planting new mangrove trees to managing tidal flows.

There are several crucial factors that demand careful consideration before implementing such a project.

Among these is the need to prioritise the protection of intact ecosystems. By safeguarding these areas, we can prevent the loss of carbon they have already sequestered and sidestep the time lag associated with re-establishing vital ecosystem services following habitat restoration. 

Additionally, it is imperative to address the underlying pressures contributing to ecosystem loss, such as sewage discharge and agricultural runoff. 

Volunteers planting spartina grasses at a salt marsh restoration event, Jamaica Bay Wildlife Refuge.
Volunteers planting spartina grasses at a salt marsh restoration event, Jamaica Bay Wildlife Refuge. Credit: Johann Schumacher / Alamy Stock Photo.

Restoration efforts must also be designed to withstand potential future challenges, such as changing land-use patterns and the projected impacts of climate change. Proactive measures to safeguard and restore coastal ecosystems should account for these complex and dynamic factors to ensure their long-term success and resilience in the face of ongoing environmental changes.

Local engagement and support for blue carbon initiatives are also needed because coastal communities often directly interact with these ecosystems for livelihoods, fishing, tourism and protection from natural disasters. Engaging these communities ensures that conservation efforts are sustainable. Additionally, tapping into the knowledge and expertise of local communities about coastal ecosystems is essential for informed decision-making. 

Integrating carbon sequestration goals with other conservation and management objectives, such as sustainable fisheries and coastal resilience, is possible by empowering local communities to lead blue carbon initiatives. This can help ensure social equity, address economic opportunities and reduce conflicts over resource use.

Ultimately, garnering people’s buy-in for blue carbon solutions is essential for their effectiveness, sustainability and equitable distribution of benefits.

Considering marine sediment

Blue carbon “solutions” can be regarded as any intervention which aims to enhance the ocean’s natural capacity to store and sequester carbon.

As such, one might consider the management of commercial species and natural populations to increase the biomass of, and thereby carbon contained in, marine organisms. Managing interactions with the seabed can also be an important blue carbon solution.

Recent estimates suggest marine sediments are the largest store of organic carbon on the planet. Therefore, activities which disrupt them, such as bottom trawling or deep-sea mining, may be stirring up this sediment and leading to carbon being released back to the atmosphere. 

Although the full picture has yet to emerge, examining the impacts of where and how trawling is conducted allows us to make choices informed by all of the potential impacts. And before deep-sea mining activities are further scaled up, a more comprehensive understanding of their impacts is vital. 

The post Guest post: The role of ‘blue carbon’ in addressing climate change appeared first on Carbon Brief.

Guest post: The role of ‘blue carbon’ in addressing climate change

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Whale Entanglements in Fishing Gear Surge Off U.S. West Coast During Marine Heatwaves

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New research finds that rising ocean temperatures are shrinking cool-water feeding grounds, pushing humpbacks into gear-heavy waters near shore. Scientists say ocean forecasting tool could help fisheries reduce the risk.

Each spring, humpback whales start to feed off the coast of California and Oregon on dense schools of anchovies, sardines and krill—prey sustained by cool, nutrient-rich water that seasonal winds draw up from the deep ocean.

Whale Entanglements in Fishing Gear Surge Off U.S. West Coast During Marine Heatwaves

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Grasslands and Wetlands Are Being Gobbled Up By Agriculture, Mostly Livestock

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A new study takes a first-of-its kind look at how farming converts non-forested areas and major carbon sinks into cropland and pasture.

Agriculture is widely known to be the biggest driver of forest destruction globally, especially in sprawling, high-profile ecosystems like the Amazon rainforest.

Grasslands and Wetlands Are Being Gobbled Up By Agriculture, Mostly Livestock

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Cropped 25 February 2026: Food inflation strikes | El Niño looms | Biodiversity talks stagnate

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We handpick and explain the most important stories at the intersection of climate, land, food and nature over the past fortnight.

This is an online version of Carbon Brief’s fortnightly Cropped email newsletter.
Subscribe for free here.

Key developments

Food inflation on the rise

DELUGE STRIKES FOOD: Extreme rainfall and flooding across the Mediterranean and north Africa has “battered the winter growing regions that feed Europe…threatening food price rises”, reported the Financial Times. Western France has “endured more than 36 days of continuous rain”, while farmers’ associations in Spain’s Andalusia estimate that “20% of all production has been lost”, it added. Policy expert David Barmes told the paper that the “latest storms were part of a wider pattern of climate shocks feeding into food price inflation”.

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NO BEEF: The UK’s beef farmers, meanwhile, “face a double blow” from climate change as “relentless rain forces them to keep cows indoors”, while last summer’s drought hit hay supplies, said another Financial Times article. At the same time, indoor growers in south England described a 60% increase in electricity standing charges as a “ticking timebomb” that could “force them to raise their prices or stop production, which will further fuel food price inflation”, wrote the Guardian.

TINDERBOX’ AND TARIFFS: A study, covered by the Guardian, warned that major extreme weather and other “shocks” could “spark social unrest and even food riots in the UK”. Experts cited “chronic” vulnerabilities, including climate change, low incomes, poor farming policy and “fragile” supply chains that have made the UK’s food system a “tinderbox”. A New York Times explainer noted that while trade could once guard against food supply shocks, barriers such as tariffs and export controls – which are being “increasingly” used by politicians – “can shut off that safety valve”.

El Niño looms

NEW ENSO INDEX: Researchers have developed a new index for calculating El Niño, the large-scale climate pattern that influences global weather and causes “billions in damages by bringing floods to some regions and drought to others”, reported CNN. It added that climate change is making it more difficult for scientists to observe El Niño patterns by warming up the entire ocean. The outlet said that with the new metric, “scientists can now see it earlier and our long-range weather forecasts will be improved for it.”

WARMING WARNING: Meanwhile, the US Climate Prediction Center announced that there is a 60% chance of the current La Niña conditions shifting towards a neutral state over the next few months, with an El Niño likely to follow in late spring, according to Reuters. The Vibes, a Malaysian news outlet, quoted a climate scientist saying: “If the El Niño does materialise, it could possibly push 2026 or 2027 as the warmest year on record, replacing 2024.”

CROP IMPACTS: Reuters noted that neutral conditions lead to “more stable weather and potentially better crop yields”. However, the newswire added, an El Niño state would mean “worsening drought conditions and issues for the next growing season” to Australia. El Niño also “typically brings a poor south-west monsoon to India, including droughts”, reported the Hindu’s Business Line. A 2024 guest post for Carbon Brief explained that El Niño is linked to crop failure in south-eastern Africa and south-east Asia.

News and views

  • DAM-AG-ES: Several South Korean farmers filed a lawsuit against the country’s state-owned utility company, “seek[ing] financial compensation for climate-related agricultural damages”, reported United Press International. Meanwhile, a national climate change assessment for the Philippines found that the country “lost up to $219bn in agricultural damages from typhoons, floods and droughts” over 2000-10, according to Eco-Business.
  • SCORCHED GRASS: South Africa’s Western Cape province is experiencing “one of the worst droughts in living memory”, which is “scorching grass and killing livestock”, said Reuters. The newswire wrote: “In 2015, a drought almost dried up the taps in the city; farmers say this one has been even more brutal than a decade ago.”
  • NOUVELLE VEG: New guidelines published under France’s national food, nutrition and climate strategy “urged” citizens to “limit” their meat consumption, reported Euronews. The delayed strategy comes a month after the US government “upended decades of recommendations by touting consumption of red meat and full-fat dairy”, it noted. 
  • COURTING DISASTER: India’s top green court accepted the findings of a committee that “found no flaws” in greenlighting the Great Nicobar project that “will lead to the felling of a million trees” and translocating corals, reported Mongabay. The court found “no good ground to interfere”, despite “threats to a globally unique biodiversity hotspot” and Indigenous tribes at risk of displacement by the project, wrote Frontline.
  • FISH FALLING: A new study found that fish biomass is “falling by 7.2% from as little as 0.1C of warming per decade”, noted the Guardian. While experts also pointed to the role of overfishing in marine life loss, marine ecologist and study lead author Dr Shahar Chaikin told the outlet: “Our research proves exactly what that biological cost [of warming] looks like underwater.” 
  • TOO HOT FOR COFFEE: According to new analysis by Climate Central, countries where coffee beans are grown “are becoming too hot to cultivate them”, reported the Guardian. The world’s top five coffee-growing countries faced “57 additional days of coffee-harming heat” annually because of climate change, it added.

Spotlight

Nature talks inch forward

This week, Carbon Brief covers the latest round of negotiations under the UN Convention on Biological Diversity (CBD), which occurred in Rome over 16-19 February.

The penultimate set of biodiversity negotiations before October’s Conference of the Parties ended in Rome last week, leaving plenty of unfinished business.

The CBD’s subsidiary body on implementation (SBI) met in the Italian capital for four days to discuss a range of issues, including biodiversity finance and reviewing progress towards the nature targets agreed under the Kunming-Montreal Global Biodiversity Framework (GBF).

However, many of the major sticking points – particularly around finance – will have to wait until later this summer, leaving some observers worried about the capacity for delegates to get through a packed agenda at COP17.

The SBI, along with the subsidiary body on scientific, technical and technological advice (SBSTTA) will both meet in Nairobi, Kenya, later this summer for a final round of talks before COP17 kicks off in Yerevan, Armenia, on 19 October.

Money talks

Finance for nature has long been a sticking point at negotiations under the CBD.

Discussions on a new fund for biodiversity derailed biodiversity talks in Cali, Colombia, in autumn 2024, requiring resumed talks a few months later.

Despite this, finance was barely on the agenda at the SBI meetings in Rome. Delegates discussed three studies on the relationship between debt sustainability and implementation of nature plans, but the more substantive talks are set to take place at the next SBI meeting in Nairobi.

Several parties “highlighted concerns with the imbalance of work” on finance between these SBI talks and the next ones, reported Earth Negotiations Bulletin (ENB).

Lim Li Ching, senior researcher at Third World Network, noted that tensions around finance permeated every aspect of the talks. She told Carbon Brief:

“If you’re talking about the gender plan of action – if there’s little or no financial resources provided to actually put it into practice and implement it, then it’s [just] paper, right? Same with the reporting requirements and obligations.”

Monitoring and reporting

Closely linked to the issue of finance is the obligations of parties to report on their progress towards the goals and targets of the GBF.

Parties do so through the submission of national reports.

Several parties at the talks pointed to a lack of timely funding for driving delays in their reporting, according to ENB.

A note released by the CBD Secretariat in December said that no parties had submitted their national reports yet; by the time of the SBI meetings, only the EU had. It further noted that just 58 parties had submitted their national biodiversity plans, which were initially meant to be published by COP16, in October 2024.

Linda Krueger, director of biodiversity and infrastructure policy at the environmental not-for-profit Nature Conservancy, told Carbon Brief that despite the sparse submissions, parties are “very focused on the national report preparation”. She added:

“Everybody wants to be able to show that we’re on the path and that there still is a pathway to getting to 2030 that’s positive and largely in the right direction.”

Watch, read, listen

NET LOSS: Nigeria’s marine life is being “threatened” by “ghost gear” – nets and other fishing equipment discarded in the ocean – said Dialogue Earth.

COMEBACK CAUSALITY: A Vox long-read looked at whether Costa Rica’s “payments for ecosystem services” programme helped the country turn a corner on deforestation.

HOMEGROWN GOALS: A Straits Times podcast discussed whether import-dependent Singapore can afford to shelve its goal to produce 30% of its food locally by 2030.

‘RUSTING’ RIVERS: The Financial Times took a closer look at a “strange new force blighting the [Arctic] landscape”: rivers turning rust-orange due to global warming.

New science

  • Lakes in the Congo Basin’s peatlands are releasing carbon that is thousands of years old | Nature Geoscience
  • Natural non-forest ecosystems – such as grasslands and marshlands – were converted for agriculture at four times the rate of land with tree cover between 2005 and 2020 | Proceedings of the National Academy of Sciences
  • Around one-quarter of global tree-cover loss over 2001-22 was driven by cropland expansion, pastures and forest plantations for commodity production | Nature Food

In the diary

Cropped is researched and written by Dr Giuliana Viglione, Aruna Chandrasekhar, Daisy Dunne, Orla Dwyer and Yanine Quiroz.
Please send tips and feedback to cropped@carbonbrief.org

The post Cropped 25 February 2026: Food inflation strikes | El Niño looms | Biodiversity talks stagnate appeared first on Carbon Brief.

Cropped 25 February 2026: Food inflation strikes | El Niño looms | Biodiversity talks stagnate

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