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.

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.

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
Climate Change
Australia’s nature is in trouble.
Australia’s new environmental standards are supposed to protect wildlife. Right now, they don’t.
We have one of the worst mammal extinction rates in the world. We’ve already lost 39 species, including the Christmas Island Shrew and the desert rat-kangaroo, while iconic species like the Hairy-Nosed Wombat, Pygmy blue whale and Swift Parrot continue to slide towards extinction. Forests are still being bulldozed at an alarming rate. Rivers and reefs are under serious pressure.

Fixing this sorry state of affairs was why the Federal Government promised to fix Australia’s broken national nature laws—a promise that culminated in the nature law reforms passed late last year.
A big part of these reforms is the creation of new “National Environmental Standards” — rules intended to guide decisions on projects that could damage nature.
But the Government’s latest draft standards—open for consultation until May 29th—fall dangerously short.
Instead of setting clear environmental guardrails, the draft rules risk making it easier for damaging projects to get approved, while nature continues to decline. Legal experts are warning that unless the standards are changed, they could weaken protections rather than strengthen them.
So what are these standards, exactly?
The new standards are a centrepiece of major reforms to the Environment Protection and Biodiversity Conservation Act (EPBC Act), which were passed late last year and are designed to fix a broken environmental regulatory system. They are meant to set clear rules for what environmental protection should actually look like.
In simple terms, they’re supposed to answer questions like:
- What measures should developers be made to put in place to protect threatened species?
- How do we ensure the most important habitats and natural places are not hacked away, “death-by-a-thousand-cuts”-style, from ongoing development proposals?
- When should a project simply not go ahead?
- What rules should states follow if they’re in charge of assessing development projects?
- How do we make sure nature is actually improving, not just declining more slowly?
If designed and implemented properly, these standards could become the backbone of strong, effective reformed nature laws.
But right now, they leave huge loopholes open.

The biggest problem: process over outcomes
The biggest problem with the draft standards is that they focus too heavily on whether companies follow a process—not whether nature is genuinely protected in the end. That might sound technical, but it has real-world consequences.
Imagine a company wants to clear critical habitat for a threatened species. Under a strong system, the key question should be: Will this project cause unacceptable or significant environmental harm?
But under the current draft standards, if the company follows the required steps and paperwork, the project could still be considered acceptable — even if the damage to nature is clear.
This is deeply ineffective. Destruction that checks bureaucratic check-boxes is still destruction. The standards should enforce the protection of nature—not just the ticking of procedural boxes.
A smaller definition of habitat could leave wildlife exposed
Another alarming change in the draft standards is the narrowing of how “habitat” is defined, which could have serious consequences for wildlife protection.
Habitat is more than just the exact spot where an animal is seen sleeping, nesting or feeding today; we need to think more holistically about habitat as a connected network of ecosystems that species may rely on to survive, including breeding grounds, migration corridors, areas used during drought or fire, and places they may need to move to as the climate changes.
But the draft standards effectively shrink the areas considered important enough to protect by defining habitat as only very small areas that if destroyed would certainly send the species extinct, rather than habitat which maintains and restores healthy populations able to thrive well into the future.
For animals already under pressure from habitat destruction and climate change, protecting only the bare minimum is a dangerous approach. In practice, that could mean that places which are essential for threatened species to recover and survive long term are destroyed just because they are not classified under the standards as ‘habitat’—a lose-lose outcome for biodiversity and the Australian government’s nature protection goals.

Offsets are still doing too much heavy lifting
Australians have heard the promise before: “Yes, this area will be damaged — but it’ll be offset somewhere else.” In practice, environmental offsets have severely failed to replace what was lost.
You can’t instantly recreate a centuries-old forest. You can’t quickly rebuild complex wildlife habitat. And some ecosystems simply cannot be replaced once destroyed. Yet the draft standards still rely heavily on offsets rather than prioritising avoiding harm in the first place.
The standards must reduce their reliance on offsets, and instead prioritise actual habitat protection. Because once extinction happens, there’s no offset for it.
Australia cannot afford another backwards step on nature
The Albanese Government came to office promising to end Australia’s extinction crisis and repair national nature laws. But this will be a broken promise if the huge loopholes in the National Environmental Standards aren’t addressed.
Right now, Australia is losing wildlife and ecosystems faster than they can recover. Scientists have warned for years that incremental change is no longer enough.
Strong standards could help turn things around by:
- stopping destruction in critical habitat,
- setting firm limits on environmental harm,
- requiring genuine recovery for nature,
- and making decision-makers accountable for real outcomes rather than process.
If the Government locks in rules that prioritise process over protection, Australia risks entrenching the very system that caused the crisis in the first place.
What needs to change?
The Government still has time to fix the draft standards before they are finalised over the next month.
Greenpeace Australia Pacific is calling on the government to:
- ensure decisions are based on outcomes, not just process
- ensure that all important habitat is protected, not just narrow areas
- ensuring that death-by-a-thousand-cuts is avoided by considering the “cumulative impacts” of multiple projects in a region
- ensuring offsets are only used as an absolute last resort
Australians were promised stronger nature laws—not more loopholes. Australia’s wildlife cannot afford another missed opportunity.You can help ensure the Federal Government’s final standards put to parliament are as strong as possible by putting in a quick submission here.
Climate Change
Duke University Plans a Data Center It Says Will Boost ‘Environmental Responsibility and Sustainability’
The small project is underway at Central Campus, with room for expansion. Its energy usage could complicate the university’s climate goals.
DURHAM, N.C.—Duke University plans to build a small data center at Central Campus, potentially the first of several similar-size projects, which has raised questions among some faculty about whether the energy- and water-intensive endeavors could derail the institution’s climate commitments.
Climate Change
UN General Assembly backs “climate obligations” set by world’s top court
The UN General Assembly on Wednesday adopted a “historic” resolution calling on countries to comply with their climate obligations, as outlined in a landmark advisory opinion issued last year by the International Court of Justice (ICJ).
Last July, in the opinion first requested by the Pacific island state of Vanuatu, the world’s top court ruled that harming the climate by increasing fossil fuel production may constitute an “international wrongful act”. This could result in affected countries claiming compensation from those responsible, the court said.
To follow up on the ICJ ruling, a dozen nations led by Vanuatu submitted a proposal to the UN’s main deliberative body to recognise the advisory opinion and identify ways of implementing it.
Several large oil-producing nations mounted a late push to weaken the text by introducing last-minute amendments, but the General Assembly rejected those and adopted the resolution with 141 countries in favour at a plenary session in New York.
The resolution urges countries to implement measures to cut carbon emissions, including by tripling renewable energy capacity, “transitioning away from fossil fuels in energy systems”, and phasing out “inefficient” fossil fuel subsidies.
It also requests the UN Secretary-General to draft a report “containing ways to advance compliance with all obligations in relation to the court’s findings” by next year’s UN General Assembly in September 2027.

Pacific islands celebrate “historic” resolution
The group of Pacific island nations, which led the diplomatic push for the resolution, as well as Latin American nations and the European Union, celebrated its adoption as a “historic” moment, while some countries noted the persistence of diverging views.
Belize’s UN representative Janine Coye-Felson said in a statement on behalf of the Alliance of Small Island States (AOSIS) that the General Assembly resolution, as well as the ICJ advisory opinion, are important because “climate change is not governed only” by the Paris Agreement, but that “climate justice requires the application of the full breath of international law”.
“When future generations look back at this moment, they will ask whether we rose to meet the defining crisis of our time with the full force of international law. Today, this General Assembly answers: yes,” she told the plenary.
The EU said in a statement during the session that, with the adoption of the resolution, countries are moving beyond “simply recognising” the ICJ’s work and instead “actively upholding the legal integrity” of the multilateral system by seeking to implement the court’s recommendations.
Yet the bloc also warned the process that follows must not “seek to establish new mechanisms or engage in any determination of state responsibility”, referring in particular to the upcoming report by the Secretary-General. Earlier drafts of the resolution contained proposals to establish a register of climate-driven loss and damage and a dedicated compensation mechanism, but these were removed during negotiations on the text.
France’s ambassador to the UN, Jérôme Bonnafont, highlighted the resolution’s provision to reduce dependence on fossil fuels, and said “science clearly establishes their role in climate change”. The recent increase in oil and gas prices, which have soared because of the war in Iran, “underscores the cost vulnerability of this dependence”, he added.
Push-back by oil-producing nations
Some oil-producing countries – among them the US, Saudi Arabia and Russia – were critical of the new resolution, arguing that it creates “quasi-binding” obligations from an advisory opinion that should be non-binding, and rejected the request for a report from the Secretary-General.
“This is a direct duplication of work that is being done at the [UN climate convention],” said Russia’s delegate. “Creating a parallel process will waste resources, will undermine the fragile consensus at the conference of the parties and will lead to the fragmentation of the climate regime.”
In an effort to weaken the resolution, a group of seven oil-producing Middle Eastern states – including Saudi Arabia, Kuwait and Iran – tabled four last-minute amendments proposing to delete certain paragraphs and softening the language on the obligations of states.
Webinar: From Santa Marta to Bonn – where next for the fossil fuel transition?
In response, Pacific island nations said these amendments sought to “reopen provisions that were [the] subject of extensive negotiation”, while the EU added that they were “difficult to reconcile with the spirit of cooperation”. They were all rejected in a series of votes.
The US, for its part, described the resolution as “highly problematic” and denied the obligation of preventing climate harm beyond its borders, as well as the assertion that climate change is an “unprecedented civilizational challenge”. The country urged others to vote against the resolution.
India, which abstained, said the text failed to address the need for climate finance flows from developed to developing countries, which is “a serious omission”. The Indian delegate pointed to the absence of the term “climate finance” in the text, which “deserves more attention in a resolution that deals with the obligations of states”.
“Turning point in accountability”, activists say
WWF’s climate chief and former COP president Manuel Pulgar-Vidal said the General Assembly’s vote was a step forward that “raises the pressure on all states to act in line with their obligations”.
Rebecca Brown, CEO of the Center for International Environmental Law (CIEL), said the UN resolution shows that “multilateralism works” and with it, countries “carry the ICJ’s historic ruling forward as a roadmap for climate action and accountability”.
“By acting together, we can prevent further climate harm, in line with science and the law, by speeding up a just and equitable transition away from fossil fuels, protecting climate-vulnerable communities, and advancing climate justice,” she added in a statement.
Vishal Prasad, director of Pacific Islands Students Fighting Climate Change – a group of young people who first made the push for an advisory opinion from the ICJ – said “the world has not only reaffirmed that ruling, but committed to making it a reality”.
“This must be a turning point in accountability for damaging the climate. Communities on the frontlines, like in the Pacific, have been waiting far too long and continue to pay too high a price for the actions of others,” he said. “The journey of this idea from classrooms in the Pacific to The Hague and the United Nations gives us continued hope that when people organise, the world can be moved to act.”
The post UN General Assembly backs “climate obligations” set by world’s top court appeared first on Climate Home News.
UN General Assembly backs “climate obligations” set by world’s top court
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