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Removing carbon dioxide (CO2) from the atmosphere is widely expected to play a key role in meeting the goals of the Paris Agreement.
But this will only be effective for slowing climate change if the CO2 can be stored securely and indefinitely.
This requires “geological carbon storage”, where captured CO2 is injected deep underground, where it can stay trapped for thousands of years.
While the current deployment of CO2 removal (CDR) technologies around the world is small, almost all facilities aim to store captured CO2 in sedimentary basins.
However, in our study in Nature, we show that current policy approaches to using these formations on a larger scale could be suffering from a false sense of abundance.
We find that – once technical, social and environmental risks are considered – the world’s available reserves of geological carbon storage are significantly more limited than most estimates suggest.
Our research shows that, of nearly 12,000bn tonnes of CO2 (GtCO2) of theoretical carbon storage capacity, just 1,460GtCO2 is risk-free.
Significantly, we find that, if all available safe carbon storage capacity were used for CO2 removal, this would contribute to only a 0.7C reduction in global warming.
In short, geological carbon storage is not limitless – on the contrary, its practical potential is a rather scarce planetary resource.
From technical potential to prudent limits
When studies estimate where carbon could be stored for the long term, they typically start by looking at all sedimentary basins worldwide to find those that are mature and stable.
However, norms of international environmental law indicate that high standards of due diligence must be applied to prevent transboundary environmental harm. As scientists, we were therefore interested in understanding how much storage capacity would be available when looking through a precautionary lens.
Our study develops the first global estimate of safe and durable carbon storage that takes into account social, environmental and technical risks – in addition to the geological qualities of the basins.
Rather than taking raw geological capacity at face value, we screen the potential locations for a number of factors:
- Seismic hazards
- Groundwater contamination.
- Proximity to population centres.
- Biodiversity protections, such as environmentally protected areas and the Arctic and Antarctic circles.
- Engineering limitations, such as basin depths that are too shallow to store carbon indefinitely or too deep underground and locations too deep in the ocean.
- Political feasibility, such as maritime areas outside of national jurisdictions or disputed geographical areas.
The results of our assessment are stark. We find that, out of nearly 12,000GtCO2 of theoretical carbon storage capacity in sedimentary basins, just 1,460GtCO2 can be considered robust for climate planning purposes.
We refer to this as “prudent” storage capacity.
This is an order of magnitude less than commonly-cited figures.
In 2005, the Intergovernmental Panel on Climate Change’s (IPCC’s) special report on carbon capture and storage estimated that there is a “technical potential of at least about 2,000GtCO2…of storage capacity in geological formations”.
Over the two decades since, estimates have ballooned to 10,000-40,000GtCO2, depending on the academic or industry source that is consulted.
What this means for warming limits
Our research finds that if all reserves of “prudent” storage were used solely for removing CO2 from the atmosphere, they would enable – at most – a 0.7C reduction in global temperatures.
This falls to as little as 0.4C if we conservatively take the lower end of the likely (>66%) range of how much warming or cooling we expect per tonne of CO2 emitted or removed, respectively.
For the first time, our new study provides an estimate for an upper limit for how much past warming could be reversed through geological storage.
However, under most low-carbon pathways available in the academic and technical literature and assessed by the Intergovernmental Panel on Climate Change, this prudent geological storage limit would be used up before 2200 – and some by 2100.
In many cases, storage is not used to draw down atmospheric CO2, but to balance the continued production of greenhouse gas and carbon pollution from human activities.
And yet, without sharp near-term cuts in gross emissions, the likely overshoot of the Paris Agreement’s 1.5C warming limit could prove irreversible.
Equity and responsibility
The maps below show how prudent storage capacity – for offshore (left) and onshore (right) basins – is not evenly distributed.
The “prudent” global storage potential (in GtCO2) for offshore (left) and onshore (right) basins, by individual countries. Darker shading indicates a greater amount of storage capacity. Source: Gidden et al. (2025)
Much of it is found in large, fossil-fuel-producing nations, such as the US, Australia, Russia and Saudi Arabia. These countries are among the world’s biggest historical emitters.
(This is not a coincidence, as these nations’ fossil-fuel-based economies are the result of relatively easily reachable geological deposits.)
However, the reality that the nations most responsible for emissions also appear best placed to store them raises equity concerns. Nations who benefitted from enabling carbon pollution would now also benefit from the clean up.
Other countries, such as Brazil and the Democratic Republic of the Congo, have substantial storage, but little domestic incentive to use it unless compensated.
Meanwhile, emissions-intensive nations would now be first in line to transform themselves from extractors to large-scale injectors of carbon – and could benefit from new business opportunities, often paid for by the public purse.
However, sovereign wealth funds – state-owned investment funds, often built on fossil revenues – could play a role in financing this shift, in line with the “polluter pays” principle.
Planning for scarcity
Treating storage as a finite and scarce resource has a knock-on effect for climate policy.
For example, governments would need to decide explicitly how they intend to allocate limited carbon storage capacity – should storage capacity be used to abate residual, industrial and fossil-fuel emissions, or for CO2 that has been directly pulled from the atmosphere?
Norms of international environmental law – and the recent “advisory opinion” on climate change from the International Court of Justice – provide guidance as to what countries ought to do. The principle of harm prevention indicates that risks of climate harm should be minimised where possible.
To limit risks to implementing climate targets, carbon capture and storage (CCS) should be seen as a complement to – but not a substitute – for rapid emissions cuts. This recommendation is not new – it has long been called for by researchers looking at the trade-offs and negative side-effects of specific negative emissions technologies, including the impacts poorly governed deployment of these technologies can have on biodiversity and food security.
Our geological storage estimate represents an assessment of reserves today – but this is likely to change with time as knowledge, preferences and governance of CO2 storage change.
CDR technologies that provide alternatives to geological storage, such as mineralisation in basalt, show promise. However, these technologies remain at pilot scale, with only a few million tonnes stored to date.
Climate strategies that rely on nascent CDR technologies would not constitute a strategy that minimises risks and potential harm to today’s and future generations.
The bottom line
Geological carbon storage is not a limitless backstop – and assuming otherwise puts the world at risk of irreversibly exceeding the Paris Agreement’s 1.5C threshold for global warming.
However, at the same time, carbon storage will almost certainly play a pivotal role in any future where global “net-zero” CO2 or greenhouse gas emissions is achieved.
By acknowledging the scarcity of carbon storage – and designating reserves for essential and strategic uses – governments can limit the risks of harm to people and the planet.
The post Guest post: How the role of carbon storage has been hugely overestimated appeared first on Carbon Brief.
Guest post: How the role of carbon storage has been hugely overestimated
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An older teaching about land acknowledgement
As I have come to understand the spirit and intention of land acknowledgement, I often return to fond memories of my grandmother and her words of wisdom. She taught that the health of the places we call home comes first, because the wellbeing of the people depends on it.
In her teaching, land acknowledgement began with the land. Long before it became a paragraph read at the start of a meeting, it was a way of recognizing a homeland: its waters, its species, its seasons, and the spirit that revealed whether the place was well.
Her teaching echoes a practice found across many Indigenous Nations. Haudenosaunee gatherings, for example, have long opened with the Ohén:ton Karihwatéhkwen, the Thanksgiving Address, often translated as “the words that come before all else.” The speaker greets and gives thanks to the people, the earth, the waters, the plants, the animals, the winds, the sun, the moon and the stars. Only after everything that sustains life has been acknowledged does the gathering turn to its own business.
That order changes what an acknowledgement is for. Its purpose was to share the story of a place with neighbours and to draw them into the work of tending it. People entered the story second, as the ones responsible for what had just been named.
Understood this way, an acknowledgement does more than open a meeting. It asks us to reconsider where we stand, and what we owe the ground beneath us.
Nations among nations
In her teaching, people are one nation among many. The salmon are a nation. So are the cedars, the bison, the medicine plants, and the pollinators. Each belongs to a place, carries its own responsibilities, and offers gifts no other nation can give.
This idea of kinship runs through many Indigenous philosophies. The phrase “all my relations,” heard in ceremonies and gatherings across Turtle Island, is a reminder that family extends beyond people to the animals, plants, waters and lands that make life possible. Some Indigenous languages carry the same understanding in their grammar, speaking of many plants, animals and natural forces as living beings rather than objects.
Sovereignty, understood through this relationship, is a kind of standing more than a form of control. Each nation belongs fully to its place and carries its share of that place’s life. No nation thrives alone, and none thrives by taking over the whole.
The land is also the source of instruction. Over generations, people watched how a river valley or a stretch of prairie kept itself well: who arrived when, who fed whom, and how much could be taken before the giving stopped. In my grandmother’s telling, those observations became instructions, and those instructions helped shape law and protocol. They guided when to harvest, where to camp, how to enter a neighbour’s territory, and what was owed in return.
Indigenous legal scholars today often describe this as law that comes from the land itself, learned by watching how living systems sustain one another. A plainer name for it is knowing how to live somewhere.
The host and the guest
One of the clearest teachings in this understanding of the world is the relationship between host and guest. My grandmother invited us to recognize that relationship in the lives of plants and animals.
A host prepares the place before anyone arrives. A beaver family dams a stream, and the pond becomes a home for fish, frogs, birds and plants. A fallen tree becomes a nurse log, feeding the next generation of seedlings as it returns to the soil.
A host offers first. A flowering plant sets out nectar. A berry bush ripens fruit. These provisions come in their own season, not whenever a visitor happens to want them.
A host also makes its presence known. Birdsong, scent and the marks left along a trail tell newcomers that a place is already inhabited. The visitor does not arrive in an empty world.
The guest has responsibilities too. A guest attends to the season and to what the place can offer. A guest does not assume that everything within reach is theirs to take. A guest leaves something that helps sustain the relationship.
A bee takes nectar and carries pollen. Read through this teaching, that exchange offers an image of visiting well: receiving a gift while helping the host continue its life.
Many Indigenous harvesting protocols carry the same ethic into daily practice: ask before taking, take only what is needed, offer thanks, and leave enough for others and for the plant or animal to recover.
None of this suggests that every relationship in nature is peaceful or generous. These are ways of seeing responsibilities that people can learn to carry.
Everyone is both
No being is only a host or only a guest.
A tree makes room for other life while depending on soil, water, sunlight, fungi, and relationships beyond itself. People, too, may welcome others into their homes while remaining dependent on the larger homeland that sustains them.
The distinction between host and guest is therefore about roles, not ranks. Everyone receives. Everyone has something to give.
The question is whether the exchange sustains the place.
A visitor who takes without restraint leaves less for those who come next. A host who neglects the place has less to offer. Both have responsibilities, and neither can fulfil them alone.
This is the heart of reciprocity, a principle found across Indigenous philosophies: relationships stay healthy when gifts move in both directions. The Haudenosaunee teaching of the seventh generation extends that exchange across time, asking that decisions made today leave the place well for those not yet born.
Mutual benefit begins here, with the recognition that different beings carry different gifts and obligations.
What people carry forward
My grandmother’s teaching connects these relationships to the ways people meet their neighbours.
The host prepares a place, offers food and rest, and explains where the visitor has arrived. The guest makes themselves known, explains why they have come, listens to the terms of the visit, and brings something in return. The gift may be material. It may also be labour, knowledge, news, or a commitment to help.
Nations around the Great Lakes carried this ethic into treaty. The Dish with One Spoon, an agreement among the Haudenosaunee, Anishinaabe and allied Nations, describes shared hunting grounds as a single dish. Everyone eats from it with one spoon, takes only what they need, leaves enough for others, and keeps the dish clean. The Two Row Wampum, between the Haudenosaunee and European newcomers, shows two vessels travelling side by side on the same river, each keeping its own ways and neither steering the other.
In this understanding, acknowledgement is more than naming the people associated with a territory. It is learning enough about a homeland to behave responsibly within it.
Whose home is this? What sustains it? What laws and agreements guide our presence? What can we receive, and what must we return?
These questions make acknowledgement a relationship rather than a recital.
They also make it diplomatic. A guest who recognizes the host’s homeland recognizes that they have entered a place with its own relationships and responsibilities. A host who welcomes the guest makes room for an encounter governed by those relationships.
Neither arrives without standing. Neither arrives without obligations.
Beginning with place
I write from the shores of the Bay of Quinte. Here, the teaching asks me to begin with the water, the shoreline, and the life they sustain. Before I describe myself, I must attend to where I am.
That does not make people or history less important. It places them within the homeland that gives them meaning. The people, their laws, their agreements, and their responsibilities all belong to the place.
In a time of longer fire seasons, troubled waters, and uncertainty about what the next season will bring, this teaching asks something difficult and useful of us: pay attention before you speak.
An acknowledgement cannot tell the story of a place if the speaker has stopped noticing it.
The land came first. Beginning there again means learning to name what sustains us, and accepting that what sustains us also asks something of us.
By Rye Karonhiowanen Barberstock
Photo by Andrik Langfield on Unsplash
The post The Land Came First appeared first on Indigenous Climate Hub.
Carbon dioxide (CO2) emissions from fossil fuels and cement are projected to fall by around 0.4% in 2026 to 38.2bn tonnes of CO2 (GtCO2), according to new figures from the Global Carbon Project.
This guest post is by:
- Dr Zeke Hausfather, Carbon Brief’s climate science contributor
- Prof Pierre Friedlingstein, chair of mathematical modelling of climate systems at the University of Exeter and part of the Global Carbon Project team.
Carbon dioxide (CO2) emissions from fossil fuels and cement are projected to fall by around 0.4% in 2026 to 38.2bn tonnes of CO2 (GtCO2), according to new figures from the Global Carbon Project.
The 21st edition of the annual “global carbon budget” report, published today, says that this small decline is largely due to a 1.9% drop in emissions from oil and the energy shock triggered by the Iran conflict and the closure of the strait of Hormuz.
Emissions from coal continue to increase slightly.
The Global Carbon Project’s projections for fossil fuel and cement CO2 emissions in 2026 are preliminary, with a range that spans a fall of -1.5% to a rise of +0.6%.
This means a small increase in emissions can not be ruled out.
Emissions from land-use change, such as deforestation, are projected to rise in 2026.
This is primarily driven by peat fires and forest degradation in south-east Asia and is linked to the development of a strong El Niño event this year.
As a result, total CO2 emissions from fossil fuels and land use are projected to reach a record high of 43.3GtCO2 in 2026 – marginally above 42.8GtCO2 in 2025.
Research published alongside the report by the same team in Nature Climate Change finds that the growth in solar, wind and electric vehicles (EVs) now offsets around two-thirds of the emissions that would otherwise come from rising energy demand.
However, the deployment of these technologies is not yet enough to push global emissions into a sustained decline, according to the study.
The 2026 global carbon budget report also estimates that:
- Fossil emissions are projected to fall in China (-0.9%), the US (-1.3%) and the EU (-1.5%) in 2026, but rise by 4.4% in India.
- Oil emissions are projected to fall in every major region, with the largest drop in China (-4.6%).
- Land-use emissions averaged 4.9GtCO2 per year over 2016-25, around 21% lower than the decade before.
- Total CO2 emissions (fossil and land-use) grew by an average 0.3% per year over the past decade (2016-25), compared with 1.7% per year over the decade before.
- The remaining carbon budget to limit warming to 1.5C is 150GtCO2, or less than four years of current emissions.
- The land sink in 2025 was the highest on record, rebounding after being weakened during the 2023-24 El Niño. The current El Niño is expected to weaken the land sink in 2027.
- The concentration of CO2 in the atmosphere is set to reach 427.7 parts per million (ppm) in 2026, 54% above pre-industrial levels.
(For more on previous editions of the Global Carbon Project’s annual report, see Carbon Brief’s coverage in 2025, 2024, 2023 and 2022.)
Total emissions edge up as land-use emissions rise
Total global CO2 emissions, which combines fossil fuels and land-use change, are projected to reach a record high of 43.3GtCO2 in 2026, up from 42.8GtCO2 in 2025.
The increase in 2026 comes entirely from a projected rise in land-use emissions, which are more challenging to estimate than fossil emissions.
(The global carbon budget groups emissions from fossil fuels and cement production as “fossil emissions”. Carbon Brief follows this convention throughout this piece.)
If land-use emissions had stayed at 2025 levels, total emissions would have fallen slightly in 2026 to around 42.6GtCO2.
Each edition of the global carbon budget updates the historical record as new data and methods become available. The chart below shows total emissions in this year’s budget compared with the five previous editions.
This year’s estimates of historical fossil emissions are around 0.3GtCO2 per year higher than in last year’s budget.
This is largely because the report now estimates a smaller “cement carbonation” sink in the wake of research published this year in Communications Sustainability. In other words, it estimates that cement is able to slowly reabsorb less CO2 over its lifetime than previously thought.
Estimates of land-use emissions have also been revised, including a spike in 2018 – visible in the chart above – linked to updated cropland data for Colombia.
The updated numbers show that total emissions have grown by 0.3% per year over the past decade (2016-25), compared with 1.7% per year over 2006-15.
Fossil emissions grew about 0.9% per year in the past decade, compared with 1.9% the decade before. Over the same period, land-use emissions have declined.
While the slowdown reflects real progress, a plateau in emissions is still a long way from the rapid declines needed to reach net-zero emissions and stabilise global temperatures.
With human-caused warming reaching 1.37C above pre-industrial levels (1850-1900) in 2025, the report estimates that the remaining carbon budget to limit warming to 1.5C, with a 50% chance, is 150GtCO2 from the start of 2027. That is less than four years of 2026 emissions.
Meanwhile, the budgets for 1.7C and 2C are 510GtCO2 and 1,035GtCO2, respectively – or around 12 and 24 years of current emissions.
Fossil emissions made up around 88% of total CO2 emissions over the past decade, with land-use change making up the remaining 12%.
This is a marked