The perception of how the land surface releases carbon dioxide (CO2) typically conjures up images of large-scale deforestation or farmers churning up the soil.
However, there is an intriguing – and underappreciated – role played by the world’s rivers.
Right now, plants and soils absorb about one-third of the CO2 released by human activity, similar to how much the oceans take up.
Over thousands to millions of years, some of this land-fixed carbon can end up being buried in sediments, where it eventually forms rocks.
The waters that feed rivers flow through plants, soils and rocks in landscapes, picking up and releasing carbon as they go.
This process is generally considered to be a sideways “leakage” of the carbon that is being taken up by recent plant growth.
However, the age of this carbon – how long it resided in plants and soils before it made it into rivers and then to the atmosphere – has remained a mystery.
If the carbon being released by rivers is young, then it can be considered a component of relatively quick carbon cycling.
However, if the carbon is old, then it is coming from landscape carbon stores that we thought were stable – and, therefore, represents a way these old carbon stores can be destabilised.
In our new study, published in Nature, we show that almost 60% of the carbon being released to the atmosphere by rivers is from these older sources.
In total, this means the world’s rivers emit more than 7bn tonnes of CO2 to the atmosphere each year – more than the annual fossil-fuel emissions from North America.
This means that there is a significant leak of carbon from old stores that we thought were safely locked away.
Previous work has shown that local land-use change, such as deforestation and climate-driven permafrost thaw, will directly release old carbon into rivers. Whether this is happening at the global scale remains a significant unknown for now.
Who are you calling old?
How do you tell how old carbon is? We employ the same technique that is used to determine the age of an archaeological relic or to verify the age of a vintage wine – that is, radiocarbon dating.
Radiocarbon is the radioactive isotope of carbon, which decays at a known rate. This enables us to determine the age of carbon-based materials dating back to a maximum age of about 60,000 years old.
We know that some of the carbon that rivers release is very young, a product of recent CO2 uptake by plants.
We also know that rivers can receive carbon from much older sources, such as the decomposition of deep soils by microbes and soil organisms or the weathering and erosion of ancient carbon in rocks.
Soil decomposition can release carbon ranging from a few years to tens of thousands of years. An example of very old soil carbon release is from thawing permafrost.
Rock weathering and erosion releases carbon that is millions of years old. This is sometimes referred to as “radiocarbon-dead” because it is so old all the radiocarbon has decayed.
Rivers are emitting old carbon
In our new study, we compile new and existing radiocarbon dates of the CO2 emissions from around 700 stretches of river around the world.
We find that almost 60% of the carbon being released to the atmosphere by rivers is from older sources (hundreds to thousands of years old, or older), such as old soil and ancient rock carbon.
In the figure below, we suggest how different processes taking place within a landscape can release carbon of different ages into rivers, driving its direct emission to the atmosphere.
So, while rivers are leaking some modern carbon from plants and soils as part of the landscape processes that remove CO2 from the atmosphere, rivers are also leaking carbon from much older landscape carbon stores.
One major implication of this finding is that modern plants and soils are leaking less carbon back to the atmosphere than previously thought, making them more important for mitigating human-caused climate change.
We find that the proportion of old carbon contributing to river emissions varies across different ecosystems and the underlying geology of the landscapes they drain.
In the figure below, we show that landscapes underlain by sedimentary rocks, which are the most likely to contain substantial ancient (or “petrogenic”) carbon, also had the oldest river emissions. We also show that the type of ecosystem (biome) was also important, although the patterns were less clear.
What is obvious is that at least some old carbon was common across most of the rivers we observed, regardless of size and location.
We provide evidence that there is a geological control on river emissions. And the variability in the ecosystem also indicates important controlling factors, such as soil characteristics, vegetation type and climate – especially rainfall patterns and temperature which are known to impact the rate of carbon release from soils and rock weathering.
Are old carbon stores stable?
Long-term carbon storage in soils and rocks is an important process regulating global climate.
For example, the UK’s peatlands are important for regulating climate because they can store carbon for thousands of years. That is why restoring peatlands is such a great climate solution.
Rivers emit more than 7bn tonnes of CO2 to the atmosphere each year – that’s equivalent to about 10-20% of the global emissions from fossil fuel burning annually.
If 60% of river carbon emissions are coming from old carbon stores, then this constitutes a significant leak of carbon from old stores we thought were safely locked away.
Another major implication of our study is that these old carbon stores can be mobilised and routed directly to the atmosphere by rivers, which would exacerbate climate change if these stores are further destabilised.
As can be seen in the figure below, we found that river carbon emissions appeared to be getting older since measurements first began in the 1990s (lower F14Catm means older radiocarbon ages).
We found that river carbon emissions appeared to be getting older since measurements first began in the 1990s.
While there are several caveats to interpreting this trend, it is a warning sign that human activities, especially climate change, could intensify the release of carbon to the atmosphere via rivers.
Given the strong link between soil carbon and river emissions, if this trend is a sign of human activity disturbing the global carbon cycle, it is likely due to landscape disturbance mobilising soil carbon.
Using rivers to monitor global soil carbon storage
Rivers collect waters from across the landscapes they flow through and therefore provide a tool to track processes happening out of sight.
A drop of water landing in a landscape travels through soils and rock before reaching the river, and its chemistry, including its radiocarbon age, reflects the processes occurring within the landscape.
Monitoring the age of carbon in rivers can therefore tell you a lot about whether their landscapes are storing or releasing carbon.
This has been shown to help identify carbon loss in degraded tropical peatlands, thawing Arctic permafrost and due to deforestation.
River radiocarbon is sensitive to environmental change and could therefore be a powerful monitoring tool for detecting the onset of climate tipping points or the success of landscape restoration projects, for example.
While we present data spread out across the world, there are quite a few gaps for important regions, notably where glacier change is happening and others where droughts and flood frequencies are changing.
These include areas with low amounts of data in Greenland, the African continent, the Arctic and Boreal zones, the Middle East, eastern Europe, western Russia, Central Asia, Australasia and South America outside of the Amazon.
All these regions have the potential to store carbon in the long-term and we do not yet know if these carbon stores are stable or not under present and future climate change.
River radiocarbon offers a powerful method to keep tabs on the health of global ecosystems both now and into the future.
The post Guest post: How the world’s rivers are releasing billions of tonnes of ‘ancient’ carbon appeared first on Carbon Brief.
Guest post: How the world’s rivers are releasing billions of tonnes of ‘ancient’ carbon
But a $345 million U.S. verdict against the environmental group hangs over the case.
A lawsuit filed by Greenpeace International against the U.S.-based fossil fuel company Energy Transfer in the Netherlands is moving forward after a Dutch court recently ruled in favor of the environmental organization in rejecting the company’s bid to toss out the case.
Greenpeace’s Dutch Anti-SLAPP Case Against Oil Pipeline Giant Advances
Go behind the scenes with executive editor Vernon Loeb and oceans correspondent Teresa Tomassoni as they discuss the search for heat-resilient coral reefs that are somehow defying the odds to survive a warming planet.
The world has already lost more than half of its coral reefs, and most of what remains is at risk of disappearing in the next 25 years.
Climate Change
DeBriefed 19 June 2026: Bonn talks end in ‘gridlock’ | Energy’s ‘new era’ | Oceans in climate negotiations
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Bonn talks close
‘SIDE-STEPPING AND STALLING’: UN climate talks in Bonn have ended in “gridlock”, according to Climate Home News. The outlet reported on the failure to balance developing countries’ need for climate-adaptation finance with “richer nations’ desire to move forward” on emissions cuts. It added that both topics were subject to “rule 16”, meaning no agreement could be reached and work will be pushed to the COP31 summit in Turkey. Inside Climate News quoted UN climate executive secretary Simon Stiell, who said the talks had seen “side-stepping and stalling”.
JUST TRANSITION: One “glimmer of hope” came from negotiations on achieving a “just transition”, reported Euronews. The news outlet said negotiators “made headway on operationalising the Belém-Antalya mechanism”, intended to support people in the shift to a low-carbon economy. However, Politico concluded that much of the focus in Bonn had “shift[ed] to efforts outside diplomatic talks – raising questions about the future of global climate negotiations”.
‘ATTACKING SCIENCE’: Agence France-Presse reported on the EU, Switzerland and “dozens of developing nations” warning of “attacks on science” by a “small group of fossil-fuels interests” in Bonn. Table Briefings explained that “the 1.5C target is increasingly being challenged” and the role of the UN climate-science panel – the Intergovernmental Panel on Climate Change (IPCC) – in an upcoming assessment of global climate progress “remains controversial”. See Carbon Brief’s full write-up of the talks for more detail.
US-Iran deal
PRICE DROP: The US and Iran announced that they have reached an interim agreement to halt the war and reopen the strait of Hormuz, reported Bloomberg. Oil prices have fallen, as the “long-awaited deal” began the process of “eas[ing]” the global energy crisis triggered by the conflict, according to the New York Times. The Associated Press noted that high fuel prices will “likely outlast the Iran war”.
‘OIL GLUT’: The Financial Times reported that the International Energy Agency (IEA) has forecast a “glut of oil” emerging next year, if the peace deal holds. The IEA said this would allow countries to build new strategic reserves, as they “review their energy strategies and policies in response to the crisis”, according to Reuters.
‘NEW ERA’: Agence France-Presse reported that oil and gas companies have “few illusions about a return to normal for the Gulf energy industry after more than three months of blockage”. One analyst told the newswire that the war “showed the oil and gas industry that Hormuz risk is no longer just a geopolitical headline”.
Around the world
- OCEAN MONITOR: The Trump administration is “abandoning its plan” to dismantle a $368m ocean monitoring system key for tracking climate change after a “bipartisan backlash on Capitol Hill”, reported the New York Times.
- CORAL HAVEN: The New York Times covered preliminary research, presented at the Our Ocean Conference in Kenya, suggesting there could be three times as many “coral refugia” – where corals are relatively safe from climate change – than previously thought.
- BAD CREDIT: Down to Earth reported that the first carbon credits issued under the Paris Agreement’s new Article 6.4 mechanism are “facing scrutiny over alleged links to institutions controlled by Myanmar’s military junta”.
- OIL BACKTRACK: Reuters reported that oil-and-gas company Equinor has dropped a renewable-energy target and scaled back clean investments, while another Reuters story noted that Shell is selling off its offshore wind assets.
1.1 billion
The number of children facing “at least three overlapping climate hazards”, according to a new Unicef report covered by Agence France-Presse.
Latest climate research
- Including the “permafrost carbon-climate feedback” in climate models increases the chance of exceeding “tipping elements” – such as the Greenland ice sheets, Atlantic Meridional Overturning Circulation or Amazon rainforest – by up to 50% | Environmental Research Letters
- The intensity of influenza outbreaks could decline in temperate regions, but increase in tropical areas over the next century, as the climate warms | PNAS Nexus
- European snow cover has declined by 20% for December and January since the start of the industrial era, revealing an “unprecedented ongoing shrinkage of European winters” | Communications Earth & Environment
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
The more than 2m battery electric vehicles (BEVs), 1m “plug-in” hybrids (PHEVs) and 100,000 electric vans on UK roads are already saving drivers a total of around £3bn a year, according to new Carbon Brief analysis. This amounts to savings of more than £1,100 a year in fuel costs for each BEV driver in the UK. The analysis comes amid reports in UK media this week that the government is considering “watering down” its EV sales targets.
Spotlight
Oceans rising at UN climate talks
The state of the world’s oceans is inextricably linked to the changing climate – and many delegates at UN climate talks want to see more focus on this issue, reports Carbon Brief.
Oceans are often described as the world’s “greatest ally” against climate change – absorbing 30% of carbon dioxide (CO2) emissions and most of the heat generated by those emissions.
They are also the site of important climate solutions, such as huge offshore windfarms and the shipping industry’s transition to cleaner fuels.
At the same time, the oceans themselves present a growing danger to coastal communities and sea life due to sea level rise, marine heatwaves and ocean acidification.
These diverse issues have led to growing calls within the UN climate process for more focus on oceans. During climate negotiations this week in Bonn – known as SB64 – nations and civil society had a chance to air these views during an “ocean and climate change dialogue”.
‘Elevate action’
Oceans first entered UN climate outcomes in 2019, when the final COP25 negotiated text requested a new “dialogue” on “the ocean and climate change to consider how to strengthen mitigation and adaptation action”.
The following years saw this dialogue established as an annual event. However, the political weight of these discussions has been limited.
COP31 is being co-led by Turkey and Australia, but with Pacific islands playing a supporting role. These small islands sometimes self-identify as “large ocean states”, stressing the ocean’s centrality in their societies.
In Bonn, figures from across the presidency threw their weight behind this issue. Chris Bowen, an Australian minister and incoming COP31 “president of negotiations”, told attendees:
“Australia, Turkey and the Pacific see an important opportunity to elevate ocean-based climate action.”
Strategies and finance
The two-day dialogue in Bonn involved a series of panels, statements and breakout groups.
One of the main topics was how oceans are integrated into national climate plans under the Paris Agreement, known as “nationally determined contributions” (NDCs).
Three-quarters of the latest round of NDCs mention oceans, with conservation of “blue carbon” ecosystems the most frequently described action. (Landscapes such as mangroves can both absorb CO2 and protect coastal areas.)
Delegates also discussed alignment with the UN biodiversity process, as well as ocean finance, which currently makes up less than 1% of all climate finance.
(As discussions were taking place in Bonn, country officials also gathered in Mombasa, Kenya for the 11th Our Ocean Conference. Carbon Brief’s associate editor Giuliana Viglione attended the conference and will publish a full summary shortly.)
Developing countries were clear that many of the ocean-related actions in their NDCs would depend on receiving more financial support.
‘Political momentum’
With the backing of the COP31 presidency, delegates were hopeful about where this year’s dialogue could lead.
Charles Hamilton, an advisor for the Bahamas who spoke for the Alliance of Small Island States (AOSIS) in the dialogue, told Carbon Brief that island representatives “are not traveling thousands of miles to just talk and pat ourselves on the back”. He added:
“A dialogue that just remains a dialogue is just more talk – no action.”
Given that, he said “discussions in the dialogue must move into COP decisions and the decisions must be actioned”, noting the importance of finance.
Marina Corrêa, oceans lead at WWF-Brazil, pointed to an upcoming UN climate change Standing Committee on Finance forum as a space to ramp up pressure on ocean finance.
More broadly, she wanted to see the presidencies translate their support into a “leader-level ocean initiative” that could “mainstream” oceans across negotiations.
“We have a really interesting opportunity, in terms of political momentum,” Corrêa told Carbon Brief.
Watch, read, listen
‘HOTTER THAN HELL’: An episode of the BBC’s Rare Earth podcast titled “hotter than hell” considered the issue of extreme heat, with input from experts and “people facing up to the hottest temperatures on the planet”.
NOT BROKEN?: John Drake, a professor of ecology at the University of Georgia, wrote an essay for Aeon – also re-published as a Guardian “long read” – questioning the framing of ecosystems and climate systems “breaking down”.
ON COURSE: On his Volts podcast, US climate journalist David Roberts interviewed UK climate minister Katie White, quizzing her about whether the UK will “stay the course with its climate plans”.
Coming up
- 20-28 June: London climate action week
- 21 June: Colombia presidential runoff
- 24 June: UK Climate Change Committee progress in reducing emissions 2026 report to parliament
Pick of the jobs
- Mongabay, managing editor – Africa | Salary: Unknown. Location: Global
- Contexte, environment reporter – Brussels | Salary: €45,000-€60,000. Location: Brussels
- Climate 200, communications director | Salary: Unknown. Location: Australia
- Energy Tracker Asia, energy transition correspondent | Salary: $3,000-$4,000 per month. Location: South-east Asia (remote)
DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.
This is an online version of Carbon Brief’s weekly DeBriefed email newsletter. Subscribe for free here.
The post DeBriefed 19 June 2026: Bonn talks end in ‘gridlock’ | Energy’s ‘new era’ | Oceans in climate negotiations appeared first on Carbon Brief.
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