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
Discussing climate change can make a difference. Focusing on the impacts in everyday life is a good place to start, experts say.
When Bad Bunny climbed onto broken power lines during his Super Bowl halftime show, millions of viewers saw a spectacle. Climate communicators saw a lesson in how to talk about climate change.
Wondering How to Talk About Climate Change? Take a Lesson from Bad Bunny
Sydney, Thursday 19 March 2026 — In response to escalating attacks on gas fields in the Middle East, including Israeli strikes on Iran’s giant South Pars gas field and Iranian retaliations on gas fields in Qatar and Saudi Arabia, the following lines can be attributed to Solaye Snider, Campaigner at Greenpeace Australia Pacific:
“The targeting of gas fields across the Middle East is a perilous escalation that reinforces just how vulnerable our fossil-fuelled world really is.
“Oil and gas have long been used as tools of power and coercion by authoritarian regimes. They cause climate chaos and environmental pollution and they drive conflict and war. The energy security of every nation still hooked on gas, including Australia, is under direct threat.
“For countries that are reliant on gas imports, like Sri Lanka, Pakistan and South Korea, this crisis is just getting started. It can take months to restart a gas export facility once it is shut down, meaning the shockwaves of these strikes will be felt for a long time to come.
“It is a gross and tragic injustice that while civilians are killed and lose their homes to this escalating violence, and families struggle with a tightening cost-of-living, gas giants like Woodside and Santos have seen their share prices surge on the prospect of windfall war profits.
“We must break this cycle. Transitioning to local renewable energy is the way to protect Australian households from the inherent volatility of fossil fuels like gas.”
-ENDS-
Images available for download via the Greenpeace Media Library
Media contact: Lucy Keller on 0491 135 308 or lkeller@greenpeace.org
Greenpeace response to escalating attacks on gas fields in Middle East
Climate Change
DeBriefed 20 March 2026: Energy crisis deepens | Brazil’s new climate plan | New Zealand climate case
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Iran war fallout continues
WORK FROM HOME: The International Energy Agency has advised its member countries to take 10 steps in response to the ongoing energy crisis fuelled by the Iran war, including reducing highway speeds and encouraging people to work from home, said the Guardian. It came after retaliatory attacks between Israel and Iran continued to destroy energy infrastructure in the Middle East, causing energy prices to soar further, said Reuters.
SUPPLY DISRUPTED: The IEA also said it is prepared to make more of its member nations’ 1.4bn-barrel oil reserves available to help ease the impacts of what it called the “biggest supply disruption in the history of the oil market”, reported Bloomberg. The outlet noted that Asian countries have been hit hardest by the shortages, caused by a “near-halt” of shipping through the Strait of Hormuz.
EU SUMMIT: The energy crisis dominated talks at an EU leaders summit on Thursday, said Politico. Arriving at the summit, Spain’s prime minister Pedro Sánchez attacked other European leaders for using the energy crisis as an excuse to “gut climate policies”, according to the EU Observer. The Financial Times said that some European leaders have asked the European Commission to overhaul its flagship emissions trading system (ETS) by summer in response to the energy crisis.
COAL BOOST: In response to the conflict, utility companies in Asia are “boosting coal-fired power generation to cut costs and safeguard energy supply”, said Reuters. UN climate change executive secretary Simon Stiell told Reuters: “If there was ever a moment to accelerate that energy transition, breaking dependencies which have shackled economies, this is the time.”
Around the world
- WINDFARM WINDFALL: The Trump administration in the US is considering a nearly $1bn settlement with TotalEnergies to cancel the French energy company’s two planned windfarms off the US east coast and have it instead invest in fossil-gas infrastructure in Texas, according to documents seen by the New York Times.
- BUSINESS CLASH: Following “clashes” with the agribusiness sector, Brazil launched its new climate plan, which calls for a 49-58% reduction in greenhouse gas emissions from 2022 levels by 2025 and includes “specific guidelines for different sectors”, reported Folha de Sao Paolo.
- SALES SLUMP: Sales of liquified petroleum gas from India’s state-run oil companies have fallen by 17% this month due to cuts in deliveries to commercial and industrial consumers “amid the widespread logistical bottlenecks triggered by the Iran war”, said the Economic Times.
- CUBAN ENERGY CRISIS: The US imposed an “effective oil blockade” on Cuba, leaving the country facing its “worst energy crisis in decades”, reported the Washington Post. Meanwhile, Chinese exports of solar panels to the island have “skyrocketed” since 2023, it added.
- RECORD HIGHS: An “unprecedented” heatwave in the western and south-western US is “shattering dozens of temperature records” and could lead to drought in California in the coming months, reported the Los Angeles Times.
- VULNERABILITY CONCERNS: Landslides that killed more than 100 people in southern Ethiopia have “renewed concerns about Ethiopia’s vulnerability to climate-related disasters”, said the Addis Standard.
1%
The percentage of England’s land surface that could be devoted to renewables by 2050, according to the long-awaited “land-use framework” released by the UK government this week and covered by Carbon Brief.
Latest climate research
- Approaching international climate action by shifting the burden of mitigation onto higher-income countries could avoid 13.5 million premature deaths from air pollution in middle- and lower-income countries by 2050 | The Lancet Global Health
- Beavers can turn the ecosystems surrounding streams into “persistent” sinks of carbon that can sequester an order of magnitude more than non-beaver-modified ecosystems can store | Communications Earth & Environment
- Mobile-phone data from seven diverse countries during the summer heatwaves of 2022-23 showed a “widespread tendency to withdraw into homes” and an increase in out-of-home activities that can offer cooling, such as indoor retail | Environmental Research: Climate
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
Carbon Brief this week published a significant update to its map of how climate change is affecting extreme weather events around the world. The map now includes 232 new extreme weather events from studies published in 2024 and 2025. Of these events, 196 were made more severe or more likely to occur by human-driven climate change, 12 were made less severe or less likely to occur and 10 had no discernible human influence. (The remaining 14 studies were inconclusive.)
Spotlight
New Zealand breaks new ground on climate litigation
This week, Carbon Brief speaks to experts about a first-of-its-kind climate lawsuit in New Zealand.
Earlier this week, representatives from two environmentally focused legal advocacy groups challenged the New Zealand government’s climate-action plan in court.
The plaintiffs argued that the measures laid out in the plan are insufficient to achieve the country’s legal obligation to hold global warming to 1.5C above pre-industrial temperatures.
The case could be “influential” in shaping lawsuits and rulings around the world, one legal expert not involved in the case told Carbon Brief.
Reductions vs removals
The new case contends that there are several issues regarding the New Zealand government’s response to climate change.
One of the key arguments the plaintiffs make is that New Zealand’s second emissions reduction plan, which covers the period from 2026-30, is overreliant on the use of tree-planting to achieve its targets.
When the plan was released in December 2024, it was “immediately clear that it was a pretty lacklustre plan”, Eliza Prestidge Oldfield, senior legal researcher at the Environmental Law Initiative, one of the groups behind the legal case, told Carbon Brief.
The plan called for large-scale planting of pine tree plantations, which are not native to New Zealand and have a high risk of burning. Because of this, there are concerns about how permanent any carbon removal provided by these plantations actually can be, experts told Carbon Brief.
Catherine Higham, senior policy fellow at the Grantham Research Institute on Climate Change and the Environment who was not involved in the case, said:
“The lawyers are arguing that there are real challenges with equating the emissions that you may be able to remove from the atmosphere through afforestation with actual emissions reductions, which are much more certain.”
‘Global dialogue’
While other climate lawsuits elsewhere in the world have also focused on the inadequacy of a government’s plan to meet its stated emissions-reduction targets, this is the first such case that addresses the role of removals head-on.
Lucy Maxwell, co-director of the Climate Litigation Network, told Carbon Brief that the lawsuit “builds on a decade of climate litigation” in national, regional and international courts.
Maxwell, who was not involved in the New Zealand case, added that there is a “real global dialogue” between, not just plaintiffs, but national courts as well. She said:
“[National courts] look to common issues that have been decided in other countries. They’re not binding on that court if it’s at the national level, but they are influential.”
Given that many other countries have legal frameworks requiring their governments to create plans outlining the pathway to their long-term climate targets, Prestidge Oldfield told Carbon Brief that other jurisdictions “should be interested in these questions around the level of certainty”.
Higham noted that, even if the case is successful, addressing the plan’s shortfalls will face its own set of challenges. She told Carbon Brief:
“A lot of these decisions are political and they can be politically contentious…Those [measures] have to be put into action through legislation and that is then subject to the usual political process. So that’s where the challenge comes in.”
While she could not speculate on the outcome of the case, Prestidge Oldfield said it was “very heartening” to see that both the judge and the opposing counsel “appreciated how much of a concern climate change is globally”.
She added:
“It’s not a given that the judge would even be interested in climate change.”
Watch, read, listen
COMMON APPROACH: The Heated podcast analysed fossil-fuel advertisements and highlighted the most common deception tactics they employed.
THREAT ASSESSMENT: Mongabay mapped the potential threat that oil extraction poses to Venezuela’s ecosystems, including the Amazon rainforest and its coral reefs.
SALT LAKES? GREAT!: High Country News interviewed journalist Dr Caroline Tracey about her new book on saline lakes – such as Utah’s Great Salt Lake – the threats that face them and what they can teach us.
Coming up
- 23 March-2 April: Third meeting of the preparatory commission for the High Seas Treaty, New York
- 24-27 March: 64th session of the Intergovernmental Panel on Climate Change, Bangkok
- 26-29 March: 14th ministerial conference of the World Trade Organization, Yaoundé, Cameroon
Pick of the jobs
- International Centre of Research for the Environment and Development (CIRAD), IPCC chapter scientist | Salary: €3,200-3,750 per month. Location: Nogent-sur-Marne, France
- Avaaz, chief of staff | Salary: Dependent on location. Location: Remote, with preferred time zones
- Green Party, social media officer | Salary: £31,592-£32,192. Location: Remote or Westminster, UK
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 20 March 2026: Energy crisis deepens | Brazil’s new climate plan | New Zealand climate case appeared first on Carbon Brief.
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