A few years ago, scientists studying satellite data discovered that there was an “unexpectedly large” source of CO2 emissions coming from tropical Africa, particularly over parts of Ethiopia and South Sudan.
This mysterious emissions source was so large, in fact, that if this region were a country, it would have been the second-largest emitter in the world, after China, in 2016 – releasing a total of 6bn tonnes of CO2, according to the study.
Now, newer research calls these results into question. Rather than using satellite data alone, it uses data taken by scientific aircraft travelling up and down the Atlantic Ocean off the western coast of tropical Africa.
This study finds that tropical Africa’s land acts as a net emitter of CO2 in the dry season, when practices such as biomass burning reach a peak, and a net sink in the wet season, when plants grow faster and take in more CO2 from the atmosphere. Thus, it concludes, tropical Africa’s land can be considered “neutral” in terms of its CO2 emissions.
However, the scientists that first reported the mysterious emissions tell Carbon Brief that they disagree with the new conclusions – and have a plan to explain where such large emissions could be coming from.
With neither study using data taken on the ground in Africa nor including African scientists, authors on both papers acknowledge the need for ground-based CO2 measurements to help solve the mystery.
Differing data
Africa is home to one-third of the world’s tropical rainforests, 3% of the world’s peatlands – including the world’s most extensive tropical peatland – and the majority of the world’s tropical savannahs. All of these ecosystems store large amounts of carbon.
Though the African tropics are a globally important carbon store, there have been few studies looking into the extent of year-to-year CO2 emissions from the land in this region.
Back in 2019, a study in Nature Communications sought to understand the extent of annual CO2 emissions from tropical Africa using data from Japan’s greenhouse gases observing satellite (GOSAT) and NASA’s orbiting carbon observatory (OCO-2).
The results showed that net CO2 emissions from Africa’s tropical land – the difference between the amount of CO2 absorbed and emitted by the land – totalled 5.4bn tonnes and 6bn tonnes in 2015 and 2016, respectively.
The maps below, taken from the paper’s supplementary information, show the extent of CO2 emissions from tropical land in 2015 and 2016. On the map, dark blue shows regions that acted as carbon sinks while yellow shows regions that were net emitters of CO2.
On the maps, a large yellow spot covers parts of Ethiopia and South Sudan – the source of the “unexpectedly large” emissions from Africa’s tropical land, the study’s lead author Prof Paul Palmer, a researcher of geosciences from the University of Edinburgh, told Carbon Brief back in 2019.
The newer study, published in the journal Global Biogeochemical Cycles, uses a different approach to study annual CO2 emissions from Africa’s tropical land.
This team of researchers used the NASA DC-8 Airborne Research Platform, an aeroplane that has been fitted out with equipment to conduct scientific research.
For four days across the northern hemisphere’s four seasons spread over the years 2016-18, the researchers flew south to north over the Atlantic Ocean to the west of tropical Africa, collecting CO2 measurements from the ocean surface to around 35,000 feet.
This approach allowed researchers to study the exhaust plume blown over to the Atlantic Ocean from tropical Africa. This plume contains particles such as dust, soot and wildfire smoke – along with gases such as CO2 .
The researchers then compared their data to estimates from models using the satellite data from the 2019 study.
The aircraft data found that Africa’s tropical land released far smaller emissions in the dry season, when compared to the estimates derived from satellite data. This led the researchers to conclude that the satellite data used in the 2019 study could have overestimated CO2 emissions from tropical Africa.
Instead of Africa’s tropical land being a large net source of CO2, the newer study concluded that it could actually be “neutral” in terms of annual CO2 emissions, says lead author Dr Benjamin Gaubert, a project scientist at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado. He tells Carbon Brief:
“Our findings suggest northern tropical Africa is a carbon source in the dry season and a sink in the wet season, with an annual exchange of around zero. Much of the seasonal biomass burning is inherently balanced over the year by photosynthetic uptake from grasses and shrubs.”
Conclusions questioned
Palmer, the author of the 2019 study, is not convinced by the new findings.
He argues that, because the aircraft data was collected over the Atlantic Ocean, to the west of tropical Africa, it is likely to be much more sensitive to CO2 plumes travelling over from western tropical Africa than from eastern tropical Africa – where his study found that most of the emissions were actually occurring. He tells Carbon Brief:
“I suspect – though I’m not 100% sure – that the team have shown with their analysis that west Africa, which is dominated by biomass burning, is close to neutral [for CO2 emissions], which would be less of a surprise.”
He added that while the Atlantic Ocean does receive plumes of CO2 blowing over from Africa’s tropical land, it is also likely to be affected by other sources of emissions from other parts of the world, muddying the ability to pinpoint emissions to specific regions.
Responding to these points, Dr Britton Stephens, co-author of the newer study and a senior scientist in the Earth Observing Laboratory at NCAR, tells Carbon Brief:
“It is true that the aircraft have a relatively broad region of influence that may not correspond precisely to the strongest postulated emission source of the [2019] study.”
He adds, however, that the emissions source from eastern tropical Africa identified in the 2019 study has not been exactly replicated by other research efforts using satellites. Instead, these studies typically produce “similar annual region-wide sources with very different within-region spatial patterns”.
Prof Emanuel Gloor is a researcher of CO2 emissions from tropical land at the University of Leeds, who was not an author on either paper. (He did act as a reviewer for the newer study.)
He tells Carbon Brief that the findings of the newer study – that Africa’s tropical land is neutral in CO2 terms – is much more in keeping with scientists’ understanding of the global carbon cycle:
“Essentially the result they find is exactly what you would expect.”
Mysterious emissions
As Gloor sees it, there were several issues with the 2019 study.
One of the major ones, he says, was that the scientists concluded that there could be a very large source of CO2 emissions coming from parts of Ethiopia and South Sudan – an area not only with very little infrastructure and commercial activity, but also very little forest cover. He tells Carbon Brief:
“Where would these emissions be coming from if they were really coming from Ethiopia? That’s not where you have massive amounts of biomass.”
Although the region is not covered by large areas of forest, it is home to some very carbon-rich soils, the 2019 study noted.
At the time, the scientists suggested that land degradation and deforestation could have potentially caused large amounts of carbon to be released from soils, with Palmer telling Carbon Brief in 2019:
“Substantial changes in land use over a region with high levels of soil organic carbon are conditions that could potentially release carbon from the soils.”
The detected CO2 spike could have also been influenced by the 2015-16 El Niño event, which was one of the strongest on record, another scientist not involved in the research told Carbon Brief at the time. (Warming can cause soils to release CO2 at a higher rate.)
Speaking to Carbon Brief in 2024, Palmer says that his research team do now have a firmer idea of where such a large amount of CO2 emissions could be coming from in the region comprising Ethiopia and South Sudan.
However, he declined to give more details on what this source was, arguing that it was still an area of active research and saying that he hoped to soon publish a research paper on his findings.
Data drought
Neither study uses data taken on the ground in Africa nor includes African scientists.
This is amid a backdrop of unequal participation for African scientists and institutions in global climate research.
Previous analysis by Carbon Brief found that just 1% of the most highly-cited climate research papers from the years 2017-21 featured African scientists.
And further Carbon Brief analysis showed that Africa has the lowest density of weather stations of any continent – hamstringing the ability to study how climate change could be affecting factors relevant to carbon loss from ecosystems, such as air and soil temperatures, soil moisture, rainfall and cloud cover.
Africa is the world’s second-largest continent and encompasses 20% of Earth’s land surface, meaning a lack of understanding of how its ecosystems are changing could hold consequences for scientists’ understanding of the global carbon cycle.
Carbon Brief asked the authors of both of the papers whether it was a weakness to not include data taken on the ground in Africa.
Stephens agrees that having “ground-based CO2 measurements in the region would be a big help”.
He adds, however, that to fully capture how emissions disperse in the atmosphere, these measurements should be complemented with a “systematic programme of airborne observations” – something his colleagues “recently started pursuing”.
Palmer also agrees that having on-the-ground measurements would have been preferable.
He adds that his team did have plans to travel to the region where they detected the large source of CO2 emissions via satellite data in order to take on-the-ground measurements. However, ongoing conflicts in South Sudan and Ethiopia made this impossible, he says.
The post Mystery over ‘unexpectedly large’ emissions from Africa’s tropical ecosystems appeared first on Carbon Brief.
Mystery over ‘unexpectedly large’ emissions from Africa’s tropical ecosystems
Transitioning to sustainable practices could boost resilience to compounding geopolitical and climate threats, experts say.
The worldwide fallout from the U.S. war in Iran isn’t limited to gas prices.
Ocean and coastal creatures are being put at risk by the spills, noise, dredging and shipping associated with new offshore oil and gas infrastructure, says a new report by a group of environmental NGOs.
The report by a group of twelve environmental groups analysed planned new offshore oil and gas blocks covering 430,000 square kilometres – an area the size of Sweden – in 11 countries.
Blocks in countries such as Kenya, Indonesia and Australia overlap with some of the planet’s hotspots for marine biodiversity, home to mangroves, coral reefs, sea turtles, sharks and whales.
Oil and gas expansion is advancing in spite of the legal protections already in place, the report says, with a third of the area being licensed overlapping with marine and coastal protected areas.
-
China’s carbon emissions rise again as more clean power is wasted
The economic powerhouse burned more coal and gas in the first quarter of 2026, despite record wind and solar build-out -
Investor climate group closes down, blaming “limits” of shareholder activism
Canadian campaign group Investors for Paris Compliance shut in May, saying efforts to push companies to tackle climate change have become less effective -
Santa Marta process can confront trade protection for fossil fuels, experts say
Academics at the first fossil fuel phase-out summit urged governments to recognise investor protection treaties as a barrier to the energy transition
“It is alarming to see the research findings and the sheer scale of fossil fuel expansion trajectories threatening the health and future of our shared ocean,” said Tyson Miller, Executive Director of Earth Insight, one of the environmental NGOs involved in the report.
At the first conference on Transitioning Away from Fossil Fuels in Santa Marta, around 60 countries floated the idea of creating “fossil-fuel-free zones”, which would seek to place limits on coal, oil and gas in areas where development would lead to severe social and environmental harm.
As part of the landmark Kunming-Montreal biodiversity deal, governments have also pledged to protect 30% of the planet’s land and marine ecosystems by 2030. This could be used as an opportunity to limit oil and gas expansion in sensitive areas, Miller said.
The report says the findings “reinforce the need for governments, financial institutions and companies to stop funding and supporting offshore oil and gas expansion”, and calls for the creation of fossil-fuel-free zones in “high-value marine and coastal areas”.
Oil bidding in biodiversity hotspots
As one of the case studies, Kenya — which is set to host the Our Ocean Conference in Mombasa later this month — has opened 50 offshore oil and gas blocks for bidding in the Lamu Basin, one of East Africa’s marine biodiversity hotspots.
These blocks overlap with all the region’s mangroves and coral reefs, the report says, which provide nursery habitats for fish, sea turtles and the vulnerable dugong.
These ecosystems are already under severe stress from climate change-related ocean heating and increased water acidity and could now face seismic surveys, offshore drilling, dredging, increased shipping traffic, oil spills, chemical discharge and underwater noise pollution.
The government estimates that oil production will start by 2026, aligning with “global best practices”, and has said the Lamu basin has vast “untapped potential”. The country is expected to open bidding for the first 10 blocks by September.
Muturi wa Kamau, network coordinator for the Kenya Oil and Gas Working Group, said in a statement that the country “is preparing to open ecologically sensitive areas for fossil fuel exploration” while positioning itself as a leader in ocean diplomacy.
“The question is: at what cost are we willing to risk these fragile ecosystems and the livelihoods of coastal communities who have depended on them for generations?” Kamau said.
Australia’s Otway Basin
After a four-year pause, Australia — which will act as co-presidency of the COP31 climate summit — resumed offshore exploration in the Otway basin last year, with American energy firm ConocoPhillips among the operators approved for exploratory drilling off the country’s southern coast.
The sites under exploration are as close as one kilometre from a series of marine reserves known as sanctuaries for pygmy blue whales, who travel thousands of kilometres to reproduce in those waters. Orange roughy, a deep-sea fish that can live for over 140 years, may also be harmed.
In total, the report analysed new LNG export projects in Argentina, Alaska, Mexico and Tanzania, as well as expanded offshore oil and gas licensing in Australia, Cameroon, Indonesia, Jamaica, Kenya, Norway, and Trinidad and Tobago.
The post Planned offshore oil and gas expansion threatens key marine ecosystems, report appeared first on Climate Home News.
Planned offshore oil and gas expansion threatens key marine ecosystems, report
As competition for minerals needed to produce clean energy technologies intensifies, a growing number of countries have resorted to an age-old mechanism to cope with the threat of scarcity: stockpiling.
The world’s biggest economies are racing to shore up reserves of cobalt, lithium, graphite and rare earths, which are needed to produce batteries, electric vehicles, wind turbines and electric systems to wean the global economy off fossil fuels. The same minerals are also increasingly sought after to manufacture military hardware and chips for AI, adding further pressure on supplies.
But the cutthroat scramble to build up reserves threatens to drive up the costs of the energy transition by intensifying competition and pushing up prices of key materials needed to produce clean energy technologies, research published today has found.
“If you undermine the financial viability of [clean energy] projects through higher raw material costs, you’re going to delay their roll-out,” co-author Hugh Miller, the critical minerals lead at the Centre for Economic Transition Expertise at the London School of Economics and Political Science, told Climate Home News.
Stockpiling “is happening, whether we like it or not”, said Miller. “But if we’re going to do it, we need to have it in a coordinated manner that means we don’t have massive market volatility and adverse implications from every country trying to go at it alone,” he added.
The rise of stockpiles
A growing number of governments have adopted national stockpiling programmes in response to heightened geopolitical tensions around mineral supply chains.
Earlier this year, US President Donald Trump announced the establishment of a critical mineral reserve known as “Project Vault” to protect American businesses from shortages after China imposed export restrictions on rare earth supplies.
Beijing suspended the measures until November as part of a trade truce with Washington but the episode spooked Western governments and exposed how strategic materials can be weaponised to achieve geopolitical objectives.
Australia, China, the EU and India have also announced measures to create strategic mineral reserves. Japan and South Korea already have long-standing mineral stockpiling programmes.
“Legitimate concerns”
“There are legitimate concerns with regards to potential global shortages of these minerals,” said Miller, citing rapidly rising and concurrent mineral demand for the energy transition, AI, data centres, and military technologies, combined with underinvestment in new supplies for some minerals, such as copper.
While stockpiling can serve as an emergency response mechanism during acute shortages, it does nothing to address the underlying concentration risks in mineral supply chains. The Democratic Republic of Congo holds around 70% of the world’s cobalt reserves, for example, while China dominates the processing of 19 out of 20 minerals deemed critical by a large number of nations.
-
Recycling could meet half of Europe’s critical mineral needs by 2050
A new report by an EU-funded research project says the bloc could harness its “urban mines” to reduce its dependence on China for energy transition minerals -
The energy transition has a rare earth problem: These startups are solving it
China’s grip on global supply chains is turbocharging efforts to find alternatives to the small group of metals that dominate EV motor technology -
The US’s critical minerals club threatens an equitable clean energy transition
Washington’s minerals trading bloc will shore up supplies for the US’s digital and military sectors and risks diverting resources away from cleantech
Uncoordinated stockpiling programmes risk heightening the price volatility they are designed to hedge against, according to the report.
Researchers found that if Australia, China, the EU, India, Japan, South Korea and the US simultaneously built reserves of minerals to cover six months of imports, the aggregate stockpile demand could represent up to 34% of global annual cobalt supply and over 10% of global lithium, graphite and copper supply. That could cause a shock to the market, triggering the shortages and price spikes they are trying to avoid.
Miller said it was unlikely that every country would stockpile at that rate, but aggregate stockpiling demand of just 5% of global mineral supply would have an impact on prices.
Coordinating stockpiles: a role for the IEA?
Researchers found that avoiding the negative impacts of stockpiling requires global coordination over how mineral stocks are accumulated and released – a mechanism which already exists for other commodities, including oil.
Coordination should include agreed rules for countries to build up their stocks over a slow and staggered timeline and pre-agreed conditions for releasing reserves to provide market predictability and reduce the risk of price spikes.
The International Energy Agency (IEA), which was established after the 1970s oil crisis to coordinate emergency oil stock releases among member countries, is best placed to oversee such a mechanism, they say.
Earlier this year, IEA member countries called on the agency to strengthen its work on critical minerals, including by providing support to countries “that choose to establish and expand critical minerals stockpiling systems”.
But Miller and his co-author Pau Morandi, a policy fellow at the Centre for Economic Transition Expertise, argue that members should go one step further and mandate the IEA to coordinate the security of supplies, rather than only helping individual governments.
The IEA has been contacted for comment.
A call to action for the G7
Miller said he hoped the research could be picked up by the G7 group of wealthy countries, which could lead on mandating the IEA to take on this coordination role.
France, which is presiding over the group this year and is hosting leaders in Evian on the shores of Lake Geneva in mid-June, has made strengthening the resilience of critical minerals value chains a priority.
In a communique last month, finance ministers agreed to “deepen and expand our cooperation among G7 members and with like-minded partners” to strengthen and diversify critical mineral supply chains and to continue discussions “on how to best organise analytical cooperation”.
Sebastien Treyer, executive director of the Paris-based Institute for Sustainable Development and International Relations (IDDRI), said he hoped the G7 leaders’ summit can help move the discussion on critical minerals towards greater international cooperation to secure the resources the world needs to build a clean economy.
From inclusive and mutually beneficial partnerships to mine resources to stockpiling minerals, “we need to coordinate more like a trade organisation than something that is about securing supply,” he said.
The post The scramble to stockpile critical minerals could drive up energy transition costs appeared first on Climate Home News.
The scramble to stockpile critical minerals could drive up energy transition costs
-
Climate Change10 months ago
Guest post: Why China is still building new coal – and when it might stop
-
Greenhouse Gases10 months ago
Guest post: Why China is still building new coal – and when it might stop
-
Greenhouse Gases2 years ago嘉宾来稿：满足中国增长的用电需求 光伏加储能“比新建煤电更实惠”
-
Climate Change2 years ago嘉宾来稿：满足中国增长的用电需求 光伏加储能“比新建煤电更实惠”
-
Climate Change2 years ago
Bill Discounting Climate Change in Florida’s Energy Policy Awaits DeSantis’ Approval
-
Renewable Energy7 months agoSending Progressive Philanthropist George Soros to Prison?
-
Carbon Footprint2 years agoUS SEC’s Climate Disclosure Rules Spur Renewed Interest in Carbon Credits
-
Greenhouse Gases11 months ago
嘉宾来稿：探究火山喷发如何影响气候预测