China Briefing handpicks and explains the most important climate and energy stories from China over the past fortnight. Subscribe for free here.
TRUMP WITHDRAWS: A government spokesperson said China’s “resolve and actions to actively respond to climate change will remain unchanged” at a press conference on 21 January. Asked by the New York Times to respond to president Donald Trump withdrawing the US from the Paris Agreement again, foreign ministry spokesperson Guo Jiakun said China was “concerned” and that “China will work with all parties to…promote a global green and low-carbon transition for the shared future of humanity”, state-supporting Global Times reported. At the World Economic Forum in Davos, China’s vice premier Ding Xuexiang reiterated that the world needs to “jointly tackle global challenges”, including climate change and energy security, said the Hong Kong-based South China Morning Post (SCMP).
BYE BYE BIDEN: Before leaving the White House, outgoing US president Joe Biden urged his successor to “tackle China’s ‘overcapacity’ and dominance in clean-energy supply chains, calling it a competition the US ‘must win’”, SCMP reported. Jennifer Granholm, Biden’s energy secretary, wrote in the New York Times that “it is no secret China wants to dominate the global market” for electric vehicles (EV) under the headline: “China will be thrilled if Trump kills America’s green economy.” One of the Biden administration’s last moves was finalising rules that will “effectively bar nearly all Chinese cars and trucks” from the US, said Reuters. He also barred five Chinese solar companies – allegedly using forced labour in Xinjiang – from entering the US market, reported the New York Times. The move has led to criticism from China’s Ministry of Foreign Affairs, which denied the forced labour claims, said BJX News. BBC News reported that tariffs from the US, Canada and the EU could force China to turn to “emerging markets”, but as the new markets “don’t have the same levels of demand…that could impact Chinese businesses that are hoping to expand, in turn hitting suppliers of energy and raw materials”. A comment for Dialogue Earth by analysts at the Centre for Research on Energy and Clean Air (CREA) said emerging markets in the global south are already driving China’s export growth.
REEVES IN BEIJING: UK chancellor Rachel Reeves visited China between 10-13 January and “secured benefits worth up to £1bn for the UK economy”, reported the Guardian. According to a UK government document, both sides agreed to “deeper cooperation across areas such as financial services, trade, investment and the climate to support secure growth”, while also agreeing on “strengthening the existing UK-China clean energy partnership”. An unbylined comment piece in China’s state-supporting Global Times said that “China-UK relations have shown signs of warming up”. It added that Reeves responded that the UK would “make decisions in our national interest” when asked whether it would follow the US and EU in imposing tariffs on Chinese EVs. Meanwhile, Zheng Zeguang, the Chinese ambassador to the UK, called on both sides to “maintain the momentum and focus on cooperation” at an event in London attended by Carbon Brief.
EU-CHINA TENSIONS: Just before Reeves’ arrival, China had “concluded that the EU’s recent [anti-subsidies] investigations into Chinese enterprises…were ‘unfair and non-transparent’”, SCMP reported. However, Beijing did not confirm whether it would “take any retaliatory measures in light of the probe’s findings”, added the newspaper. Bloomberg reported that the EU was “set to warn” that the bloc is “facing stiffening pressure” from nations including China. China’s president Xi Jinping, nevertheless, told European Council president Antonio Costa that “China has always regarded Europe as an important pole in a multipolar world”, reported Xinhua. In her own Davos speech, European Commission president Ursula von der Leyen noted concerns over “a second China shock – because of state-sponsored over-capacity”, but said “we should…strive for mutual benefits in our conversation with China”.
OIL PEAKING?: As much as 10% of China’s oil-refining capacity could be closed in the next 10 years due to “an earlier-than-expected peak” in oil demand, Reuters reported. Chinese oil imports in 2024 fell 1.9% to 11.04m barrels per day, the “first annual decline in two decades outside of pandemic-induced falls”, another Reuters article said. A Financial Times “big read” – titled “Has China already reached peak oil?” – attributed the decline to China’s property crisis and rising electrification of transport. It quoted the head of oil giant Saudi Aramco claiming plastic and petrochemical demand could sustain demand going forward, but also quoted an International Energy Agency analyst saying the decline in transport oil use would outweigh this. The sale of petrol-powered cars in China “plunged” last year, as sales of all types of EVs rose more than 40%, according to the Associated Press.
COAL POWER-UP: China’s thermal power generation – largely coal – rose 1.5% in 2024 to 6,340 terawatt-hours (TWh), Reuters reported, “defying “expectations that coal generation was peaking”. However, the aggregate data mask a “very significant breakpoint”, it quoted CREA lead analyst Lauri Myllyvirta saying, as an 11% “spike” in coal-fired power growth in January and February was followed by a plateau from March to November. Total power consumption reached 9,852TWh, up 6.8% year-on-year, BJX News reported. On Twitter, David Fishman, senior manager at consultancy Lantau Group, said growth in power consumption in the past six months of 2024 “was considerably slower than in the [first] half of the year”.
RENEWABLE RECORDS: China has broken its “own records for new wind and solar power installations again” in 2024, reported Reuters. Solar capacity grew to nearly 890 gigawatts (GW), up 45% – or 277GW – year-on-year, Jiemian reported, while wind capacity grew 79GW to around about 520GW. The news outlet added that thermal power “is still the largest source of electricity” in China overall. To “keep pace with surging renewable generation”, China’s State Grid Corporation will spend 650bn yuan ($89bn) – a record amount – on upgrading the nation’s power infrastructure this year, Bloomberg said. It added that most of this would likely go to “ultra-high-voltage power lines” and “smaller networks linking rooftop solar panels”.
MEE CONFERENCE: China’s Ministry of Ecology and Environment (MEE) confirmed eight “key tasks” for 2025, including expanding the national carbon market and promoting “green, low-carbon and high-quality development”, at its annual work conference on 14-15 January, reported Shanghai-based media outlet the Paper. The ministry also announced that “approximately 80% of the nation’s crude steel production capacity has undergone either comprehensive ultra-low emission transformations or targeted upgrades in key segments of their production processes”, according to the Communist party-affiliated People’s Daily. At a separate press conference, MEE said it has approved environmental investments worth 980bn yuan ($133bn) in 2024, while pledging to “refine the conviction and sentencing standards for falsifying environmental assessments” within the legal system in China.
EMISSIONS ACCOUNTING: Meanwhile, China released its first “national database of emission factors” for “improving the accuracy” of greenhouse gas emission calculations, Science and Technology Daily reported. It also released the “first batch of carbon footprint accounting rules”, covering steel, cement, EV batteries and 12 other “industrial products”, said China Energy Network.
China is the world’s largest market for energy storage, followed by the US and Europe, according to BloombergNEF. The storage industry has attracted investments worth hundreds of billions of yuan and rapidly developed in recent years.
However, rapid growth has caused other problems, such as “temporary structural overcapacity” and low utilisation.
In this issue, Carbon Brief explores how China has been driving the sector forwards and how it fits into the nation’s wider energy transition. The full article is available on Carbon Brief’s website.
China is experiencing a renewable energy boom, adding a massive 301 gigawatts (GW) of renewable capacity, including solar, wind and hydro, in 2023 alone – more than the total renewable generating capacity installed in most countries over all time.
However, the country’s power system still struggles to absorb all of the generation, making energy storage – which bridges temporal and geographical gaps between energy supply and demand – a key tool for the country to improve its renewable energy integration.
Pumped hydro storage is the most common utility-scale storage system and has a long history in China. As of 2023, pumped hydro storage surpassed 50GW, making up more than half of the country’s overall storage capacity.
The remaining half is comprised primarily of batteries and emerging technologies, such as compressed air and flywheels, as well as thermal energy.
These technologies, known as the “new type” energy storage in China, have seen rapid growth in recent years. Lithium-ion batteries dominate the “new type” sector.
The deployment of “new type” energy storage capacity almost quadrupled in 2023 in China, increasing to 31.4GW, up from just 8.7 GW in 2022, according to data from the National Energy Administration (NEA).
This means that China surpassed its target of reaching 30GW of the “new type” energy storage by 2025 two years earlier than planned. The goal had been set by the NEA and China’s top economic planner the National Development and Reform Commission, under the 14th “five year plan”.
(Read Carbon Brief’s Q&A: What does China’s 14th ‘five year plan’ mean for climate change?)
To promote battery storage, China has implemented a number of policies, most notably the gradual rollout since 2017 of the “mandatory allocation of energy storage” policy (强制配储政策), which is also known as the “new energy plus storage” model (新能源+储能).
Under the mandate, which applies in dozens of provinces, renewable companies are required to include a certain amount of energy storage capacity alongside new solar and wind generation projects, with the storage allocation rate ranging between 5% to 20%.
Cheaper costs led by technology innovation have also helped the market’s increasing adoption of batteries, Sun Yongping, researcher of emissions trading and vice-dean of the Institute of State Governance at Huazhong University of Science and Technology, told Carbon Brief.
Despite its positive intentions, the mandatory storage policy has had unintended consequences. Notably, a significant portion of the installed storage capacity remains underutilised.
In regions covered by the State Grid – the government-owned operator that runs the majority of the country’s electricity transmission network – more than four-fifths of the storage systems operate less than 10% of the time, with many used only once every two days, according to a Bloomberg report.
Another challenge, according to Guo, is the additional project costs and lack of effective incentives, as many storage facilities were built or rented to fulfil government requirements, but went unused afterwards.
Both Guo and Sun argue that China needs a deeper level of electricity market pricing reforms to create incentives to use storage.
Guo said: “We still hope that each place deploys new energy storage according to its needs and understands its own situation instead of adopting a ‘one-size-fits-all’ approach.”
Earlier this year, the NEA named the energy storage sector as a “new driving force” for the country’s “new quality productive forces ” (NQPF).
(Read more on Carbon Brief’s Q&A: “What China’s push for ‘new quality productive forces’ means for climate action.”)
Regional governments also saw the economic opportunity in energy storage. Guangdong, for example, aimed to make energy storage a “strategic pillar industry” by 2025.
Meanwhile, Zhejiang, Anhui and Guangdong also have ambitious targets of installing local storage capacity of 3GW each by 2025, according to a recent tally by Greenpeace East Asia, based on government documents.
The booming market has attracted more than 100bn yuan ($14bn) since 2021.
But risks of market turmoil also exist. According to battery industrial information provider Gaogong Industrial Institute, last year China saw more than 70,000 newly registered companies in the sector, which indicated that the market – already seeing fierce competition – may now be undergoing an “overcapacity” period.
Guo said this period of “overcapacity”, however, is “temporary”. She adds:
“There exists a temporary structural overcapacity, as the current expansion of new type energy storage is outpacing the market needs.
“However, if the regional governments could provide more policy support for the application of storage projects, this ‘excess capacity’ due to insufficient market demand could be avoided.”
This Spotlight was written by freelance climate journalist Yuan Ye for Carbon Brief.
CARBON ‘SPIRIT’: Zheng Shanjie, head of China’s top planner National Development and Reform Commission (NDRC), wrote a comment for People’s Daily about the “spirit” of the Central Committee of the Communist party, including insisting on the “dual-carbon” goals.
PARIS ‘THREATS’: Caixin published a speech by former Chinese central bank governor Zhou Xiaochuan arguing that the Paris Agreement faces “mounting threats”, with funding for climate change initiatives “remain[ing] critically insufficient”.
CBAM SOLUTION: A comment for the 21st Century Business Herald by Lin Boqiang, dean at the China Institute for Studies in Energy Policy of Xiamen University, discussed developing China’s carbon market as a response to the EU’s carbon border tariff (CBAM).
US-CHINA CLIMATE: US thinktank the Brookings Institution released a video recording of a panel discussion on the “evolving dynamics of US-China relations on climate change and green technology”.
Maximum carbon uptake potential through progressive management of plantation forests in Guangdong province, China
Communications Earth & Environment
Harvesting young planted forests and then replanting over a 20-year period could sequester 2.5 times more carbon than simply preserving forests, according to new research on China’s Guangdong province. The authors used satellite data, forest growth models and machine learning to identify “key drivers of carbon accumulation”. The study found that the optimal scenario for carbon sequestration, described above, “could yield a potential carbon stock of 0.5 gigatonnes of carbon by 2060, without expanding forest cover”.
Evaluation and future projection of compound extreme events in China using CMIP6 models
Climate change
A new study evaluated the simulation performance of CMIP6 climate models for “six types of compound extreme event” in China. The research found four major results including “the performance of general circulation models (GCMs) in the simulation of extreme temperature indices is better than that for extreme precipitation indices, and positive biases exist in extreme precipitation indices for most models”. It added that the frequency of warm extremes may increase in the future, while cold extremes showed a decreasing trend.
China Briefing is compiled by Wanyuan Song and Anika Patel. It is edited by Wanyuan Song and Dr Simon Evans. Please send tips and feedback to china@carbonbrief.org
This has seen China become the world’s largest market for energy storage deployment. Its capacity of “new type” energy storage systems, such as batteries, quadrupled in 2023 alone.
This rapid growth, however, has caused other problems, such as what one analyst described as “temporary structural overcapacity” and low utilisation.
In this Q&A, Carbon Brief explores how China has been driving the sector forwards and how it fits into the nation’s wider energy transition.
China is currently the world’s largest market for energy storage, followed by the US and Europe, according to BloombergNEF.
This position was driven by a combination of market need for balancing renewable energy and government efforts to build a “new power system”.
China installed a massive 301 gigawatts (GW) of renewable capacity including solar, wind and hydro in 2023 alone – more than the total renewable generating capacity installed in most countries over all time.
As of May 2024, “clean energy” generated a record-high 44% of China’s electricity, according to Carbon Brief analysis.
However, despite the renewable energy boom, China’s power system still struggles to absorb all of the generation, making energy storage – which bridges temporal and geographical gaps between energy supply and demand – a key tool for the country to improve its renewable energy integration.
The majority of China’s storage capacity comes from large-scale storage projects, such as hydropower with reservoirs on the Yangtze River and gigawatt-level battery energy storage systems in Inner Mongolia.
Pumped hydro storage is the most common utility-scale storage system and has a long history in China. It pumps water uphill to a reservoir and then releases it to generate electricity. As of 2023, pumped hydro storage surpassed 50GW, making up over half of the country’s overall storage capacity.
The remaining half is comprised primarily of batteries and emerging technologies, such as compressed air, flywheel, as well as thermal energy.
These technologies, known as the “new type” energy storage in China, have seen rapid growth in recent years. Lithium-ion batteries dominate the “new type” sector.
The deployment of “new type” energy storage capacity almost quadrupled in 2023 in China, increasing to 31.4GW, up from just 8.7GW in 2022, according to data from the National Energy Administration (NEA).
This means that China surpassed its target of reaching 30GW of the “new type” energy storage by 2025 two years earlier than planned. The goal had been set by the NEA and China’s top economic planner the National Development and Reform Commission, under the 14th “five year plan”.
(Read Carbon Brief’s Q&A: What does China’s 14th ‘five year plan’ mean for climate change?)
Wang Shurui, researcher at the Institutes of Science and Development, Chinese Academy of Sciences, tells Carbon Brief:
“Advancements in the storage sector will enable a greater integration of renewable energy into the power grid, enhancing grid stability and helping accelerate China’s emissions reduction.”
To promote battery storage, China has implemented a number of policies, most notably the gradual rollout since 2017 of the “mandatory allocation of energy storage” policy (强制配储政策), which is also known as the “new energy plus storage” model (新能源+储能).
Under the mandate, which applies in dozens of provinces, renewable companies are required to include a certain amount of energy storage capacity alongside new solar and wind generation projects, with the storage allocation rate ranging between 5% to 20%.
“This mandate is driving storage growth, as it pushes the build-out of large-scale energy storage stations,” says Guo Shiyu, climate and energy campaigner from Beijing-based thinktank Greenpeace East Asia. She tells Carbon Brief:
“The stations may not look huge separately, but they are mostly built on the generation side [alongside generating capacity], which are still quite big compared to industrial and commercial self-built storage [on the demand side].”
Cheaper costs led by technology innovation have helped the market’s increasing adoption of batteries too, Sun Yongping, researcher of emissions trading and vice-dean of the Institute of State Governance at Huazhong University of Science and Technology, tells Carbon Brief.
“An interviewee told me in a recent field study that the cost had fallen by over a half these years,” says Sun. “Local development is so fast that too often you can’t grasp it [in a] timely [way] just by looking at the statistical numbers,” he adds.
Despite its positive intentions, the mandatory storage policy has had unintended consequences. Notably, a significant portion of the installed storage capacity remains underutilised.
In regions covered by the State Grid – the government-owned operator that runs the majority of the country’s electricity transmission network – over four-fifths of the storage systems operate less than 10% of the time, with many used only once every two days, according to a Bloomberg report.
Another challenge, according to Guo, is the additional project costs and lack of effective incentives, as many storage facilities were built or rented to fulfil government requirements but went unused afterwards.
Both Guo and Sun argue that China needs a deeper level of electricity market pricing reforms to create incentives to use storage.
For example, having electricity prices that change at different hours could encourage the adoption of storage technologies in China, suggests Sun.
Guo says: “We still hope that each place deploys new energy storage according to its needs and understands its own situation instead of adopting a ‘one-size-fits-all’ approach.”
In 2024, the NEA named the energy storage sector as a “new driving force” for the country’s “new quality productive forces ” (NQPF). It could “propel the upstream and downstream industrial chains, promote scientific and technological innovation, talent training, investment and employment”, said the NEA.
(Read more on Carbon Brief’s Q&A: What China’s push for ‘new quality productive forces’ means for climate action.)
Regional governments are also exploiting the economic opportunity in energy storage. Guangdong, for example, aimed to make energy storage a “strategic pillar industry” of its economy by setting a target of 600bn yuan ($85bn) in annual revenue from the energy storage industry by 2025, eyeing the domestic and overseas market as the global energy transition deepens.
Meanwhile, Zhejiang, Anhui and Guangdong also have ambitious targets of installing local storage capacity of 3GW each by 2025, according to a recent tally by Greenpeace East Asia, based on government documents.
The booming market has attracted more than 100bn yuan ($14bn) since 2021.
But risks of market turmoil also exist. According to battery industrial information provider Gaogong Industrial Institute, last year China saw over 70,000 newly registered companies in the sector, which indicated that the market – already seeing fierce competition – may now be undergoing an “overcapacity” period.
Guo says this period of “overcapacity”, however, is rather “temporary”. She adds:
“There exists a temporary structural overcapacity, as the current expansion of new type energy storage is outpacing the market needs.
“However, if the regional governments could provide more policy support for the application of storage projects, this ‘excess capacity’ due to insufficient market demand could be avoided.”
Solar power output in the EU more than tripled between 2014 and 2024, the report shows, with last year seeing coal generation overtaken for the first time.
Meanwhile, wind generation has more than doubled over the same period.
Wind and solar growth over the past decade pushed EU fossil-fuel generation in 2024 to its lowest level in 40 years, despite the long-term decline of nuclear power.
The increase in wind and solar generation in the EU also helped avoid €59bn in fossil-fuel imports over the past five years, Ember says.
Without the increase in solar and wind capacity since 2019, the EU would have imported an extra 92bn cubic metres (bcm) of gas and 55m tonnes (Mt) of hard coal. Ember says this helped avoid cumulative emissions of some 460m tonnes of carbon dioxide (MtCO2).
Accelerated wind and solar growth facilitated by permitting reform and other measures could help the EU end Russian energy imports entirely, adds Ember.
Last year marked five years since the passing of the European Green Deal, officially declaring a “climate emergency” and requiring the European Commission to adapt all its proposals to fall in line with limiting global warming to 1.5C above pre-industrial levels.
Since then, the EU’s electricity sector has seen a “deep transformation”, according to Ember, with a “surge” in renewables driving down the use of fossil fuels and related CO2 emissions.
In 2019, fossil fuels provided 39% – some 1,130 terawatt hours (TWh) – of the EU’s electricity, while renewables provided 34% (979TWh). By the end of 2024, fossil fuels had fallen to 29% (793TWh) – the lowest level in at least 40 years – while renewables had grown to nearly half of the mix (47%, 1,300TWh).
The growth of wind and solar ensured that, despite a decline in nuclear over the past 10 years, coal and gas are both being squeezed out of the electricity generation mix in the EU, as shown in the chart below.
The growth of solar and wind over the past five years has cumulatively avoided 736TWh of fossil-fired generation. This is equivalent to 460m tonnes of CO2 (MtCO2), or roughly the same as the power-sector emissions of Italy over the past five years, Ember states.
The emissions intensity of electricity fell by 26% over this period, to 213 grams of CO2 per kilowatt hour (gCO2 per kWh). This is a steeper decline than that seen in other major economies such as the US, notes Ember, where the emissions intensity of electricity generation fell by 13% over the same period.
Over the past five years, EU solar capacity tripled from 120 gigawatts (GW) to 338GW, continuing the rapid expansion seen in the previous five years. Wind capacity has grown by 37%, from 169GW in 2019 to 231GW in 2024.
Hydropower capacity since the passage of the Green New Deal has remained flat at 130GW and nuclear capacity has fallen from 110GW to 96GW, Ember notes.
The continued growth of wind and solar means EU electricity generation from coal has now dropped by nearly two thirds over the past decade, as the chart below shows. This is despite a small, temporary uptick in response to Russia’s invasion of Ukraine in 2021.
Moreover, while gas-fired generation in 2024 was slightly higher than it was a decade earlier, it has also dropped every year for the past five years, Ember’s data shows.
Without the growth in renewables since the Green New Deal was brought in, the EU would have spent €59bn on fossil-fuel imports for power generation, according to Ember. Of this, €53bn would have been spent on gas and €6bn on coal.
In total, the EU avoided importing approximately 92bcm, or around 18% of gas consumed in the power sector between the end of 2019 and the end of 2024. It also avoided imports of 55Mt of hard coal.
Coal has been particularly impacted by the growth of solar and wind, falling from 16% of the EU electricity mix in 2019 to less than 10% in 2024. This has more than cancelled out the impact of the temporary uptick in 2021 and 2022 during the gas crisis.
In 2024, coal provided less than 5% of the power mix in 16 EU countries, Ember says, 10 of which had no operating coal power plants.
Portugal phased coal out of its electricity mix completely and a new wave of coal power plant closures is “imminent”, says Ember. There are 11 EU countries that have announced plans to totally phase out coal from their electricity mix in the next five years.
Along with the fall in coal power, gas fell by a quarter over the past five years from providing 20% of EU power in 2019 to 16% in 2024, according to Ember.
This drop has contributed to efforts to limit EU reliance on Russian gas, although imports from the nation still accounted for 14% of total gas consumption in 2024.
While this was down from around 50% in 2019, it was an increase of 18% on the previous year, mainly due to increased imports into Italy, the Czech Republic and France.
According to Ember, the power sector consumed approximately 88bcm of gas in 2024, of which 10bcm (12%) was Russian, as shown in the figure below. These imports provided the country with an estimated €4bn in revenue.
Even with the uptick in 2024, the EU’s power sector is far less reliant on importing Russian gas than it was five years earlier, Ember’s data shows.
There was a record increase in solar generation in 2024, up 54TWh (+22%) year-on-year, according to Ember. This is despite the sector having already seen growth of 40TWh in 2023.
Additionally, 2024 saw record annual capacity additions, with the EU solar fleet growing by 66GW, 4% more than the 63GW addition seen in 2023.
This growth rate is above what national targets would require and nearly sufficient to hit the EU’s 2030 goal, notes Ember, as shown in the figure below.
Ember says this is “highlighting a disconnect between the rapid pace of on-the-ground market trends and the slow response of governments in updating their targets”.
In 2024, solar output grew in all EU members and 16 countries generated more than 10% of their electricity from the technology, the report notes – three more than the previous year.
However, in some countries, solar is getting close to exceeding demand during peak hours, according to Ember. Its report says that 12 EU countries saw solar generating 80% or more of power demand for at least one hour in 2024.
As such, plentiful solar is pushing hourly power prices to zero or even below. In 2024, negative or zero price hours became more common, growing from 2% of hours in 2023 to 4% in 2024 across the EU.
The increase in negative pricing periods highlights the business case for more flexibility options, notes Ember, with consumers able to save money by shifting demand to periods of abundant generation or using battery storage to take advantage of low-cost solar generation by selling it back to the grid during demand peaks.
While the deployment of battery storage has been growing in recent years – doubling to 16GW in 2023 from 8GW in 2022, the report notes – capacity is concentrated in a small number of countries, with Germany and Italy together housing 70% of existing battery capacity in the EU as of the end of 2023.
Additionally, demand flexibility and smart electrification could help consumers reduce their bills, Ember states. Grids and cross-border interconnectors can help to provide additional flexibility across the EU, it adds.
Beyond solar, wind generation grew 7TWh year-on-year in 2024, to reach 477TWh, according to Ember.
While this growth is lower than the average of 30TWh seen between 2019 and 2023, the technology remains cost-competitive with fossil power and installation rates are expected to increase in coming years, the report says.
Between 2010 and 2021, the cost of European onshore and offshore wind fell by 68% and 60%, respectively, Ember notes, based on levelised costs, a standardised metric used to gauge the average cost of electricity generation of a technology.
However, wind costs have broadly plateaued since then, according to the report, due to high inflation and supply chain problems following the Covid-19 pandemic and the global energy crisis.
While these issues have affected a range of sectors, the wind industry has felt them more acutely than solar, according to Ember, due to longer lead times and relatively higher upfront investment requirements.
This has been seen around the world, with the UK and the US amongst the nations to have seen their wind sectors knocked by higher prices.
Despite the impact of these factors on the deployment costs of wind, it remains competitive compared to gas generation, argues Ember. The price of buying gas fuel on European markets has grown throughout 2024, sitting at around €50 per megawatt hour (MWh) at the end of the year – well above the pre-crisis norm of €20/MWh.
As such, the average short-run marginal cost of EU gas-fired power across 2024 reached a high of around €125/MWh in December, continues Ember. This remains above the typical costs of both onshore and offshore wind.
In addition to facing macroeconomic headwinds, Ember says that expanding grids, permitting new projects and managing grid connections have been “inadequate for the pace of the energy transition”.
Action is being taken by governments within the EU however, for example, rules brought in to cut the permitting times for onshore wind from six years to two years.
Permitting rates were higher in the first half of 2024 than the previous year in most markets, which Ember says boosts confidence that the project pipeline for wind is strengthening.
In Germany, for example, approvals reached 12GW, up by 60% compared to the same period in 2023, notes the report.
Turbine orders also recovered, up 40% between January and September 2024 compared to the same period in 2023, while auctions awarded contracts to a record 28GW of new capacity across the EU in 2024.
However, while there are signs of growth, delays in recent years have created a wider delivery gap between market forecasts and EU ambition, the report notes.
In a statement, Dr Chris Rosslowe, senior analyst and lead author of the report, says:
“While the EU’s electricity transition has moved faster than anyone expected in the last five years, further progress cannot be taken for granted…However, the achievements of the past five years should instil confidence that, with continued drive and commitment, challenges can be overcome and a more secure energy future be achieved.”
The report calls on the EU to build on the momentum seen in the past five years. Ember suggests this could include ending Russian energy imports, supporting the European wind industry and enacting permitting reforms, among other changes.
They are responsible for around 45% of global warming to date, as well as millions of premature deaths each year.
Cutting emissions of these non-CO2 pollutants, which include methane, hydrofluorocarbons and black carbon, is seen as one of the quickest ways to tackle climate change.
Studies have shown how global action to reduce emissions of super pollutants could avoid four times more warming by 2050 than decarbonisation policies alone.
At the same time, it could prevent some 2.4 million deaths a year caused by air pollution.
And, yet, emissions of many super pollutants are soaring.
In this article, we unpack what super pollutants are and why they have an outsized impact on the climate and public health.
CO2 is responsible for around 55% of global warming to date. The other 45% comes from super pollutants: methane; black carbon; fluorinated gases; nitrous oxide; and tropospheric ozone.
These pollutants are present at lower concentrations in the atmosphere than CO2. But each tonne of these substances has a more powerful warming impact than a tonne of CO2 – up to tens of thousands of times more. As a result, they are still responsible for a lot of warming.
Most super pollutants remain in the atmosphere for less time than CO2, ranging from a few days to a few decades. These are known collectively as “short-lived climate pollutants”.
Others, including nitrous oxide and some fluorinated gases, can have very long lifetimes – even tens of thousands of years in some cases.
As well as being substantial contributors to global warming, super pollutants are a major threat to human health.
Poor air quality caused by these pollutants has been linked to a series of heart and respiratory diseases, as well as lung cancer and strokes.
Methane, black carbon and tropospheric ozone are the super pollutants with the most significant impacts on health.
Methane is the second-largest contributor to climate change after CO2. In its first 20 years in the atmosphere, when it is most potent, methane has a warming potential more than 80 times greater than CO2.
Methane has both human-related and natural sources. Global human-caused methane emissions come from three main areas:
Recent research has shown that methane emissions have continued to rise, with “no hint of a decline”. According to the World Meteorological Organization, atmospheric concentrations of methane in 2023 were 265% higher than pre-industrial levels.
Methane impacts public health indirectly in a number of ways.
By increasing atmospheric temperatures, disrupting rainfall patterns and contributing to the formation of tropospheric ozone, emissions of the gas contribute to crop failures which exacerbate food insecurity. The gas has been estimated to cause up to 12% of annual agricultural losses of staple crops.
Increased food insecurity has a number of implications for human health. Research has indicated that nearly half of deaths among children under five are linked to undernutrition. These mostly occur in low- and middle-income countries.
However, the biggest impact methane has on health is its contribution to the creation of tropospheric ozone.
Tropospheric ozone is among the shortest-lived super pollutants, with an atmospheric lifetime of just days to weeks.
But, despite its short-lived nature, the greenhouse gas has a major impact on human health. It has been linked to around 600,000 to 1 million premature respiratory deaths annually and a similar number of premature cardiovascular deaths.
The greenhouse gas does not have any direct sources, but is formed when hydrocarbons – including methane, volatile organic compounds (VOCs) and carbon monoxide – react with nitrogen oxides in the presence of sunlight.
Concentrations of this harmful pollutant are rising. Soaring emissions of its precursor gas – methane – are believed to be responsible for up to half of the observed increase.
As a major component of smog, tropospheric ozone can worsen bronchitis and emphysema, trigger asthma and permanently damage lung tissue. Children, the elderly and people with lung or cardiovascular diseases are particularly at risk from ozone exposure.
In addition to harming human health, studies have shown that many species of plants are sensitive to ozone, including agricultural crops, grassland and trees. Tropospheric ozone damages plants in many ways, including by entering pores in their leaves and burning plant tissue during respiration.
As a result, ozone emissions are a growing threat to food security.
Black carbon is formed by the incomplete combustion of wood, biofuels and fossil fuels in a process which also creates carbon dioxide, carbon monoxide and VOCs.
Commonly known as soot, black carbon has a warming impact up to 1,500 times stronger than CO2 per tonne. The pollutant dims sunlight that reaches the Earth, interferes with rainfall patterns and disrupts monsoons. Where it settles on snow and ice, it reduces reflectivity and increases melt rates.
Black carbon is a major component of fine particulate matter air pollution (PM2.5), which has been linked to a raft of negative health outcomes, including premature death in adults with heart and lung disease, strokes, heart attacks, chronic respiratory diseases such as bronchitis, aggravated asthma and other cardio-respiratory symptoms.
Each year, around 4–8 million deaths globally are associated with long-term exposure to PM2.5.
While untangling how many deaths are directly attributable to black carbon is tricky, there is growing evidence of its specific health impacts.
Studies have shown that exposure to black carbon correlates with high blood-pressure levels more strongly than PM2.5 overall. Exposure to the pollutant in pregnancy has also been found to impact the development and health of newborn children and is associated with reduced birthweight.
There has been growing political momentum around the threat of super pollutants.
One clear example of this is the Global Methane Pledge, an initiative launched at the COP26 climate summit in Glasgow in 2021. The pledge, which has been backed by 158 countries and the European Union, commits governments to collectively reduce global human-caused methane emissions by at least 30% below 2020 levels by 2030.
However, methane emissions are going in the wrong direction. Emissions are currently on track to increase by 5-13% above 2020 levels by 2030, according to a 2022 analysis from the Climate and Clean Air Coalition and United Nations Environment Programme.
Building awareness of the health consequences of climate change can encourage policymakers to set ambitious limits on super pollutant emissions. It can also underline the importance of a joined-up policy approach to climate and health, where emissions reduction pledges can help spur policies that improve lives.
The Global Methane Pledge and the Kigali Amendment – an international agreement to reduce the production and use of hydrofluorocarbons – are just two pledges that could have immediate and dramatic effects on public health, if fully implemented.
Cutting emissions of super pollutants is one of the most effective ways to “keep 1.5C alive” in the near-term, while protecting health and avoiding tipping points that could cause irreversible shifts in the Earth system.
Combined with the health benefits, rapidly reducing emissions of these pollutants is a clear win-win for people and the planet.
中国可再生能源的快速发展将煤电占比推至历史最低水平，同时全国碳市场覆盖的行业范围也进一步扩大。
在全球层面，中国在阿塞拜疆巴库举办的COP29联合国气候谈判上发挥了重要作用。然而，由于中美贸易关系日趋紧张，此前给全球气候行动带来希望的两国合作受到威胁。
在即将上任的特朗普政府的领导下，美国在气候谈判中的影响力预计将减弱，因此中国在气候雄心方面的表态——例如其计划在2025年发布的国际气候承诺——将成为决定国内外脱碳进程速度的重要因素。
Carbon Brief向10位顶尖专家询问了他们对中国未来一年的期待。他们的回答已经过编辑，以保证简洁明了。
Ember高级电力政策分析师
2025年，中国需要在保持经济增长与推进脱碳议程之间找到微妙的平衡。要实现这一平衡，不仅需要扩大风能、太阳能和储能等可再生能源的规模，还需要对长期以来在中国能源安全和经济活动中占据核心地位的煤电进行重大转型。
这不仅仅是关闭少数几家燃煤电厂那么简单，而是要处理好煤电生态系统衰退所带来的更广泛的紧张关系和冲突。这些影响将波及电企、物流公司、采矿企业、设备制造商以及煤化工行业，以及围绕它们建立的社会经济体系。
随着中国临近关键的转折点——预计在2026年开始的“十五五规划”内实现煤炭消费的绝对减少——中国现在就需开始为这一转型进行规划。在维护经济稳定、确保能源安全和履行气候承诺的同时，成功驾驭这一复杂过程将是中国在2025年及以后取得成功的关键。
中国能源政策研究院院长
2025年，中国能源和气候发展的重点是通过几项关键举措推进“双碳”目标。“新能源”的部署将加速，海上风电、分布式光伏和分散式风电预计将显著增长。新增风电和光伏装机容量预计将至少达到200GW。（去年新增装机超过300GW）。核电将稳步推进，预计到2025年底，核电运行装机容量将达到65GW。同时，促进“煤炭清洁高效利用”工作也将取得进展，更清洁和灵活的煤电系统将继续支持风电和光伏的快速增长。
储能技术和智能电网将进一步扩展，从而促进可再生能源的大规模并网，而虚拟电厂和大规模车网互动试点的发展也将提升电网效率与能源交互能力。电动汽车（EV）配套基础设施将受到更多关注，以支持电动汽车普及率的快速提高。碳市场有望扩大到更多领域，碳价格也将逐步提高。
绿色和平东亚分部全球政策顾问
今年将是一个重要的里程碑。作为“十四五规划”的最后一年，我们将看到中国能否回到实现既定能源和碳强度目标的轨道上来。中国未来十年的气候计划（即新的国家自主贡献）也将发布，其雄心也将接受考验。
这也是我们或可确认中国能源消费结构转变的一年，其标志着碳达峰是否到来。这一趋势的关键指标是可再生能源能否满足所有新增电力需求。
一个更为严峻的考验是，气候方面的当务之急能否以及如何应对地缘政治的挑战。中国将面对白宫易主，以及来自欧盟在清洁产业领域日益激烈的竞争，因此中国与其传统气候伙伴之间的关系需要重塑。希望到2025年，新的气候伙伴关系能够适应不断变化的经济和地缘政治环境。
阿德菲（Adelphi）碳市场与定价高级经理
展望2025年，我认为中国碳市场的发展在几个方面大有可为。其中包括：
其中，前两点几乎可以确定将在2025年实现，我希望其能顺利实施。后两点已被生态环境部的政策制定者提及，我希望政府能为其制定明确的时间表和实施路线图。
战略与国际研究中心中国商业与经济理事会主席、高级研究员
我关注的是中国如何应对日益紧张的对外商业关系，以及国际上对中国海外直接投资需求的增长。清洁技术——尤其是太阳能、锂电池和电动汽车这“新三样”——处于这些紧张关系的核心。
围绕气候技术制造和贸易未来的全球竞争正在酝酿，而这在很大程度上取决于中国产业的发展，包括国内需求和中国企业的盈利能力。同样重要的是，包括美国在内的中国的贸易伙伴（在未来的对华政策中）将倾向于何种类型的权衡和交易。
普林斯顿大学博士后研究员
2025年将是中国电动汽车发展的关键一年。中国国内市场的激烈竞争将进一步压低价格，激励先进驾驶辅助系统等功能上的创新，并使中国继续从燃油车向电车过渡。值得关注的是，中国出现的趋势是否会成为全球趋势的先兆，比如增程式（混合动力）电动车的流行和电池更换技术的改进。
在国际市场，中国的电动车和电池制造商正在开拓新市场，并通过在欧洲和东南亚等地大规模投资海外工厂来应对不断上升的贸易壁垒。一个重大问题是，这些投资能否得到回报，或这些市场的电动车需求是否会因当地充电基础设施不足等其他因素而受到制约。另一个关键问题是，其他国家将在多大程度上选择融入中国的电动车供应链，亦或尝试在中国周围建立供应链。
北卡罗来纳大学公共政策、环境、生态与能源副教授
我对中美在气候与能源政策上继续开展次国家层面合作的前景充满期待，尤其是两国在COP29上表现出强烈的兴趣。华盛顿州与中国代表团之间的多次技术交流等……都是令人鼓舞的发展。在过去一年所取得进展的基础上，我们已经制定了将这一对话持续到2025年的计划。
我尤其关注第三方国家和地区能否作为中立平台促进合作。例如，随着美国可能退出气候合作，中方与东盟的合作机会显著增加。中国在COP29上的积极行动，尤其是其在自愿气候融资方面的努力，使其有望在支持东南亚国家脱碳方面发挥领导作用，为区域可持续发展创造双赢局面。
英国开放大学国际发展教育讲师
2025年，中国在能源和气候方面的若干发展值得关注。国务院在2024年设定了新目标，标志着中国朝2060年实现碳中和这一更广泛目标迈出重要一步。
这些国内政策正在影响中国的国际投资。我们可以预见，中国将加大在全球南方的小规模可再生能源项目的投资，这反映了其自身在可再生能源发展中的经验。
这一战略还包括加强与富含能源转型所需重要矿产的国家的合作，尤其是非洲国家。2025年1月，中国外长王毅展开了自2013年以来对非洲的第57次访问。他访问了乍得、刚果共和国、纳米比亚和尼日利亚，突显了这一重点，这些国家都拥有丰富的能源转型所需的矿产资源。
总体而言，这些进展表明中国正在全球气候行动和能源转型中，扮演更积极的领导角色。
世界资源研究所中国金融项目主任
随着在巴库举行的COP29会议设定了“新气候融资集体量化目标”，中国可通过南南合作，继续支持发展中国家的低碳和韧性转型。我们的研究显示，中国已是气候融资的重要提供者，2013年至2022年间年均提供近45亿美元。
数据显示，疫情后中国在海外的气候融资有所下降，但在过去三年一直在缓慢回升。未来气候融资增长的一个重要驱动力可能是中国及其利益相关方在发展中国家清洁能源转型中的持续投资。最近的一个例子是，在印度尼西亚总统普拉博沃·苏比安托（Prabowo Subianto）去年11月访问北京期间，中国和印尼签署了关于清洁能源生产和基础设施的协议。这类合作有助于能源转型，创造更多就业机会，并有助于全球南方实现其他可持续发展目标。
亚格里菲斯大学亚洲研究中心主任、经济学教授
2025年，在伙伴国日益增长的能源转型需求的驱动下，中国在绿色能源领域的参与可能通过“一带一路”倡议进一步发展。例如，印尼总统普拉博沃在2024年12月的G20会议上宣布加速绿色能源计划，并与中国签署新协议，突显了（与中国的）针对性合作在解决本地能源的优先事项方面的作用。这不仅包括对可再生能源的投资，还涉及电池制造等关键技术。
我也希望在以下三方面取得进展：一是加速低碳能源投资的同时逐步减少化石燃料投资；二是让本地员工更多地从绿色能源转型中获益，尤其是在西方对中国绿色科技产品实施更多贸易限制的情况下；三是如何在“一带一路”倡议中加快工业和自备能源的绿色转型。未来几年的一个特别之机是与亚洲其他许多能源国企分享中国国企在电力行业的经验教训。
HEAVY-HEARTED HANDOVER: Outgoing US president Joe Biden used his final televised speech from the Oval Office to issue warnings about climate change and social media disinformation, BBC News reported. The Democrat pointed to “powerful forces” with “unchecked influence” set on “eliminat[ing]” the steps his government had taken to tackle climate change. This came after a separate valedictory address on Monday – covered by NPR – where Biden called on Donald Trump to carry forward his work on climate.
TRUMP LOOMS: Chris Wright – Trump’s pick to head the US Department of Energy – told senators at a confirmation hearing that he would support all forms of energy, including wind and solar power, and that he believed climate change was a “global challenge that we need to solve”, the New York Times reported. This came after the US Supreme Court said it would not hear an appeal from oil and gas companies trying to block climate lawsuits, according to the Associated Press.
GRIM RECORDS: As the Los Angeles wildfires continue to burn, officials have confirmed that the death toll has risen to 25, the Los Angeles Times reported. Meanwhile, Al Jazeera noted that the Eaton fire is now the “most destructive and deadliest” wildfire in southern California’s history, while the Palisades fire is the “second most destructive”. Carbon Brief covered the causes, impacts and political and media response to the wildfires.
CLIMATE TO BLAME: A rapid attribution study found that climate change was responsible for around 25% of the “fuel” available for the fires, according to CNN. The research – carried out by scientists at the University of California, Los Angeles – said the fires have been “larger and burned hotter than they would have in a world without planet-warming fossil fuel pollution”.
MYTHS SPREAD: As the fires continued to burn, prominent right-wing figures spread “bigoted criticism” about the response to – and cause of – the fires, according to the Guardian, including narratives blaming the fire department’s diversity and inclusion initiatives. France 24 reported that California governor Gavin Newsom accused Elon Musk – leading shareholder of Twitter and Trump confidante – of spreading “lies”.
The total estimated economic damage and loss of the Los Angeles wildfires, according to AccuWeather.
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
The chart above illustrates the institutional affiliations of the authors of the top 25 most-shared climate papers of 2024, broken down by continent. It shows that 85% of authors of the most-mentioned climate papers of 2024 are affiliated with institutions from the global north, whereas only two authors are from Africa. The findings come from Carbon Brief’s full analysis of the 25 most featured climate-related papers of 2024, which was published this week.
Carbon Brief reports on a new literary prize which aims to grow the climate fiction genre.
It is 2025. Wildfires have scorched southern California, while a right-wing US president has been elected on a ticket to axe “wasteful” government programmes.
This is not a summary of recent news headlines, but the setting of Octavia E Butler’s 1993 novel Parable of the Sower, seen by many as an early classic of the climate fiction – or “cli-fi” – genre.
Thirty years after Butler’s prescient tale was published, cli-fi is rising in prominence.
This spring, the inaugural UK Climate Fiction Prize will announce its first winner, awarding £10,000 to a novel that engages with climate change.
Imran Khan, one of the founders of the prize, told Carbon Brief the aim of the prize was to expand a genre that had been growing in recent years. He said:
“We wanted to try to tilt the field in favour of more stories that centre the possibilities of what the future looks like if we start to take climate more seriously – both the good and the bad. We didn’t want it just to be climate dystopias. We wanted to be stories of hope, change and possibility as well.”
The nine books on the longlist make for an eclectic reading list, spanning genres, continents and different planets.
In the mix is the Booker Prize-winning Orbital by Samantha Harvey, a meditation on the beauty and fragility of Earth, told from the vantage point of astronauts circling it. It is facing off against And So I Roar by Abi Daré, which explores themes of climate justice through the eyes of a teenage girl from Nigeria, and The Mars House by Natasha Pulley, a sci-fi novel about the marriage of an Earth refugee and an anti-immigration Martian politician.
Abby Rabinowitz teaches a climate-fiction seminar to dozens of undergraduate engineering students each year at NYU Tandon School of Engineering. She told Carbon Brief that climate fiction had assumed a “more central role in a literary way” since 2018, albeit from a low baseline.
Rabinowitz said she launched the seminar in 2021 after observing that “very few people had dealt seriously with climate change and the climate crisis in fictions, both in literary works and on the screen”. She said:
“The Day After Tomorrow, which came out in 2004, remains the one climate disaster blockbuster that I’m aware of. That was 20 years ago.”
Parable of the Sower is on Rabinowitz’ syllabus, which she said covers “apocalyptic imaginings, speculative fiction storytelling and metaphorical and allegorical treatments of climate change” in books and film. Kim Stanley Robinson’s The Ministry of the Future, Stephen Markley’s The Deluge and Adam McKay’s film Don’t Look Up also feature.
There is some debate about whether climate stories inspire action. A 2018 study of US readers found the majority of cli-fi was prompting them to associate climate change with “intensely negative reactions”, which “could prove counterproductive to efforts at environmental engagement”.
However, the research suggests that non-dystopian climate stories with “positive frames” – at the time in shorter supply – might be able to motivate readers to act.
Climate fiction is important, according to Khan, because it can paint a more “vivid” picture of future warming than scientific data, plus “change the story of what is possible”.
Parable of the Sower – which depicts a climate-ravaged world, but also a protagonist with a vision for change – is a case in point, he said:
“It is one of the best examples of… what really good climate fiction can do. It inspires emotions of rage and anger, but also hope and care. Science alone hasn’t solved this issue – and it won’t solve this issue. We need people to care enough to do something.”
COMBUSTIBLE AGE: The New Yorker placed the Los Angeles fires in the context of historic fires that ravaged US cities – and asked what is next in a climate-changed world.
RADIO DADAAB: A stateless journalist told the story of climate refugees in the world’s second-largest refugee camp via a short Environmental Justice Foundation documentary.
NUDGE UNIT: Neuroscientist, science communicator and UCL Climate Action Unit director Kris de Meyer spoke to Your Brain on Climate about how to tell “stories of action”.
DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.
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This is what the latest data shows from the Mauna Loa observatory in Hawaii, where measurements of CO2 levels in the atmosphere have been collected for more than 60 years.
In 2024, the rise in atmospheric CO2 was one of the fastest on record.
Emissions of CO2 and other greenhouse gases from human activity have so far caused human-caused global warming to reach about 1.3C above pre-industrial levels.
If warming is to be limited to 1.5C, as set out in the Paris Agreement, the build-up of CO2 and other greenhouse gases in the atmosphere will need to slow to a halt and then go into reverse.
And, yet, the rise in atmospheric CO2 concentrations is still showing no signs of slowing.
The third working group report of the IPCC’s sixth assessment report (AR6), published in 2022, presented a set of seven “illustrative pathways” that highlight how different mitigation choices across major economic sectors translate into future greenhouse gas emissions and global temperatures.
In the three most-ambitious pathways, global warming has a 50% chance of either staying below 1.5C, or overshooting it by only 0.1C (for up to several decades) before then returning to below 1.5C:
As the table below shows, the build-up of atmospheric CO2 in these three scenarios slows from the 2010s average of 2.41 parts per million per year (ppm/year) to 1.33-1.79ppm/year in the 2020s.
It then slows still further and goes into reverse either in the 2030s or 2040s – in other words, the level of CO2 in the atmosphere actually begins to fall.
| Decade | Projected average CO2 rise (ppm/year) in scenarios limiting global warming to1.5C | ||
| C1-IMP-LD | C1-IMP-REN | C1-IMP-SP | |
| 2020s | 1.33 | 1.75 | 1.79 |
| 2030s | -0.14 | 0.13 | 0.57 |
| 2040s | -0.53 | -0.46 | -0.7 |
| 2050s | -0.65 | -0.61 | -0.41 |
Yet, not only are atmospheric CO2 concentrations still rising, the rate of rise is accelerating.
The build-up of CO2 in the atmosphere has been monitored at the Mauna Loa observatory in Hawaii since 1958.
As illustrated by the iconic Keeling Curve below, the increase has been accelerating over the decades (blue line) due to ongoing emissions of CO2 from burning fossil fuels and changing land use.
So while the curve needs to rapidly bend in the other direction to hold warming to 1.5C (light red line), the rate of rising CO2 marches onwards and upwards.
chart
The table below sets out decadal averages of the annual rise in CO2 concentrations at Mauna Loa. The first half of the 2020s has seen an average CO2 rise of 2.58ppm/year, which is 44-94% higher than it needs to be to track the IPCC 1.5C-compatible scenarios.
| Decade | Observed average CO2 rise (ppm/year) |
|---|---|
| 1960s | 0.86 |
| 1970s | 1.22 |
| 1980s | 1.58 |
| 1990s | 1.55 |
| 2000s | 1.91 |
| 2010s | 2.41 |
| 2020s (2020-2024) | 2.58 |
In fact, the annual rise of 3.58ppm/year between 2023 and 2024 at Mauna Loa was the fastest on record.
The global average, which has been monitored by satellite since 2003, also showed a large rise last year – and, at 2.9ppm/year, this was the second largest on record after 2015-16.
(While the rise at Mauna Loa mirrors the global rise over long periods, in the short term it can also be affected by localised effects, such as fires upwind or in the same hemisphere, before the CO2 disperses more evenly across the globe.)
Global CO2 emissions were also at a record high in 2024, but a further key factor was that natural land carbon “sinks” were substantially weaker, allowing more of the emitted CO2 to remain in the atmosphere.
At least some of this weakening of land carbon sinks was associated with the El Niño conditions in the first part of the year. El Niño events shift weather patterns around the globe, leading to hotter, drier conditions in many parts of the tropics. This means that vegetation grows less well and more carbon is released from decay in soils and from wildfires, leading to land ecosystems removing less carbon from the atmosphere than usual.
With the El Niño now subsided and conditions shifting more towards the opposite pattern of La Niña, natural land carbon sinks can be expected to recover again, at least to some extent.
As a result, in our Met Office forecast of the CO2 rise at Mauna Loa, we predict a slower rate of rise between 2024 and 2025 than between 2023 and 2024. The projected increase is 2.26ppm (with an uncertainty range of ±0.56ppm) – slightly slower than it would have been without the effects of La Niña.
However, even this is still too fast to stay on track with the IPCC 1.5C-compatible scenarios. This is highlighted in the chart below, which shows the annual change in CO2 levels at Mauna Loa since 1995 (blue lines) and how our forecast for 2025 (red point) exceeds a pathway consistent with 1.5C (grey plume).
The specific reasons for the very large increase in CO2 in 2024 are not yet completely clear, although weaker land carbon sinks appear to be implicated.
We had forecast the 2023-24 CO2 rise at Mauna Loa to be 2.84ppm (±0.54) – faster than the average of the previous decade due to the El Niño. We had also highlighted the possibility that it could be the fastest annual rise on record.
However, the actual CO2 rise of 3.58ppm was even faster than expected. This was above the upper limit of our uncertainty range, which should include the forecast value 95% of the time.
Although carbon emissions from fossil fuel burning and deforestation were also at a record high in 2024, this does not fully explain the shortfall in our forecast.
Our forecast method uses the global emissions from the previous year as one of the inputs. The emissions in 2024 were estimated to have been 11.3bn tonnes of carbon (GtC), slightly higher than the 2023 value of 11.1GtC used in our forecast.
This 0.2GtC difference is equivalent to about 0.09ppm of CO2 in the atmosphere. So, even if we had used the larger value in our forecast, the observed rise would still have been beyond our uncertainty range.
Therefore, the origin of the discrepancy must be related to natural carbon sinks, which must have been even weaker than the expected weakening that occurred as a result of the 2023-24 El Niño.
Scientists had already established that land carbon sinks were exceptionally weak in 2023, with very high temperatures worldwide playing a part in this.
2024 was then even hotter than 2023 – and indeed was the first calendar year where warming exceeded 1.5C above pre-industrial levels. It can be expected that the climatic conditions this warmer year once again led to weaker global land carbon sink.
Both North and South America saw high temperatures and exceptionally severe fires in 2024, including in regions not normally affected by El Niño such as Canada, and extending beyond the season of El Niño influence.
Global fire emissions were estimated as 1.6-2.2GtC over January-September 2024, 11-32% above the 2014-23 average for the same months.
Moreover, fire emissions in the northern hemisphere were 0.5-0.6 GtC per year, which was 26-44% above the average of 2014-23. Since Mauno Loa is in the northern hemisphere, this may explain why the local rise there was even larger than the global average.
A portion of these fire emissions may already be accounted for in the above estimate of land-use emissions, but it is not possible to quantify this. Nevertheless, widespread fire activity likely contributed to the large rise in atmospheric CO2 concentrations in 2024. Further analysis is needed to quantify the size of this contribution.
Climate change itself may have played a role in enhancing fire emissions. For example, human-caused warming made the “unprecedented” wildfires that spread across Brazil’s Pantanal wetlands in June 2024 between four and five times more likely.
Although land carbon sinks are generally increasing as a result of rising CO2, Earth system model projections have long indicated that ongoing global warming would reduce this effect, leading to a greater proportion of human-caused emissions remaining in the atmosphere.
Calculations suggest that this has already been occurring in recent years, so a key question is whether the last two years have seen an acceleration. If natural carbon sinks weaken more than already expected, this would further increase the difficulty of slowing the rise in atmospheric CO2 concentrations.
Alternatively, there are a number of historical years for which our CO2 forecast procedure gives almost as large departures between predictions and outcomes as for 2024. For example, 2003 saw a large rise at Mauna Loa despite not being an El Niño year, due to large fires in Siberia. It will therefore be important to see whether there is a higher-than-expected rise in CO2 in 2025, or whether the large exceedance in 2024 is a temporary phenomenon.
With global warming ongoing, extremely high temperatures will continue to occur more frequently and severely, so events such as those seen in 2023 and 2024 could play an ever more important role in the global carbon cycle.
The contribution of fires attributed to climate change is consistent with model simulations which suggest that global fire activity will already be weakening land carbon sinks. Further monitoring of the global carbon cycle will help to reveal whether this is indeed the case.
The study, published in Science, finds that the global land surface affected by these extreme events has expanded at a rate of nearly 50,000 square kilometres (km2) per year in the past four decades – an area larger than Switzerland each year.
The authors identify multi-year droughts – which can last from years to decades – that occurred around the world between 1980 and 2018.
They find that multi-year droughts can cause significant declines in vegetation in ecosystems such as grasslands. These impacts can also translate into severe impacts for humans, including water scarcity.
Study author Dr Dirk Karger, a senior researcher at the Swiss Federal Research Institute (WSL), tells Carbon Brief:
“Everybody was talking about droughts, [that they] will be more [frequent] with climate change, but there [was] no clear database where we could look. We finally have a good baseline of what is happening…[and] provide a new way of thinking about the impact the [multi-year droughts have].”
“Multi-year” droughts – those lasting at least two years and for as long as decades – can have dramatic impacts on nature and societies.
These long-lasting events can deplete soil moisture and leave rivers, lakes and reservoirs parched. This, in turn, can result in “devastating impacts”, such as massive crop failures, tree mortality or reduced water supply, according to the study.
(For more on the different ways that droughts can be defined, see Carbon Brief’s guest post.)
In recent years, multi-year droughts have occurred around the world, including Chile, the western US and Australia. For example, a 2015 study found that the so-called “megadrought” that persisted in Chile from 2010 to 2019 led to a “marked decline in water reservoirs and an extended forest fire season”.
The new study maps the distribution of multi-year drought events between 1980 and 2018. It identifies droughts by looking at a “drought index” based on changes in rainfall and potential evapotranspiration, which measures the amount of water that escapes the soil and plants into the atmosphere.
The researchers also rank the drought events by their severity – based on a combination of the extent and duration, along with the magnitude of the drought index. Then, they use the index to estimate the impact of multi-year droughts on global vegetation.
They identify more than 13,000 multi-year drought events during the four-decade study period, spanning every continent except Antarctica.
The map below shows the location and characteristics of the 10 most severe events, with the colours representing each individual drought and its length.
The longest multi-year drought occurred in the eastern Congo basin. It lasted for almost a decade, from 2010 to 2018, and affected an area of almost 1.5m square kilometres (km2).
The study finds that the most affected ecosystems by these extreme events are temperate grasslands.
However, not all multi-year droughts result in significant damage to ecosystems.
In the humid tropics, which are home to rainforests such as the Amazon, the lack of rainfall is not strong enough to diminish vegetation. This suggests that plants in those regions might have a “greater resistance” to drought conditions, the authors write.
Boreal forests in the far-northern hemisphere and tundra ecosystems also had a “minor response” to these events. The authors say this is because their vegetation productivity is more dependent on temperature than on the presence or absence of rainfall.
The drought with the most severe vegetation impacts occurred in Mongolia from 2000 to 2011 and reduced vegetation “greenness” by almost 30%.
For Karger, it is difficult to pinpoint the strongest multi-year drought ever because it depends on what aspect is considered: the drought that had the largest extent or the one that lasted the longest. He continues:
“With our database we can easily answer any of these questions, it’s just a matter of what we sought for, since we provide that open source and open data”.
The research reveals that multi-year droughts have increased in size, temperature, dryness and duration.
The global land area affected by this kind of drought increased at a rate of 49,279km2 per year during that time – equivalent to a size larger than Switzerland per year.
The factors behind the intensification of multi-year droughts are increased potential evapotranspiration, decreased rainfall and rising temperatures, the study says.
The researchers note that during multi-year drought events, the “precipitation deficit” – the difference in the amount of rain compared to a baseline over a certain period and region – has surged over time.
For the 10 most severe multi-year droughts, the precipitation deficit has increased, on average, by 7mm per year over nearly four decades.
At the same time, the temperature during these events has increased by 0.26-0.35C per decade.
The study attributes the higher temperatures during multi-year droughts to climate change, noting that the warming “align[s] well” with global changes. It also notes that the years with the largest areas under multi-year drought have followed the El Niño events of 1998, 2010 and 2015.
Dr Maral Habibi, a researcher at the University of Graz, in Austria, and who was not involved in the study, tells Carbon Brief:
“The study clearly illustrates how rising temperatures amplify drought through increased evapotranspiration, precipitation deficits and vicious feedback loops (such as reduced cloud cover exacerbating heat).”
The research says that the most severe multi-year droughts identified in the study “represent valuable case studies to prepare for similar events that may occur more regularly in the 21st century”.
It also says that analysing droughts at a global level, rather than focusing on a single drought event, “paves a more realistic way to develop adequate and fair mitigation strategies”.
Dr Ruth Cerezo-Mota, a researcher at the National Autonomous University of Mexico (UNAM) who was also not involved in the study, tells Carbon Brief that the world needs more data, including high-quality and continuous observations, and more investment in science to “understand these dynamic processes”.
Habibi agrees on the need for “enhanced monitoring tools and predictive climate models”. She adds that “investments in AI-driven drought forecasting and cross-border water resource management are also vital” to “mitigate and adapt to the challenges of a warming, drying world”.
This is an online version of Carbon Brief’s fortnightly Cropped email newsletter. Subscribe for free here.
ANIMAL IMPACT: At least 25 people died in blazing wildfires that tore through 40,000 acres of land in Los Angeles, NBC News reported. Vox examined how the fires “affected the animals and wildlife who call Los Angeles their home”. Videos showed people evacuating with everything from chickens to horses, Vox said, and one animal shelter took in more than 300 animals. Gavin Jones, an ecologist at the US Forest Service, told the outlet in 2023: “In this new era of rapidly changing fire regimes, we don’t have a great roadmap for how to conserve wildlife.” Al Jazeera explained that wildfires can result in “some wildlife [losing] their habitat”, which can lead to ecosystem imbalance.
AGRI AFFECTED: The fires affected farm infrastructure and animals in the surrounding region, an agricultural meteorologist told RFD TV. A citrus and avocado farm in Pauma Valley, more than two hours from Los Angeles, was impacted by the fire-fuelling Santa Ana winds. Farmer Andy Lyall told ABC News that gusts blew down fruit from his trees, ruining around half of his crops. The “strong and gusty” Santa Ana winds occur several times a year in southern California, BBC News outlined, creating “ripe conditions” for wildfires. (See Carbon Brief’s article on the role of climate change in the fires.)
PARKS AND TREES: Satellite images published in Al Jazeera showed how houses, trees and other infrastructure were scorched in the fires. The Palisades fire – the largest of the fires – “destroyed” historic buildings and other infrastructure at two major parks, according to a statement from California State Parks. Meanwhile, the Los Angeles Times looked at claims and counter-claims about the risk shrubs and brush posed to the spread of the wildfires. Chief Brian Fennessy from the Orange County Fire Authority told the newspaper that clearing brush is “very effective” at limiting fire spread on a normal day, but not against the strength of these fires and winds.
ROCKY WATERS: Brazil’s government cancelled a bid for a “dredging project” to aid the docking of cruise ships in Belém when it hosts COP30 later this year, according to Folha de São Paulo. The dredging, which would remove sediment from the bottom of the port, was expected to impact “the composition of sediments, the behaviour of aquatic mammals and the quality of the water itself”, the newspaper said. The project was aimed to increase accommodation amid a shortage of hotel rooms for the climate summit.
‘RISKY’ SHIPPING PLANS: Meanwhile, Mongabay looked at Brazil’s plans to develop new shipping channels in Amazon waterways, which experts say could “result in conversion of traditional peoples’ lands to carbon-intensive agriculture”. The outlet said the country is “poised” to invest in developing more than 2,000km of channels for agribusiness transport in “shrinking rivers”. Dr José Marengo, a climatologist and hydrology specialist, said it is “crazy” to consider creating the shipping channels in certain rivers because of the “extremely low [water] levels, mainly due to the droughts of 2023 and 2024. It’s very risky.”
SOY PACT: Elsewhere in Brazil, the supreme court will soon rule on a request challenging a state law that would end tax breaks for grain traders who avoid soy from recently deforested areas of the Amazon, Reuters reported. The legislation was passed in Mato Grosso last year, but will not take effect until a final court decision in February, the newswire said. The law added “growing pressure” to Brazil’s soy moratorium – the “voluntary pact” to ban the purchase of soy from deforested Amazon areas after 2008, Reuters noted. Last month, a farmer lobby group asked the country’s antitrust agency to investigate the signatories of this pact, describing them as a “purchasing cartel”, the newswire said.
In this Spotlight, Carbon Brief explores the curious case of the illegal reintroduction of four Eurasian lynx in the Scottish Highlands.
A few days ago, a pair of labrador-sized cats with dappled fur and tufty ears were spotted wandering free in Cairngorms national park in the Scottish Highlands.
They were quickly identified as Eurasian lynx, a species of big cat that went extinct in the UK more than 1,000 years ago. (They are still widely found across Europe and Asia).
The cats were released illegally, according to the police and the national park authority. The animals – along with a second pair caught on camera traps a day later – were captured humanely and brought to a nearby wildlife park. One has since died.
While there is a growing movement advocating for the reintroduction of lynx in order to “rewild” Scotland, none of the conservation groups involved with such calls have claimed responsibility for the release.
One charity called the move “reckless” and “highly irresponsible”, warning the cats were most likely raised in captivity and would have died after being left alone in the wild.
Despite this, there is “speculation” that the most likely culprit is “someone who had grown frustrated with the slow progress” of the campaign to reintroduce lynx to Scotland and decided to “take matters into their own hands”, according to the Guardian.
Guerrilla rewilding
The UK has a long history of illegal animal releases shaping its ecosystems.
Multiple introductions of grey squirrels since the 1890s has all but wiped out the native red across most of the country. Further illicit releases, once blamed on the US musician Jimi Hendrix, have allowed feral green parakeets to spread across London and its surrounding areas.
More recently, conservationists have warned of the growing practice of “beaver bombing”, the covert release of beavers into natural areas by advocates who think the government is not moving fast enough to reintroduce the rodents as part of rewilding efforts. (The new Labour government is reportedly blocking plans to legalise beaver releases in England.)
Both beavers and lynx are considered to be “keystone species”, meaning they can have an outsized impact on the environment surrounding them.
A group of beavers released illegally in the River Otter in Devon were given official permission to stay by the government after a five-year trial showed that their dam-building helped to alleviate flood risk and local pollution.
Climate carnivores
Advocates of reintroducing lynx to Scotland say that the predators could help to reshape the forest ecosystem surrounding them through the “ecology of fear”.
In essence, lynx litter the landscape with their faeces and urine, prompting roe deer – their main prey – to keep moving, rather than staying still and overgrazing on young vegetation before it has had a chance to establish.
Over time, this could help to create a denser forest environment, with benefits for storing carbon and boosting biodiversity, it is argued.
However, research has found that local communities in Scotland have mixed feelings about reintroducing lynx.
A study published in 2023 involving interviews with more than 40 people found that some locals were in favour of reintroducing lynx, either for economic or environmental reasons, while others were “unconvinced” of the evidence supporting the benefits or felt strongly opposed to the idea of big cats being set loose.
The farmers’ union NFU Scotland opposes the reintroduction of lynx over fears the animals could hunt and kill livestock.
BIDEN BACKTRACKS: The Biden administration “abruptly” stepped back from a plan to protect old-growth forests after “pushback from Republicans and the timber industry”, the Associated Press reported. This ended a “years-long process to…better protect old trees that are increasingly threatened by climate change”, the newswire said. Opponents argued that restricting logging in older forests was not necessary, partly because “many forested areas already are protected”, the AP said. Alex Craven from the Sierra Club conservation group said there was a “scientific necessity and public expectation” to protect these forests.
WATER WOES: Climate change is “wreaking havoc” on the Earth’s water cycle, according to the Global Water Monitor’s 2024 report, covered by the Indian Express. Last year, water-related disasters killed at least 8,700 people, displaced 40 million and resulted in economic losses exceeding $550bn globally, the newspaper said. At the same time, there were 38% more record-dry months, compared to the period 1995-2005. In 2025, droughts could intensify in northern South America, southern Africa and parts of Asia, it added.
KOALAS AT RISK: Logging in the proposed “Great Koala national park” in New South Wales, Australia, has increased since 2023, according to an analysis covered by the Guardian. In March 2023, a new Labor state government came into power, promising to protect the area. But the report, from the conservation group North East Forest Alliance, found that more than 7,000 hectares of forest has been logged in the region since then, the newspaper said. New South Wales agriculture minister Tara Moriarty said “the claims in the report are not true” and the government was “getting on with delivering a Great Koala national park while at the same time ensuring a sustainable timber industry”.
BOTSWANA ADAPTATION: Botswana has put forward a new climate plan to the UN, prioritisting adaptation measures, such as introducing drought-tolerant crops and cows, over measures to cut its already-low emissions, Climate Home News reported. Botswana’s climate plan, known as a “nationally determined contribution” (NDC), said that, “as Botswana is one of the lowest emitters in the world, the limited financial resources available will be prioritised for adaptation”. Climate Home News said that the move has been “praised by African climate negotiators as a model that low-emitting, vulnerable countries should follow”.
FUTURE CROP YIELDS: Senior officials in India believe that rice and wheat yields will drop by 6-10% in future due to climate change, the Press Trust of India reported, via the Kashmir Observer. This will “significantly impac[t] farmers and food security”, Mrutyunjay Mohapatra, the director general of the India Meteorological Department, told the newspaper. In 2023-24, India’s wheat output exceeded 113m tonnes – about 14% of the global output, the outlet noted. The country also produced more than 137m tonnes of rice.
BACK IN TIME: The possibilities and scientific developments around species “de-extinction” were discussed in a Yale Environment 360 feature.
ON THE MOVE: An article in Vox explored how wildlife migrations are “increasingly threatened” by roads, climate-fuelled extreme weather and agricultural fields.
DAILY FIX: An editorial in the Financial Times examined how climate change is “mostly to blame” for skyrocketing coffee and chocolate prices.
‘UNIT OF NATURE’: In the first Georgina Mace Review, an annual conservation biology journal named after the late UK scientist, a group of biologists examine whether it is possible to create a standardised measure for biodiversity, otherwise known as a “unit of nature”.
Cropped is researched and written by Dr Giuliana Viglione, Aruna Chandrasekhar, Daisy Dunne, Orla Dwyer and Yanine Quiroz. Please send tips and feedback to cropped@carbonbrief.org
However, climate change still made headlines.
Thousands of peer-reviewed journal articles were published over the course of the year, helping shape online discourse around climate change.
Tracking these mentions was Altmetric, an organisation that scores research papers according to the attention they receive online.
To do this, it tracks how often published peer-reviewed research is mentioned online in news articles, as well as on blogs, Wikipedia and on social media platforms such as Facebook, Reddit, Twitter and – in a new addition for 2024 – Bluesky. (Carbon Brief explained how Altmetric’s scoring system works in this article.)
Carbon Brief has parsed the data to compile its annual list of the 25 most talked-about climate-related papers of the past year.
The infographic above highlights the most mentioned climate papers of 2024, while the article analyses the top 25 research papers in greater detail, including the diversity and country affiliation of authors.
Overall, Altmetric’s data reveals the papers which generated the most online buzz in 2024 were – for the fourth year running – associated with Covid-19, with five of the 10 most talked-about papers of the year related to the virus.
However, a number of the most-shared studies were about climate change, from how warming is impacting ocean currents, the economy and timekeeping, through to efforts aimed at mapping historical temperatures using proxy data.
After a blockbuster year for online mentions of climate science in 2023, last year saw a return to more typical levels.
The most widely shared climate paper of 2024 has a score of 5,414, placing it at the bottom end of the range for top climate papers over the past seven years.
By contrast, the three most talked-about climate papers of 2023 received the highest attention scores recorded across all of Carbon Brief’s annual reviews, which date back to 2015. They clocked scores of 13,886, 8,686 and 7,821.
(For Carbon Brief’s previous Altmetric articles, see the links for 2023, 2022, 2021, 2020, 2019, 2018, 2017, 2016 and 2015.)
The graph below shows how the score given to the top paper in Carbon Brief’s annual review has changed over the past 10 years.
A spokesperson for Altmetric says the falling popularity of climate papers was not due to any adjustments to its methodology, noting that its scoring system “had not changed”. They tell Carbon Brief that online mentions of papers – across all disciplines – have declined in recent years from a peak in 2020, resulting in lower average scores across the board.
The spokesperson said it was unclear why the average number of mentions had fallen since 2020, but hypothesised that several factors could be at play. This includes a surge of policy citations during the Covid-19 pandemic and changes in how people use social media – such as a decline in posts on public Facebook feeds and a spike in Twitter posts in 2021.
Later in this article, Carbon Brief looks at the rest of the top 25, and provides analysis of the most featured journals, as well as the gender diversity and country of origin of authors.
The most talked-about climate paper of 2024 is a Science Advances study that finds the Atlantic Meridional Overturning Circulation (AMOC) – a system of ocean currents that brings warm water up to Europe from the tropics and beyond – is “on route to tipping”.
The research, titled “Physics-based early warning signal shows that AMOC is on tipping course”, marks the first time that an AMOC tipping event has been identified in a cutting-edge climate model, in this case the Community Earth System Model.
The study’s Altmetric score of 5,414 shoots it to the top of Carbon Brief’s leaderboard and 1,272 points ahead of the second-placed paper.
However, as illustrated in the graph above, the research is the lowest-scoring climate paper to reach the top of the leaderboard since 2017.
The researchers from the Institute for Marine and Atmospheric Research Utrecht describe the paper’s finding as “bad news for the climate system and humanity”. They explain:
“Up until now one could think that AMOC tipping was only a theoretical concept and tipping would disappear as soon as the full climate system, with all its additional feedbacks, was considered.”
The study paints a grisly picture of the consequences of a collapse of AMOC. This includes a 10-30C drop in winter temperatures in northern Europe within a century, and a “drastic change” in rainfall patterns in the Amazon. The paper states:
“These – and many more – impacts of an AMOC collapse have been known for a long time, but thus far have not been shown in a climate model of such high quality.”
Papers exploring the stability of AMOC have dominated Carbon Brief’s climate science leaderboard in recent years, coming in fourth and second place, respectively, in 2023 and 2021.
Media coverage has been amplified by disagreement over what metrics to use to measure the strength of AMOC. Previous studies have used sea surface temperature to make projections about when the tipping point may occur.
The Science Advances paper reaches its conclusions using a new, “physics-based” early warning signal for the breakdown of the vital ocean currents based on the salinity of water in the southern Atlantic.
Overall, the study racked up 601 news mentions, with the Times, Guardian, Daily Telegraph, Associated Press and CNN all reporting on its findings. It was also featured in 39 blogs, the highest of any paper in the top 25, and was shared more than 3,866 times on Twitter.
Study author Dr René van Westen tells Carbon Brief he believes the paper owes its popularity to its alarming conclusion that AMOC is approaching a tipping point, as well as the detail it offers around the “large-scale changes” and “substantial” climate impacts such an event could trigger. He explains:
“The urgency of the situation, suggesting that we are heading toward this collapse, underscores the need for immediate action to prevent such a scenario. We believe that the combination of these far-reaching climate impacts and the risk of AMOC collapse contributed to the extensive media coverage of our study.”
The second highest-scoring climate paper of 2024, published in the journal Nature, is “The economic commitment of climate change”. The study has an Altmetric score of 4,142 and clocks in at second in the 2024 rankings.
The three-person authorship team, from Germany’s Potsdam Institute for Climate Impact Research, used 40 years of data on damages from temperature and rainfall from more than 1,600 regions around the world to assess how damages could increase under a warming climate.
They estimate that the world economy is committed to an income reduction of 19% within the next 26 years, regardless of how rapidly humanity now cuts emissions. These damages are six times higher than the mitigation costs required to limit global warming to 2C in the near term, the authors say.
They also warn that climate change is likely to exacerbate existing inequalities, adding:
“The largest losses are committed at lower latitudes in regions with lower cumulative historical emissions and lower present-day income.”
The study was mentioned 55 times on Bluesky. It has also been cited by Wikipedia seven times, including in pages on climate justice and climate change mitigation.
The study’s lead author, Dr Maximilian Kotz, tells Carbon Brief:
“We think we made a helpful contribution by pushing the limits of the spatial scales, climate information and assumptions around long-term persistence which are used in these kinds of studies.”
However, he said the media coverage mainly focused on the final numbers, speculating that “part of the wide interest in the media was likely that these numbers were large”. He told Carbon Brief that, in his experience, it is “normal for the media not to pay much attention to the kind of details a researcher finds important”.
Kotz added that since his study came out, a number of other papers have been published using different approaches, but arriving at similar final numbers.
Coming in third place is a Nature paper which uses temperatures reconstructed from tree rings to conclude the northern hemisphere summer of 2023 was the hottest in two millennia.
To build a picture of summer temperatures stretching back to AD1, the researchers turn to nine of the longest temperature-sensitive tree ring chronologies in North America and Europe, as well as observational data for 1901-2010.
The study, “2023 summer warmth unparalleled over the past 2,000 years”, finds the average summer temperature in the non-tropical area of the northern hemisphere in 2023 was 2.2C warmer than the average observed between AD1-1890.
It also reveals that temperatures in the summer of 2023 were 3.93C higher than the coldest summer of the last two millennia, which was AD536 – when a large volcanic eruption cooled the Earth.
The paper owes its Altmetric score of 4,100 largely to widespread coverage in news media. The New York Times, Newsweek, Bloomberg, BBC News, Reuters and the Daily Mail were among the publications to cover the story.
In fourth place, with an Altmetric score of 3,907, is a paper that assesses whether the classification system for tropical cyclone wind speed needs to be expanded to reflect storms’ growing intensity in a warming world. It was published in Proceedings of the National Academy of Sciences.
The research, “The growing inadequacy of an open-ended Saffir-Simpson hurricane-wind scale in a warming world”, says climate change has led to more intense storms, which could justify a new category on the Saffir-Simpson scale.
Introduced in the 1970s, the scale is used to communicate the risk tropical cyclone winds present to property. Events are ranked from category 1, for storms with winds of 74-95 miles per hour (mph), to category 5 for storms with a wind-speed of 157mph and above.
The study highlights how five tropical cyclones of the last nine years were so intense they could sit in a hypothetical sixth category, which could cover storms with winds of 192mph and above.
The study received more news coverage than any other in this year’s top 25, amassing 720 mentions.
In fifth and sixth place, with scores of 3,757 and 3,248, respectively, are a pair of Nature papers.
The first, “Critical transitions in the Amazon forest system”, finds that by 2050, 10-47% of the Amazon forest will be exposed to “compounding disturbances” that may trigger a tipping point, causing a shift from lush rainforest to dry savannah. Carbon Brief covered the study.
The second is a paper looking at how rising ocean temperatures are endangering the Great Barrier Reef. It cautions that without “urgent intervention” the world’s largest coral reef system is at risk of experiencing “temperatures conducive to near-annual coral bleaching” with negative consequences for biodiversity and ecosystem services.
The seventh-placed paper finds a reduction in sulphur emissions from ships – driven by cleaner fuel regulations introduced in 2020 – has led to “substantial radiative warming” that could lead to a “doubling (or more)” of the rate of warming this decade. (Carbon Brief published its own analysis of how low-sulphur shipping rules are affecting global warming in 2023.)
The Communications Earth & Environment study goes on to suggest that marine cloud brightening – a geoengineering technique where marine low clouds are “seeded” with aerosols – may be a “viable” climate solution.
Coming in eighth is a paper which finds that ice melt in Greenland and Antarctica is delaying an observed acceleration of Earth’s rotation, with consequences for global timekeeping.
The Nature paper, “A global timekeeping problem postponed by global warming”, finds the redistribution of mass on Earth as polar ice melts means timekeepers will have to remove a second from global clocks around 2029. If it were not for the acceleration in polar ice melt, this second would have been due for removal by 2026, it says.
Timekeepers are no strangers to tweaking time to adjust for the Earth’s rotation; 27 leap seconds have been added to Coordinated Universal Time (UTC) since the 1970s. However, the paper cautions the first-ever removal of a second is set to pose “an unprecedented problem” for computer network timing.
(Similarly, in 25th place is a Proceedings of the National Academy of Science paper that finds melting ice sheets and glaciers are redistributing the planet’s mass, causing days to become longer by milliseconds.)
In ninth place is a Nature Communications paper which finds that rates of glacier area shrinkage on the Juneau ice field, which straddles Alaska and British Columbia, were five times faster over 2015-19 relative to 1948-79.
Rounding out the top 10 is a Science study that uses proxy data to conclude that the Earth’s average surface temperature has varied between 11C and 36C over the past 485m years.
The rest of the top 25 contains a varied mix of papers that were typically well-received by the scientific community, including research on oil and gas system emissions (15th), mortality due to tropical cyclones in the US (16th) and the latest “state of wildfires” update (22nd).
Paper number 12 finds that a “record-low planetary albedo”, mainly caused by low cloud cover in the northern mid-latitudes and tropics, may have been an important driver of the record-high global temperatures in 2023.
Published on 5 December in the journal Science, it is a relatively late entry into the annual rankings. Despite its late publication date, the study tops the charts for Bluesky mentions, gaining 376 mentions in less than one month.
A Communications Earth & Environment study, called “A recent surge in global warming is not detectable yet”, sits at number 21, with an Altmetric score of 2,018. The study uses statistical methods to search for a recent acceleration in global warming, and concludes that it is not possible to detect one.
The lead author of the study told Carbon Brief that the findings do not rule out that an acceleration might be occurring. She said that “the point of the paper is that it will take additional years of observations to detect a sustained acceleration”. However, some scientists questioned the utility of the methods used in the study, arguing there is evidence of an acceleration in warming.
At number 23 is a study in the journal Science which evaluates 1,500 climate policies that have been implemented over the past 25 years. The lead author of the study told Carbon Brief that taxes are “the only policy instrument that has been found to cause large emission reductions on their own”. The study received 30 mentions in blogs and more than 200 news mentions.
Some studies receive a lot of attention because they provoke discussion or a significant backlash, which drives up news stories and discussion on social media.
For example, the paper ranking at number 14 is a Nature Climate Change study claiming that the planet has already exceeded the 1.5C warming threshold set under the Paris Agreement.
The authors use proxy data from sea sponges in the Caribbean Sea to create a record of ocean temperatures from AD700 to the present day. They find that warming started 40 years before the IPCC’s pre-industrial baseline period began, and argue that this means “warming is 0.5C higher than [Intergovernmental Panel on Climate Change] estimates”.
However, many experts were critical, warning Carbon Brief that the framing of the study is misleading, and arguing that the finding has no bearing on the Paris Agreement 1.5C limit. One expert, who was also not involved in the study, said that “the way these findings have been communicated is flawed, and has the potential to add unnecessary confusion to public debate on climate change”.
The study received 262 news mentions, with some outlets – including the Guardian and New Scientist – highlighting the disagreements over the study’s framing.
All the final scores for the top 25 climate papers of 2024 can be found in this spreadsheet.
Across the top 25 papers in Carbon Brief’s leaderboard this year, Nature features most frequently with seven papers. Nature is perennially high-placed in this analysis, taking first or joint first spot in Carbon Brief’s top 25 six times – 2021, 2020, 2019, 2018, 2017 and 2015.
In joint-second place this year are Science, Proceedings of the National Academy of Sciences and Communications Earth & Environment with three papers each.
Earth System Science Data has two papers, and there are seven journals that each have one paper.
The top 25 climate papers of 2024 cover a wide range of topics and scope. However, analysis of their authors reveals an all-too-familiar lack of diversity. Carbon Brief recorded the gender and country of affiliation for each of these authors. (The methodology used was developed by Carbon Brief for analysis presented in a special 2021 series on climate justice.)
In total, the top 25 climate papers of 2024 have 275 authors. This is fewer than in the past two years, partly due to the absence of the Lancet Countdown report, which typically has more than 100 authors.
The analysis reveals that the authors of the climate papers most featured in the media in 2024 are predominantly men from the global north.
The chart below shows the institutional affiliations of all authors in this analysis, broken down by continent – Europe, North America, Oceania, Asia, South America and Africa.
The analysis shows that 85% of authors are affiliated with institutions from the global north – defined as North America, Europe and Oceania. Meanwhile, only two authors are from Africa.
Further data analysis shows that there are also inequalities within continents. The map below shows the percentage of authors from each country in the analysis, where dark blue indicates a higher percentage. Countries that are not represented by any authors in the analysis are shown in grey.
The top-ranking countries on this map are the US and the UK, with 26% and 18% of the total authors, respectively. Germany ranks third on the list with 15% of the authors.
Meanwhile, only one-third of authors from the top 25 climate papers of 2024 are women. And only five of the 25 papers have a woman as a lead author.
The plot below shows the number of authors from each continent who are men (purple) and women (yellow).
The full spreadsheet showing the results of this data analysis can be found here. For more on the biases in climate publishing, see Carbon Brief’s article on the lack of diversity in climate-science research.
