Published

5 months ago

September 27, 2025

Alice Rush

Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.

This week

China’s new climate pledge

GUTERRES DEMANDS: UN secretary general António Guterres hosted a special climate action summit in New York on Wednesday, the Associated Press reported, alongside the closing day of the UN general assembly. It added that at the “marathon session”, where 121 world leaders were scheduled to speak, Guterres said: “The science demands action. The law commands it. The economics compel it. And people are calling for it.”

CHINA CUTS: First billing went to President Xi Jinping, who unexpectedly appeared via video to announce a target of cutting emissions – from all greenhouse gases and across China’s entire economy – to 7-10% below peak levels by 2035, according to Bloomberg. This is a significant moment for global climate efforts, noted BBC News, as it is the first time that China has pledged to reduce its emissions in absolute terms.

CAUTIOUS RESPONSE: However, the pledge fell short of the “at least 30%” cut observers had said was needed, BBC News added. Carbon Brief has published a detailed Q&A on China’s new climate pledge and will host a free webinar on the topic. Sign up for free.

PLEDGE CONFUSION: The Guardian said “120 countries and the EU announced new goals” at the summit. However, Carbon Brief analysis of the speeches and official submissions found that only 11 countries offered new targets. Following the summit, countries representing half of global emissions have now announced or submitted their 2035 climate pledges, according to analysis just published by Carbon Brief.

Trump’s new climate sledge

‘CLIMATE CON’: The day before the Guterres summit, Donald Trump had used a nearly hour-long speech to the UN general assembly to deliver what the Bloomberg Green newsletter called a “blizzard” of “climate misinformation”. He attracted blanket coverage – and multiple factchecks – for false claims including that climate change was the “greatest con job ever” and that warming predictions were “wrong”.

FACTCHECK: Contrary to Trump’s claims, human-induced warming is an “established fact”, according to the IPCC, as is an increase in the strength and frequency of extreme weather events. Regarding climate models, Carbon Brief climate science contributor Dr Zeke Hausfather noted on Bluesky that projections of warming have been “pretty spot on”.

Around the world

RENEWABLE RECORD: Global investment in renewable energy grew 10% year-on-year to a record $386bn in the first half of 2025, the Guardian said.
CARBON CLUB: COP30 host Brazil is “trying to build a coalition of countries, including the EU and China, to unify carbon markets”, Bloomberg reported.
FOSSILS OUT?: Colombia will host the first-ever international conference on phasing out fossil fuels in 2026, according to Climate Home News. Meanwhile, E&E News covered the latest UN “production gap” report saying, despite a COP28 pledge to transition away from fossil fuels, “many are planning for even more production”.
SUPER TYPHOON: Ragasa, a category 5 “super typhoon” and the world’s most powerful tropical cyclone this year, killed 17 people in Taiwan, BBC News said. The storm, which was “intensified” by climate change according to the Hong Kong Free Press, caused nearly two million residents to be evacuated in China, added Xinhua,
DEFORESTATION DELAY: The EU has delayed the start of its anti-deforestation law “by another year”, Reuters said, blaming “IT system concerns”.
AIRPORT APPROVAL: The UK government approved a second runway at London’s Gatwick airport, said BBC News. The Sunday Times reported that it was also “poised to soften” its ban on new drilling in the North Sea.

62,700

The number of deaths in Europe linked to heat-related causes in 2024, the continent’s hottest year on record, according to new research covered by Reuters.

Latest climate research

Extreme and “unprecedented” global water-scarcity events – or “day-zero droughts” – could happen in the 2020s and 2030s | Nature Communications
The drying of the Ganga river, of great economic and cultural importance to millions of people in India, Nepal and Bangladesh, is “unprecedented in the last 1,300 years” | Proceedings of the National Academy of Sciences
The likelihood of “severe bushfires danger” in Australia driven by a positive Indian Ocean Dipole has increased by 16-32% due to climate change | Journal of Geophysical Research: Atmospheres

(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)

Captured

China’s new climate pledge, outlined by President Xi Jinping, includes a target to reduce “economy-wide net greenhouse gas emissions” to 7-10% below peak levels by 2035. But, as Carbon Brief explained in a detailed Q&A, this falls short of what would have been needed to contribute to limiting warming to 1.5C, according to experts.

Spotlight

Can COP30 respond to the 1.5C challenge?

With hopes fading of keeping global warming below 1.5C, despite new pledges at a UN summit in New York, this spotlight looks at the road to COP30 in Brazil and how the climate talks might respond.

After 2024 marked the hottest year on record and the first above 1.5C, 2025 was supposed to offer a chance to “course correct” through new, more ambitious national climate plans.

Instead, many countries have missed repeated deadlines for updated “nationally determined contributions” (NDCs) under the Paris Agreement, setting out their plans to 2035.

Despite some new pledges in New York this week – including from China – collective efforts still “fall short” of limiting warming to the Paris goals of “well-below” 2C while “pursuing efforts” towards 1.5C.

Drumbeat of ‘disappointment’

This message is likely to be reinforced by a UN “synthesis report”, compiling the impact of new NDCs and due to be published on 24 October.

It will likely be reiterated in early November by the UN’s annual “emissions gap” report. Last year’s report had called for a “quantum leap” in ambition, which has yet to materialise.

This is all despite an advisory opinion from the International Court of Justice in July, which said that 1.5C should be considered the “primary temperature goal” of global climate efforts – and that countries should make “adequate contributions” towards meeting it.

Meanwhile, amid oil and gas advocacy from the Trump administration, debate is raging over whether fossil fuels have peaked – and whether climate efforts need a “pragmatic” reset.

This is set to culminate with a battle to control the narrative around the International Energy Agency (IEA) World Energy Outlook for 2025, also due in early November.

Avantika Goswami, programme manager for climate change at India’s Centre for Science and Environment, told Carbon Brief that the global climate regime was at a “turning point”, where agreements had been signed and targets set, but action was “stalling”. She said:

“Implementation is weak, finance is undelivered and trust in the UN system is eroding, amid trade wars, militarism, debt crises and fractured multilateralism.”

Can COP30 respond?

Just days after the raft of new reports, on 6-7 November, heads of state and government will gather in the Brazilian city of Belém for a leaders summit ahead of the COP30 climate talks.

Views differ on how COP30 should respond to the current challenges.

The Brazilian presidency is pushing for a formal COP decision on any “disappoint[ment]” over NDCs falling short, collectively, of what is needed to avoid dangerous global warming.

During initial consultations, the EU said it wanted climate ambition to be added to the COP agenda, while the groups of least developed countries (LDCs), small island states and Latin American countries supported a formal COP decision on the matter. Others pushed back.

Catherine Abreu, director of the International Climate Politics Hub, told Carbon Brief that COP30 would need to respond in some way. She said:

“It’s clear that credibility at COP30 will require a response to the fact that countries’ climate pledges don’t add up to the level of ambition needed to tackle the crisis. The question after this week is, how will the COP outcomes enrich our definition of ambition beyond a headline emissions reduction goal?”

Abreu added that COP30 would need to address barriers, including “the equitable finance needed to implement goals and a lagging transition away from fossil fuels”.

Amid frustration over slow progress, calls for reform of the COP process are getting louder.

Goswami concluded: “The needs and ambitions of the global south must now shape the climate narrative – and COP30 must reckon with this new balance of power.”

Watch, read, listen

GAME OVER?: A feature in the Wall Street Journal said that, as Trump “doubles down on fossil fuels”, the US is “forfeiting the clean-energy race to China”.

POPULIST PUSHBACK: The Drilled podcast talked to a sociologist and a political scientist about “the intersection between the rise of rightwing populism and increasing resistance to acting on climate”.

ADULTS ONLY: For the New York Times, the Asia Society Policy Institute’s Li Shuo wrote that China was “the adult in the room on climate now”, despite its “modest” new pledge.

Coming up

22-26 September: Fifth world congress of biosphere reserves, Hangzhou, China
27 September: Seychelles elections
28 September: Moldova elections
30 September-1 October: 42nd UN water meeting, Geneva, Switzerland

Pick of the jobs

Indigenous Climate Action, research coordinator | Salary: $55,000-$68,000. Location: Remote
Greater London Authority, head of climate change | Salary: £91,268. Location: London
Stockholm Environment Institute, research fellow: climate impact and climate finance | Salary: Unknown. Location: Nairobi, Kenya

DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.

This is an online version of Carbon Brief’s weekly DeBriefed email newsletter. Subscribe for free here.

The post DeBriefed 26 September 2025: China leads new climate pledges; Trump calls warming a ‘con job’; What comes next appeared first on Carbon Brief.

DeBriefed 26 September 2025: China leads new climate pledges; Trump calls warming a ‘con job’; What comes next

Climate Change

On the Farm, the Hidden Climate Cost of America’s Broken Health Care System

Published

24 hours ago

March 7, 2026

Alice Rush

American farmers are drowning in health insurance costs, while their German counterparts never worry about medical bills. The difference may help determine which country’s small farms are better prepared for a changing climate.

By Jordan Gass-Pooré

Samantha Kemnah looked out the foggy window of her home in New Berlin, New York, at the 150-acre dairy farm she and her husband, Chris, bought last year. This winter, an unprecedented cold front brought snowstorms and ice to the region.

On the Farm, the Hidden Climate Cost of the Broken U.S. Health Care System

Climate Change

A Little-Used Maneuver Could Mean More Drilling and Mining in Southern Utah’s Redrock Country

Published

1 day ago

March 6, 2026

Alice Rush

Two Utah Congress members have introduced a resolution that could end protections for Grand Staircase-Escalante National Monument. Conservation groups worry similar maneuvers on other federal lands will follow.

By Georgina Gustin

Lawmakers from Utah have commandeered an obscure law to unravel protections for the Grand Staircase-Escalante National Monument, potentially delivering on a Trump administration goal of undoing protections for public conservation lands across the country.

A Little-Used Maneuver Could Mean More Drilling and Mining in Southern Utah’s Redrock Country

Climate Change

Heatwaves driving recent ‘surge’ in compound drought and heat extremes

Published

1 day ago

March 6, 2026

Alice Rush

Drought and heatwaves occurring together – known as “compound” events – have “surged” across the world since the early 2000s, a new study shows.

Compound drought and heat events (CDHEs) can have devastating effects, creating the ideal conditions for intense wildfires, such as Australia’s “Black Summer” of 2019-20 where bushfires burned 24m hectares and killed 33 people.

The research, published in Science Advances, finds that the increase in CDHEs is predominantly being driven by events that start with a heatwave.

The global area affected by such “heatwave-led” compound events has more than doubled between 1980-2001 and 2002-23, the study says.

The rapid increase in these events over the last 23 years cannot be explained solely by global warming, the authors note.

Since the late 1990s, feedbacks between the land and the atmosphere have become stronger, making heatwaves more likely to trigger drought conditions, they explain.

One of the study authors tells Carbon Brief that societies must pay greater attention to compound events, which can “cause severe impacts on ecosystems, agriculture and society”.

Compound events

CDHEs are extreme weather events where drought and heatwave conditions occur simultaneously – or shortly after each other – in the same region.

These events are often triggered by large-scale weather patterns, such as “blocking” highs, which can produce “prolonged” hot and dry conditions, according to the study.

Prof Sang-Wook Yeh is one of the study authors and a professor at the Ewha Womans University in South Korea. He tells Carbon Brief:

“When heatwaves and droughts occur together, the two hazards reinforce each other through land-atmosphere interactions. This amplifies surface heating and soil moisture deficits, making compound events more intense and damaging than single hazards.”

CDHEs can begin with either a heatwave or a drought.

The sequence of these extremes is important, the study says, as they have different drivers and impacts.

For example, in a CDHE where the heatwave was the precursor, increased direct sunshine causes more moisture loss from soils and plants, leading to a drought.

Conversely, in an event where the drought was the precursor, the lack of soil moisture means that less of the sun’s energy goes into evaporation and more goes into warming the Earth’s surface. This produces favourable conditions for heatwaves.

The study shows that the majority of CDHEs globally start out as a drought.

In recent years, there has been increasing focus on these events due to the devastating impact they have on agriculture, ecosystems and public health.

In Russia in the summer of 2010, a compound drought-heatwave event – and the associated wildfires – caused the death of nearly 55,000 people, the study notes.

Saint Basil's Cathedral, on Red Square, in Moscow, was affected by smog during the fires in Russia in the summer of 2010. — Saint Basil’s Cathedral, on Red Square, in Moscow, was affected by smog during the fires in Russia in the summer of 2010. Credit: ZUMA Press, Inc. / Alamy Stock Photo

The record-breaking Pacific north-west “heat dome” in 2021 triggered extreme drought conditions that caused “significant declines” in wheat yields, as well as in barley, canola and fruit production in British Columbia and Alberta, Canada, says the study.

Increasing events

To assess how CDHEs are changing, the researchers use daily reanalysis data to identify droughts and heatwaves events. (Reanalysis data combines past observations with climate models to create a historical climate record.) Then, using an algorithm, they analyse how these events overlap in both time and space.

The study covers the period from 1980 to 2023 and the world’s land surface, excluding polar regions where CDHEs are rare.

The research finds that the area of land affected by CDHEs has “increased substantially” since the early 2000s.

Heatwave-led events have been the main contributor to this increase, the study says, with their spatial extent rising 110% between 1980-2001 and 2002-23, compared to a 59% increase for drought-led events.

The map below shows the global distribution of CDHEs over 1980-2023. The charts show the percentage of the land surface affected by a heatwave-led CDHE (red) or a drought-led CDHE (yellow) in a given year (left) and relative increase in each CDHE type (right).

The study finds that CDHEs have occurred most frequently in northern South America, the southern US, eastern Europe, central Africa and south Asia.

Charts showing spatial and temporal occurrences over study period — Spatial and temporal occurrence of compound drought and heatwave events over the study period from 1980 to 2023. The map (top) shows CDHEs around the world, with darker colours indicating higher frequency of occurrence. The chart in the bottom left shows how much land surface was affected by a compound event in a given year, where red accounts for heatwave-led events, and yellow, drought-led events. The chart in the bottom right shows the relative increase of each CDHE type in 2002-23 compared with 1980-2001. Source: Kim et al. (2026)

Threshold passed

The authors explain that the increase in heatwave-led CDHEs is related to rising global temperatures, but that this does not tell the whole story.

In the earlier 22-year period of 1980-2001, the study finds that the spatial extent of heatwave-led CDHEs rises by 1.6% per 1C of global temperature rise. For the more-recent period of 2022-23, this increases “nearly eightfold” to 13.1%.

The change suggests that the rapid increase in the heatwave-led CDHEs occurred after the global average temperature “surpasse[d] a certain temperature threshold”, the paper says.

This threshold is an absolute global average temperature of 14.3C, the authors estimate (based on an 11-year average), which the world passed around the year 2000.

Investigating the recent surge in heatwave-leading CDHEs further, the researchers find a “regime shift” in land-atmosphere dynamics “toward a persistently intensified state after the late 1990s”.

In other words, the way that drier soils drive higher surface temperatures, and vice versa, is becoming stronger, resulting in more heatwave-led compound events.

Daily data

The research has some advantages over other previous studies, Yeh says. For instance, the new work uses daily estimations of CDHEs, compared to monthly data used in past research. This is “important for capturing the detailed occurrence” of these events, says Yeh.

He adds that another advantage of their study is that it distinguishes the sequence of droughts and heatwaves, which allows them to “better understand the differences” in the characteristics of CDHEs.

Dr Meryem Tanarhte is a climate scientist at the University Hassan II in Morocco, and Dr Ruth Cerezo Mota is a climatologist and a researcher at the National Autonomous University of Mexico. Both scientists, who were not involved in the study, agree that the daily estimations give a clearer picture of how CDHEs are changing.

Cerezo-Mota adds that another major contribution of the study is its global focus. She tells Carbon Brief that in some regions, such as Mexico and Africa, there is a lack of studies on CDHEs:

“Not because the events do not occur, but perhaps because [these regions] do not have all the data or the expertise to do so.”

However, she notes that the reanalysis data used by the study does have limitations with how it represents rainfall in some parts of the world.

Compound impacts

The study notes that if CDHEs continue to intensify – particularly events where heatwaves are the precursors – they could drive declining crop productivity, increased wildfire frequency and severe public health crises.

These impacts could be “much more rapid and severe as global warming continues”, Yeh tells Carbon Brief.

Tanarhte notes that these events can be forecasted up to 10 days ahead in many regions. Furthermore, she says, the strongest impacts can be prevented “through preparedness and adaptation”, including through “water management for agriculture, heatwave mitigation measures and wildfire mitigation”.

The study recommends reassessing current risk management strategies for these compound events. It also suggests incorporating the sequences of drought and heatwaves into compound event analysis frameworks “to enhance climate risk management”.

Cerezo-Mota says that it is clear that the world needs to be prepared for the increased occurrence of these events. She tells Carbon Brief: