Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
‘Lukewarm’ end to COP30
BYE BELÉM: The COP30 climate talks in Belém ended last weekend with countries agreeing on a goal to “triple” adaptation finance by 2035 and efforts to “strengthen” climate plans, Climate Home News reported. The final deal “fell short on the global transition away from oil, gas and coal”, the outlet said, as Brazil announced that it would bring forward voluntary roadmaps to phase out fossil fuels and deforestation, before the next COP. It was a “frustrating end” for more than 80 countries who wanted a roadmap away from fossil fuels to be part of the formal COP agreement, BBC News said.
WHAT HAPPENED?: Carbon Brief published its in-depth analysis of all the key outcomes from COP30, spanning everything from negotiations on adaptation, just transition, gender and “Article 6” carbon trading through to a round-up of pledges on various issues. Another Carbon Brief article summed up outcomes around food, forests, land and nature. Also, Carbon Brief journalists discussed the COP in a webinar held earlier this week.
ART OF THE DEAL: The “compromise” COP30 deal – known as the “global mutirão” – “exposed deep rifts over how future climate action should be pursued”, Reuters noted. The “last-ditch” agreement was reached after fossil-fuel wording negotiations between the EU and Saudi Arabia, according to the Guardian. Meanwhile, Carbon Brief revealed the “informal” list of 84 countries said to have “opposed” the inclusion of a fossil-fuel roadmap in the mutirão decision, but analysis of the list exposed contradictions and likely errors.
UNITY, SCIENCE, SENSE: The final agreement received “lukewarm praise”, said the Associated Press. Palau ambassador Ilana Seid, who chaired the coalition of small-island nations, told the newswire: “Given the circumstances of geopolitics today, we’re actually quite pleased…The alternative is that we don’t get a decision and that would have been [worse].” UN climate chief Simon Stiell said that amid “denial, division and geopolitics”, countries “chose unity, science and economic common sense”, reported the Press Trust of India.
Around the world
- Floods and landslides killed more than 200 people in Thailand and Indonesia this week, reported Bloomberg. At least 90 people also died in recent floods in Vietnam, said Al Jazeera.
- New measures to cut energy bills and a “pay-per-mile” electric-vehicle levy were among the announcements in the UK’s budget, said Carbon Brief.
- The Group of 20 (G20) leaders signed off on a declaration “addressing the climate crisis” and other issues, reported Reuters, which had no input from the US who boycotted last week’s G20 summit in South Africa.
- Canadian prime minister Mark Carney signed a deal with the province of Alberta “centred on plans for a new heavy oil pipeline”, said the Guardian, adding that Canadian culture minister and former environment minister, Steven Guilbeault, resigned from cabinet over the deal.
- Greenpeace analysis, covered by Reuters, found that permits for new coal plants in China are “on track to fall to a four-year low” in 2025.
27
The number of hours that COP30 talks went over schedule before ending in Belém last Saturday, making it the 11th-longest UN climate summit on record, according to analysis by Carbon Brief.
Latest climate research
- The risk of night-time deaths during heatwaves increased “significantly” over 2005-15 in sub-Saharan Africa | Science Advances
- Almost half of climate journalists surveyed showed “moderate to severe” symptoms of anxiety | Traumatology
- Lakes experienced “more severe” heatwaves than those in the atmosphere over the past two decades | Communications Earth & Environment
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
The key COP30 agreement – termed the “global mutirão” – contained 69 inactive verbs, which require no action from countries, compared to 32 active ones. “Recognises”, “recalls” and “acknowledges” were used far more often than more active verbs, such as “decides”, “calls” and “requests”, showed Carbon Brief analysis.
Spotlight
Nine warnings from a UK climate and nature ‘emergency’ briefing
This week, Carbon Brief’s Orla Dwyer reports from an event where experts and campaigners sounded the alarm bell on climate change and nature loss.
Naturalist and broadcaster Chris Packham urged attendees at a climate and nature “emergency briefing” in London yesterday to “listen to the science” on climate change amid a “dangerous wave of misinformation and lies”.
The “first-of-its-kind” event heard from nine experts on the links between climate change, nature loss, health, food production, economics and national security.
Event host, Prof Mike Berners-Lee from Lancaster University, called for a “World War II level of leadership” to tackle the interconnected crises.
Hundreds of people showed up, including Green Party, Labour and Liberal Democrat MPs, leader of the Greens Zack Polanski, musician Brian Eno and actress Olivia Williams.
Here is a snapshot of what the nine speakers said in their short, but stark, presentations.
Prof Kevin Anderson, professor of energy at University of Manchester
Anderson focused on the risks of a warmer world and the sliver of emissions left in the global carbon budget, noting:
“We have to eliminate fossil fuels or temperatures will just keep going up.”
He urged a “Marshall-style” plan – referencing the 1948 post-war US plan to rebuild Europe – to ramp up actions on retrofitting, public transport and electrification.
Prof Nathalie Seddon, professor of biodiversity at University of Oxford
Nature is not a “nice to have”, but rather “critical national infrastructure”, Seddon told attendees. She called for the “need to create an economy that values nature”.
Prof Paul Behrens, British Academy global professor at University of Oxford
Behrens discussed the food security risks from climate change. Impacts such as poor harvests and food price inflation are “barely acknowledge[d]” in agricultural policy, he said.
He also emphasised the “unsustainable” land use of animal agriculture, which “occupies around 85% of total agricultural land” in the UK.
Prof Tim Lenton, chair in climate change and Earth system science at Exeter University
Lenton outlined the “plenty” of evidence that parts of the Earth system are hurtling towards climate tipping points that could push them irreversibly into a new state.
He discussed the possibility of the shutdown of the Atlantic Meridional Overturning Circulation, which he said could cause -20C winters in London. He also noted positive tipping points, such as momentum that led the UK to stop burning coal for electricity last year.
Prof Hayley Fowler, professor of climate change impacts at Newcastle University
One in four properties in England could be at risk of flooding by 2050, Fowler said, and winters are getting wetter.
She discussed extreme weather risks and listed the impacts of floods in recent years in Germany, Spain and Libya, adding:
“These events are not warnings of what might happen in the future. They’re actually examples of what is happening right now.”
Angela Francis, director of policy solutions at WWF-UK
Francis factchecked several claims made against climate action, such as the high cost of achieving net-zero.
She noted that the estimated cost for the UK to achieve net-zero is about £4bn per year, which is less than 0.2% of GDP.
Lieutenant general Richard Nugee, climate and security advisor
Discussing the risks climate change poses to national security, Nugee said:
“Climate change can be thought of as a threat multiplier, making existing threats worse or more frequent and introducing new threats. Climate shocks fuel global instability.”
Tessa Khan, environmental lawyer and executive director of Uplift
Khan said the rising cost of energy in the UK is “turning into a significant political risk for the energy transition”.
She discussed the cost of fossil-fuel dependency and the fact that these fuels cost money to burn, but renewable “input[s], sun or wind [are] free forever”.
Prof Hugh Montgomery, professor of intensive care medicine at University College London
Montgomery discussed the health and economic benefits of climate actions, such as eating less meat and using more public transport, noting:
“The climate emergency is a health emergency – and it’s about time we started treating it as one.”
Watch, read, listen
WATER WORRIES: ABC News spoke to three Iranian women about the impacts of Tehran’s water crisis amid the “worst drought in 60 years”.
CLIMATE EFFORT: The BBC’s Climate Question podcast looked at the main outcomes from COP30 and discussed the “future of climate action” with a team of panelists.
CRIMINAL BEHAVIOUR:New Scientist interviewed criminal psychologist Julia Shaw about the psychology behind environmental crimes.
Coming up
- 24 November-5 December: COP20 on international trade in endangered species of wild fauna and flora, Samarkand, Uzbekistan
- 29-30 November: First part of global youth environment assembly, Nairobi, Kenya
- 3-4 December: Second round of Egyptian parliamentary elections
- 5 December: World soil day, global
Pick of the jobs
- Aldersgate Group, head of policy | Salary: £56,650-£66,950 per year. Location: London
- Ofgem, climate resilience expert | Salary: £61,446-£86,547. Location: Cardiff, Glasgow or London
- Green Climate Fund, integrity risk management lead | Salary: $171,200. Location: Incheon, South Korea
- Isles of Scilly Wildlife Trust, project manager – seabird recovery | Salary: Up to £45,000 per year. Location: Isles of Scilly, UK
DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.
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The post DeBriefed 28 November 2025: COP30’s ‘frustrating’ end; Asia floods; UK ‘emergency’ climate event appeared first on Carbon Brief.
DeBriefed 28 November 2025: COP30’s ‘frustrating’ end; Asia floods; UK ‘emergency’ climate event
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.
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.
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:
“These [risk assessments and strategies] need to be carried out at the local level to understand the complexities of each region.”
The post Heatwaves driving recent ‘surge’ in compound drought and heat extremes appeared first on Carbon Brief.
Heatwaves driving recent ‘surge’ in compound drought and heat extremes
Greenhouse Gases
DeBriefed 6 March 2026: Iran energy crisis | China climate plan | Bristol’s ‘pioneering’ wind turbine
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Energy crisis
ENERGY SPIKE: US-Israeli attacks on Iran and subsequent counterattacks across the Middle East have sent energy prices “soaring”, according to Reuters. The newswire reported that the region “accounts for just under a third of global oil production and almost a fifth of gas”. The Guardian noted th