Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Eve of COP30
MULTILATERAL HOPES A gathering of world leaders kicked off in Belém, Brazil, ahead of the official opening of COP30 next week. The leaders of China, the US and India – the “planet’s three biggest polluters” – are “notably absent” from the two-day leaders summit, reported the Associated Press. Some Latin American leaders “were openly critical” of the US president’s stance on climate change in their speeches at the “diminished” summit, noted the Financial Times.
‘MORAL FAILURE’: Speaking at the world leaders summit, UN secretary-general António Guterres described failing to remain below 1.5C as a “moral failure and deadly negligence”, reported the Guardian. Guterres added: “Every fraction of a degree means more hunger, displacement and loss – especially for those least responsible.” The UN chief’s speech came as the World Meteorological Organization confirmed that 2025 is “on track to be the second or third warmest globally”, noted Reuters.
‘POSITIVE TIPPING POINT’: The Brazilian COP presidency published a “Baku to Belém roadmap” detailing how climate finance for developing nations could be scaled up to $1.3tn a year by 2035, Climate Home News reported. The roadmap was published ahead of the UN climate talks, but will not be formally discussed as part of the negotiations, the outlet added. Read Carbon Brief’s summary of what the roadmap means for climate finance.
FORESTS NOT FOREVER: Brazil also launched its Tropical Forests Forever Facility (TFFF) this week, said Agence France-Presse, designed to help tropical countries protect their forests. Norway has joined France and Brazil in investing in the fund, while Germany will announce its contribution on Friday, noted Bloomberg. The Guardian dubbed the UK’s decision to opt out as “a major letdown”. For more on the TFFF, see Carbon Brief’s explainer.
UN report says world is heading for 2.8C
UNFULFILLING: The United Nations Environment Programme (UNEP) annual “emissions gap” report warned that global temperature rise could be heading for 2.8C this century, if only current policies are fulfilled, the Financial Times reported. The rise could be limited to 2.5C, if unconditional national pledges are met in full – or to 2.3C, if pledges conditional on financial support are put into action, the newspaper noted.
STALLED PROGRESS: The world’s warming trajectory is now “0.3C lower than it was a year ago…meaning new plans announced this year have done little to move the needle”, noted Reuters. Some of this progress will be “cancelled” out, the New York Times added, once the US withdrawal from the Paris Agreement takes effect. See Carbon Brief’s in-depth coverage of the UNEP report.
Around the world
- WATERED DOWN: The EU finally confirmed a “significantly weakened” plan to cut emissions to 90% below 1990 levels by 2040, reported the Financial Times.
- DEADLY DISASTER: The Philippines is in a state of emergency after Typhoon Kalmaegi left at least 114 people dead and nearly 130 missing.
- DROPPING COMMITMENTS: The junior partner in Australia’s opposition Coalition – the Nationals – has formally abandoned a commitment to reach net-zero emissions by 2050, reported ABC News.
- MAYORAL WIN: Zohran Mamdani won New York City’s mayoral election, having “refram[ed] climate policy as a quality-of-life issue”, Inside Climate News reported.
100
The number of proposed indicators to track progress towards the “global goal on adaptation” that will be negotiated at COP, according to Carbon Brief‘s new Q&A.
Latest climate research
- Rising temperatures could affect the muscles that Arctic bumblebees use to generate their “charismatic buzz” | Nature Communications
- The release of CO2 from the the Southern Ocean has been “underestimated” by up to 40% in previous studies | Science
- Outdoor heat stress has led to a 10% decline in labour capacity in “rural to urban migration hotspots” in India | Environmental Research Letters
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
IPCC funding shortfall
Carbon Brief covered the latest meeting of the Intergovernmental Panel on Climate Change (IPCC) in Lima, Peru. Alongside funding from parent organisations the World Meteorological Organization (WMO) and UN Environment Programme, voluntary contributions by countries help pay for the work of the IPCC. The biggest contributors so far in 2025 are Norway, the UNFCCC, Canada and the WMO. The red bars show how US contributions have dropped off during Trump’s two terms in office. Having provided 30% of direct contributions throughout the IPCC’s history, the US has not made a contribution so far this year.
Spotlight
‘With knowledge comes responsibility’: the changing role of climate scientists in a warming world
This week, Carbon Brief speaks to a researcher about the different ways climate scientists are feeling and taking responsibility for the knowledge they hold.
From calling for action in Belém to defending science against attempts to discredit or downplay it, climate scientists are responding to world events in ever-more visible ways.
Dr Friederike Hartz is a research and policy associate at University College London.
For her PhD thesis, carried out at the University of Cambridge, Hartz interviewed 77 experts who participated in IPCC reports, the world’s most authoritative global assessments of climate science coordinated by the UN.
‘You can’t unsee it’
Hartz’s findings show how climate scientists can feel a sense of responsibility, as those who bear the knowledge and evidence of climate change.
Some interviewees felt a sense of “representational responsibility” – motivated by the wish to improve the lives of the vulnerable or underrepresented communities they belong to.
Others expressed a sense of “intergenerational responsibility”, resolving to contribute to a better world for their children and grandchildren.
Hartz called this the “inescapability” of climate knowledge. She told Carbon Brief:
“Once you know, you know. As one of my interviewees shared with me, you simply can’t unsee it. Especially as a scientist, you’re trained to see those things.”
Taking responsibility
Hartz’s research looked at what it means for climate scientists to act on the sense of responsibility they feel, beyond producing the science itself.
Some take part in formal IPCC assessments. Others “have come to accept and further embrace a responsibility for communicating” their knowledge, Hartz noted in her paper.
Beyond the IPCC, some scientists take on additional responsibility for evidence-based “advocacy” or even call for more “activism” in science.
Similarly, on the grounds that “with knowledge comes responsibility”, some have called for scientists to “step beyond their traditional roles” or act as “sentinels” to alert society to threats. Hartz told Carbon Brief:
“This is all part of what I call ‘science enactment’: putting science into action or putting it in the hands of other people who can act on it.”
Navigating what it means to take responsibility is a very individual thing, said Hartz, which speaks to late biologist Stephen Schneider’s “double ethical bind” – the balance between a commitment to the “scientific method” and the “wish to see the world a better place”.
Lived experience
Hartz pointed to research suggesting the traditional view – that engaging in activism or advocacy can damage a scientist’s credibility – may be unwarranted. But there can be other downsides, she noted, including the emotional toll. As one of her interviewees expressed it:
“As scientists, we are not droids…And, so, to say that we are not at all influenced by what is going on in science is not true.”
Hartz suggested that scientists can simultaneously experience feelings of enthusiasm about their work and frustration about its uptake. Or as she noted in her thesis, citing a seminal political science study:
“Knowledge can only speak ‘truth to power’ to the extent that ‘power listens to truth’.”
Watch, read, listen
‘WHITE HOUSE EFFECT’: A Netflix documentary looked at how a “crucial opportunity” to take climate action was “deliberately undermined” during the George HW Bush administration.
‘COP OF TRUTH’: Brazil’s president, Luiz Inácio Lula da Silva, wrote in the Guardian ahead of COP30 about the need to act “with the urgency the climate crisis demands”.
HUMAN STORIES: A video by the Grantham Institute at Imperial College London explored the pivotal moments leading to the historic establishment of a loss and damage fund.
Coming up
- 10 November: UN Climate Change conference (COP30) begins in Belém, Brazil
- 12 November: IEA World Energy Outlook 2025 launch, Paris
- 13 November: Global Carbon Budget annual update released
Pick of the jobs
- Project Drawdown, program manager, research fellow and senior analyst | Salary: Various. Location: Remote
- UK Centre for Ecology and Hydrology, laboratory assistant | £26,206 – £27,808. Location: Lancaster, UK
- Ofwat, Wales environmental policy lead | £57,783 – £72,000. Location: Cardiff, UK
- UNEP, mitigation expert on sand and dust storms | Salary: Not specified. Location: Riyadh, Saudi Arabia
- Conservation International, senior manager, climate & landscape restoration | Salary: Not specified. Location: Acornhoek, South Africa.
DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.
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The post DeBriefed 7 November 2025: Belém COP begins; UN warns of 1.5C breach; changing roles of climate scientists appeared first on Carbon Brief.
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 that shipping traffic through the strait of Hormuz, which normally ferries 20% of the world’s oil, “all but ground to a halt”. The Financial Times reported that attacks by Iran on Middle East energy facilities – notably in Qatar – triggered the “biggest rise in gas prices since Russia’s full-scale invasion of Ukraine”.