Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
World court’s ‘landmark’ climate opinion
POLLUTERS ‘ACCOUNTABLE’: The UN’s highest court has told “wealthy” countries “they must comply with their international commitments to curb pollution or risk having to pay compensation to nations hard hit by climate change”, reported Reuters. The International Court of Justice (ICJ) issued a much-awaited advisory opinion that small island states have described as a “legal stepping stone to make big polluters accountable”, the newswire added.
‘INHERENT RIGHT’: The Associated Press said that, during a two-hour hearing to present the unanimous opinion, Japanese judge Yuji Iwasawa told the court that the “human right to a clean, healthy and sustainable environment is…inherent in the enjoyment of other human rights”. The newswire said activists described this as a “turning point in international climate law”.
‘LEGAL WEIGHT’: The Times noted that the “view is non-binding on governments, including the [UK], and the US does not recognise the court’s jurisdiction”. However, the “ICJ’s advisory opinions carry great legal weight and are seen to contribute to the clarification of international law”, the newspaper added. Carbon Brief has just published an in-depth Q&A on what the opinion means for climate change.
Renewables ‘breakthrough’
BRINK OF BREAKTHROUGH: UN secretary-general António Guterres said on Tuesday that the “world is on the brink of a breakthrough in the climate fight and fossil fuels are running out of road”, the Guardian reported, as two new reports were published illustrating the growing dominance of renewable energy. In his online speech, Guterres said the global energy transition is now “unstoppable” due to “smart economics”.
RENEWABLES ‘CHEAPER’: The first of the new reports, from the International Renewable Energy Agency (IRENA), said that around 90% of renewable power projects globally are now cheaper than fossil fuel alternatives, Reuters said. The second, from the UN drawing on data from multiple international agencies, found that renewables made up 92.5% of all new electricity capacity additions and 74% of electricity generation growth in 2024, the Financial Times reported. Carbon Brief pulled out five key takeaways from both reports.
Around the world
- IN DANGER: The Trump administration has “drafted a plan to repeal a fundamental scientific finding”, known as the “endangerment finding”, that “gives the US government its authority to regulate greenhouse-gas emissions and fight climate change”, reported the New York Times.
- EU-CHINA SUMMIT: The EU and China have “committed to leading the world in the fight against climate change” in a joint statement released on Thursday following a meeting between the two superpowers, Bloomberg said. Carbon Brief’s China Briefing newsletter provided more details.
- JAPAN EYES NUCLEAR: A Japanese utility has become the first since the Fukushima nuclear disaster 14 years ago to take steps towards building a new reactor, reported Channel News Asia.
- SHELL QUITS INITIATIVE: Shell and other fossil-fuel companies have “abandoned” a six-year-long attempt to define a net-zero emissions strategy “after being told that such a standard would require them to stop developing new oil and gas fields”, according to the Financial Times.
- FLASH FLOODS: Ongoing flash flooding in Pakistan has killed at least 266 people over the past month, the Hindu reported.
50C
The temperature in some parts of Iran this week – as authorities asked people to limit drinking water amid an ongoing drought crisis, reported the Guardian.
Latest research
- Climate change is creating “new vulnerabilities” for pandemics | Carbon Brief
- South American lands stewarded by “Afro-descendant” people coincide with areas with “high biodiversity” and are associated with a 29-55% reduction in forest loss, compared to control sites | Communications Earth & Environment
- The “true price” of solar geoengineering is “much higher than its modest technical costs would indicate” | npj Climate Action
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
New research covered by Carbon Brief this week found that one in three people in informal settlements in the global south live in floodplains and are at risk of a “disastrous flood”. The chart above draws on data from the study, published in Nature Cities, to illustrate where in the world has the highest number of “slum residents” living in floodplains.
Spotlight
Antarctica’s oldest ice arrives in UK
Carbon Brief recently visited British Antarctic Survey scientists responsible for uncovering the secrets of Antarctica’s oldest ice.
Standing in a freezer in Cambridge – with a -25C chill licking at his nostrils – British Antarctic Survey (BAS) lab manager Jack Humby excitedly opens up an unassuming polystyrene box.
Using his bare hands, he pulls out its contents. Long square-shaped sections of crystal clear ice – wrapped in plastic labelling which way is up – are revealed.
Little about the appearance of the ice gives away that it is at least 1.2m years old.
It has journeyed to the BAS headquarters on the outskirts of Cambridge from an ice core drilling camp in East Antarctica.
In January, scientists at the camp vertically drilled a 2,800m-long ice core, with on-site tests revealing it was likely to be at least 1.2m years old. The ice was then flown to a nearby port and shipped to Europe aboard the Italian icebreaker Laura Bassi.
The ice was drilled as part of the Beyond Epica Oldest Ice project, a large-scale field operation involving multiple research teams and laboratories across Europe.
‘One shot’
Owing to its specialist equipment and research expertise, BAS has been tasked with analysing the ice to reveal its secrets.
Though not visible to the human eye, the ice contains organic compounds and tiny pockets of air from periods stretching back hundreds of thousands of years.
Over the next seven weeks, the research team at BAS will work around the clock to analyse these features. However, in order to do so, they will have to melt the ice.
Dr Liz Thomas, head of the ice cores team at BAS, told journalists:
“It’s a huge responsibility because this is a one shot. Given how much effort has gone into drilling these cores, we have to get this absolutely right.”
To conduct their analysis, the team plan to use a gold-plated instrument to melt the square-shaped sections of ice being stored in the freezer room.
The meltwater will then be piped into a specially designed lab next door, which contains millions of pounds worth of analysis equipment, according to Humby.
Climates past
The analysis will help scientists work out how old the ice actually is. Though initial tests suggest it is at least 1.2m years old, but the team believe it could be up to 1.5m years old or even older.
It will also enable researchers to paint a more detailed picture of Earth’s past climates.
In turn, this could inform scientists’ understanding of how large swings in temperature in the past have affected various parts of the Earth climate system, including its ice sheets and ecosystems.
Ultimately, this could help researchers to make more informed projections about the likely impacts of human-caused climate change, Thomas explained:
“As climate scientists, it’s our job to provide as much information as we can. What we’re relying on to understand the next steps is climate models. They are fantastic, but they’re only as good as the information we put into them. That really is the justification for looking back in time.”
Watch, read, listen
COP30 LOOMS: A long-read in the Brazilian culture magazine Piauí examined the fraught road that the nation faces to host the next UN climate summit in November.
ARCTIC ‘MELTING POINT’: In Nature Communications, researchers recounted how the Arctic island of Svalbard is facing a “dramatic shift” to high air temperatures and rainfall in the depths of winter.
STUDENT VICTORY: The Guardian spoke to a group of students from the Pacific islands who started the campaign for the world’s top court, the ICJ, to take on the issue of climate change.
Coming up
- 23-31 July: COP15 of the Ramsar Convention on Wetlands, Victoria Falls, Zimbabwe
- 30 July: International Energy Agency electricity mid-year update
- 30 July: Advancing the implementation of the Chilean framework Law on Climate Change, Santiago, Chile
Pick of the jobs
- Boston Globe, climate science and environment reporter | Salary: Unknown. Location: Boston, US
- Science Museum London, curator of climate and earth sciences | Salary: £41,770. Location: London
- Netflix, manager, sustainability standards and partnerships | Salary: Unknown. Location: Amsterdam, Netherlands
DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.
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The post DeBriefed 25 July 2025: World court delivers climate ‘turning point’; Renewables ‘unstoppable’; Antarctica’s oldest ice examined 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”.
‘RISK’ AND ‘BENEFITS’: Bloomberg reported on increases in diesel prices in Europe and the US, speculating that rising fuel costs could be “a risk for president Donald Trump”. US gas producers are “poised to benefit from the big disruption in global supply”, according to CNBC. Indian government sources told the Economic Times that Russia is prepared to “fulfil India’s energy demands”. China Daily quoted experts who said “China’s energy security remains fundamentally unshaken”, thanks to “emergency stockpiles and a wide array of import channels”.
‘ESSENTIAL’ RENEWABLES: Energy analysts said governments should cut their fossil-fuel reliance by investing in renewables, “rather than just seeking non-Gulf oil and gas suppliers”, reported Climate Home News. This message was echoed by UK business secretary Peter Kyle, who said “doubling down on renewables” was “essential” amid “regional instability”, according to the Daily Telegraph.
China’s climate plan
PEAK COAL?: China has set out its next “five-year plan” at the annual “two sessions” meeting of the National People’s Congress, including its climate strategy out to 2030, according to the Hong Kong-based