Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Record temperatures
RECORD LEVELS: The Copernicus Climate Change Service has warned that extreme weather across the globe is set to continue, following April marking the 11th month in a row where global average temperatures were at record highs, reported the Financial Times. April was 0.67C above the 1991-2020 average for the month and 1.58C above pre-industrial levels, it added.
SURGING SEA TEMPERATURES: Analysis of the Copernicus data by BBC News found that the world’s oceans have broken temperature records every single day over the past year and, on some days, this has been by a “huge margin”. In February and March 2024, sea surface temperatures reached a new global average daily high of 21.09C, according to the analysis.
Climate scientists speak out
PAST 1.5C: A survey by the Guardian has found that the majority of the world’s leading climate scientists expect global temperature to rise to at least 2.5C above pre-industrial levels by 2100, given the current level of action by countries. The survey of 380 Intergovernmental Panel on Climate Change (IPCC) scientists found that almost half anticipate 3C of warming, while only 6% thought the internationally agreed 1.5C limit will be met.
EXHAUSTED EXPERTS: In an accompanying piece in the Guardian, the experts shared their views. One scientist from Mexico told the newspaper she felt “hopeless and broken” by the pace of rising climate impacts, while another expert said thinking of the future was “infuriating, distressing, overwhelming”. A separate piece spoke to the female scientists surveyed, a fifth of whom have decided not to have children or to have fewer.
AVOIDING DESPAIR: The Guardian published an editorial alongside the above articles, urging readers not to despair. Although the “future can feel overwhelming and unfixable”, it notes, we need to “build collective awareness, a sense that change is possible and momentum for wider systemic progress”. Additionally, an opinion article by former UN climate chief Christiana Figueres similarly argues that “stubborn optimism may be our only hope”.
Around the world
- BRAZIL FLOODS: Record-breaking floods in southern Brazil have killed more than 105 people and affected more than 1.7 million, with more rain expected, reported O Globo.
- EU AND CHINA TALK TRADE: EU commissioner Ursula von der Leyen has restated readiness to launch a trade war with China over imports of clean energy technologies during a meeting with president Xi Jinping, reported the Guardian. Elsewhere, the South China Morning Post reported that the new climate envoys from China and the US have met for the first time.
- SOUTH ASIA HEATWAVES: Governments across south and south-east Asia have issued health warnings as schools shut and crops fail, as extreme heat continues to grip the region, the Guardian reported. In the Himalayan state of Uttarakhand, five people have been killed by forest fires, reported the Hindustan Times.
- AUSTRALIAN GAS: Australia’s government has announced plans to ramp up the extraction and use of gas to “2050 and beyond”, BBC News reported. The prime minister is now facing an internal revolt from his party, the Guardian added.
- KENYA DAY OF MOURNING: Kenya’s president William Ruto has declared a public day of mourning following the deaths of 238 people due to ongoing flooding, which will be marked by tree-planting, reported the Associated Press.
- LONDON MAYOR: Labour’s Sadiq Khan has pledged further “world-leading green action” after winning a historic third term as London Mayor, reported Bloomberg. Khan’s victory came despite speculation his ambitious air pollution and climate measures could turn off voters.
30%
The proportion of global electricity that came from renewables last year – a new record, according to analysis covered by Carbon Brief.
Latest climate research
- Fewer cooler days due to climate change could make existing varieties of lychee “unsuitable for cultivation in production areas in southern Taiwan”, a new study in Climate Services said.
- Tornado-producing tropical storms may increase “substantially” in the US by 2050 as climate change worsens, new research in Weather and Climate Extremes found.
- New research published in Nature Climate Change found that the transport of ocean heat through the Bering Strait has a more substantial influence on Arctic warming than previously recognised.
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Tuesday, Wednesday, Thursday and Friday.)
Captured
“Residual emissions” are those that remain once a nation has gone as far as it thinks is possible to cut its emissions. These emissions tend to come from sectors that are considered hard to decarbonise, such as livestock farming and heavy industry. The concept is closely tied with net-zero targets. That is, a country must remove CO2 from the atmosphere that is equivalent in volume to its residual emissions, in order to say it has reached net-zero. A new study covered by Carbon Brief explored national strategies for managing residual emissions. Of the 71 countries examined, just 26 have long-term plans to tackle these emissions. These nations could have residual emissions of up to 2.9bn tonnes of CO2 equivalent by 2050, equal to around 5% of total global emissions. Countries include major emitters such as the US, Canada and Australia (as shown in the above chart). The chart shows residual emissions (red) as a share of each nation’s peak emissions (blue) – or its most recent annual emissions, if its emissions have not yet peaked.
Spotlight
The Thames Barrier at 40
Carbon Brief visits London’s Thames Barrier, the second-largest flood defence barrier in the world, as it turns 40-years-old.
With sea levels rising and flood risks increasing, the UK’s Environment Agency (EA) is working to develop the next era of protections for London and the wider Thames Estuary.
On 25 April, Carbon Brief visited the Thames Barrier to discuss its origins and look forward to its next 40 years.
History
In 1953, London and the east coast of England were devastated by the North Sea Flood, which killed more than 300 people and caused an estimated £50m in damage (approximately £5bn in today’s money) in the region.
While, previously, the UK government had broadly taken a reactive approach to floods, progressively raising the walls and banks of the Thames river, this flood made it clear that such an approach was not sustainable.
In response, one of the first ever “rising sector gates” was built across a 520m-long stretch of the River Thames near Woolwich.
The Thames Barrier was designed by Charles Draper of the London-based Rendel, Palmer and Tritton architectural company, who took inspiration from a gas tap on his cooker. He built a working model in 1969, ahead of construction five years later. The barrier started being used in 1982.
On 8 May 1984, the Queen Elizabeth II officially opened the £535m (£2.4bn in today’s money) Thames Barrier, which remains the second-largest flood defence barrier in the world.
Operation
Now, 40 years on, the Thames Barrier continues to protect 1.4 million people and £321bn of property from tidal flooding.
The Thames Barrier includes 10 steel gates positioned across the width of the river that can be rotated to rise out of the water. Once raised, each 3,300-tonne main gate stands as high as a five-story building and is as wide as the opening of London’s iconic Tower Bridge.
Over the past four decades, it has been closed 221 times for flood defence purposes, including a particular spike in 2013-2014 when it was closed 50 times in 13 weeks.
Andy Batchelor, Thames tidal defences operations manager, who started work at the barrier the day the Queen opened it, said in a statement:
“Having witnessed and worked on the Thames Barrier’s opening, I am immensely proud of the protection it has provided London for the past 40 years and will continue to provide for years to come.
“Its reliability and effectiveness demonstrate the sophistication of its design by a very talented group of engineers and the continued maintenance and operation carried out by the barrier team.”
The next 40 years
The Thames Barrier was only designed to last until 2030. However, the EA, which operates and maintains the site, is confident it will continue to run until 2070.
However, sea levels are predicted to rise 1.5m by the end of the century, increasing the potential for a significant tidal flood. Additionally, with England becoming increasingly wet, the barrier is expected to be called on increasingly – about half of the closures to date have been for river flood protection.
If closing the barrier 50 times in a year becomes the norm, it could fail, the EA has warned, as this does not provide the necessary time for workers to maintain it.
As such, the agency is working on preparing for the next era of flood protection.
The agency is planning to work with partners to continuously review the best available options, including building a new barrier or developing more flood storage, and decide on an end-of-century option by 2040.
Meanwhile, from 2021-27, the government is set to invest £5.6bn in creating new flood and coastal defences to protect hundreds of thousands of properties.
Watch, read, listen
THE $9TN QUESTION: A “big read” in the Financial Times explored how governments worldwide are looking to foot the “immense” bill for the green transition.
BIG BRANDS GREEN CLAIMS: BBC Panorama looked at the “green claims” made by the world’s biggest brands, exposing serious flaws and side-effects of their reliance on carbon offsetting.
ASIAN HEATWAVES: On Himal South Asian’s podcast, environmental social scientist and Carbon Brief contributing editor Dr Chandni Singh discussed why the extreme heat facing the subcontinent this summer is unlike the “heat of the past”.
Coming up
- 13 May: Fourth phase of India’s election
- 14 May: International Energy Agency (IEA) conference on clean cooking in Africa, Paris, France
- 15-17 May: UN Environment Programme: Accelerating urban nature-based solutions: A Latin American-European collaboration, Barcelona, Spain
- 15 May-1 June: IEA-COP29 high-level dialogues, Paris, France
Pick of the jobs
- Carbon Brief, journalist internship | Salary: £13.50 per hour and £100 travel expenses. Location: London
- Conservation International, director of African natural climate solutions roadmap | Salary: Unknown. Location: Nairobi, Kenya
- UK Department of Energy Security and Net Zero, environmental manager | Salary: £69,485-£76,525. Location: Aberdeen, Birmingham, Cardiff, Darlington, Edinburgh or Salford
DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.
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The post DeBriefed 10 May 2024: 11 months of record heat; Climate scientists ‘hopeless and broken’; 40 years of the Thames Barrier 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