A record number of heat-related “emergencies” have been triggered by councils this year to help rough sleepers in England and Wales, Carbon Brief analysis reveals.
As climate change drives more heat extremes, there is a growing recognition that homeless people face a higher risk of illness and even death when temperatures soar.
This summer has been the hottest on record in the UK, with official warnings about heat-related health threats issued across every part of England and Wales.
The main tool councils have to help people sleeping rough during dangerously hot periods is the “severe weather emergency protocol” (SWEP).
Freedom-of-information (FOI) requests submitted by Carbon Brief to 93 local authorities across England and Wales with significant rough-sleeper populations reveal that SWEP use has surged this year.
Many councils have used the protocol to provide water, sunscreen and “cool spaces” for rough sleepers.
However, at least 20 councils said they have never triggered a SWEP during the summer months and others failed to provide any information when asked.
Dangerous heat
Climate change is increasing the severity of dangerously hot weather in the UK and these conditions harm certain groups more than others.
People sleeping rough are both more exposed to heat due to their living conditions and more likely to experience heat-related illness, due to underlying health conditions and other issues.
Councils shoulder much of the responsibility for helping homeless people in England – the part of the UK that faces the most extreme heat – as well as in Wales.
The main mechanism councils have to deal with weather extremes is the SWEP, which can involve giving emergency shelter to rough sleepers, among other things. There is no legal obligation to use SWEPs, meaning their implementation is not consistent or universal.
SWEPs have traditionally been a response to cold weather, but there has been growing awareness in the UK of the risk posed by heat, particularly since the extreme temperatures of summer 2022.
Charities and researchers have highlighted this issue and argued for hot-weather use of SWEPs as a necessary precaution to protect rough sleepers during heatwaves. In 2023, the UK government issued its first guidance for helping homeless people during hot weather.
Record SWEP
To investigate how local authorities are helping rough sleepers deal with heat extremes, Carbon Brief sent FOI requests to 90 councils in England and three in Wales.
This covers all areas with a sizable rough-sleeper population (see: Methodology). It also includes 33 London boroughs, which together are home to a quarter of the homeless population in England and Wales, plus the Greater London Authority.
Carbon Brief asked whether councils had been using SWEPs, how often and on which dates, during the summer months from 2022 to 2025.
This period saw the UK Health Security Agency (UKHSA) announce around 40 “heat-health alerts” across different parts of England, indicating temperatures that threaten public health.
The council FOI results reveal a surge in SWEP usage in 2025, as the UK faced its hottest ever summer. Just half way through summer in mid-July, councils had already collectively triggered SWEPs at least 149 times – up from 93 in the entirety of summer in 2024, as the chart below shows.
Not all SWEP activations are the same, with some councils using it for single days and others triggering it for longer stretches.
Nevertheless, roughly the same trend emerges when looking at the total number of days that councils have activated SWEPs since 2022. By mid-July, 2025 had already seen the longest period of SWEP activation, as the chart below shows.
The surge in SWEP activation mirrors both the record UK heat in 2025 and the growing salience of this issue, with more councils making use of it during the summer months. By July, 48 councils had triggered heat-related use of SWEPs this year, compared to just 36 two years earlier.
The increase may also reflect the numbers of people sleeping rough, which have surged in England over this time period, while remaining relatively steady in Wales.
‘Inadequate’ assistance
Previous analysis in 2023 by the Museum of Homelessness, a London-based organisation that researches homelessness, concluded that SWEPs were “inconsistently applied” and “inadequate”. It highlighted particular shortcomings in heat-related use of SWEPs.
Despite the surge in SWEP use this year, the data provided to Carbon Brief suggests that some councils are still not responding urgently to periods of extreme heat.
Of the 93 councils that Carbon Brief requested data from, 59 – or 63% – confirmed that they had activated SWEPs at least once during the summer months between 2022 and 2025, as shown in the figure below.
Common provisions resulting from this activation included the distribution of sunscreen, bottles of water and sun hats, as well as making “cool spaces” available and providing extra welfare checks. Most councils did not mention providing emergency accommodation.
Among the remainder, 14 councils either did not hold the data requested or never responded.
This leaves 20 councils that stated they did not trigger SWEPs at all during summers over this period, including those in Manchester, Nottingham and Cornwall.
All of the regions covered by these local authorities were issued with heat-health alerts in 2025.
Some of these councils said they were mindful of hot weather and mentioned other actions taken during these periods, some of which overlapped with SWEP responses.
Other councils, including Plymouth, Hastings and the London boroughs of Waltham Forest and Barking and Dagenham, did not mention any provisions for rough sleepers during periods of extreme heat.
Matthew Turtle, co-director of the Museum of Homelessness, tells Carbon Brief:
“These findings, like our own research, show that many councils opt not to help people who need it the most when there is extreme weather…This is not just smaller councils, but includes major towns and cities across the UK, who simply have no emergency protocol in place to protect people who are homeless during spells of extreme weather.”
Turtle argues that the use of SWEP should be made a legal duty in order to guarantee protection from extreme weather for those sleeping rough.
Researchers have argued that extreme heat should be taken more seriously by authorities when dealing with rough sleepers, with one study finding that homeless people in London were 35% more likely to be hospitalised at 25C compared to 6C. The authors suggest this is because people are better prepared for the threat of cold weather.
Dr Becky Ward, a researcher at the University of Southampton who is investigating how climate change interacts with homelessness, tells Carbon Brief that “the conversation is changing and awareness is building” about this issue. She adds:
“There’s a more fundamental need to improve the provision of shelter for people experiencing homelessness, alongside providing psychological support to address the causes and maintaining factors for people who are rough sleeping.”
Methodology
Carbon Brief obtained the list of 93 local authorities with significant rough-sleeping populations in England and Wales from the Museum of Homelessness. The criteria for this included being in one of the top 50 most populated cities in the UK, having a rough sleeping count of at least 15 people and/or being a London borough. These councils make up 28% of the 317 local authorities in England and 14% of those in Wales.
FOI requests were sent to these councils, asking for details of when SWEPs were activated and for how long over the summers of 2022-2025, as well as information about what activities this involved. (These requests were sent in mid-July, meaning data for 2025 is only for half the summer period.)
Carbon Brief asked for SWEP activations between June and September, mirroring the timescale used by the UKHSA and the Met Office for their heat-health alert service.
The results demonstrate the ad-hoc nature of SWEP use, with different councils using it in different ways and some relying on third-party organisations to coordinate their responses. Nevertheless, the combined results capture overall trends.
Some 20 councils said they did not record SWEP activations, or only kept partial records. Another five never responded to Carbon Brief’s FOI request.
In this article, Carbon Brief has used the term “rough sleeper” when referring to people sleeping outside or in other spaces not designed for people to stay. When referring to studies or datasets that cover the wider homeless population, the term “homeless” has been used.
The post Revealed: Use of heat ‘emergencies’ for rough sleepers hits record in England and Wales appeared first on Carbon Brief.
Revealed: Use of heat ‘emergencies’ for rough sleepers hits record in England and Wales
The head of the United Nations has launched an initiative aimed at holding artificial intelligence companies accountable for their exploding environmental impacts, including their carbon emissions, the amount of water and land used for data centres, and the energy they consume.
During a speech at London Climate Action Week on Tuesday, António Guterres noted that AI can accelerate climate solutions, among other key challenges, and said its potential must be harnessed.
“But AI is also hungry for land, water and power,” he emphasised, adding that the data centres needed to run AI models already consume more electricity than most countries.
The UN Secretary-General repeated a call he first made in July 2025 for all big AI companies to commit to power every data centre with renewable energy by 2030.
Some tech firms have announced they are sourcing or building out clean energy to run their hubs, but growing power demand is also contributing to gas-fired generation in the US, according to data from Global Energy Monitor.
The International Energy Agency (IEA) estimates that data centres are set to more than double the emissions from the electricity they use between 2024 and 2030 in a high-growth scenario. But AI’s use could lead to far larger reductions in the energy sector through efficiency gains if adopted widely.
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‘No more hidden costs’
Proposing the new “AI Environmental Transparency Initiative” on Tuesday, Guterres also urged big AI firms companies to measure and publicly disclose the full environmental impact of their systems, including their carbon, water, and land footprints.
“No more hidden costs. No more shifting the burden onto those least able to bear it. It is time to come clean,” he said in a major speech on responding to the world’s twin climate and energy crises. “If AI is to help build a better future, it must be honest about what it costs us now.”
A report issued earlier this month by the UN University Institute for Water, Environment and Health noted that most current assessments of AI’s environmental cost focus on carbon emissions from training models. But, it added, this misses a substantial part of the picture.
Every kilowatt-hour of electricity for AI also carries a water footprint, from cooling and generation, and a land footprint, from infrastructure and supply chains, it said.
Explainer: Will AI data centres make or break the energy transition?
The report estimated that AI data centres globally could consume 945 terawatt-hours of electricity annually by 2030 – more power than all but five countries and roughly twice France’s 2025 consumption.
Offsetting this carbon footprint by 2030 would require growing some 6.7 billion trees over 10 years, it calculated. Producing power for the data centres would consume water equal to the basic needs of 1.3 billion people in sub-Saharan Africa for a year and take up land of more than 14,500 square kilometers, roughly twice the Jakarta metropolitan area.
The European Union said earlier this month it will develop minimum energy-efficiency standards for both new and existing data centres, with a “needs assessment” due by 2027, Reuters reported. It’s also planning a sustainability label for data centres, covering criteria including water use and clean energy supply – but that has been delayed.
US community push-back
Asked after his speech what the response had been, the UN chief said “we’ll see”, without giving more details.
But, he argued that, in his view, the push for transparency “is perfectly reasonable and even positive for the AI industry, because eventually some people will say that they consume much more than they really do”. “I think the truth is essential,” he added.
Concerns about the environmental impacts of AI and the infrastructure needed to run the technology have led to growing opposition in some communities, especially in the US.
This month, Monterey Park in Los Angeles County was the first city in the United States to enact a citywide prohibition on data centres through a voter-approved ballot measure. The developers behind a proposed centre in the area had already pulled the project in April amid an increasingly hostile local environment and regulatory uncertainty.
The vote that stopped a data center: US communities query resource-hungry AI
According to nonprofit Data Center Watch, around $64 billion-worth of data centre projects nationwide were delayed or blocked between May 2024 and March 2025 as communities pushed back against them.
Industry lobby groups argue that data centres can provide economic benefits in their host communities. According to the US-based Data Center Coalition, which represents big operators and developers, data centres generate tax revenue, support construction and technical jobs, and provide infrastructure needed for cloud computing, scientific research and AI development.
The industry has also challenged claims that data centers necessarily raise electricity costs for households.
Force for good?
The UN chief said benefits can be few in the places that are home to the data centre, while “communities are often left in the dark about the environmental impact of the infrastructure rising around them”.
Guterres said companies have an “obligation” to be clear and open about the services they are offering but also the level of resources they require.
“Transparency is essential for the decisions that communities must make – and transparency is essential even for the future of artificial intelligence, and to make sure that artificial intelligence is essentially a force for good,” he told an audience of climate professionals in London
A senior UN official told journalists ahead of Tuesday’s announcement that the AI industry has started to talk about and disclose some of their impacts, but those efforts are not yet comprehensive enough.
The hope is that the new initiative will “encourage the industry to come together and take further action on it”, the official said.
The post UN asks AI companies to reveal full environmental impacts appeared first on Climate Home News.
Phillipe Ciais has spent almost four decades researching the planet’s carbon cycle – and the ways in which humans have been impacting its balance.
Based at the Laboratoire des Sciences du Climat et de l’Environnement (LSCE) on the outskirts of Paris, Ciais (pronounced “see-es”) has been listed as an author on more than 1,300 peer-reviewed studies.
In fact, analysis of Carbon Brief’s Cosmos database reveals that – by some distance – he is the most highly cited climate scientist in the world.
In a wide-ranging interview, he discusses:
The post Prof Philippe Ciais: The world’s most highly cited climate scientist appeared first on Carbon Brief.
https://www.carbonbrief.org/prof-philippe-ciais-the-worlds-most-highly-cited-climate-scientist/
Climate Change
Cited 23 June 2026: Project Cosmos launch | Science ‘under attack’ at Bonn | Emissions inequality
Welcome to Cited, your essential guide to new climate research.
In the news
SCIENCE ‘UNDER ATTACK’: Climate Home News reported that “dozens” of countries called out “coordinated attacks” aimed at “undermining the role of climate science” at UN climate talks in Bonn, Germany, last week. According to the outlet, the countries said that UN decision-making had to remain based on the “best available science”, including the reports of the Intergovernmental Panel on Climate Change. One negotiator said that India and Saudi Arabia “opposed calls in draft texts to encourage scientific work on scenarios that would minimise the magnitude and duration of any overshoot of 1.5C”, the article noted. For more, read Carbon Brief’s summary of the negotiations.
REPORT OPPOSITION: “Oil industry allies” in the US are targeting a report on extreme weather attribution, due to be published by the National Academies of Sciences, Engineering and Medicine, according to Politico. The outlet reported that the “heightened scrutiny – which involves a secretive opposition research group scouring scientists’ emails – has prompted two people to leave the 15-person panel tasked with producing the report”. Separately, the Guardian reported that the Trump administration has “reversed its decision” to dismantle the Ocean Observatories Initiative, a $368m deep-sea observation system.
SUPER EL NIÑO: BBC News reported that the US National Oceanic and Atmospheric Administration announced that El Niño had “officially begun”. Forecasts suggest the event could be among the “strongest ever recorded”, it added. Meanwhile, a “vigorous debate” is taking place about whether climate change is making the El Niño phenomenon more intense, according to the New York Times. The outlet explained that some scientists see the run of “comparatively strong” El Niño events in recent decades as an indication that “climate change is supercharging El Niño”. However, it added that “others say there is no clear evidence to support that theory”.
Research picks
Water
- Global sea level rise has nearly tripled the number of days since the 1970s when coastal water levels have surpassed average tide gauge readings | Science Advances
- As the Arctic warms, increased iceberg activity could “reshape” deep-sea habitats and “elevate” navigational hazards as maritime traffic expands | Nature
- Sea level rise has quadrupled the frequency of extreme coastal sea-level events since the year 1900 | Nature Climate Change
Inequality
- The top 10% of consumers are responsible for $1.7-5.7tn of environmental damage each year, surpassing international climate and biodiversity financing gaps | Communications Sustainability
- Calculating an individual’s emissions based on their asset ownership suggests that wealthier people are responsible for an even higher share of global greenhouse gas emissions than indicated by past studies | Nature Climate Change
- A plan that places equity at the “centre” of climate adaptation efforts in cities is needed to address the “stark disparities” between “affluent” and “disadvantaged” urban communities’ ability to prepare for extreme heat | PLOS Climate
Extremes
- In the western US, 42% of burned area over 2001-24 occurred during, and immediately following, heatwaves | Science Advances
- “Hot-to-wet” whiplash events have become more frequent across Australia over the past century, with south-eastern Australia emerging as a hotspot | Journal of Climate
- Rapid urbanisation, combined with more intense rainfall from tropical cyclones, have increased people’s exposure to “extreme” rainfall from tropical cyclones across China | Journal of Hydrometeorology
Captured
One billion additional people face at least one day of “extreme heat stress” every year compared to the 1970s, according to research published in Nature Climate Change.
The chart shows changes in “strong” (top), “very strong” (middle) and “extreme” (bottom) heat stress, defined as a “universal thermal climate index” above 32C, 38C and 46C, respectively. The grey bar shows the percentage of the global population exposed to at least one, 30 or 90 days of heat stress in 1970. The light and dark blue bars show the number of additional people experiencing heat stress over 2015-24 due to population growth and rising global temperatures, respectively.
10%
Equivalent damage to the UK’s GDP caused by climate change if global warming reaches 4C by 2100, according to new research in Nature Climate Change. The study estimates a range of 2-20%.
Spotlight
Introducing: Project Cosmos
Carbon Brief explains how it built a major new database of climate science research and unveils a new ranking of the 500 most highly cited publications, authors and institutions in climate science.
This week, Carbon Brief launched Project Cosmos – the world’s largest and most complete database of climate change research.
The database features more than 1.8m academic papers, books and reports, capturing the vast body of human knowledge about climate change that has accumulated over more than a century of academic study.
The climate science “universe” is based on reports from the Intergovernmental Panel on Climate Change (IPCC), which are recognised as the world’s most authoritative summaries of the latest climate science.
Since its first report was published in 1990, humanity’s knowledge about human-caused climate change has ballooned. The IPCC has published six sets of reports in total – each one longer than the last.
In total, IPCC reports reference more than 100,000 other papers, books and reports. This is the core of our climate science universe. Carbon Brief then built on this core, by looking at four other sources of data. Read more about how the Cosmos database was created here.
Every single publication in the Cosmos database is linked to at least one other through references. Visualising these links reveals a “galaxy” of references. In the image above, each colour and cluster reveals different topics and densities of research. Explore the galaxy in an interactive map here.
Cosmos 500
As part of an initial wave of preliminary analysis to demonstrate the scope of the Project Cosmos database, Carbon Brief has ranked the 500 most highly cited publications, authors and institutions in the database.
The most highly cited climate scientist is Prof Philippe Ciais, who has spent almost four decades researching the planet’s carbon cycle – and the ways in which humans have been impacting its balance. Carbon Brief recently interviewed Ciais in Paris.
The US tops the tables for the most highly-cited authors and institutions. Almost half of the 500 most highly-cited authors are from US institutions. This raises particular concerns for the future of climate science, as American climate scientists and institutions are coming under attack under the Trump administration.
Experts from global south countries account for only 4% of all authors in the Cosmos 500. China stands out as the most highly-cited global south country. Meanwhile, only 10% of authors in the Cosmos 500 are women.
There are many possibilities for future avenues of research using the Cosmos database. Over time, the database could be used to reveal, for example, how interest in different areas of climate science has changed over time, plus identify potential knowledge gaps and, thus, opportunities for future research.
Carbon Brief invites researchers – including academics, journalists and analysts – to submit their own proposals for co-authored studies, literature reviews and analytical projects.
Preprints to watch
Carbon Brief’s pick of new papers still going through peer review
- Regional reductions in aerosol emissions can “temporarily amplify” the likelihood of record-breaking heat events | Environmental Research: Climate
- Analysis of Reddit posts suggests the Fridays for Future movement has created “wider awareness” of global warming by drawing attention to climate change and “climate actions” | npj climate action
- Periods of simultaneous low wind and solar power generation, known as “renewable energy droughts”, will “intensify progressively” as the planet warms | Nature portfolio
Noticeboard
- 28-30 June: Seventh global conference on climate and sustainable development goal synergies, Bangkok, Thailand
- 29 June-1 July: Exeter climate conference, Exeter, UK
- 29 June-1 July: National Academy of Sciences hybrid workshop on seabed critical mineral resources, Irvine, US
- 30 June: Submission deadline for abstracts for MedCLIVAR conference, scheduled for 21-25 September in Limassol, Cyprus
- 30 June: Application deadline for postdoctoral position in ice-ocean interactions at the Physics Laboratory of Ecole Normale Supérieure de Lyon | Salary: €3,071-4,714 per month. Location: Lyon, France
- 30 June: Submissions open for abstracts for the pan-African conference on environment, climate change and health, scheduled for 21-24 October in Nairobi, Kenya
- 8 July: Application deadline for position as research officer in climate science and law at the Grantham Research Institute | Salary: £43,277-51,714. Location: London, UK
- 10 July: Application deadline for position as associate or senior editor at Nature Water | Salary: Unknown. Location: Shanghai, Beijing or Milan
Cited is researched and written by Cecilia Keating, Robert McSweeney, Ayesha Tandon, Daisy Dunne and Dr Giuliana Viglione.
Please send tips, feedback and upcoming climate research to cited@carbonbrief.org
This is an online version of Carbon Brief’s fortnightly Cited email newsletter. Subscribe for free here.
The post Cited 23 June 2026: Project Cosmos launch | Science ‘under attack’ at Bonn | Emissions inequality appeared first on Carbon Brief.
Cited 23 June 2026: Project Cosmos launch | Science ‘under attack’ at Bonn | Emissions inequality
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