More than three-quarters of prisons in England and Wales face a “high risk” of overheating during summer months over the next 15 years, according to government figures.
A freedom of information (FOI) request submitted by Carbon Brief reveals the internal assessments conducted by the Ministry of Justice (MoJ) to help prepare its facilities for rising temperatures due to human-caused climate change.
As well as overheating in summer, more than a third of the 122 prisons and young offenders institutions assessed face a high risk of flooding due to increased winter rainfall. This is based on a scenario in which global emissions fall faster in the next two decades than they are expected to under existing climate policies.
Prisoners have been identified in the UK and elsewhere as being particularly vulnerable to climate hazards. Unsuitable prison infrastructure and a general lack of resources mean they can be left facing uncomfortable and even dangerous conditions.
The analysis of 1,128 prisons, probation facilities, courts and offices managed by the MoJ across England and Wales is part of the climate adaptation strategy set out by the previous Conservative government.
The figures emerge amid reports that UK prisons are nearing full capacity and in poor condition after years of neglect. Experts tell Carbon Brief that preparing the nation’s aged, overcrowded prison estate for climate change will be a major challenge for the new Labour government.
Vulnerable prisoners
Extreme heat and other weather events can be dangerous for anyone, but some populations are particularly vulnerable.
Civil society groups and researchers have stressed that prisoners – who are often confined in close proximity to each other, unable to move to cooler areas or find other ways to cool down – make up one of these populations.
A 2017 report by HM Inspectorate of Prisons found evidence of UK prisoners being exposed to high temperatures in summer months with poor ventilation. Citing this report, government advisors at the Climate Change Committee (CCC) noted in a July 2022 report that “inmates in prisons have little capacity to adapt to increased indoor temperatures”.
In the summer of 2022, when the UK recorded a temperature of more than 40C for the first time, reports emerged of prisoners overheating in cells like “ovens” without the means to cool down.
The MoJ set out its first climate adaptation strategy in 2020, under then prime minister Boris Johnson. Responding to recommendations by the CCC, it identified “key priorities” that needed to be addressed in prisons and other MoJ buildings, including dealing with flooding and overheating.
One of these priorities was to use a set of UK-specific climate analysis tools produced by the UK Met Office – called the UK Climate Projections 2018 (UKCP18) – to assess the risk posed by high temperatures and floods as global temperatures continue to rise. The strategy says these assessments should be used to inform adaptation plans at MoJ sites.
Carbon Brief submitted FOI requests to the MoJ between January and June 2024 seeking details of how it was progressing with its climate adaptation strategy. This included the outcomes of the climate risk assessments conducted for MoJ properties.
Heat and floods
The response to the FOIs reveal that the MoJ has assessed the climate risk facing 1,128 prisons, probation facilities, courts, offices and other buildings that it oversees across England and Wales. (The MoJ is not responsible for the smaller number of sites – including 20 prisons – in Scotland and Northern Ireland.)
For each site, UKCP18 was used to assess the risk of flooding from increased winter rainfall, increases in average annual temperatures, overheating from increased maximum summer temperatures and flooding and coastal erosion due to sea level rise.
The risk assessment scores used by the MoJ, from “negligible” to “very high”, are based on an internal system to “identify high-priority assets across the portfolio to focus further work”. According to the FOI results obtained by Carbon Brief, the scores rely on a combination of:
- Vulnerability of the site (which is established by combining asset sensitivity with exposure to the climate hazard).
- Evaluation of the impacts and consequences if the hazard were to occur.
- Qualitative risk assessment, based on the vulnerability, impacts and consequences.
Buildings might be judged as particularly “sensitive” to climate hazards based on, for example, their age or whether they have experienced such events before.
The MoJ’s UKCP18 analysis is based on modelling RCP2.6 50th percentile and RCP8.5 90th percentile climate scenarios, over the periods 2020-39 and 2040-59.
The RCPs, or “Representative Concentration Pathways”, describe different levels of greenhouse gases and other radiative forcings that might occur in the future. The “percentiles” refer to the likelihood of different levels of warming occurring at those emissions levels – with the 50th representing the “central estimate”, or median, produced by models and the 90th representing the highest 10% of results.
The RCP2.6 scenario involves the world meeting the Paris Agreement target of keeping the global temperature rise below 2C by the end of the century.
RCP8.5 is a scenario of very high emissions through the 21st century, meaning the global average temperatures rise by more than 4C. It is broadly not considered to be a likely outcome, due to the climate action already taking place in many nations.
At the same time, given that current pledges and policies are expected to result in around 2.7C of warming, achieving an RCP2.6 outcome would require a significant scale up in international climate action.
Nevertheless, out of the two scenarios used by the MoJ, it is closer to currently warming trajectories. It also indicates the scale of climate threats that could be facing UK prisons, even if the world limits warming to 2C.
Carbon Brief has used the risk assessment data from this “low-emissions” scenario to explore the conditions that prisoners in England and Wales will face in the coming years.
Prisons are not the only MoJ properties in England and Wales that are at risk as global temperatures rise.
Under low emissions, 76% of 406 courts across the two nations, and 25% of the 514 properties that are used by probation services to supervise offenders, face “high” or “very high” risk of overheating.
Compared to prisons, other MoJ facilities are relatively safe from flooding.
However, there is a significant increase in risk at these sites over the longer term. For example, the proportion of at-risk courts increases from 9% in 2020-39 to 43% by 2040-59 under the low-emissions scenario.
‘Critical’ adaptation
In an update to its climate adaptation strategy, published in April this year under the previous Conservative government, the MoJ states:
“It is critical that we adapt our sites and operations to the risks of the current and future climate. If our sites are closed or impacted by climate events, this has a direct impact on our ability to protect the public, reduce reoffending and deliver swift access to justice.”
Much of the evidence for prisoners suffering in the rising heat has come from the US, which is home to roughly a quarter of the world’s incarcerated population. Reports and lawsuits have described prisoners with no air conditioning being “cooked to death” in Texas and facing deadly heat exposure in outdoor cells in Georgia.
One study concluded that three-day summer heatwaves increased US prison mortality by 7%. The study’s lead author, environmental epidemiologist Dr Julie Skarha of Brown University, tells Carbon Brief that the experience of heat in prison is very different from the outside world:
“When it’s hot outside, moving to a shaded area, drinking extra water, taking a cold shower or going swimming, sitting in front of a fan, wearing looser clothing, or going to an air-conditioned room may not be options for people in prison. This can mean that even mild warm days can have dangerous health consequences inside prisons.”
Conditions in the UK are far less extreme than those in Texas. Nevertheless, the prison population is still vulnerable, especially amid a wider crisis in the nation’s prison system.
Around a quarter of the prison population in England and Wales live in buildings constructed in the Victorian era. A failure to carry out basic maintenance has meant more than 2,700 prison spaces out of roughly 90,000 in total have been lost due to dilapidation over the past five years.
Pia Sinha, chief executive of the Prison Reform Trust, tells Carbon Brief it is vital that the new Labour government acts to address the nation’s overcrowded and poor-quality prisons. She says:
“Despite promises by successive governments to build new, modern prisons and close those which are no longer fit for purpose, Victorian and pre-Victorian prisons remain in operation, and even those built more recently are not immune to similarly poor living conditions.”
Following the publication of its climate adaptation strategy, the previous government highlighted the vulnerability of prisons to climate hazards in its 2022 risk assessment. It then set out a work programme to reduce that risk in its third national adaptation programme (NAP3).
Much of this work is focused on undertaking research and piloting interventions, informed by the MoJ’s climate assessments and with a deadline of 2027. This includes research to understand overheating in English prisons and how it is affecting prisoners and staff.
Prof Dominique Moran, a University of Birmingham researcher who focuses on the geography of incarceration, tells Carbon Brief that with the UK prisons system facing a capacity crisis, it is not easy to make much-needed preparations for climate change:
“Pressure on the estate means that it’s very difficult to take establishments…out of use so that they can be retrofitted.”
Moreover, security concerns mean architectural features that could help reduce overheating – from windows that open to “brise-soleils” on external walls – are often avoided in prisons. Moran adds that governments often find it difficult to justify channelling resources into prisoners:
“It’s easy to make an argument that hospitals and schools need certain environmental improvements…[But] it’s conventionally thought to be more difficult to make that argument for prisons. It’s thought that the public doesn’t have the same appetite for investment in the prison estate.”
Under the previous government, the MoJ committed to expanding the prison estate with 20,000 “modern and innovative” new prison places by 2025. NAP3 says new prisons will be built with climate risks in mind, and in line with the MoJ’s building research establishment environmental assessment method (BREEAM) policy.
However, only a quarter of the new prison places promised were ultimately delivered by the Conservatives by the time they left office in July.
Nonetheless, the FOI results obtained by Carbon Brief highlight that within some of the recently opened prisons – such as the privately operated HMP Five Wells and HMP Fosse Way – “some natural ventilation” and windcatchers to prevent overheating have been used.
Research has highlighted the impact that improved environmental conditions can have in prisons beyond mitigating the impacts of climate change.
For example, there is evidence that access to green spaces can improve prisoner wellbeing, reduce violence and cut the number of sick days taken by staff. Moran tells Carbon Brief:
“I think there is a bigger piece of work around trying to explain more clearly what it is that prisons are for, and that the deprivation of liberty is itself the punishment. The punishment is not being accommodated in an environment which is difficult to live in and potentially overheated.”
Responding to the analysis, a government spokesperson tells Carbon Brief:
“The climate and nature crisis are the greatest long-term global challenge that we face as a nation and we will improve our climate resilience across government, including in our prisons.
“The MoJ published a climate change adaptation strategy in April that addresses climate impacts such as flooding and overheating. We will keep this under review and continue to research solutions to overheating across the justice estate.”