The highest court of the UN has issued a landmark “advisory opinion” stating that nations can be held legally accountable for their greenhouse-gas emissions.
Recognising the “urgent and existential threat” facing the world, the International Court of Justice (ICJ) concluded that those harmed by human-caused climate change are entitled to “reparations”.
Their opinion largely rests on the application of existing international law, clarifying that climate “harms” can be clearly linked to major emitters and fossil-fuel producers.
The case, which was triggered by a group of Pacific island students and championed by the government of Vanuatu, saw unprecedented levels of input from nations.
In a unanimous decision issued on 23 July, the 15 judges on the ICJ concluded that the production and consumption of fossil fuels “may constitute an internationally wrongful act attributable to that state”.
The opinion also says that limiting global warming to 1.5C should be considered the “primary temperature goal” for nations and, to achieve it, they are obliged to make “adequate contributions”.
While the ICJ opinion is not binding for governments, it is expected to have a significant impact as vulnerable groups and nations fight for climate compensation in court.
Below, Carbon Brief explains the most important aspects of the ICJ’s 133-page advisory opinion and speaks to legal experts about its implications.
- How did this case come about?
- How has the case been decided?
- What does the ICJ say about climate science?
- What does the ICJ say about countries’ climate obligations?
- What does it say about the legal consequences of breaches?
- What does it say about historical responsibility and reparations?
- What does it say about the Paris Agreement and 1.5C?
- What does it say about fossil fuels?
How did this case come about?
The case stems from a campaign led by 27 students from the University of the South Pacific in Fiji.
In 2019, they established a youth-led grassroots organisation – dubbed the Pacific Island Students Fighting Climate Change (PISFCC) – and began efforts to persuade the leaders of the Pacific Islands Forum to take the issue of climate change to the world’s top court.
PISFCC joined forces with other youth organisations from around the world in 2020, lobbying state representatives to take action.
In 2021, the government of Vanuatu announced that it would lead efforts to gain an “advisory opinion” from the ICJ. It worked to engage with the Pacific island community first, to build a “coalition of like-minded vulnerable countries”, reported Climate Home News.
Following on from this work, Vanuatu received a unanimous endorsement for its efforts from the 18 members of the Pacific Island Forum. It continued to work diplomatically, engaging in discussions across Europe, Asia, Africa and Latin America to encourage other countries to join the effort.
After three rounds of consultations with other states, the resolution was put before the UN general assembly with the backing of 105 sponsor countries.
Finally, on 29 March 2023, the assembly unanimously adopted the resolution formally requesting an “advisory opinion” from the ICJ.
The resolution posed two questions for the ICJ. In answering these questions, it asked the court to have “particular regard” to a range of laws and principles, including the UN climate regime and the universal declaration on human rights.
First, the resolution asked what are the legal obligations of states under international law to “ensure the protection of the climate system”.
Second, it asked what are the legal consequences flowing from these obligations if states, by their “acts or omissions”, have caused “significant harm to the climate”.
The resolution asked for the court to consider, in particular, states that are “specially affected” or are “particularly vulnerable” to the impacts of climate change.
It also pointed to “peoples and individuals of the present and future generations affected by the adverse effects of climate change”.
Therefore, the advisory opinion issued this week by the ICJ, in response to these questions, is the culmination of a years-long process.
Although the opinion is not binding on states, it is binding on UN bodies and is likely to have far-reaching legal and political consequences at a national level.
How has the case been decided?
The ICJ was tasked with interpreting international law and arriving at an advisory opinion. While its legal advice will, therefore, not be binding for nations, it will be binding for other UN bodies.
This two-year process involved the judges defining the scope and meaning of the broad questions put to them by the UN general assembly. (See: How did the case come about?)
They then considered which international laws and principles were relevant for these questions.
Among the relevant laws identified were the three UN climate change treaties – the UNFCCC, the Kyoto Protocol and the Paris Agreement.
They also considered various other treaties covering biodiversity, ozone depletion, desertification and the oceans, as well as legal principles such as the principle of “prevention of significant harm to the environment”.
The ICJ’s process has also seen nations and international groups, such as the Organisation of the Petroleum Exporting Countries (Opec), offer their views on the case.
These groups had the opportunity to feed into the judges’ deliberations over several stages, including two sets of written submissions, followed by oral statements to the court.
In total, the court received 91 written statements, a further 107 oral statements – delivered at the Hague in December 2024 – and 65 responses to follow-up questions by the judges.
This is the “highest level of participation in a proceeding” in the court’s history, according to the ICJ. Some nations, including island states such as Barbados and Micronesia, appeared before the court for the first time ever.
These contributions demonstrated broad agreement among nations that climate change is a threat and that emissions should be cut in order to meet the objectives of the Paris Agreement.
But there were major divergences on the breadth and nature of obligations under international law to act to limit global warming, as well as on the consequences of any breaches, as specifically being addressed by the ICJ.
Overall, the main divisions were between high-emitting nations trying to limit their climate obligations and low-emitting, climate-vulnerable nations, who were pushing for broader legal obligations and stricter accountability for any breaches.
Specifically, “emerging” economies such as China and Saudi Arabia, along with historical high-emitters such as the UK and EU, argued that climate obligations under international law should be defined solely by reference to the UN climate regime.
In contrast, vulnerable nations said that wider international law should also apply, bringing additional obligations to act – and the potential for legal consequences, including reparations.
This is a departure from UN climate talks, where the main divide tends to be between “developed” and “developing” countries – with the latter encompassing both high- and low-emitting nations.
In an unusual move, the ICJ judges also organised a private meeting in November 2024 with scientists representing the Intergovernmental Panel on Climate Change (IPCC).
Among those present were IPCC chair Prof Jim Skea and eight other climate scientists from various countries and with different areas of expertise.
A statement issued by the ICJ said this was an effort to “enhance the court’s understanding of the key scientific findings which the IPCC has delivered”.
On 23 July 2025, after some seven months of deliberation, the ICJ issued a unanimous opinion in response to the UN general assembly’s request.
This is only the fifth time the court has delivered a unanimous result, according to the ICJ, after nearly 88 years in operation and 29 opinions.
(In addition to the unanimous opinion of the full court, several of the ICJ judges also issued their own declarations and opinions, individually or in small groups.)
What does the ICJ say about climate science?
When considering the “context” for the issuing of the advisory opinion on climate change, the court provides information on the “relevant scientific background”.
This was drawn from reports by the IPCC, which the court says “constitute the best available science on the causes, nature and consequences of climate change”.
It comes after ICJ judges held a private meeting with IPCC scientists in 2024. (See: How has the case been decided?)
The advisory opinion states that it is “scientifically established that the climate system has undergone widespread and rapid changes”, continuing:
“While certain greenhouse gases [GHGs] occur naturally, it is scientifically established that the increase in concentration of GHGs in the atmosphere is primarily due to human activities, whether as a result of GHG emissions, including by the burning of fossil fuels, or as a result of the weakening or destruction of carbon reservoirs and sinks, such as forests and the ocean, which store or remove GHGs from the atmosphere.”
It continues that the “consequences of climate change are severe and far-reaching”, listing impacts including the “melting of ice sheets and glaciers, leading to sea level rise”, “more frequent and intense” extreme weather events and the “irreversible loss of biodiversity”. The document adds:
“These consequences underscore the urgent and existential threat posed by climate change.”
The advisory opinion further adds that the “IPCC notes that adaptation measures are still insufficient” and that “limits to adaptation have been reached in some ecosystems and regions”.
On the need to address rising emissions, the document quotes the IPCC directly, saying:
“According to the panel, climate change is a threat to ‘human well-being and planetary health’ and there is a ‘rapidly closing window of opportunity to secure a liveable and sustainable future for all’ (very high confidence). It adds that the choices and actions implemented between 2020 and 2030 ‘will have impacts now and for thousands of years’.”
It adds that the “IPCC has also concluded with ‘very high confidence’ that risks and projected adverse impacts and related loss and damage from climate change will escalate with every increment of global warming”.
In regards to how states should consider climate science when implementing climate policies and measures, the court says that countries should exercise the “precautionary principle”, adding:
“The court observes that where there are threats of serious or irreversible damage, lack of full scientific certainty should not be used as a reason for postponing cost-effective measures to prevent environmental degradation.”
What does the ICJ say about countries’ climate obligations?
In response to the first question on legal obligations, the ICJ says that countries have “binding obligations to ensure protection of the climate system” under the UN climate treaties.
However, the court’s unanimous opinion flatly rejects the argument, put forward by high emitters, such as the US, UK and China, that these treaties are the end of the matter.
These nations had argued that the climate treaties formed a “lex specialis”, a specific area of law that precludes the application of broader general international law principles.
On the contrary, the ICJ says countries do have legal obligations under general international law, including a duty to prevent “significant harm to the environment”, with further obligations arising under human rights law and from other treaties.
As such, the court, “essentially sided with the global south and small island developing states”, says Prof Jorge Viñuales, Harold Samuel professor of law and environmental policy at the University of Cambridge.
Moreover, the court finds that countries’ obligations extend not only to greenhouse gas emissions, but also to fossil-fuel production and subsidies, says Viñuales, who acted for Vanuatu in the case.
Speaking to Carbon Brief in a personal capacity, he says: “That is important because major producers are not necessarily major emitters and vice-versa.”
In terms of the UN climate treaties, such as the Paris Agreement, the court affirms that these give countries binding obligations including adopting measures to mitigate greenhouse gas emissions and adapt to climate change.
Developed countries – parties listed under Annex I of the UNFCCC – have “additional obligations to take the lead in combating climate change”, the ICJ notes.
States also have a “duty” to cooperate with each other in order to achieve the objectives of the UNFCCC, acting in “good faith” to prevent harm, it adds.
Beyond the climate treaties, it says that “states have a duty to prevent significant harm to the environment”. Therefore, they must act with “due diligence” and use “all means at their disposal” to prevent activities carried out within their jurisdiction or control from causing “significant harm” to the climate system.
The court sets out the “appropriate measures” that would demonstrate due diligence, including “regulatory mechanisms…designed to achieve deep, rapid and sustained reductions” in emissions. This repeats language from the IPCC, but attaches it to countries’ legal obligations.
As with action under the climate treaties, countries’ obligations under broader international law should be taken in accordance with the principle of “common but differentiated responsibilities” it adds, a point reaffirmed throughout the advisory opinion.
Furthermore, countries have obligations to act on climate under a raft of other international agreements, covering the ozone layer, biological diversity, desertification and the UN convention on the law of the sea, the ICJ notes.
The court affirms that states that are not party to UN climate treaties must still meet their equivalent obligations under customary international law. This “addresses the unique situation of the US, but without naming it”, notes Sébastien Duyck, a senior attorney at the Center for International Environmental Law, on Bluesky.
Following his re-election last year, US president Donald Trump signed an order to pull the country out of the Paris Agreement again. As such, there is a question around how the ICJ’s opinion might apply to the US – the country that has contributed more to human-caused climate change than any other nation.
Additionally, states have obligations under international human rights law to “respect and ensure the effective enjoyment of human rights by taking necessary measures to protect the climate system and other parts of the environment”, according to the ICJ.
This follows a ruling from the European Court of Human Rights (ECHR) in 2024 that found that the Swiss government’s climate policies violated human rights, as governments are obliged to protect citizens from the “serious adverse effects” of climate change.
Announcing the opinion to the Hague, judge Iwasawa Yuji, president of the court, said:
“The human right to a clean, healthy and sustainable environment is essential for the enjoyment of other human rights.”
What does it say about the legal consequences of breaches?
The second part of the advisory opinion deals with the “legal consequences” of countries causing “significant harm to the climate system and other parts of the environment”.
This refers to nations breaching their “obligations”, as defined in the first part of the opinion. (See: What does the ICJ say about countries’ climate obligations?)
Crucially, the court says that countries can, in principle, face liability for climate harms, opening the door to potential “reparations” for loss and damage. Prof Viñuales tells Carbon Brief:
“Perhaps the main take away from the opinion is that the court recognised the principle of liability for climate harm, as actionable under the existing rules.”
Prof Viñuales notes that the court says “climate justice is governed by the general international law of state responsibility, which provides solutions for the recurrent arguments levelled to escape liability for climate harm”.
Essentially, the ICJ rejects the notion that it is too difficult to hold countries accountable for climate damages.
Examples of breached obligations given by the court include failing to set out or implement climate pledges – known as nationally determined contributions (NDCs) – under the Paris Agreement, or to sufficiently “regulate emissions of greenhouse gases”.
The ICJ stresses that it is not responsible for pointing fingers at particular countries, only for issuing a “general legal framework” that countries can follow.
As part of this process, it lays out a justification for why states can be held responsible for climate change.
During the ICJ process, some countries argued that greenhouse gas emissions are not like other environmental damage, such as localised chemical pollution. They said that emissions arise from all sorts of regular activities and it is difficult to tie climate damage to specific sources.
Others argued that it is perfectly possible to attribute such damage to states that, for example, have laws to “promote fossil-fuel production and consumption”.
This is important, as the ICJ points out that attribution is necessary if an activity is to be defined as an “internationally wrongful act”. Ultimately, the court agrees that it is feasible to attribute climate damage to specific states, on a “case-by-case” basis.
The court also finds that it is possible, at least in principle, to link climate disasters to countries’ emissions, though it notes that the causal links may be “more tenuous” than for localised pollution. It cites IPCC findings that climate change has amplified heatwaves, flooding and drought, stating:
“While the causal link between the wrongful actions or omissions of a state and the harm arising from climate change is more tenuous than in the case of local sources of pollution, this does not mean that the identification of a causal link is impossible.”
With this established, the court sets out what the consequences could be for countries that are deemed to have carried out “wrongful acts”.
First, the ICJ stresses that nations must meet their existing climate obligations. This means that if, for example, a government publishes an “inadequate” NDC, a “competent court or tribunal” could order it to supply one that is consistent with its obligations under the Paris Agreement.
Second, it also says that if a state is found responsible for climate damage, it must stop and ensure that it does not happen again.
States may be required to “employ all means at their disposal” to carry out this duty, according to the ICJ. In practice, the court says that this could mean governments revoking administrative or legislative acts in order to cut emissions.
In theory, this could lead to more stringent climate policies. For example, Dr Maria Antonia Tigre, director of global climate change litigation at the Sabin Centre for Climate Change Law, tells Carbon Brief:
“The ICJ made clear that the standard of due diligence is stringent and that each state must do its utmost to submit NDCs reflecting its highest possible ambition. That may strengthen pressure – political, legal and public – on states to raise their climate targets, especially before the next global stocktake.”
Finally, the ICJ opens the door for countries to seek “reparations” for climate harms from other countries.
It says these reparations could be expressed in different ways – including paying compensation or issuing formal apologies for wrongdoing.
This outcome was widely celebrated by climate justice activists and vulnerable nations, who see it as ushering in a “new era” in the fight to obtain financial compensation for climate disasters.
Harj Narulla, a barrister at Doughty Street Chambers and legal counsel for the Solomon Islands, tells Carbon Brief:
“The ICJ’s ruling has provided a legal pathway for developing states to seek climate reparations from developed States…States can bring claims for compensation or restitution for all climate-related damage. This includes claims for loss and damage, but importantly extends to any harm suffered as a result of climate change.”
What does it say about historical responsibility and reparations?
One of the most significant parts of the ICJ opinion is the assertion that nations and “injured individuals” can seek “reparations” for climate damage.
This ties in with a long and contentious history of climate-vulnerable nations in the global south seeking compensation from high-emitting nations.
The notion of “climate reparations” has often been linked to developing countries pushing for so-called “loss and damage” finance in UN climate negotiations, including the – ultimately successful – fight for a “loss-and-damage fund”.
However, the US and other big historical emitters have ensured that any progress on loss-and-damage funding has not left them legally accountable for their past emissions.
The Paris Agreement states explicitly that its inclusion of loss and damage “does not involve or provide a basis for any liability or compensation”.
Crucially, the ICJ opinion makes it clear that such language does not override international law and states’ responsibilities to provide “restitution”, “compensation” and “satisfaction” to those harmed by climate change.
Danilo Garrido Alves, a legal counsel for Greenpeace International, tells Carbon Brief that this means loss-and-damage finance is not a replacement for reparations:
“If a state contributes to the loss and damage fund and at the same time breaches obligations…that does not mean they are off the hook.”
Legal experts, including Prof Viñuales, tell Carbon Brief that this outcome is not surprising, given its grounding in international law. He says:
“It is the correct understanding of international law, but, in law, progress often takes the form of moving from the implicit to the explicit and that’s what the court did.”
Nevertheless, the outcome could have major implications for climate politics and lead to a wave of new climate litigation. Dr Tigre, at the Sabin Centre for Climate Change Law, tells Carbon Brief:
“[It] could shift the conversation from voluntary climate finance to legal obligations to repair harm, particularly for vulnerable communities and states already suffering loss and damage.”
Notably, the court says that while some states are “particularly vulnerable” to climate change, international law “does not differ” depending on such status. This means that, in principle, all nations are “entitled to the same remedies”.
As for individuals or groups taking legal action for both “present and future generations”, the ICJ notes that their ability to do so does not depend on rules around “state responsibility”. Instead, they would depend on obligations being breached under “specific treaties and other legal instruments”.
The ICJ says that reparations would be determined on a case-by-case basis, noting that the “appropriate nature and quantum of reparations…depends on the circumstances”. It also notes that:
“In the climate change context, reparations in the form of compensation may be difficult to calculate, as there is usually a degree of uncertainty.”
The question of precisely which nations will be liable for paying climate reparations is also predictably complex. Much of this discussion centres around responsibility for emissions, both currently and in the past.
Under the Paris Agreement, “developed” countries – a handful of nations in the global north – are obliged to provide climate finance to “developing” countries, which includes major emitters such as China.
In ICJ submissions, major emitters and fossil-fuel producers categorised as “developing” under the UN system stressed their low historical emissions. Some developing countries blamed climate change on a small group of “developed states of the global north”.
For their part, some countries with high historical emissions argued that it is difficult to assign responsibility for climate change.
However, the ICJ concludes that this is not the case. It says it is “scientifically possible” to determine each state’s contribution, accounting for “both historical and current emissions”.
Therefore, while the court explicitly avoids identifying the countries responsible for paying reparations, it makes clear that historical responsibility should be accounted for when considering whether states have met their climate obligations.
Finally, the court also says that “the status of a state as developed or developing is not static” and that it depends on the “current circumstances of the state concerned”.
This is notable, given that the current definitions of these terms – which determine who gives and receives climate finance – are based on definitions from the early 1990s.
What does it say about the Paris Agreement and 1.5C?
The advisory opinion offers clear guidance on the Paris Agreement and its aim to limit global temperature rise to “well-below” 2C by 2100, with an aspiration to keep warming below 1.5C.
It says that limiting temperature increase to 1.5C should be considered countries’ “primary temperature goal”, based on the court’s interpretation of the Paris Agreement.
The court adds that this interpretation is consistent with the Paris Agreement’s stipulation that efforts to tackle climate change should be based on the “best available science”.
(In 2018, four years after the Paris Agreement, a special report from the IPCC spelled out how limiting global warming to 1.5C rather than 2C could, among other things, save coral reefs from total devastation, stem rapid glacier loss and keep an extra 420 million people from being exposed to extreme heatwaves.)
Following this, the advisory opinion also makes it clear that countries are not just encouraged – but “obliged” – to put forward climate plans that “reflect the[ir] highest possible ambition” to make an “adequate contribution” to limiting global warming to 1.5C.
(The climate plans that countries submit to the UN under the Paris Agreement are known as “nationally determined contributions” or “NDCs”.)
Moreover, contrary to the arguments of some countries, the advisory opinion states:
“The court considers that the discretion of parties in the preparation of their NDCs is limited.
“As such, in the exercise of their discretion, parties are obliged to exercise due diligence and ensure that their NDCs fulfil their obligations under the Paris Agreement and, thus, when taken together, are capable of achieving the temperature goal of limiting global warming to 1.5C.”
Dr Bill Hare, a veteran climate scientist and CEO of research group Climate Analytics, noted that the court’s stipulations on the 1.5C and NDCs represent a “fundamental set of findings”. In a statement, he said:
“The ICJ finds that the Paris Agreement’s 1.5C limit is the primary goal because of the urgent and existential threat of climate change and that this requires all countries to work together towards the highest possible ambition to limit warming to this level.
“All countries have an obligation to put forward the highest possible ambition in their NDCs that represent a progression over previous NDCs; it is not acceptable to put forward a weak NDC that does not align with 1.5C.
“The ICJ points to potential for serious legal consequences under customary international law if countries do not put forward targets aligned to 1.5C.”
The court also notes that the concept of equity is essential to the Paris Agreement and other climate legal frameworks, commonly referred to by text noting that countries have “common but differentiated responsibilities and respective capabilities”.
Significantly, it adds that the Paris Agreement differs from other climate frameworks by also stating that these responsibilities and capabilities should be considered “in the light of different national circumstances”.
The advisory opinion continues:
“In the view of the court, the additional phrase does not change the core of the principle of common but differentiated responsibilities and respective capabilities; rather, it adds nuance to the principle by recognising that the status of a state as developed or developing is not static. It depends on an assessment of the current circumstances of the state concerned.”
The verdict comes after debate – considered highly controversial by many – about whether “emerging” economies, such as China and India, should be considered “developing countries” at climate summits.
What does it say about fossil fuels?
One of the most eye-catching paragraphs of the advisory opinion relates to its verdict on fossil fuels.
In a section labelled “determination of state responsibility in the climate change context”, the court specifically addresses countries’ obligations when it comes to producing, using and economically supporting fossil fuels. (See below).
The court says that fossil-fuel production, consumption, the granting of exploration licences or the provision of subsidies “may constitute an internationally wrongful act” attributable to the state or states involved.
It comes after multiple analyses have concluded that any new oil and gas projects globally would be “incompatible” with limiting global warming to 1.5C.
Speaking to Carbon Brief, climate law expert Prof Jorge Viñuales notes that the clear mention of fossil fuels comes despite not being featured in the questions posed to the court:
“The request characterised the conduct to be assessed by reference to emissions, so the court could have stayed there. Yet, the relevant conduct was expanded to production and consumption of fossil fuels, including subsidies.”
Though the advisory opinion is not legally binding on countries, it could influence domestic decision-making around granting permissions to new fossil fuel projects going forward, adds Joy Reyes, a policy officer at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics. She tells Carbon Brief:
“Litigants can cite the advisory opinion in future climate litigation, which includes the language around fossil fuels. While not legally binding, the advisory opinion carries moral weight and authority, and can influence domestic decision-making around new fossil-fuel projects. If states and corporations fail to transition away from fossil fuels, their risk for liability increases.”
The post ICJ: What the world court’s landmark opinion means for climate change appeared first on Carbon Brief.
ICJ: What the world court’s landmark opinion means for climate change
Last month, COP31 president-designate Murat Kurum launched a target for 35% of the world’s final energy to come from electricity by 2035.
In an interview with Carbon Brief, Kurum says that the target was not a political choice, but instead reflects the latest evidence on “what is needed to keep 1.5C within reach”.
The ongoing Hormuz crisis means there is an “urgent” need for renewables and electrification, which are the “surest and cleanest way to protect citizens” from high energy prices.
Kurum says that the Brazilian and Ethiopian presidencies of COP30 and COP32, as well as the EU, UK and Canada, have welcomed the target.
He adds that “all have confirmed it will be central to discussions at COP31”.
In the interview, Kurum – who is also Turkey’s minister of environment, urbanisation and climate change – tells Carbon Brief where the target came from and what he expects to happen next.
Carbon Brief: You recently launched a target for 35% of the world’s final energy to come from electricity by 2035. Where did this idea come from?
Murat Kurum: The “35 by 35” target is grounded in technical data and based on the IEA [International Energy Agency] and IRENA [International Renewable Energy Agency] analysis of what is needed to keep [the 1.5C Paris Agreement target] within reach. The level was not chosen politically. Rather, it reflects what the science and the energy modelling tell us is required.
CB: Why do you think an electrification target is important right now?
MK: The case for the target is urgent right now. The latest war in the Gulf has made energy diversification – and, in particular, renewable energy transition and electrification – a top global priority, because it is the surest and cleanest way to protect citizens around the world from high and volatile energy prices.
At a time of real fragmentation in international relations, a single, shared target is needed to focus global efforts by aligning governments, businesses and investors behind a common benchmark and to send a clear market signal.
CB: Which countries are supporting this target so far?
MK: The reaction so far has been extremely positive and, while we presented our target at the UN June climate meetings in Bonn, our earlier conversations with parties at both the Petersberg and Copenhagen climate dialogues paved the way for this launch.
For example, the EU, UK, and Canada have welcomed the target, as have the Brazilian COP30 and Ethiopian COP32 presidencies. All have confirmed it will be central to discussions at COP31.
This support has been reflected in the business community as well, with polling by the We Mean Business Coalition showing that 90% of businesses expect to have largely electrified their operations by 2035 and that 88% expect electrification will make their business more competitive.
CB: How do you hope and expect to see this taken forward at the COP? Could it be in the formal COP outcomes, or part of the second global stocktake?
MK: We are now taking electrification forward as an “action agenda” initiative to bring actors together and drive progress. The action agenda and the [formal COP] negotiations are separate, but complementary, with different processes and thresholds, and it is too early to say what all countries might be able to agree in the negotiations. That is for parties to determine as the year progresses.
We are focused and determined to use COP31 as a moment to spark a global conversation about electrification.
CB: What are the key priorities for reaching the target?
MK: The critical sectors for reaching the target are buildings, transport and industry, which together account for around 45% of global emissions. Financial support for the developing world and investment in grids and infrastructure is also crucial.
The target also builds on COP28’s target to triple renewable energy capacity and seeks to take advantage of the tumbling cost of renewable power and other technologies critical to the energy transition. This is a journey that Turkey itself is taking ambitious steps on, including our plan to reach 120GW [gigawatts] of renewable capacity by 2035.
This interview was first published in the 10 July 2026 edition of Carbon Brief’s DeBriefed weekly newsletter. Sign up for free.
The post Interview: COP31 president says electrification is ‘surest way to protect citizens’ appeared first on Carbon Brief.
Interview: COP31 president says electrification is ‘surest way to protect citizens’
Climate Change
DeBriefed 10 July 2026: Deadly Europe heat | EU electrification leak | COP31 president interview
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
‘Catastrophic’ climate impacts
RECORD HEAT: Western Europe experienced its hottest June on record – some 3C above average – according to analysis covered by the Guardian. It said the finding came “as the UK enters its third heatwave of the year and wildfires ravage France and Spain”. Le Monde said 10,000 people had been evacuated due to wildfires in southern France.
‘EXCESS DEATHS’: The June heatwave killed more than 2,700 people in France, according to a guest post analysis for Carbon Brief. Similar analysis for Germany said there had been more than 5,000 “excess deaths”, reported Bloomberg. Meanwhile, an ongoing heatwave in the US has killed at least 30 people, said USA Today.
STORM TEST: Floods have killed 39 people in Guangxi province in southern China, said state-run newspaper China Daily. Scientists warned that climate change and the weather phenomenon El Niño are exposing China to “catastrophic storms” that will test its resilience in 2026, reported Reuters. The nation’s latest official climate report found that “extreme weather and climate events…have become more frequent and severe”, said China National Radio.
Around the world
- EU ELECTRIFICATION: The European Commission is set to unveil a 2040 target for EU electrification on 17 July, reported Bloomberg. Citing a leaked draft, it said the plan would aim to cut oil use in half and gas use by two-thirds.
- PEAKING PLAN: China has published an “action plan” for peaking emissions during the 15th five-year plan period to 2030, reported Xinhua. It lists targets including “new energy vehicles” making up 30% of cars on the road by 2030, said Reuters.
- CLIMATE ‘FLAT EARTHER’: The Trump administration has appointed Matthew Wielicki, described by Politico as a “climate critic”, to lead the office in charge of the US national climate assessment. Common Dreams quoted a scientist describing the move as “like putting a flat-earther in charge of NASA”.
- UGANDAN SUIT: A group of farmers from Uganda have launched a legal suit in London against the East African oil pipeline, according to Climate Home News.
23%
The share of Irish electricity used by data centres in 2025, reported the Irish Times.
2%
The share of global electricity used by data centres in the same year, according to Carbon Brief analysis of the Energy Institute statistical review.
Latest climate research
- Meltwater from the western Himalayan glaciers will peak at around 2C of warming, before declining at higher warming levels | Environmental Research Letters
- Current coral restoration efforts may be unsuitable for temperate reefs, including those in the Mediterranean | Nature Ecology & Evolution
- People tend to underestimate the level of “broad public support” for climate action | Nature Climate Change
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
Carbon Brief explained – via eight facts – why air conditioning rates in some parts of Europe are relatively low, as the technology emerges as a new front in the global “culture war” over climate action. Analysis for the article illustrated that, in many parts of the world’s fastest-warming continent, air conditioning simply was not needed in the past.
Spotlight
COP31 president speaks to Carbon Brief on electrification
This week, Carbon Brief interviews Murat Kurum, president-designate of the COP31 UN climate talks in November and Turkey’s minister of environment, urbanisation and climate change, on his target to boost global electrification.
Carbon Brief: You recently launched a target for 35% of the world’s final energy to come from electricity by 2035. Where did this idea come from?
Murat Kurum: The “35 by 35” target is grounded in technical data and based on the IEA [International Energy Agency] and IRENA [International Renewable Energy Agency] analysis of what is needed to keep [the 1.5C Paris Agreement target] within reach. The level was not chosen politically. Rather, it reflects what the science and the energy modelling tell us is required.
CB: Why do you think an electrification target is important right now?
MK: The case for the target is urgent right now. The latest war in the Gulf has made energy diversification – and, in particular, renewable energy transition and electrification – a top global priority, because it is the surest and cleanest way to protect citizens around the world from high and volatile energy prices.
At a time of real fragmentation in international relations, a single, shared target is needed to focus global efforts by aligning governments, businesses and investors behind a common benchmark and to send a clear market signal.
CB: Which countries are supporting this target so far?
MK: The reaction so far has been extremely positive and, while we presented our target at the UN June climate meetings in Bonn, our earlier conversations with parties at both the Petersberg and Copenhagen climate dialogues paved the way for this launch.
For example, the EU, UK, and Canada have welcomed the target, as have the Brazilian COP30 and Ethiopian COP32 presidencies. All have confirmed it will be central to discussions at COP31.
This support has been reflected in the business community as well, with polling by the We Mean Business Coalition showing that 90% of businesses expect to have largely electrified their operations by 2035 and that 88% expect electrification will make their business more competitive.
CB: How do you hope and expect to see this taken forward at the COP? Could it be in the formal COP outcomes, or part of the second global stocktake?
MK: We are now taking electrification forward as an “action agenda” initiative to bring actors together and drive progress. The action agenda and the [formal COP] negotiations are separate, but complementary, with different processes and thresholds, and it is too early to say what all countries might be able to agree in the negotiations. That is for parties to determine as the year progresses.
We are focused and determined to use COP31 as a moment to spark a global conversation about electrification.
CB: What are the key priorities for reaching the target?
MK: The critical sectors for reaching the target are buildings, transport and industry, which together account for around 45% of global emissions. Financial support for the developing world and investment in grids and infrastructure is also crucial.
The target also builds on COP28’s target to triple renewable energy capacity and seeks to take advantage of the tumbling cost of renewable power and other technologies critical to the energy transition. This is a journey that Turkey itself is taking ambitious steps on, including our plan to reach 120GW [gigawatts] of renewable capacity by 2035.
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HEATED: A Financial Times long read asked if Europe – the world’s fastest-warming continent – is “prepared for a world of extreme heat”.
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The post DeBriefed 10 July 2026: Deadly Europe heat | EU electrification leak | COP31 president interview appeared first on Carbon Brief.
DeBriefed 10 July 2026: Deadly Europe heat | EU electrification leak | COP31 president interview
As successive heatwaves hit Europe, air-conditioning (AC) has emerged as a new front in the international “culture war” over climate action.
France, Germany and the UK have experienced record-breaking heat and thousands of heat-related deaths this summer, with June temperatures in many regions passing 40C.
This has drawn attention to the relatively low rates of AC use in these countries – and in Europe as a whole – especially when compared to its widespread adoption in the US.
Legacy newspapers, bloggers and even Elon Musk have all weighed in on “European hostility” to AC, criticising Europe’s “cultural conservatism” and “overbearing governments”.
Right-wing politicians, including National Rally in France and the UK Conservatives, have styled themselves as champions of AC, while opposing efforts to tackle climate change.
Missing from most of these interventions is the fact that human-caused climate change has made once-rare heat far more common, in what is the world’s fastest warming continent.
Carbon Brief analysis for this article shows that, until the 2020s, it was rare for many European cities to see days above 30C, making AC an unnecessary expense.
Here, Carbon Brief explains – via eight facts – why AC rates in some parts of Europe are relatively low, as well as clarifies and contextualises some of the misleading claims circulating about the technology.
- Much of Europe has not needed AC in the past
- AC is already widely used in hotter parts of Europe
- Some European nations have ‘resisted’ AC – but its popularity is growing
- AC emissions are growing, but its climate impact could be limited
- Heat from AC can contribute to directly warming cities
- More AC could help to reduce heat deaths in Europe
- ‘Net-zero rules’ are not blocking AC installation in the UK
- AC is not the only answer to overheating cities
Much of Europe has not needed AC in the past
AC installation rates in northern parts of Europe are very low. The best available estimates suggest that 6% of households in Germany and just 4% in England use AC.
However, these rates are largely explained by the historical climates in these nations.
Unlike the US, much of the housing stock and infrastructure in Europe was built at a time when AC did not exist and was not necessary.
Moreover, nations such as France, Germany and the UK have only started to regularly experience extreme heat in recent decades.
The chart below shows the average number of days per year, in each decade since the 1950s, when maximum temperatures have exceeded 30C in major European cities. Capitals such as London and Paris have seen a significant jump since around 2000.
Prof Jan Rosenow, an energy and climate researcher at the University of Oxford, tells Carbon Brief:
“For most of the 20th century, northern Europe simply didn’t need cooling. Homes in Britain and Germany were built to keep heat in, not out, because winters were cold and summers rarely hot.”
Much of the commentary about the relatively low rates of European AC use focuses on cultural or “ideological” factors. (See: Some European nations have ‘resisted’ AC – but its popularity is growing.)
However, Rosenow says people’s views on AC in these countries likely stem from their historically colder climates. He adds:
“Attitudes formed around those facts, not the other way round…There is a cultural element, but it is the product of climate, not of some green ideological project.”
In the past, many in Europe relied on traditional methods to keep buildings cool. Richard Black, head of communications at Climate Analytics, made this point in a post on LinkedIn:
“Once, residents of cities such as Paris could cope with summer heatwaves by opening shutters and windows during the night, and closing them again in the morning to trap the cool air inside…We’ve reached a limit to this sort of adaptation.”
Now, with Europe around 2.5C warmer than pre-industrial levels, climate change is routinely driving record-breaking heatwaves, even in the north of the continent.
This is forcing a reappraisal of societies that were “built for a climate that no longer exists”, as the UK’s Climate Change Committee (CCC) put it in a recent report.
Experts broadly agree that much of Europe will indeed need more AC, particularly in spaces housing the most vulnerable populations, such as care homes, schools and hospitals.
At the same time, they also emphasise broader, “passive” efforts to make cities and homes cooler alongside increased AC use. (See: AC is not the only answer to overheating cities.)
AC is already widely used in hotter parts of Europe
During periods of extreme heat, articles criticising “European hostility” towards the technology frequently note that “only about 20%” of households in Europe have AC.
Often, this is contrasted with the US, where more than 90% of households have AC installed. (In fact, the US is something of a global outlier, matched only by Japan.)
However, the continent-wide figure for Europe obscures the reality. In southern Europe – where temperatures are and have always been higher – AC is relatively common.
The map below, based on official EU data, shows that southern European nations use far more household energy for “space cooling” than those in the north.
Government figures show that nearly 60% of Italian households have AC. Household-level data in many countries is patchy, but various analyses have placed that figure at 70-80% in Greece and 41% in Spain – with higher penetration in the hotter, southern part of the country.
The same pattern can be seen within France. International coverage has stressed the country’s “cultural resistance to AC”, citing a nationwide figure from 2020 that suggests “only” 25% of French households have AC.
However, polling data from customers of the Hello Watt energy app suggests that there is a distinct north-south divide in French uptake. At least 60% of households in Mediterranean regions of France are equipped with AC, according to these figures.
This can be seen in the map below, with households across northern regions, including Paris, reporting far lower AC installation rates, often below 5%.
Finally, when making such comparisons to Europe, it is worth noting that high rates of AC use reported for the entire US also obscure significant differences between – and within – US states. This, too, aligns with differences in regional climate.
Hotter states in the US south have near-universal AC access. But in Washington, a north-western state with a climate more comparable to that of western Europe, 66% of people have AC in their homes.
Some European nations have ‘resisted’ AC – but its popularity is growing
International commentators have written extensively about Europe’s “longstanding resistance to cooling technology”, especially when compared to the US.
Newspaper editorials in the Washington Post and the Wall Street Journal, alongside numerous op-eds and blog posts, have added fuel to this “culture war”. Elon Musk has even promoted an AI-generated message stating that Europeans “should just install AC”.
Often, European attitudes are attributed to “guilt” about AC’s energy demand, “cultural conservatism” or “overbearing governments”. One commentator ascribed divergent attitudes in Europe and the US to “different ideas about physical suffering and sacrifice”.
Meanwhile, right-leaning commentators and climate-sceptic groups have blamed “climate policies, which view AC as an unnecessary luxury”.
In general, these critiques often fail to consider the most obvious explanation, which is that AC adoption is low in northern Europe because the historical climate made AC unnecessary.
Critical articles have instead drawn attention to restrictions on AC use in some European countries, as well as the lack of support for AC in official heatwave guidance.
For France, in particular, polling has indeed highlighted widespread disapproval of AC, both on environmental grounds and due to alleged health impacts. Such messages have also been voiced regularly in French media and by left-leaning and green politicians.
However, across Europe there are plenty of signs that such attitudes are shifting, following successive spells of extreme heat.
Amid the June heatwave, there were reports from Germany, France and the UK of “skyrocketing” AC sales. This surge was even acknowledged by the foreign ministry in China, due to the nation’s role in supplying many of these products.
The shift is taking place in politics as well. Marine Tondelier, leader of the French Green party – which has traditionally opposed AC – recently stated that “there are places where we just can’t do without AC anymore”.
Overall, AC has been on the rise across Europe, with France, Spain and the Netherlands all using more than twice as much energy for AC and other “space cooling” technologies in 2024 as they did in 2015.
AC production in Germany has also risen by at least 75% in recent years and a growing share of German homes are being built with it installed.
Notably, there is little evidence that “climate policies” are blocking Europeans from installing AC. Polling in Germany shows that, while people are concerned about environmental impacts, the high costs of installing and running it are perceived as greater barriers.
Finally, there is an important distinction between individual AC units in people’s homes and installing them in public spaces, such as hospitals, care homes and schools.
While neither is widespread in France, support for the latter can increasingly be found across the political spectrum, from Greens to the far-right National Rally (RN).
AC emissions are growing, but its climate impact could be limited
Some people have noted that a wider rollout of AC in Europe could drive up emissions.
As noted in the Financial Times by columnist and chief data reporter John Burn-Murdoch, there is a logic to this argument, “at least superficially”. He writes:
“AC uses a lot of energy; if the proposed defence against emissions-driven global warming means emitting more, then we have an obvious problem.”
The emissions impact of AC depends heavily on the generation mix of a country’s power sector.
According to the International Energy Agency (IEA), “space cooling” – mostly AC, but this does include some fans – used 2,100 terawatt-hours (TWh) of power globally in 2022.
As such, it was responsible for 1bn tonnes of carbon dioxide (CO2) from electricity use globally. This equates to around 2.7% of total CO2 emissions globally from fossil fuels and industry.
(As well as indirect emissions through power use, AC units can also directly release greenhouse gases – used as AC refrigerants – when they leak or are improperly disposed of. Following the 2016 Kigali Amendment, countries are progressively trying to phase down the use of potent greenhouse gases in AC units.)
In a LinkedIn post, Lauri Myllyvirta, lead analyst at the Centre for Research on Energy and Clean Air and regular Carbon Brief contributor, says:
“There is a lot of alarmist messaging about how much electricity AC uses. However, on an annual basis, the demand is not that substantial. Currently, AC uses about 1% of electricity in the EU and catching up to adoption rates in the US would double this.”
According to the IEA estimates from 2018, “if left unchecked, energy demand from AC will more than triple by 2050”, reaching 6,200TWh of power.
By mid-century, households would contribute the most to the increase (70%), with at least two-thirds of the world’s households potentially having AC, according to the Paris-based agency.
Decarbonising electricity grids and energy-efficiency improvements can reduce AC emissions and their impact on climate.
For instance, in countries with a low-carbon electricity mix – such as France, where nuclear energy accounts for 67% of its electricity generation – expanding AC would have a more limited climate impact than in other countries.
In countries such as India, there could be a more significant increase in emissions as AC is adopted, due to the role coal plays in the country’s energy mix, especially during the night. Demand is growing fast – following low access historically – and many AC units are inefficient, with high electricity use.
According to a new working paper from the India Energy and Climate Center (IECC) at the University of California, Berkeley, “room AC” – portable plug-in units, as opposed to those permanently installed in buildings – already accounts for nearly one-quarter of India’s peak electricity demand (60-70GW) – and this is before the majority of Indian households have bought their first AC unit.
Dr Nikit Abhyankar, co-faculty director of the IECC, tells Carbon Brief that, as AC use is expanded across the world, it should be paired with solar and battery storage, where the “economics have completely shifted” in the last few years. This will help to cut both energy bills and emissions.
According to the IEA, accelerating energy efficiency improvements could deliver more than one-third of all CO2 emission reductions between now and 2030.
The global energy demand needed to run ACs alone in 2050 could be reduced by 1,300GW – the equivalent of all of China and India’s coal plants – through energy efficiency measures, it estimates.
Aditya Valiathan Pillai, a climate adaptation researcher at King’s College London, tells Carbon Brief that, as the use of AC expands, there is a conversation to be had about where and “what type of technology [is used] and who gets access” to it.
A final point is that many AC units are air-to-air heat pumps, which can efficiently heat homes, as well as keeping them cool. As such, wider AC adoption could boost the adoption of electrified heat, helping to cut emissions from gas boilers.
Heat from AC can contribute to directly warming cities
Some critics of AC mention its electricity demands and associated CO2 emissions from fossil-fuel combustion, which contribute to raising the temperature of the entire planet. (See: AC emissions are growing, but its climate impact could be limited.)
But AC also has a localised impact. It works by removing heat from indoor air and pushing it outdoors, raising temperatures on the street and exacerbating the “urban heat island” effect.
Left-leaning French politicians are among those citing this as an argument against AC, particularly in cities. Indeed, Emmanuel Grégoire, the Socialist mayor of Paris, appeared to be making this point in an interview with Le Monde, during the June heatwave:
“[AC] can be useful for cooling collective spaces and protecting the most vulnerable populations, but individual AC is a scourge – it makes the problem worse by heating the city even more.”
One study concludes that, in a city such as Phoenix, Arizona, where the technology is widespread, AC use during a heatwave can raise night-time temperatures by 1-1.5C.
Another models a nine-day heatwave in Paris – in a future with “massive” AC use – and finds an increase in external temperature of more than 2C, due to heat emitted by the units.
Given this, some scientists argue that AC can be a form of climate “maladaptation” – referring to actions that backfire and make people more vulnerable to global warming.
The Intergovernmental Panel on Climate Change (IPCC) has highlighted this issue, concluding:
“AC may constitute a maladaptation because of its high demands on energy and associated heat emissions, especially in high-density cities.”
Compared to the US, more people in Europe live in dense, urban areas. According to Dr Vincent Viguié, a climate change economist at École des Ponts ParisTech, this could leave Europeans more exposed to heat from AC units. He tells Carbon Brief:
“If you live in a neighbourhood that is not dense, like in a suburban neighbourhood or in the countryside, you don’t care about this…So, once again, there is a key difference between US and European cities.”
Viguié is among the experts arguing that other climate-adaptation measures should be considered alongside AC, to keep entire cities cool – not just individual homes. He says:
“It’s not to say that the heat released by AC by itself is a reason to forbid AC…It’s just that not taking that into account may lead to bad decisions.”
More AC could help to reduce heat deaths in Europe
Heatwaves can be deadly, especially for older or vulnerable members of society.
According to climate scientists at World Weather Attribution, “heatwaves cause more deaths in Europe than all other natural hazards combined”.
The heatwave in June 2026 is estimated to have killed more than 20,000 people in Europe. In France – which has seen some of the hottest temperatures – the heatwave caused more than 2,700 heat-related deaths, according to analysis published by Carbon Brief.
AC does help to protect people from the effects of extreme heat. A 2021 study found that globally, AC averted an estimated 190,000 heat-related deaths annually during 2019-21.
With its much higher penetration of AC, the US has fewer deaths due to extreme heat than Europe.
Heat kills around 11 people out of every 100,000 in Europe, compared to around two people in the US, according to analysis by data scientist Dr Hannah Ritchie from Our World in Data.
Several publications have pointed out that “Europe’s heatwaves are deadlier than American gun violence”. While this is technically accurate in absolute terms, Ritchie says the comparison is “a bit silly” for a number of reasons, not least because on a per-capita basis, US gun deaths are higher.
However, experts suggest that AC is only one part of a wider effort to protect people from extreme heat.
A 2020 study looking at heat-related mortality in Canada, Japan, Spain and the US, found that excess deaths due to heat decreased between 1972 and 2009.
For example, the proportion of deaths due to extreme heat fell from 1.7% to 0.5% over the period in the US and 3.5% to 2.8% in Spain.
However, an increase in AC only explained 16.7% of the drop in the US and 14.3% in Spain.
The research concludes that “other factors have played an equal or more important role in increasing the resilience of populations”. This is supported by research that shows changes to cities, such as planting more trees, as well as behavioural shifts and public-health measures, can all protect people from dangerous heat.
Additionally, across Europe there is already a range of policies and measures in place to protect the most vulnerable from heatwaves. Many of these were brought in following the unprecedented summer of 2003, when 70,000 died from extreme heat.
These policies were highlighted by French environment minister Agnès Pannier-Runacher, in response to the far-right National Rally (RN) party’s AC proposals:
“The incompetent RN has just found out that nursing homes need air-conditioned rooms. Thank you, but it’s actually been mandatory since 2004.”
Another study found that measures that have already been rolled out in France would cut the projected death toll of a 2003-like heatwave by more than 75%. This is in part due to the expansion of AC in places such as nursing homes, but also other approaches, such as heat action plans.
For example, France has a multi-tiered action plan, which includes local governments ensuring access to cooled spaces and water, keeping a list of vulnerable individuals for targeted interventions, as well as national information campaigns.
According to the UN’s office for disaster risk reduction, this French plan has led to a “significant reduction in heat-related mortality”.
While action plans have proved successful in a number of nations, less than half of European countries have such a plan in place.
‘Net-zero rules’ are not blocking AC installation in the UK
In the UK, Conservative politicians and right-leaning media have tried to pit the adoption of AC against net-zero policy.
Writing in the climate-sceptic Daily Telegraph, columnist Matthew Lynn claimed falsely:
“Strict net-zero rules now mean that aircon is effectively banned in the UK.”
(Further down the article, he concedes: “AC is not strictly speaking banned in new-build homes in the UK. But tough environmental rules mean that it is very hard, and expensive, to install in practice.”)
The same narrative has been used in articles by GB News, the Sun and others. A separate article in the Daily Telegraph’s “money” section goes further, claiming that AC had been “torn from homes under net-zero clampdown”.
A blog post from the Ministry of Housing, Communities and Local Government rebuts these claims, stating:
“There has been media coverage this week suggesting that AC is banned in homes. This is incorrect.”
For the UK, while it is true that fewer than 5% of homes currently have AC, this is largely due to the fact that it was not hot enough in the past to warrant the expense. Historically, the focus has therefore been on keeping buildings warm, rather than cool.
Extreme heat has previously been rare in the country, so homes were built with insulation and other measures to keep heat in during the “dank winters”. (See: Much of Europe has not needed AC in the past.)
Current regulations do not ban the installation of AC outright. However – as the government’s blog post notes – there is no blanket rule, meaning there are some localised differences.
Certain areas – or certain kinds of properties – may be subject to additional complications for installing AC.
In a 2025 video on Instagram, shadow secretary of state for energy security and net-zero Claire Coutinho referenced the London plan, for example, which is a framework for development in the capital launched in 2021. She said:
“[London mayor] Sadiq Khan says no. The London plan says we shouldn’t have air con because it uses too much energy. But this is mad! This is a poverty mindset that we need to get away from.”
The London Plan does not stop homes from having AC. It simply says that, for new buildings, passive design measures should be prioritised, such as the orientation of the building, the window design and incorporation of measures such as external shading and trees.
A recent response from the mayor added further measures, such as the need to “minimise the necessity for the operation of mechanical measures including AC, which would further add to the heat island effect within urban areas and add operational cost to residents”.
Elsewhere, new-build homes across England must meet the requirements of “part O” of the 2022 building regulation updates. This includes addressing overheating in buildings through energy-efficient design and prioritising passive cooling, with AC as a last resort.
For existing buildings, most AC units fall under “permitted development rights”, meaning no planning application is required to install them.
Additionally, regulations were relaxed in 2025 to make it easier to install an air-to-air heat pump – which can both heat and cool air – without planning permission.
This means that, far from blocking the expansion of AC, net-zero policy has made it easier to install specific cooling systems.
Speaking to Carbon Brief, Andrew Sissons, director of sustainable future at Nesta, says the government must now implement its announced £2,500 subsidy for air-to-air heat pumps “as quickly as possible”, to further ensure that the technology can be rolled out efficiently. He adds:
“[The government] should also continue to expand permitted development rights for air-to-air heat pumps, with a particular focus on flats and homes in denser areas. As long as heat pumps meet the MCS [Microgeneration Certification Scheme] noise test, there are few reasons to limit their use via the planning system.”
Some properties, such as large homes, listed buildings or those in conservation areas, may still require planning permission to install an air-to-air heat pump or other AC. Sissons notes that this can add cost and delay to installation.
While it cannot be said that AC has been blocked or banned due to net-zero, neither has it been prioritised.
This may shift as temperatures continue to rise. UK government advisors at the Climate Change Committee (CCC) suggest that 22% of the UK’s housing stock will likely need active cooling, such as AC, to cope with 2C of global warming.
The CCC’s recent adaptation report also calls for all new homes to be built using low-cost, passive cooling measures, alongside more AC.
Active cooling such as AC is more likely to be needed for retrofitting existing homes, the report adds.
AC is not the only answer to overheating cities
AC has become increasingly politicised in Europe, as demonstrated by France’s RN party announcing its “grand plan for AC” in all public buildings.
As noted by Dutch MEP Gerben-Jan Gerbrandy, this “far-right” embrace of AC is coming from the same people who for years have “delayed emissions reductions”.
In response, left-leaning policymakers in Europe have frequently downplayed the role of AC, prioritising programmes of urban greening and retrofitting older buildings.
Such approaches for dealing with extreme heat have already proved successful. Therefore, many experts argue that these methods, alongside AC, will be essential to prepare for a hotter world.
According to the IPCC’s sixth assessment report, adaptive infrastructure, such as urban forests and green roofs, can reduce energy use because of cooling, with co-benefits for climate, air quality, physical and mental health.
While retrofitting older buildings for heat as well as insulating them from the cold might prove challenging, urban greening and an active shade policy – one that determines how much of every street is exposed to direct sunlight – are simple measures cities can adopt.
Some experts have also warned about the high cost of running AC, expressing concerns that excessive reliance on the technology could increase energy poverty.
In a Carbon Brief guest post published in 2025, researchers at the Basque Centre for Climate Change found that framing AC as the “default solution” can miss the opportunity to design “more inclusive, human-centred responses” to rising temperatures.
William Lewis, a PhD candidate and one of the guest post’s authors, tells Carbon Brief it is not a case of “one or the other”, when considering AC and other options:
“We have this opportunity in European countries to choose a slightly different path [from the US], which isn’t AC in every single home.”
King’s College London’s Pillai says that, by centring the debate on AC, the far-right response to the heatwaves in Europe has “completely neglected the science of how you cool human beings”.
There are many solutions, he adds, that are already widely used across hot developing countries, such as ceiling fans, windows that open and cross-ventilation, as well as strategies to reduce cumulative hours of heat exposure.
Pillai tells Carbon Brief that, while places reaching 42C and higher “definitely need to think about AC very seriously”, places in the “low to mid 30Cs” could rely on these alternatives.
Behavioural change, he adds, is the “least glamorous part” of heat policy, but “pulls most of the weight” of protecting people. These include a wide range of actions and responses – from reducing heat exposure, to wearing lighter clothing and drinking more water and fluids.
There are also workplace protections. Pillai tells Carbon Brief that these could include legislation on mandatory work breaks, cooling and shade requirements at workplaces, as well as health insurance that covers heat stress days that have been lost by heat-exposed workers.
The post Eight facts about air conditioning amid an overheated global debate appeared first on Carbon Brief.
Eight facts about air conditioning amid an overheated global debate
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