A controversial way of measuring how much methane warms the planet has stirred debate in recent years – particularly around assessing the climate impact of livestock farming.
The metric – known as GWP* (global warming potential star) – was designed to more precisely account for the warming impact of short-lived greenhouse gases, such as methane.
No country so far has used GWP* to measure emissions, but New Zealand is currently considering its use.
In June, a group of climate scientists from around the world wrote an open letter advising against this.
They argued that the metric “creates the expectation that current high levels of methane emissions are allowed to continue”.
Climate experts tell Carbon Brief that there is “no strong debate” on the science behind GWP* and that it can accurately assess the global warming effect of methane.
But many experts also firmly caution against its use in national climate targets, believing it could allow countries to prolong high levels of emissions at a time when they should be drastically cut.
Some researchers tell Carbon Brief that GWP* is an “accounting trick” and a “get-out-of-jail-free card for methane emitters”. A 2021 Bloomberg article called the metric “fuzzy methane math”.
Prof Myles Allen, one of the scientists who created GWP*, tells Carbon Brief that the metric is “nothing more” than one way of better understanding the climate impact of different actions as part of efforts to limit warming under the Paris Agreement.
In this Q&A, Carbon Brief explains the science behind GWP*, why the metric is so divisive and the ways in which its use has been considered.
- What is GWP*?
- What are the main controversies around using GWP*?
- Do any countries currently use GWP* to measure methane emissions?
- What do experts think about the use of GWP*?
What is GWP*?
Global warming is caused by a build up of greenhouse gases – mainly from burning fossil fuels – trapping heat in the atmosphere.
Different gases cause differing levels of warming and remain in the atmosphere for varying lengths of time. For example, carbon dioxide (CO2), the main contributor to warming, lingers for centuries, whereas other gases last decades or even millennia.
To account for these variables, scientists use a metric known as global warming potential (GWP), which assesses the warming caused by different gases compared to CO2, which has a GWP of 1.
Using GWP, emissions of other gases are calculated in terms of their “CO2 equivalent” over a given amount of time.
In their reports, the Intergovernmental Panel on Climate Change (IPCC) set out three GWP variants measured over 20 years (GWP20), 100 years (GWP100) and 500 years (GWP500).
GWP100 is the most common approach and is used to calculate emissions under the Paris Agreement.
Methane is a short-lived gas that only remains in the atmosphere for around 12 years before breaking down. But it causes a large burst of initial warming that is around 80 times more powerful than CO2, according to the IPCC.
This means that one tonne of methane causes the same amount of warming as around 80 tonnes of CO2, when measured over a period of 20 years.
When calculated over 100 years, methane’s shorter lifetime means it causes around 30 times more warming than CO2.
Some experts have criticised the use of GWP100, saying it does not sufficiently account for the fact that methane leaves the atmosphere much more quickly than CO2 and does not actually last for 100 years. This is the issue that GWP* was designed to fix.
GWP* calculates the warming contributions of long- and short-lived gases at different rates, accounting for their varying lifetimes in the atmosphere.
One of the researchers behind GWP*, Dr Michelle Cain, explained in a 2018 Carbon Brief guest post that a constant rate of methane emissions can maintain stable atmospheric concentrations of the gas, assuming methane sinks remain constant as well.
In contrast, a constant rate of CO2 emissions “leads to year-on-year increases in warming, because the CO2 accumulates in the atmosphere”, Cain wrote. CO2 does not leave the atmosphere after a decade or so, as methane does, and continues to build over time until emissions stop.
Cain, formerly a researcher at the University of Oxford and now a senior lecturer at Cranfield University, added:
“For countries with high methane emissions – due to, say, agriculture – this can make a huge difference to how their progress in emission reductions is judged.”
Methane emissions that slowly decline or remain stable over time are calculated as contributing “no additional warming” to the planet, which is not the case with other GWP calculations.
The chart below shows simplified emissions scenarios for CO2 and methane, highlighting the different impacts they have on global warming over time.
The chart below shows how using the two different metrics – GWP* and GWP100 – affects the same emissions pathway throughout the 21st century, given the different warming impacts of greenhouse gases.
If, for example, a country emitted 4m tonnes of methane annually from 1990-2005, these emissions would now be considered “climate-neutral” using GWP*, as they are not actively contributing new warming to the atmosphere, but rather maintaining the existing levels of methane in the atmosphere in 1990.
This would not be the case under GWP100, which looks at the warming potential of emissions over the course of a century and does not account for their different atmospheric lifetimes.
GWP* can be used for other short-lived gases, such as some hydrofluorocarbons, but methane is the most significant short-lived gas when it comes to climate change.
The IPCC notes that converting methane emissions into CO2 equivalent using GWP100 “overstates the effect of constant methane emissions on global surface temperature by a factor of 3-4” and understates the impact of new methane emissions “by a factor of 4-5 over the 20 years following the introduction of the new source”.
GWP* was created by several researchers, including Prof Myles Allen, the head of atmospheric, oceanic and planetary physics at the University of Oxford. The concept was detailed in a 2016 study and first named in a 2018 study. It was further updated by the authors in 2019 and 2020.
Allen tells Carbon Brief that the researchers involved were “reluctant” to give their new metric a name, as it “was just a way of using reported numbers to calculate warming impact”. He adds:
“I think it’s really unfortunate that people have latched onto GWP*. It doesn’t matter. We could forget about GWP* entirely, we can just use a climate model to work out the warming impact…GWP* is a handy way of calculating the warming impact of activities. Nothing more.”
What are the main controversies around using GWP*?
Efforts to cut methane emissions are widely viewed as a “quick-win” to help limit the effects of climate change in the short term.
More than 100 countries signed a pledge, launched at COP26 in 2021, to cut global methane emissions by 30% by 2030.
Cutting methane would also help to counteract an acceleration in warming due to declining aerosol emissions, which are currently masking around half a degree of warming.
Experts Carbon Brief spoke to agree on the importance of cutting methane emissions, but disagree on whether GWP* helps or hinders these efforts.
The debate around the metric centres on the possible impacts of its use, rather than the soundness of the science behind it.
Prof Joeri Rogelj, a climate science and policy professor at Imperial College London, explains:
“At the global level, at any level, the method of GWP* actually provides a good, new way to translate the trajectory of methane emissions into equivalent emissions of CO2, or emissions of CO2 that would have an equivalent warming effect…The debate is on the application.”
Allen says he is a “little frustrated” that discussions around the use of GWP* have “become so emotive”. He tells Carbon Brief:
“Every action we take has both a temporary impact on global temperature and a permanent one. How much is in both areas depends on the action. We need to know those two things in order to make decisions about choices of action in pursuit of a temperature goal…GWP* gives you a handy way of doing that.”
Below, Carbon Brief details some of the main discussion points and controversies around GWP*.
Carbon cycle
A misleading claim frequently made about livestock is that cows do not contribute much to global warming because the methane they emit eventually returns to the land through the carbon cycle – the set of processes in which carbon is exchanged between the atmosphere, land and ocean, as well as the organisms they contain.
Those in favour of using GWP* to measure methane emissions often also stress the difference between methane emissions that come from animals – known as biogenic methane – and methane from fossil fuels.
Rogelj tells Carbon Brief that biogenic and fossil-sourced methane are “slightly different, but that difference is really second-order” when it comes to climate change.
Methane warms the planet while it is in the atmosphere, so the “climate effect is exactly the same, irrespective of which source the methane comes from”, Rogelj adds.
The differences become more significant when methane breaks down in the atmosphere and oxidises into water vapour and CO2.
CO2 that originated from a cow can be reabsorbed by plants and the land. But the CO2 resulting from fossil methane – which stems from sources such as flaring from oil and gas drilling – stays in the atmosphere. Although fossil methane has a “bit of a longer effect”, Rogelj says:
“This is a bit of a red herring, because the main effect is, of course, the effect that the methane has while it is methane and not what the carbon molecule of that methane has after [the] methane has been broken down or oxidised to CO2.”
He adds that there are ways of reducing agricultural methane, such as “diet change” or “management measures”, but no way to remove the emissions “100%”.
The graphic below shows the digestive process through which a cow emits methane.
Agriculture also causes other significant environmental harms. It is responsible for around 80% of global deforestation and is a key driver of biodiversity loss and water pollution.
Prof Frank Mitloehner, a professor and air-quality specialist at the University of California, Davis (UC Davis), is one of the main proponents of GWP*, frequently speaking about it in public presentations and discussions with the farming sector.
He tells Carbon Brief that, while animal agriculture can cause environmental harm, it is a “silly argument” to say these impacts are being ignored in carbon-cycle discussions.
He gives an example of discussions on deaths from car accidents excluding mentions of the emissions from cars, saying that these wider impacts are still important and can be discussed separately.
He adds that it is an “urban myth” that biogenic methane emissions are not a concern because of the carbon cycle.
‘No additional warming’
Under GWP*, methane emissions stop causing new warming once they reduce by 10% over the course of 30 years – around 3% each decade, or 0.3% each year.
These emissions are then described in research and policy as causing “no additional warming”.
For example, a 2021 study from Mitloehner and other UC Davis researchers, found that methane emissions from the US cattle industry “have not contributed additional warming since 1986”, based on GWP* calculations. It also said that the dairy industry in California “will approach climate neutrality” by the 2030s, if methane emissions are cut by just 1% annually.
(According to the US Environmental Protection Agency, methane emissions from enteric fermentation – the digestive process through which cows produce the greenhouse gas – increased by more than 5% over 1990-2022.)
However, many critics take issue with the “no additional warming” concept.
The main criticism is that, although a gradually reducing herd of cattle may stabilise methane emissions, it still emits the polluting gas. If animal numbers were instead drastically reduced, this would cut methane emissions and lower warming rather than maintaining current levels.
Dr Caspar Donnison, a postdoctoral researcher at Lawrence Livermore National Laboratory in the US, says the term no additional warming is “absolutely misleading” in the context of GWP*. He tells Carbon Brief:
“You just assume, on the face of it, that this means it has a neutral impact on the climate…But ‘no additional warming’ means that you’re still sustaining the warming that the herd is causing.”
Allen says that the debate focuses on the “stock of warming versus additional warming”. He compares it to accounting for historical emissions of CO2:
“If a country got rich by burning CO2, they’ve caused a lot of warming in the past. If they reduce their CO2 emissions to zero, then people are generally happy to call what they’re doing climate-neutral, even though they may be sitting on a huge heap of historical warming caused by their CO2 emissions while they were burning [fossil fuels].
“And yet, temperature-wise, that’s exactly the same thing as having a source of methane that’s declining by 3% per decade.”
Climate ambition
Another criticism around the use of GWP* is that countries or companies with high agricultural methane emissions could use the metric to make small emission reductions appear larger.
Dr Donal Murphy-Bokern, an independent agricultural and environmental scientist, believes that the metric can be used as a “get-out-of-jail-free card for methane emitters”. He adds:
“It’s all about saying carry on as we are; we’ll manage this by slightly reducing our emissions over a critical period in history, so as to appear at that critical period in history to be so-called ‘climate-neutral’.”
Mitloehner disagrees with this, noting that, while reductions in methane emissions appear significant under GWP*, increases also appear significant. He says:
“It is simply not true that GWP* is a get-out-of-jail-free card. It’s not. If you reduce emissions, it makes your contributions look less. If you increase emissions, it makes your contributions much worse.”
Rogelj says he has not seen GWP* being used to advocate for the “highest possible ambition” in cutting methane emissions.
However, Allen says that “no metric tells you what to do”. He adds:
“How you measure emissions and how you measure warming has absolutely no bearing on whether you think a country has an obligation to undo some of the damage to the climate they’ve caused in the past.
“This is where the ‘free-pass’ argument makes no sense to me, because the existence of a method to calculate the warming impact of your emissions allows you to make decisions about emissions in light of their warming impact, sure, but it doesn’t tell you what the outcomes of those decisions should be.”
Allen adds that the livestock sector is “unsustainable globally”, with animal numbers and methane levels still rising.
The chart below shows how atmospheric methane concentrations have increased in recent decades.
Allen tells Carbon Brief:
“Do we need to eliminate livestock agriculture to stop global warming? No…[but] we do need to start decreasing it. And if we can decrease it faster than 3% per decade then that would help reduce warming that’s caused by other sectors or, indeed, undo some of the warming that the livestock sector has caused in the past.”
Mitloehner says considerations on the fairness of using GWP* are “real from a policy standpoint and they have to be addressed from a policy standpoint”. He adds:
“But, from a scientific standpoint – and that’s where I’m coming from – I think it’s not controversial.”
Baseline and historical emissions
The baseline year from which emissions reduction targets are set is significant, as it helps form the scope of climate ambition.
For example, high-emitting countries, such as the UK, have set 1990 as their baseline year for emissions-cutting targets, whereas many low-emitting countries may choose further back or more recent years, depending on their needs. Rogelj says:
“Because GWP* translates a change in emissions into either an instantaneous emission or instantaneous removal of CO2, your starting point becomes really important.
“If you start with very high emissions of methane and you did not in any way account for this high starting point, then even very minor, unambitious reductions in methane would result in creating credits for high-polluting countries.”
However, he notes that this is just one way of applying the metric and that there could be ways to avoid this “inequitable outcome”, such as applying GWP* globally and allocating each country a per-capita methane budget, instead of assessing based on national current or past emissions. (Rogelj and Prof Carl-Friedrich Schleussner discussed other possible GWP* equity measures in a 2019 study.)
The chart below, adapted from that study, shows how GWP* can significantly change the per-capita methane emissions of different countries. Some countries with high agricultural methane emissions, such as New Zealand, change from high to low per-capita emitters.
A 2025 study used a climate model to quantify future national warming contributions for Ireland under different emissions scenarios and found that “no additional warming” approaches, such as GWP*, are “not a robust basis for fair and effective national climate policy”.
Discussing baseline concerns, Allen says these considerations are the same for any other metric:
“It depends on how much account you want to take of [the] warming you’ve caused in the past – and at what point you want to take responsibility for the warming your actions had caused.”
He believes that most climate experts agree that it is good to understand the impact emissions have on global temperatures, but “where the controversy arises is about what you consider someone’s nominal emissions to be today”. He adds:
“This is where everybody gets upset, because if you use GWP*, then a livestock sector that’s reducing its emissions by 3% per decade – which most global-north livestock sectors are doing – it looks like their emissions are quite small.
“But that’s only a problem if you think that the main issue is working out whose fault global warming is, rather than working out what we should do about it.”
Communication
Many experts Carbon Brief spoke to took issue with how GWP* has been discussed by some of its proponents.
Murphy-Bokern criticises how Mitloehner and other experts communicate the metric. He says:
“The confusion arises from the activities of Mitloehner, in particular, where he presents the farming community – and the industry in general – with the idea that you can magic away the warming effect of methane simply by looking at the rate of change of methane emissions.”
Mitloehner says he has no regrets about his communication of GWP*, adding that he has “always emphasised to the livestock sector that reductions of methane are important”. He tells Carbon Brief:
“I’m proud because I have been able to take the livestock sector along with the understanding that reductions are needed and that they can be part of a solution if they understand that.”
The New York Times reported in 2022 that the research centre led by Mitloehner at the University of California, Davis “receives almost all its funding from industry donations and coordinates with a major livestock lobby group on messaging campaigns”. Other reports note his discussions about GWP* with stakeholders in various countries.
In response to these reports, Mitloehner says he believes it is important to work with the sector you are researching, adding that he receives both public and private funding. He tells Carbon Brief:
“The problem is not that they [the meat industry] are investing in research and communications and extension. The problem is that they are not putting in enough, because the public sector is withdrawing from this.
“Climate research is being slashed…If the government is not paying into research to quantify and reduce emissions – and those people who are critical of what we do say ‘oh, industry shouldn’t do it’ – then, I ask you, who should?”
Colin Woodall, the chief executive of the National Cattlemen’s Beef Association, a US lobby group, said in 2022 that GWP* is the “methodology we need to make sure everybody is utilising in order to tell the true story of methane”, Unearthed reported. According to the outlet, he added:
“We’re working with our partners around the globe to ensure that everybody is working towards adoption of GWP*.”
Asked if he regrets anything about his communication of GWP*, Allen tells Carbon Brief:
“When we first introduced this – and, perhaps, this is one thing I do regret – I was, perhaps, a little naive in that I thought everybody would seize on focusing on [the] warming impact because it was, from a policy perspective, potentially much easier for the agricultural sector.
“I thought that this would actually be welcomed. But, sadly, it’s not been. And I think part of that is because of this narrative of blame.”
Do any countries currently use GWP* to measure methane emissions?
GWP* is not yet used by any country in methane emission reporting or targets. But it has been considered by New Zealand, Ireland and other nations with high agricultural emissions.
A 2024 statement from dozens of NGOs and environmental organisations called for countries and companies not to use GWP* in their greenhouse gas reporting or to guide their climate mitigation policies. They wrote:
“The risks of GWP* significantly outweigh the benefits.”
New Zealand
New Zealand is currently considering changing its biogenic methane target, including applying the “no additional warming” approach used in GWP*. If it does so, it could become the first country to adopt GWP*.
The nation is a major livestock producer and agriculture generates nearly half of all its greenhouse gas emissions.
The chart below shows that the agricultural sector is also responsible for more than 90% of the country’s methane emissions.
New Zealand has a legally binding target to reach net-zero greenhouse gas emissions by 2050. However, biogenic methane has separate targets to reduce by 10% by 2030 and by 24-47% by 2050, compared to a baseline of 2017 levels.
In late 2024, a review from the nation’s Climate Change Commission recommended that the government change its 2050 greenhouse gas targets, including to increase the biogenic methane goal to a 35-47% reduction by 2050.
At the same time, an independent panel commissioned by the New Zealand government reviewed how the country’s climate targets would look under the “no additional warming” approach.
The resulting report, which did not look specifically at GWP*, but used a similar concept, found that a 14-15% cut in biogenic methane by 2050 would be “consistent with meeting the ‘no additional warming’ condition”, under mid-range global emissions scenarios that keep temperatures below 2C.
The government is “currently considering” these findings, a spokesperson for the Ministry for the Environment tells Carbon Brief in a statement.
The spokesperson says that the report is “part of the body of evidence” that the government will use in its response to the Climate Change Commission’s review, which it must publish by November 2025.
Cain, the Cranfield University lecturer who co-created GWP*, wrote in Climate Home News in 2019 that New Zealand reducing biogenic methane by 24% would “offset the warming impact” of the rest of the country’s emissions, adding:
“New Zealand could declare itself climate-neutral almost immediately, well before 2050 and only because farmers were reducing their methane emissions. That’s a free pass to all the other sectors, courtesy of New Zealand’s farmers.”
A report on GWP* by the Changing Markets Foundation found that, in 2020, 16 industry groups in New Zealand and the UK “urged” the UN’s Intergovernmental Panel on Climate Change to use GWP* to assess warming impacts.
Australia
The Guardian reported in May 2024 that Cattle Australia, a cattle producer trade group, was “lobbying the red-meat sector to ditch its net-zero target in favour of a ‘climate-neutral’ goal that would require far more modest reductions in methane emissions”.
Cattle Australia’s senior adviser and former chief executive, Dr Chris Parker, tells Carbon Brief in a statement that the organisation is “working with the Australian government to ensure methane emissions within the biogenic carbon cycle are appropriately accounted for in our national accounting systems”. He adds:
“We believe GWP* offers a more accurate way of assessing methane’s temporary place in the atmosphere and its impact on the climate. Australian cattle producers are part of the climate solution and we need policy settings to enable them to participate in carbon markets.”
Australia’s Department of Climate Change, Energy, the Environment and Water did not respond to Carbon Brief’s request for comment.
Ireland
Internal documents assessed for the Changing Markets Foundation’s GWP* report “suggest” that Ireland’s Department of Agriculture, Food and the Marine has advocated for GWP* “at the international level”, including at the UN’s COP26 climate summit in 2021.
Allen and Mitloehner were involved in a 2022 Irish parliamentary discussion on methane, in which Allen advocated for the country to “be a policy pioneer” by using GWP* in its methane reporting alongside standard methods.
The country’s coalition government, formed earlier this year, pledged to “recognise the distinct characteristics of biogenic methane” and also “advocate for the accounting of this greenhouse gas to be re-classified at EU and international level”.
A spokesperson for Ireland’s Department of Agriculture, Food and the Marine tells Carbon Brief that this does not refer to using GWP* specifically. They say the country is “in favour of using accurate, scientifically validated and internationally accepted emission measurement metrics”, adding:
“It is important that the nature of how biogenic methane interacts in the environment is accurately reflected in how it is accounted for. This does not mean the use of the metric GWP*.”
In December 2024, Ireland’s Climate Change Advisory Council proposed temperature neutrality pathway options to the government that do not specifically refer to GWP*, but use the same concept of no “additional warming”.
The Irish Times reported that this was “in part to reduce potential disruption from Ireland’s legal commitment to achieve national ‘climate neutrality’ by 2050”.
The climate and energy minister, Darragh O’Brien, said he has “not formed a definitive view” on this, the newspaper noted, and that expert views will feed into ongoing discussions on the 2031-40 carbon budgets, which are due to be finalised later in 2025.
In an Irish Times opinion article, Prof Hannah Daly from University College Cork, described the temperature neutrality consideration as “one of the most consequential climate decisions this government will make”. She wrote that the approach “amounts to a free pass for continued high emissions” of livestock methane.
Paraguay
Paraguay mentioned GWP* in a national submission to the UN in 2023 after agribusiness representatives “pushed” to adopt the metric, according to Consenso, a Paraguayan online newsletter.
The country’s National Directorate of Climate Change told Consenso for a separate article related to GWP* that it is “aware” of questions around the metric, but that it “has the option of using other measurement systems” for emissions reporting.
UK
The National Farmers’ Union, the main farming representative group in England and Wales, is in favour of using GWP* to measure agricultural methane emissions.
Carbon Brief understands that the UK government is not currently considering using GWP* in addition to, or instead of, GWP100 in its emissions reporting.
What do experts think about the use of GWP*?
Most experts Carbon Brief spoke to agreed that GWP* could be a useful metric to apply to global methane emissions, but that it is difficult to apply equitably in individual countries or sectors. Rogelj believes that are are some contexts in which GWP* could be used, but adds:
“You cannot just take targets that were set and discussed historically with one greenhouse gas metric in mind – GWP100 under the UNFCCC [United Nations Framework on Climate Change] and the Paris Agreement and all that – [and] then simply apply a different metric to it. They change meaning entirely.
“So, if one would like to use GWP*, one should build the policy targets and frameworks from the ground up to take advantage of the strengths of that metric, but also put in place safeguards that ensure that the weaknesses and limitations of that metric do not result in unfair or undesirable outcomes.”
A 2022 study says that using GWP* in climate plans “would ask countries to start from scratch in terms of their political target setting processes”, calling it a “bold ask” for policymakers.
It adds that achieving net-zero emissions, as measured with GWP*, “would only lead to a stabilisation of temperatures at their peak level”.
However, a 2024 study found that GWP* gives a “dynamic” assessment of the warming impact of emissions that “better aligns with temperature goals” than GWP100, when measuring methane emissions from agriculture.
Allen believes that criticism over the use of GWP* is similar to “saying it’s a meaningless question” to consider the warming impact of a country or company’s actions. He adds:
“That seems a very strange position to me, because we need to know how different activities are contributing to global warming because we have a temperature target.
“In saying GWP* is a bad thing, what people are actually saying is it’s a bad thing to know the warming impact of our actions, which is a very strange thing to say.”
He says that such metrics help countries to make informed decisions on climate action, but that “we can’t expect metrics to make these decisions for us”.
Murphy-Bokern notes that GWP* could be useful in modelling global, rather than national, methane emissions to avoid high-emitting countries making small methane cuts to achieve “no additional warming”, rather than significantly reducing these emissions.
He says the metric would be particularly useful if global emissions were close to zero, as a way to target the final remaining emissions. But, he adds:
“We are so far away from that very happy situation, that the discussion now with GWP* is a huge distraction from the key objective, which is to reduce emissions.”
Mitloehner – and every expert Carbon Brief spoke with – agrees with this wider point. He says:
“The main point is we need to reduce emissions. In the case of livestock, we need to reduce methane emissions. And the question is how do we get it done? And how do we quantify the impacts that [that reduction] would have accurately and fairly? The other issues are issues that politicians have to answer.”
The post Q&A: What the ‘controversial’ GWP* methane metric means for farming emissions appeared first on Carbon Brief.
Q&A: What the ‘controversial’ GWP* methane metric means for farming emissions
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.
Watch, read, listen
HEATED: A Financial Times long read asked if Europe – the world’s fastest-warming continent – is “prepared for a world of extreme heat”.
LITIGATED: The Outrage and Optimism podcast spoke to Prof Joana Setzer and Catherine Higham about the latest trends in climate litigation.
‘SHATTERED’: Confidence in fossil-fuel exports via the strait of Hormuz has been “shattered”, wrote IEA chief Fatih Birol for Foreign Policy.
Coming up
- 13-17 July: Meeting of open-ended working group on the Montreal Protocol, Bangkok, Thailand
- 13-24 July: International Seabed Authority Council, Kingston, Jamaica
- 16 July: International Energy Agency critical minerals outlook 2026, online
Pick of the jobs
- Wellcome Trust, head of policy – climate and health | Salary: £84,640-£105,800. Location: London
- Financial Times, senior reporter, Sustainable Views | Salary: Unknown. Location: London
- North Texas Public Broadcasting, climate, energy and environment reporter | Salary: $70,000-$78,000. Location: Fort Worth, Texas
- Energy & Climate Intelligence Unit, head of communications and engagement | Salary: £65,000-£70,000. Location: London
DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.
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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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