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Recent years have seen a rapid succession of climate-related records broken.

To name just a few, the world has witnessed record warmth in the Atlantic, unprecedented glacier melt, all-time low Antarctic sea ice extent, the Amazon’s worst drought since observations began and UK temperatures soaring past 40C for the first time.

In a review article, published in Nature Reviews Earth & Environment, my coauthors and I look at how the frequency of weather records is changing as the planet warms.

We find that the number of hot temperature records observed around the world since 1950 far exceed what would be expected in a million years in a world without human-caused climate change.

Specifically, we show that “all-time” daily hot records on land were more than four times higher in 2016-24 than they would have been in a world without climate change.

Meanwhile, daily maximum rainfall records were up 40% over the same time period and record cold events were twice as rare.

A key finding of our research is that it is the pace of global warming that controls the occurrence of records.

We show that, if the pace of warming were to slow down, the frequency of record-breaking hot events would start to decline – even if global temperatures continue to rise.

Counting records

By definition, records are supposed to be rare events, at least in a system that is not changing.

Statistics of record occurrence are remarkably simple. They are expected to become rarer the longer a measurement series gets.

The chance of observing a new record after 20 years of measurement is one in 20, or 5%. And after 100 years of observations, the chances of a new record drops to 1%.

For example, this is why it becomes increasingly difficult to break records in athletics as time goes by, unless training methods or sports equipment improve.

Record-breaking weather events – for example, the highest windspeed, most intense rainfall or hot and cold temperatures – also face these odds in a climate that is “stationary”.

However, today’s climate is not stationary, but warming at a very high pace. This has significant implications for the record count.

The plot below shows how the frequency of all-time hot records (dashed red line) and record cold events (dashed blue line) has changed since the 1960s. This is compared to the probability that would be expected under a stationary climate (black line).

(The plot uses ERA5, a reanalysis dataset, which combines observations and models from the European Centre for Medium-Range Weather Forecasts (ECMWF).)

It illustrates how the frequency of hot events declined more slowly than would be expected in a stationary climate since 1950, before increasing in the last 15 years. Meanwhile, the frequency of record cold events is declining more quickly than expected.

The frequency of all-time hot records (dashed red line) and cold records (dashed blue line) over global land regions shown as a nine-year running average over 1950-2024, as represented by the Copernicus/ECMWF ERA5 surface temperature reanalysis. This is contrasted with the theoretical probability of new records expected in a stationary climate as the temperature measurement series expands (black line). Credit: Amended from Fischer et al (2025).
The frequency of all-time hot records (dashed red line) and cold records (dashed blue line) over global land regions shown as a nine-year running average over 1950-2024, as represented by the Copernicus/ECMWF ERA5 surface temperature reanalysis. This is contrasted with the theoretical probability of new records expected in a stationary climate as the temperature measurement series expands (black line). Credit: Amended from Fischer et al (2025).

The record ratio

Tracking the ratio between the measured number of records and the one theoretically expected in a stationary climate – the “record ratio” – reveals the fingerprint of climate change.

Analysis of ERA5 data and Berkeley Earth surface temperature observations finds that the record ratio over the last decade for hot records over global land regions is more than four. For cold records, it is between 0.2 and 0.5, showing that record-breaking cold has declined

In other words, there were more than four times as many hot record events and less than half as many cold record events than would be expected without global warming.

In 2023 and 2024, the record ratio for hot events reached 5.5 and 6.2, respectively.

Record ratios tend to be higher over global oceans than on land. They are also higher for monthly or seasonal record temperatures than all-time daily records.

This is because natural variability in the climate tends to be smaller over oceans and for longer averaging periods, such as months and seasons.

Record counts directly relate to the relationship between rates of warming and natural fluctuations in the climate. This is sometimes referred to as the “signal-to-noise ratio”. (The “signal” being the long-term trend of climate change and “noise” referring to short-term fluctuations of natural variability.)

As a result, event types and regions with a higher signal-to-noise ratio tend to see a greater number of records.

Another way of illustrating the signal of climate change is by counting the total number of records in a measurement series.

In a stationary climate, there should be about five records in 100 years of temperature measurements, 7.5 in 1,000 years and less than 10 in 10,000 years.

However, our analysis of records in two measurement series shows how the number of record-breaking events has become significantly higher as the climate has changed.

For example, as the figure on the left below illustrates, a new annual record for average global temperature has been set 25 times over the past 175 years.

Meanwhile, the figure on the right shows how, in the Pacific north-west, a new five-day average heat record has been set 14 times within the last 75 years. The spike in temperature in 2021 reflects the brutal heatwave that killed hundreds of people and brought devastating wildfires that almost entirely destroyed the Canadian village of Lytton.

(In both figures, the warm records are marked by pink circles.)

According to fundamental laws of statistics, 14 new records would not be expected in more than a million years in a climate that is not warming.

Left: Global annual average temperature anomalies between 1850-2025, relative to 1850-1900, based on Berkeley Earth Surface Temperatures (BEST) data. Twenty-five warm records are marked by pink circles. Right: Annual five-day maxima of average temperature in the Pacific north-west, based on ERA5 reanalysis, along with 14 heat records marked by pink circles. Credit: Erich Fischer.

It is worth noting that some climate variables, including ocean heat content, sea level rise and minimum glacier or ice sheet volumes, are changing so relentlessly that new record levels are currently set every year.

Record-shattering events

Record-shattering events are a subset of record-breaking events whose magnitude exceeds the previous event by a large margin.

In our research, we define this as more than one standard deviation, which is a measure of how spread out data is from the average.

(The exact value of standard deviation varies for different parts of the world. For example, when it comes to year-to-year average temperatures, one standard deviation is typically 2-3C in the Arctic, but less than 0.5C over the ocean).

These events of unprecedented intensity are often very impactful as they strongly exceed the conditions that society or ecosystems have experienced in the past.

The 2021 heatwave in the Pacific north-west, mentioned above, is a forbidding example.

Our research finds that the large number of record-shattering events in the past three decades is the consequence of a very high warming rate.

Using a simple timeseries model, we illustrate why the pace of warming is the key factor explaining the occurrence of record-shattering events.

In the left-hand figure, we assume a 150-year period of no warming followed by some linear warming at three different rates, which is a very simplistic approximation of historical and future warming pathways.

The right-hand figure illustrates what happens to the probability of record-shattering events in the Pacific north-west region under these three simplified pathways. It shows that the probability of record-shattering events at first rapidly increases and then stabilises. And the level at which the probability stabilises is greater the higher the rate of warming.

Left: Three illustrative warming pathways with +/- 20% differing warming rates from a timeseries model. Right: Annual probability of record-shattering events (at or beyond one standard deviation) for different warming rates. Residual variability is used from Community Earth System Model 2 simulations for annual five-day maxima over the Pacific north-west. Credit: Amended from Fischer et al (2025).
Left: Three illustrative warming pathways with +/- 20% differing warming rates from a timeseries model. Right: Annual probability of record-shattering events (at or beyond one standard deviation) for different warming rates. Residual variability is used from Community Earth System Model 2 simulations for annual five-day maxima over the Pacific north-west. Credit: Amended from Fischer et al (2025).

We therefore conclude that the high frequency of record-shattering hot extremes in recent years is controlled by the very high rate of warming caused by human-caused greenhouse gas emissions.

This tight coupling of record counts to the rate or speed of warming implies that there will be early benefits of slowing down global warming.

In our research, we look at how the probability of hot and cold records changes under different emissions reduction scenarios. To do this, we analysed the occurrence of record hot and cold events in climate model projections in the CMIP6 archive.

The figure below shows how stabilising temperatures by achieving net-zero carbon emissions (SSP1-1.9 and SSP1-2.6) will lead to a rapid decline of records, even if temperatures remain higher than in the historical period.

(It is worth noting that, while the number of records will decline under this lower-emissions scenario, the number of heatwaves would remain higher than today.)

Under intermediate (SSP2-4.5), high (SSP3-7.0) and very high emission (SSP5-8.5) scenarios, the number of records would continue to increase to levels much higher than today.

Projected changes in record hot and cold records under different Shared Socioeconomic Pathways (SSP), including SSP1-1.19 (light blue), SSP1-2.6 (dark blue), SSP2-4.5 (yellow), SSP3-7.0 (orange) and SSP5-8.5 (dark red). The record ratio is calculated as the probability of all-time record daily hot or cold temperatures across global land regions, relative to the theoretically expected occurrence in a stationary climate. The black line represents the historical record. Credit: Fischer et al. (2025)
Projected changes in record hot and cold records under different Shared Socioeconomic Pathways (SSP), including SSP1-1.19 (light blue), SSP1-2.6 (dark blue), SSP2-4.5 (yellow), SSP3-7.0 (orange) and SSP5-8.5 (dark red). The record ratio is calculated as the probability of all-time record daily hot or cold temperatures across global land regions, relative to the theoretically expected occurrence in a stationary climate. The black line represents the historical record. Credit: Fischer et al. (2025)

Rainfall records

We would also expect rainfall records to become progressively rarer in a stationary climate.

However, we find that record-breaking heavy precipitation occurred about 40% more often in 2015-24 than would be expected in a stationary climate. Many record-shattering heavy rainfall extremes occurred in the mid-latitudes and led to flooding which had large impacts.

(Calculating the frequency of records is more challenging for rainfall than for temperature, given small-scale variations and uncertainties in rainfall observations.)

The greater number of record-breaking rainfall events is due to an increase in precipitation intensity over most land regions as the atmosphere warms, as well as larger variations of rainfall intensity on a day-to-day, season-to-season and year-to-year basis .

We also find that the margin by which previous rainfall records are broken tends to become larger and larger in time. This is due to the “non-symmetric” distribution of rainfall – where there are many days with little precipitation, less with heavy precipitation and very few with very extreme precipitation.

It is therefore not surprising to see record-shattering precipitation events exceeding previous records by 20-50% in intensity, even if overall precipitation intensity increases by roughly 7% per degree of warming.

Preparing for the future

Efforts to adapt to climate change are typically informed by the worst events observed in recent generations.

This means that society is often underprepared for record-shattering events – which by their very definition are of unprecedented intensity.

Qualitative and quantitative storyline methods can offer insight into the many record-breaking events to come into the future – and, thus, help society prepare for escalating climate impacts.

These methods combine information from historical and paleoarchives, long measurement series, targeted climate model experiments, statistical and machine learning methods and weather forecasting systems.

Ultimately, these methods can improve society’s preparedness to climate change, so that the next record-shattering extreme does not come as a surprise.

The post Guest post: How climate change is fuelling record-breaking extreme weather appeared first on Carbon Brief.

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Permitting reform: A major key to cutting climate pollution 

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Permitting reform: A major key to cutting climate pollution

By Dana Nuccitelli, CCL Research Coordinator

Permitting reform has emerged as the biggest and most important clean energy and climate policy area in the 119th Congress (2025-2026). 

To make sure every CCL volunteer understands the opportunities and challenges ahead, CCL Vice President of Government Affairs Jennifer Tyler and I recently provided two trainings about the basics of permitting reform and understanding the permitting reform landscape.

These first introductory trainings set the stage for the rest of an ongoing series, which will delve into the details of several key permitting reform topics that CCL is engaging on. Read on for a recap of the first two trainings and a preview of coming attractions.

Permitting reform basics

Before diving into the permitting reform deep end, we need to first understand the fundamentals of the topic: what is “permitting”? What problems are we trying to solve with permitting reform? Why is it a key climate solution?

In short, a permit is a legal authorization issued by a government agency (federal and/or state and/or local) that allows a specific activity or project to proceed under certain defined conditions. The permitting process ensures that public health, safety, and the environment are protected during the construction and operation of the project.

But the permitting process can take a long time, and in some cases it’s taking so long that it’s unduly slowing down the clean energy transition. “Permitting reform” seeks to make the process more efficient while still ensuring that public health, safety, and the environment are protected.

There are a lot of factors involved in the permitting reform process, including environmental laws, limitations on lawsuits, and measures to expedite the building of electrical transmission lines that are key for expanding the capacity of America’s aging electrical grid in order to allow us to connect more clean energy and meet our energy affordability and security and climate needs.

But if we can succeed in passing a good, comprehensive permitting reform package through Congress, it could unlock enough climate pollution reductions to offset what we lost from this year’s rollback of the Inflation Reduction Act’s clean energy investments. Permitting reform is the big climate policy in the current session of Congress.

Watch the Full Training Here

Understanding the permitting reform landscape

In the second training of this series, we sought to understand the players and the politics in the permitting reform space, learn about the challenges involved, and explore CCL’s framework and approach for weighing in on this policy topic.

Permitting reform has split some traditional alliances along two differing theories about how to best address climate change. Some groups with a theory of change relying on using permitting and lawsuits to slow and stop fossil fuel infrastructure are least likely to be supportive of a permitting reform effort. Groups like CCL that recognize the importance of quickly building lots of clean, affordable energy infrastructure are more supportive of permitting reform measures.

The subject has created some strange bedfellows, because clean energy and fossil fuel companies and organizations all want efficient permitting for their projects, and hence all tend to support permitting reform. For CCL, the key question is whether a comprehensive permitting reform package will be a net benefit to clean energy or the climate — and that’s what we’re working toward.

The two major political parties also have different priorities when it comes to permitting reform. Republicans tend to view it through a lens of reducing government red tape, ensuring that laws and regulations are only used for their intended purpose, and achieving energy affordability and security. Democrats prioritize building clean energy faster to slow climate change, addressing energy affordability, and protecting legacy environmental laws and community engagement.

Watch the Full Training Here

As we discussed in the training, there are a number of key concepts that will require compromise from both sides of the aisle in order to reach a durable bipartisan permitting reform agreement. We’ll delve into the details of these in these upcoming trainings:

The Challenge of Energy Affordability and Security

First, with support from CCL’s Electrification Action Team, on February 5 I’ll examine what’s behind rising electricity rates and energy insecurity in the U.S. and how we can solve these problems. Electrification is a key climate solution in the transition to clean energy sources. But electricity rates are rising fast and face surging demand from artificial intelligence data centers. Permitting reform can play a key role in addressing these challenges.

Transmission Reform and Key Messages

Insufficient electrical transmission capacity is acting as a bottleneck slowing down the deployment of new clean energy sources in the U.S. Reforming cumbersome transmission permitting processes could unlock billions of tons of avoided climate pollution while improving America’s energy security and affordability. In this training on March 5, Jenn and I will dive into the details of the key clean energy and climate solution that is transmission reform, and the key messages to use when lobbying our members of Congress.

Build Faster and Key Messages

Clean energy projects often encounter long, complex permitting steps that slow construction and raise costs. Practical permitting reforms can help ensure that good projects move forward faster while upholding environmental and community protections. In this training on March 19, Jenn and I will examine permitting reforms to build energy infrastructure faster, some associated tensions and compromises that they may involve, and key messages for congressional offices.

Fair Permitting Certainty

Presidents from both political parties have taken steps to interfere with the permitting of certain types of energy infrastructure that they oppose. These executive actions create uncertainty that inhibits the development of new energy sources in the United States. For this reason, ensuring fair permitting certainty is a key aspect of permitting reform that enjoys bipartisan support. In this training on April 2, Jenn and I will discuss how Congress can ensure certainty in a permitting reform package, and key messages for congressional offices.

Community Engagement and Key Messages

It’s important for energy project developers to engage local communities in order to address any local concerns and adverse impacts that may arise from new infrastructure projects. But it’s also important to strike a careful balance such that community input can be heard and addressed in a timely manner without excessively slowing new clean energy project timelines. In this training on May 7, Jenn and I will examine how community engagement may be addressed in the permitting reform process, and key messages for congressional offices.

We look forward to nerding out with you in these upcoming advanced and important permitting reform trainings! 🤓

Want to take action now? Use our online action tool to call Congress and encourage them to work together on comprehensive permitting reform.

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DeBriefed 30 January 2026:  Fire and ice; US formally exits Paris; Climate image faux pas

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Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.

This week

Fire and ice

OZ HEAT: The ongoing heatwave in Australia reached record-high temperatures of almost 50C earlier this week, while authorities “urged caution as three forest fires burned out of control”, reported the Associated Press. Bloomberg said the Australian Open tennis tournament “rescheduled matches and activated extreme-heat protocols”. The Guardian reported that “the climate crisis has increased the frequency and severity of extreme weather events, including heatwaves and bushfires”.

WINTER STORM: Meanwhile, a severe winter storm swept across the south and east of the US and parts of Canada, causing “mass power outages and the cancellation of thousands of flights”, reported the Financial Times. More than 870,000 people across the country were without power and at least seven people died, according to BBC News.

COLD QUESTIONED: As the storm approached, climate-sceptic US president Donald Trump took to social media to ask facetiously: “Whatever happened to global warming???”, according to the Associated Press. There is currently significant debate among scientists about whether human-caused climate change is driving record cold extremes, as Carbon Brief has previously explained.

Around the world

  • US EXIT: The US has formally left the Paris Agreement for the second time, one year after Trump announced the intention to exit, according to the Guardian. The New York Times reported that the US is “the only country in the world to abandon the international commitment to slow global warming”.
  • WEAK PROPOSAL: Trump officials have delayed the repeal of the “endangerment finding” – a legal opinion that underpins federal climate rules in the US – due to “concerns the proposal is too weak to withstand a court challenge”, according to the Washington Post
  • DISCRIMINATION: A court in the Hague has ruled that the Dutch government “discriminated against people in one of its most vulnerable territories” by not helping them to adapt to climate change, reported the Guardian. The court ordered the Dutch government to set binding targets within 18 months to cut greenhouse gas emissions in line with the Paris Agreement, according to the Associated Press.
  • WIND PACT: 10 European countries have agreed a “landmark pact” to “accelerate the rollout of offshore windfarms in the 2030s and build a power grid in the North Sea”, according to the Guardian
  • TRADE DEAL: India and the EU have agreed on the “mother of all trade deals”, which will save up to €4bn in import duty, reported the Hindustan Times. Reuters quoted EU officials saying that the landmark trade deal “will not trigger any changes” to the bloc’s carbon border adjustment mechanism.
  • ‘TWO-TIER SYSTEM’: COP30 president André Corrêa do Lago believes that global cooperation should move to a “two-speed system, where new coalitions lead fast, practical action alongside the slower, consensus-based decision-making of the UN process”, according to a letter published on Tuesday, reported Climate Home News

$2.3tn

The amount invested in “green tech” globally in 2025, marking a new record high, according to Bloomberg.


Latest climate research

  • Including carbon emissions from permafrost thaw and fires reduces the remaining carbon budget for limiting warming to 1.5C by 25% | Communications Earth & Environment 
  • The global population exposed to extreme heat conditions is projected to nearly double if temperatures reach 2C | Nature Sustainability
  • Polar bears in Svalbard – the fastest-warming region on Earth – are in better condition than they were a generation ago, as melting sea ice makes seal pups easier to reach | Scientific Reports

(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)

Captured

EV sales just overtook petrol cars in EU for the first time. Chart shows monthly new passenger card registrations in the EU.

Sales of electric vehicles (EVs) overtook standard petrol cars in the EU for the first time in December 2025, according to new figures released by the European Automobile Manufacturers’ Association (ACEA) and covered by Carbon Brief. Registrations of “pure” battery EVs reached 217,898 – up 51% year-on-year from December 2024. Meanwhile, sales of standard petrol cars in the bloc fell 19% year-on-year, from 267,834 in December 2024 to 216,492 in December 2025, according to the analysis.

Spotlight

Looking at climate visuals

Carbon Brief’s Ayesha Tandon recently chaired a panel discussion at the launch of a new book focused on the impact of images used by the media to depict climate change.

When asked to describe an image that represents climate change, many people think of polar bears on melting ice or devastating droughts.

But do these common images – often repeated in the media – risk making climate change feel like a far-away problem from people in the global north? And could they perpetuate harmful stereotypes?

These are some of the questions addressed in a new book by Prof Saffron O’Neill, who researches the visual communication of climate change at the University of Exeter.

The Visual Life of Climate Change” examines the impact of common images used to depict climate change – and how the use of different visuals might help to effect change.

At a launch event for her book in London, a panel of experts – moderated by Carbon Brief’s Ayesha Tandon – discussed some of the takeaways from the book and the “dos and don’ts” of climate imagery.

Power of an image

“This book is about what kind of work images are doing in the world, who has the power and whose voices are being marginalised,” O’Neill told the gathering of journalists and scientists assembled at the Frontline Club in central London for the launch event.

O’Neill opened by presenting a series of climate imagery case studies from her book. This included several examples of images that could be viewed as “disempowering”.

For example, to visualise climate change in small island nations, such as Tuvalu or Fiji, O’Neill said that photographers often “fly in” to capture images of “small children being vulnerable”. She lamented that this narrative “misses the stories about countries like Tuvalu that are really international leaders in climate policy”.

Similarly, images of power-plant smoke stacks, often used in online climate media articles, almost always omit the people that live alongside them, “breathing their pollution”, she said.

Ayesha Tandon with panellists at London’s Frontline Club. Credit: Carbon Brief
Ayesha Tandon with panellists at London’s Frontline Club. Credit: Carbon Brief

During the panel discussion that followed, panellist Dr James Painter – a research associate at the Reuters Institute for the Study of Journalism and senior teaching associate at the University of Oxford’s Environmental Change Institute – highlighted his work on heatwave imagery in the media.

Painter said that “the UK was egregious for its ‘fun in the sun’ imagery” during dangerous heatwaves.

He highlighted a series of images in the Daily Mail in July 2019 depicting people enjoying themselves on beaches or in fountains during an intense heatwave – even as the text of the piece spoke to the negative health impacts of the heatwave.

In contrast, he said his analysis of Indian media revealed “not one single image of ‘fun in the sun’”.

Meanwhile, climate journalist Katherine Dunn asked: “Are we still using and abusing the polar bear?”. O’Neill suggested that polar bear images “are distant in time and space to many people”, but can still be “super engaging” to others – for example, younger audiences.

Panellist Dr Rebecca Swift – senior vice president of creative at Getty images – identified AI-generated images as “the biggest threat that we, in this space, are all having to fight against now”. She expressed concern that we may need to “prove” that images are “actually real”.

However, she argued that AI will not “win” because, “in the end, authentic images, real stories and real people are what we react to”.

When asked if we expect too much from images, O’Neill argued “we can never pin down a social change to one image, but what we can say is that images both shape and reflect the societies that we live in”. She added:

“I don’t think we can ask photos to do the work that we need to do as a society, but they certainly both shape and show us where the future may lie.”

Watch, read, listen

UNSTOPPABLE WILDFIRES: “Funding cuts, conspiracy theories and ‘powder keg’ pine plantations” are making Patagonia’s wildfires “almost impossible to stop”, said the Guardian.

AUDIO SURVEY: Sverige Radio has published “the world’s, probably, longest audio survey” – a six-hour podcast featuring more than 200 people sharing their questions around climate change.

UNDERSTAND CBAM: European thinktank Bruegel released a podcast “all about” the EU’s carbon adjustment border mechanism, which came into force on 1 January.

Coming up

Pick of the jobs

DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.

This is an online version of Carbon Brief’s weekly DeBriefed email newsletter. Subscribe for free here.

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Factcheck: What it really costs to heat a home in the UK with a heat pump

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Electric heat pumps are set to play a key role in the UK’s climate strategy, as well as cutting the nation’s reliance on imported fossil fuels.

Heat pumps took centre-stage in the UK government’s recent “warm homes plan”, which said that they could also help cut household energy bills by “hundreds of pounds” a year.

Similarly, innovation agency Nesta estimates that typical households could cut their annual energy bills nearly £300 a year, by switching from a gas boiler to a heat pump.

Yet there has been widespread media coverage in the Times, Sunday Times, Daily Express, Daily Telegraph and elsewhere of a report claiming that heat pumps are “more expensive” to run.

The report is from the Green Britain Foundation set up by Dale Vince, owner of energy firm Ecotricity, who campaigns against heat pumps and invests in “green gas” as an alternative.

One expert tells Carbon Brief that Vince’s report is based on “flimsy data”, while another says that it “combines a series of worst-case assumptions to present an unduly pessimistic picture”.

This factcheck explains how heat pumps can cut bills, what the latest data shows about potential savings and how this information was left out of the report from Vince’s foundation.

How heat pumps can cut bills

Heat pumps use electricity to move heat – most commonly from outside air – to the inside of a building, in a process that is similar to the way that a fridge keeps its contents cold.

This means that they are highly efficient, adding three or four units of heat to the house for each unit of electricity used. In contrast, a gas boiler will always supply less than one unit of heat from each unit of gas that it burns, because some of the energy is lost during combustion.

This means that heat pumps can keep buildings warm while using three, four or even five times less energy than a gas boiler. This cuts fossil-fuel imports, reducing demand for gas by at least two-fifths, even in the unlikely scenario that all of the electricity they need is gas-fired.

Simon Evans on BlueSky (@drsimevans.carbonbrief.org): "Going slow on heat pumps could mean UK consumers having to pay an extra £3bn for imported gas 2026-2030, says Energy UK Says UK govt foot-dragging is "increasing costs for energy customers & hampering future system planning"

Since UK electricity supplies are now the cleanest they have ever been, heat pumps also cut the carbon emissions associated with staying warm by around 85%, relative to a gas boiler.

Heat pumps are, therefore, the “central” technology for cutting carbon emissions from buildings.

While heat pumps cost more to install than gas boilers, the UK government’s recent “warm homes plan” says that they can help cut energy bills by “hundreds of pounds” per year.

Similarly, Nesta published analysis showing that a typical home could cut its annual energy bill by £280, if it replaces a gas boiler with a heat pump, as shown in the figure below.

Nesta and the government plan say that significantly larger savings are possible if heat pumps are combined with other clean-energy technologies, such as solar and batteries.

Chart showing that clean electric tech could save households £1,000 a year, compared to gas boilers
Annual energy bill savings (£) for a typical household from April 2026, by using different clean-energy technologies in comparison with a gas boiler. Source: Nesta analysis, using data from Ofgem, the Centre for Net Zero and an Octopus Energy tariff.

Both the government and Nesta’s estimates of bill savings from switching to a heat pump rely on relatively conservative assumptions.

Specifically, the government assumes that a heat pump will deliver 2.8 units of heat for each unit of electricity, on average. This is known as the “seasonal coefficient of performance” (SCoP).

This figure is taken from the government-backed “electrification of heat” trial, which ran during 2020-2022 and showed that heat pumps are suitable for all building types in the UK.

(The Green Britain Foundation report and Vince’s quotes in related coverage repeat a number of heat pump myths, such as the idea that they do not perform well in older properties and require high levels of insulation.)

Nesta assumes a slightly higher SCoP of 3.0, says Madeleine Gabriel, the organisation’s director of sustainable future. (See below for more on what the latest data says about SCoP in recent installations.)

Both the government and Nesta assume that a home with a heat pump would disconnect from the gas grid, meaning that it would no longer need to pay the daily “standing charge” for gas. This currently amounts to a saving of around £130 per year.

Finally, they both consider the impact of a home with a heat pump using a “smart tariff”, where the price of electricity varies according to the time of day.

Such tariffs are now widely available from a variety of energy suppliers and many have been designed specifically for homes that have a heat pump.

Such tariffs significantly reduce the average price for a unit of electricity. Government survey data suggests that around half of heat-pump owners already use such tariffs.

This is important because on the standard rates under the price cap set by energy regulator Ofgem, each unit of electricity costs more than four times as much as a unit of gas.

The ratio between electricity and gas prices is a key determinant of the size and potential for running-cost savings with a heat pump. Countries with a lower electricity-to-gas price ratio consistently see much higher rates of heat-pump adoption.

(Decisions taken by the UK government in its 2025 budget mean that the electricity-to-gas ratio will fall from April, but current forecasts suggest it will remain above four-to-one.)

In contrast, Vince’s report assumes that gas boilers are 90% efficient, whereas data from real homes suggests 85% is more typical. It also assumes that homes with heat pumps remain on the gas grid, paying the standing charge, as well as using only a standard electricity tariff.

Prof Jan Rosenow, energy programme leader at the University of Oxford’s Environmental Change Institute, tells Carbon Brief that Vince’s report uses “worst-case assumptions”. He says:

“This report cherry-picks assumptions to reach a predetermined conclusion. Most notably, it assumes a gas boiler efficiency of 90%, which is significantly higher than real-world performance…Taken together, the analysis combines a series of worst-case assumptions to present an unduly pessimistic picture.”

Similarly, Gabriel tells Carbon Brief that Vince’s report is based on “flimsy data”. She explains:

“Dale Vince has drawn some very strong conclusions about heat pumps from quite flimsy data. Like Dale, we’d also like to see electricity prices come down relative to gas, but we estimate that, from April, even a moderately efficient heat pump on a standard tariff will be cheaper to run than a gas boiler. Paired with a time-of-use tariff, a heat pump could save £280 versus a boiler and adding solar panels and a battery could triple those savings.”

What the latest data shows about bill savings

The efficiency of heat-pump installations is another key factor in the potential bill savings they can deliver and, here, both the government and Vince’s report take a conservative approach.

They rely on the “electrification of heat” trial data to use an efficiency (SCoP) of 2.8 for heat pumps. However, Rosenow says that recent evidence shows that “substantially higher efficiencies are routinely available”, as shown in the figure below.

Detailed, real-time data on hundreds of heat pump systems around the UK is available via the website Heat Pump Monitor, where the average efficiency – a SCoP of 3.9 – is much higher.

Charts showing that recent heat-pump installations tend to be far more efficient
Number of installations by heat pump efficiency, in the electrification of heat trial (left) and on the website Heat Pump Monitor (right). An efficiency of three means that each unit of electricity delivers three units of heat, on average, across a year. Source: Heat Pump Monitor.

Homes with such efficient heat-pump installations would see even larger bill savings than suggested by the government and Nesta estimates.

Academic research suggests that there are simple and easy-to-implement reasons why these systems achieve much higher efficiency levels than in the electrification of heat trial.

Specifically, it shows that many of the systems in the trial have poor software settings, which means they do not operate as efficiently as their heat pump hardware is capable of doing.

The research suggests that heat pump installations in the UK have been getting more and more efficient over time, as engineers become increasingly familiar with the technology.

It indicates that recently installed heat pumps are 64% more efficient than those in early trials.

Jan Rosenow on BlueSky (@janrosenow.bsky.social): "Well-installed heat pumps installed in the UK today achieve on average a 64% higher efficiency than those during the early trials 15 years ago. It is testament to the brilliant installers and to the technology getting better. More in our recent paper"

Notably, the Green Britain Foundation report only refers to the trial data from the electrification of heat study carried out in 2020-22 and the even earlier “renewable heat premium package” (RHPP). This makes a huge difference to the estimated running costs of a heat pump.

Carbon Brief analysis suggests that a typical household could cut its annual energy bills by nearly £200 with a heat pump – even on a standard electricity tariff – if the system has a SCoP of 3.9.

The savings would be even larger on a smart heat-pump tariff.

In contrast, based on the oldest efficiency figures mentioned in the Green Britain Foundation report, a heat pump could increase annual household bills by as much as £200 on a standard tariff.

To support its conclusions, the report also includes the results of a survey of 1,001 heat pump owners, which, among other things, is at odds with government survey data. The report says “66% of respondents report that their homes are more expensive to heat than the previous system”.

There are several reasons to treat these findings with caution. The survey was carried out in July 2025 and some 45% of the heat pumps involved were installed between 2021-23.

This is a period during which energy prices surged as a result of Russia’s invasion of Ukraine and the resulting global energy crisis. Energy bills remain elevated as a result of high gas prices.

The wording of the survey question asks if homes are “more or less expensive to heat than with your previous system” – but makes no mention of these price rises.

The question does not ask homeowners if their bills are higher today, with a heat pump, than they would have been with the household’s previous heating system.

If respondents interpreted the question as asking whether their bills have gone up or down since their heat pump was installed, then their answers will be confounded by the rise in prices overall.

There are a number of other seemingly contradictory aspects of the survey that raise questions about its findings and the strong conclusions in the media coverage of the report.

For example, while only 15% of respondents say it is cheaper to heat their home with a heat pump, 49% say that one of the top three advantages of the system is saving money on energy bills.

In addition, 57% of respondents say they still have a boiler, even though 67% say they received government subsidies for their heat-pump installation. It is a requirement of the government’s boiler upgrade scheme (BUS) grants that homeowners completely remove their boiler.

The government’s own survey of BUS recipients finds that only 13% of respondents say their bills have gone up, whereas 37% say their bills have gone down, another 13% say they have stayed the same and 8% thought that it was too early to say.

The post Factcheck: What it really costs to heat a home in the UK with a heat pump appeared first on Carbon Brief.

Factcheck: What it really costs to heat a home in the UK with a heat pump

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