Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Deadly extremes
FLOODING: Up to 700 people are believed to have been killed by flash floods in Nigeria, reported BBC News. Northern Nigeria has faced “prolonged dry spells worsened by climate change”, followed by “excessive rainfall”, which can cause flash flooding, reported the Associated Press.
FIRES: In Canada, continuing wildfires forced the evacuation of more than 26,000 people, “with heavy smoke choking millions of Canadians and Americans and reaching as far away as Europe”, reported Le Monde. CBC News reported that authorities in the Canadian state of Saskatchewan have been “battling the worst wildfire [the state has] seen in decades”. Scientist Prof Colin Laroque told the broadcaster: “This is classic climate change…This is our new normal.”
DEVASTATION: In northeastern India, at least 48 people have been killed in flash floods, Al Jazeera reported. Meanwhile, in China’s southwestern Yunnan province, heavy rainfall over the weekend triggered “flash floods and mudslides”, damaging roads and disrupting power supplies to around 5,000 people, reported Reuters.
Trumping at the bit
DRILL, BABY, DRILL: The Trump administration in the US announced plans to eliminate Biden-era protections across millions of acres of the Alaskan Arctic, opening the area up for drilling and mining “in some of the last remaining pristine wilderness in the country”, the New York Times reported. According to US energy secretary, Chris Wright, Trump wants to “double the amount of oil coursing through Alaska’s vast pipeline system” and build a “massive natural gas project as its ‘big beautiful twin’”, reported the Associated Press.
‘GOLD STANDARD’: Elsewhere, more than 6,000 scientists and academics signed an open letter opposing a new push by Trump to impose what he called a restoration of “gold standard science” across federal agencies and national laboratories, reported the the New York Times. It explained: “The executive order puts his political appointees in charge of vetting scientific research and gives them the authority to ‘correct scientific information’, control the way it is communicated to the public and the power to ‘discipline’ anyone who violates the way the administration views science.” Meanwhile, CNN reported that “NASA scientists describe ‘absolute sh*tshow’ at agency as Trump budget seeks to dismantle top US climate lab”.
Around the world
- BIG TECH: Meta signed a 20-year deal with an Illinois nuclear plant for energy to power its AI and data centres, reported the Financial Times.
- BIG SOLAR: Builders will be required to fit solar panels to the “vast majority” of new-build homes in England under changes to be published this year, according to energy secretary Ed Miliband, said BBC News.
- BIG TARGET: The EU’s climate science adviser warned the bloc against watering down climate targets, a day after it was reported that EU climate commissioner Wopke Hoekstra “successfully lobbied Germany’s coalition government to endorse a controversial measure that weakens the EU’s next climate target”, said Politico.
- BIG PROBELÉM: Civil society groups raised the alarm on how the “exorbitant price of accommodation” and “high cost of flights” will undermine Brazil’s civil society participation at COP30 in Belém, reported Dialogue Earth.
$2.2 trillion
How much global investment in clean-energy technologies, including renewables, nuclear and energy storage, is expected in 2025, according to the International Energy Agency. This is “twice the amount expected for fossil fuels”, reported Reuters.
Latest climate research
- A study in Communications Earth & Environment warned that the world has “likely” already reached a tipping point in the West Antarctic ice sheet and that its collapse would result in four metres of sea level rise over a timescale that “could be millennia”.
- Nature Communications published research which found that poor air quality in Europe could lead to 282,000 premature deaths a year by 2100 under a low-ambition climate scenario – but drop to 67,000 if ambitious action is taken to cut emissions.
- Climate change-driven atmospheric evaporative demand – sometimes known as “atmospheric thirst” – caused around 40% of increased drought severity globally from 1981-2022, according to new research in Nature.
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
The UK’s sunniest spring generated a record amount of solar power, according to new Carbon Brief analysis. The data revealed that the nation’s solar sites generated a record 7.6 terawatt hours (TWh) of electricity from January to May 2025. This is 42% higher than the 5.4TWh generated in the same period last year, as well as marking a much larger 160% increase over the past decade, the analysis said. It added: “The solar electricity generated in 2025 to date has avoided the need to import gas costing around £600m, which would have released 6m tonnes of carbon dioxide (MtCO2) when burned.” The Times and BBC News covered the analysis.
Spotlight
Lessons from 20 years of Japanese ‘Cool Biz’
This week, Carbon Brief examines a “casual dress” policy that has been “surprisingly effective” at driving emissions savings in Japan.
For many people, the thought of Japan conjures up images of thronging cities, bright lights and smartly dressed “salary-men” unwinding in an “izakaya” (Japanese pub) after a gruelling day at the office.
Every morning, in cities around Japan, some 38 million office workers put on a uniform of suits and ties and make their way to work.
Come summer, however, and the morning commute adopts a laid-back Friday feel. Men’s suit jackets and neckties are replaced by open collars and short sleeves. Venture to the southern island of Okinawa and you might spot a salary-man in a Hawaiian-style “kariyushi” shirt.
This was not always the case. Twenty years ago this month, then-environment minister Yuriko Koike introduced Japan – and the world – to the term “Cool Biz”.
“Cool Biz” – literally Cool Business – is an enduring campaign aimed at reducing energy consumption from air conditioning in the hot summer months when temperatures routinely exceed 30C.
‘No necktie’
Introduced in 2005, the same year the Kyoto protocol finally “entered into force”, Cool Biz mandated that government office buildings turn down the air conditioning to 28C and encourage employees to cool off by wearing less formal clothing. The campaign was characterised by the pithy slogan: “No jacket, no necktie.”
The impact was near immediate. By official estimates, nearly half a million tonnes of CO2 were saved in the first year of Cool Biz. The following year the savings tripled.
In 2012, the policy was estimated to have saved Japan 2.2 MtCO2 of emissions. (This is equivalent to the emissions of Montenegro that year.)
While temperature regulations were only mandated in government buildings, the impacts of the campaign extended far wider.
Thanks to a widespread publicity campaign – which included a Cool Biz fashion show of Japanese public figures and business leaders – name recognition reached 96% in its first year, according to a survey by the Ministry of Environment.
Uniqlo, Japan’s largest clothes retailer, recorded a 14% sales bump – which it attributed to its range of Cool Biz-appropriate casual workwear. And the Federation of Japanese Necktie Unions petitioned the government, after it forecast a 30% sales slump worth approximately £1bn.
‘Accidental steering’
Twenty years on, working in relaxed attire in summer has become “firmly established in Japanese society”, Atsushi Watabe, programme director of sustainable consumption and production at Japan’s Institute for Global Environmental Strategies, told Carbon Brief.
But research into its popularity revealed that concerns about climate change are unlikely to have played a major role in the uptake.
Surveys with members of the public found that Cool Biz had little or no impact on peoples’ reported environmental awareness or commitment, according to Prof Elizabeth Shove, an emeritus professor of sociology at Lancaster University,
Cool Biz’s actual success was a case of “accidental steering” through a combination of social, material and historical factors, said Shove.
Government officials led by example, she said. Japan’s then prime minister Junchiro Koizumi insisted that Cool Biz be worn for cabinet meetings and appeared in interviews in open-collar shirts.
“If the ministers are wearing a tie, their subordinates would feel uneasy about not wearing it,” prime minister Koizumi said at the time. “So the ministers should not wear a tie.”
Turning down the air conditioning in government buildings, likewise, set a standard for other businesses to follow.
Timing also played a role, according to Watabe. Women working in Japanese offices were some of the earliest to support Cool Biz, having been subjected to cooling conventions adapted for male workers, he said, adding:
“Gradually, men who had always considered wearing suits outside as the norm also accepted the change and began to feel its benefits.”
A key lesson is that the success of Cool Biz came from shifting societal norms rather than targeting the behaviour of individuals, said Shove:
“Norms and values don’t just exist – they come from histories of standards, regulations and building research… [Cool Biz] was surprisingly effective by not changing individual behavior, but by just setting a new standard in the government’s own buildings and in industry.”
Watch, read, listen
DRILLED: A new podcast series explored how ”Greenpeace, which was only tangentially involved in the Standing Rock [oil pipeline] protests, has been slapped with a $666m bill for damages”.
REPUBLICANS ‘SCARED’: The Guardian interviewed former Democratic presidential candidate Bernie Sanders on a wide range of issues, including his thoughts on why some Republicans are “scared” to speak about the reality of climate change.
SELLING NEGATIVE EMISSIONS: A feature in the Financial Times examined the “battle to create a carbon trading market for negative emissions” in the UK.
Coming up
- 7 June: Ocean Rise and Coastal Resilience Summit, Nice, France
- 7-8 June: Blue Economy and Finance Forum, Monaco
- 9-13 June: Third UN Ocean Conference, Nice, France
- 11-13 June: Global NDC Conference 2025, Berlin, Germany
Pick of the jobs
- Asia Society Policy Institute, senior programme officer, China climate industrial policy | Salary: $58,500-70,000). Location: Washington DC
- Greenpeace, senior communications advisor | Salary: AUD$116,562.56. Location: Australia
- The Hertie School, research associate or postdoctoral researcher – climate politics | Salary: Unknown. Location: Berlin, Germany
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.
The post DeBriefed 6 June 2025: Nigeria’s deadly flash floods; UK’s record spring drives solar surge; Lessons from Japan’s ‘Cool Biz’ appeared first on Carbon Brief.
Greenhouse Gases
DeBriefed 13 June 2025: Trump’s ‘biggest’ climate rollback; UK goes nuclear; How Carbon Brief visualises research
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Trump’s latest climate rollback
RULES REPEALED: The US Environmental Protection Agency (EPA) has begun dismantling Biden-era regulations limiting pollution from power plants, including carbon dioxide emissions, reported the Financial Times. Announcing the repeal, climate-sceptic EPA administrator Lee Zeldin labelled efforts to fight climate change a “cult”, according to the New York Times. Politico said that these actions are the “most important EPA regulatory actions of Donald Trump’s second term to date”.
WEBSITE SHUTDOWN: The Guardian reported that the National Oceanic and Atmospheric Administration (NOAA)’s Climate.gov website “will imminently no longer publish new content” after all production staff were fired. Former employees of the agency interviewed by the Guardian believe the cuts were “specifically aimed at restricting public-facing climate information”.
EVS TARGETED: The Los Angeles Times reported that Trump signed legislation on Thursday “seeking to rescind California’s ambitious auto emission standards, including a landmark rule that eventually would have barred sales of new gas-only cars in California by 2035”.
UK goes nuclear
NEW NUCLEAR: In her first spending review, UK chancellor Rachel Reeves announced £14.2bn for the Sizewell C new nuclear power plant in Suffolk, England – the first new state-backed nuclear power station for decades and the first ever under a Labour government, BBC News reported. The government also announced funding for three small nuclear reactors to be built by Rolls-Royce, said the Times. Carbon Brief has just published a chart showing the “rise, fall and rise” of UK nuclear.
MILIBAND REWARDED: The Times described energy secretary Ed Miliband as one of the “biggest winners” from the review. In spite of relentless negative reporting around him from right-leaning publications, his Department of Energy Security and Net Zero (DESNZ) received the largest relative increase in capital spending. Carbon Brief’s summary has more on all the key climate and energy takeaways from the spending review.
Around the world
- UN OCEAN SUMMIT: In France, a “surge in support” brought the number of countries ratifying the High Seas Treaty to just 10 short of the 60 needed for the agreement to become international law, according to Sky News.
- CALLING TRUMP: Brazil’s president Luiz Inácio Lula da Silva said he would “call” Trump to “persuade him” to attend COP30, according to Agence France-Presse. Meanwhile, the Associated Press reported that the country’s environmental agency has fast tracked oil and highway projects that threaten the Amazon.
- GERMAN FOSSIL SURGE: Due to “low” wind levels, electricity generation from renewables in Germany fell by 17% in the first quarter of this year, while generation from fossil-fuel sources increased significantly, according to the Frankfurter Allgemeine Zeitung.
- BATTERY BOOST: The power ministry in India announced 54bn rupees ($631m) in funding to build 30 gigawatt-hours of new battery energy storage systems to “ensure round-the-clock renewable energy capacities”, reported Money Control.
-19.3C
The temperature that one-in-10 London winters could reach in a scenario where a key Atlantic ocean current system “collapses” and global warming continues under “intermediate” emissions, according to new research covered by Carbon Brief.
Latest climate research
- A study in Science Advances found that damage to coral reefs due to climate change will “outpace” reef expansion. It said “severe declines” will take place within 40-80 years, while “large-scale coral reef expansion requires centuries”.
- Climatic Change published research which identified “displacement and violence, caregiving burdens, early marriages of girls, human trafficking and food insecurity” as the main “mental health” stressors exacerbated by climate change for women in lower and middle-income countries.
- The weakening of a major ocean current system has partially offset the drying of the southern Amazon rainforest, research published in Environmental Research has found, demonstrating that climate tipping elements have the potential to moderate each other.
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
Aerosols – tiny light‑scattering particles produced mainly by burning fossil fuels – absorb or reflect incoming sunlight and influence the formation and brightness of clouds. In this way they have historically “acted as an invisible brake on global warming”. New Carbon Brief analysis by Dr Zeke Hausfather illustrated the extent to which a reduction in aerosol emissions in recent decades, while bringing widespread public health benefits through avoided deaths, has “unmasked” the warming caused by CO2 and other greenhouse gases. The chart above shows the estimated cooling effect of aerosols from the start of the industrial era until 2020.
Spotlight
How Carbon Brief turns complex research into visuals
This week, Carbon Brief’s interactive developer Tom Pearson explains how and why his team creates visuals from research papers.
Carbon Brief’s journalists will often write stories based on new scientific research or policy reports.
These documents will usually contain charts or graphics highlighting something interesting about the story. Sometimes, Carbon Brief’s visuals team will choose to recreate these graphics.
There are many reasons why we choose to spend time and effort doing this, but most often it can be boiled down to some combination of the following things.
Maintaining editorial and visual consistency
We want to, where possible, maintain editorial and visual consistency while matching our graphical and editorial style guides.
In doing this, we are trying to ease our audience’s reading experience. We hope that, by presenting a chart in a way that is consistent with Carbon Brief’s house style, readers will be able to concentrate on the story or the explanation we are trying to communicate and not the way that a chart might have been put together.
Highlighting relevant information
We want to highlight the part of a chart that is most relevant to the story.
Graphics in research papers, especially if they have been designed for a print context, often strive to illustrate many different points with a single figure.
We tend to use charts to answer a single question or provide evidence for a single point.
Paring charts back to their core “message”, removing extraneous elements and framing the chart with a clear editorial title helps with this, as the example below shows.
Ensuring audience understanding
We want to ensure our audience understands the “message” of the chart.
Graphics published in specialist publications, such as scientific journals, might have different expectations regarding a reader’s familiarity with the subject matter and the time they might be expected to spend reading an article.
If we can redraw a chart so that it meets the expectations of a more general audience, we will.
Supporting multiple contexts
We want our graphics to make sense in different contexts.
While we publish our graphics primarily in articles on our website, the nature of the internet means that we cannot guarantee that this is how people will encounter them.
Charts are often shared on social media or copy-pasted into presentations. We want to support these practices by including as much context relevant to understanding within the chart image as possible.
Below illustrates how adding a title and key information can make a chart easier to understand without supporting information.
When we do not recreate charts
When will we not redraw a chart? Most of the time! We are a small team and recreating data graphics requires time, effort, accessible data and often specialist software.
But, despite these constraints, when the conditions are right, the process of redrawing maps and charts allows us to communicate more clearly with our readers, transforming complex research into accessible visual stories.
Watch, read, listen
SPENDING $1BN ON CLIMATE: New Scientist interviewed Greg de Temmerman, former nuclear physicist turned chief science officer at Quadrature Climate Foundation, about the practicalities and ethics of philanthropic climate-science funding.
GENDER HURDLES: Research director Tracy Kajumba has written for Climate Home News about the barriers that women still face in attending and participating in COPs.
OCEAN HEATWAVES: The New York Times presented a richly illustrated look at how marine heatwaves are spreading across the globe and how they affect life in the oceans.
Coming up
- 16-26 June: Bonn climate talks, Bonn, Germany
- 16 June: 79th meeting of the World Meteorological Organization executive council, Geneva, Switzerland
- 17 June: International Energy Agency (IEA) Oil 2025 report launch
Pick of the jobs
- Inside Climate News, California environmental reporter | Salary: Unknown. Location: Southern California
- Natural Resources Wales, lead marine and energy policy advisor | Salary: £45,367-£50,877. Location: Wales
- Children’s Investment Fund Foundation, senior manager, climate | Salary: £82,000. Location: London/hybrid
- Green Party,social media and digital content officer | Salary: £33,211. Location: London/remote
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.
The post DeBriefed 13 June 2025: Trump’s ‘biggest’ climate rollback; UK goes nuclear; How Carbon Brief visualises research appeared first on Carbon Brief.
The UK’s chancellor Rachel Reeves gave the green light this week to the Sizewell C new nuclear plant in Suffolk, along with funding for “small modular reactors” (SMRs) and nuclear fusion.
In her spending review of government funding across the rest of this parliament, Reeves pledged £14.2bn for Sizewell C, £2.5bn for Rolls-Royce SMRs and £2.5bn for fusion research.
The UK was a pioneer in civilian nuclear power – opening the world’s first commercial reactor at Calder Hall in Cumbria in 1956 – which, ultimately, helped to squeeze out coal generation.
Over the decades that followed, the UK’s nuclear capacity climbed to a peak of 12.2 gigawatts (GW) in 1995, while electricity output from the fleet of reactors peaked in 1998.
The chart below shows the contribution of each of the UK’s nuclear plants to the country’s overall capacity, according to when they started and stopped operating.
The reactors are dotted around the UK’s coastline, where they can take advantage of cooling seawater, and many sites include multiple units coded with numbers or letters.
Since Sizewell B was completed in 1995, however, no new nuclear plants have been built – and, as the chart above shows, capacity has ebbed away as older reactors have gone out of service.
After a lengthy hiatus, the Hinkley C new nuclear plant in Somerset was signed off in 2016. It is now under construction and expected to start operating by 2030 at the earliest.
(Efforts to secure further new nuclear schemes at Moorside in Cumbria failed in 2017, while projects led by Hitachi at Wylfa on Anglesey and Oldbury in Gloucestershire collapsed in 2019.)
The additional schemes just given the go-ahead in Reeves’s spending review would – if successful – somewhat revive the UK’s nuclear capacity, after decades of decline.
However, with the closure of all but one of the UK’s existing reactors due by 2030, nuclear-power capacity would remain below its 1995 peak, unless further projects are built.
Moreover, with the UK’s electricity demand set to double over the next few decades, as transport, heat and industry are increasingly electrified, nuclear power is unlikely to match the 29% share of generation that it reached during the late 1990s.
There is an aspirational goal – set under former Conservative prime minister Boris Johnson – for nuclear to supply “up to” a quarter of the UK’s electricity in 2050, with “up to” 24GW of capacity.
Assuming Sizewell B continues to operate until 2055 and that Hinkley C, Sizewell C and at least three Rolls-Royce SMRs are all built, this would take UK capacity back up to 9.0GW.
Methodology
The chart is based on data from the World Nuclear Association, with known start dates for operating and retired reactors, as well as planned closure dates announced by operator EDF.
The timeline for new reactors to start operating – and assumed 60-year lifetime – is illustrative, based on published information from EDF, Rolls-Royce, the UK government and media reports.
The post Chart: The rise, fall and rise of UK nuclear power over eight decades appeared first on Carbon Brief.
Chart: The rise, fall and rise of UK nuclear power over eight decades
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 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.
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.
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.
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.
Guest post: How climate change is fuelling record-breaking extreme weather
DeBriefed 13 June 2025: Trump’s ‘biggest’ climate rollback; UK goes nuclear; How Carbon Brief visualises research
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