The term “global warming” is typically used to describe increasing global temperatures as a result of human emissions of carbon dioxide (CO2) and other greenhouse gases.
However, unusually cold events are often portrayed as being made worse by human activity, as a result of increased variability or a disruption of the “polar vortex” in a fast-warming world.
There is significant debate in the scientific community about whether rapid Arctic warming and sea ice loss could disrupt atmospheric circulation patterns and lead to cold-air outbreaks in the northern hemisphere mid-latitude regions.
In a new analysis, Carbon Brief shows that few places in the world have seen an increase in extreme cold days over the past 55 years.
If climate change is influencing atmospheric circulation, any effects on extreme cold appear to be more than compensated by the rapid winter warming the world has experienced.
A controversial hypothesis
In an episode of Marketplace’s How We Survive podcast last year, the host – US radio journalist Kai Ryssdal – noted that climate change is expected to cause “hotter hots [and] colder colds in unexpected parts of the world”.
This is not an uncommon sentiment, with the media commonly attributing extreme cold events to human activity, particularly during episodes of bitter cold or polar-vortex events.
Some researchers have argued that these extreme cold snaps might be becoming more frequent due to reduced sea ice and Arctic amplification – the phenomenon where the Arctic warms more quickly than the global average.
At the core of the hypothesis that Arctic warming could influence mid-latitude cold extremes is the fact that a rapidly warming Arctic changes the temperature difference between the poles and the equator.
Normally, the strong contrast in temperature between these regions drives key patterns of atmospheric circulation, including the jet stream. According to proponents of this theory, when Arctic temperatures rise faster than those farther south, atmospheric circulation can weaken, meander, or buckle more frequently. As a result, cold polar air can spill down into areas that are usually less frigid.
A related argument focuses on how diminished sea ice – particularly in the Barents and Kara seas – might disrupt the atmosphere. Less sea ice means more heat and moisture escapes from the ocean surface into the air, which can potentially alter weather patterns downstream. This can boost the odds of “blocking high” weather systems, or unusual circulation patterns that pull cold air into mid-latitudes.
However, there are relatively few studies that attribute an increase in cold extremes – or an individual extreme cold event – to human activity.
Carbon Brief’s attribution map – which charts extreme weather events around the world and their links to human-caused warming – includes 33 studies that examine extreme cold events specifically.
Of these, 24 studies found that the extreme cold was made less likely due to climate change, six found no discernible human influence and three found insufficient data to conclude either way. Only one extreme event attribution study in the database found that a cold extreme – severe frosts in Western Australia in 2016 – was made more likely due to climate change. However, even that study noted that “warmer temperatures may have offset or countered this effect of the circulation driver”.
Many climate scientists disagree with the hypothesis that warming could lead to increased cold outbreaks, arguing that cold extremes are decreasing overall in a warming world.
Others contend that causality cannot yet be proved and that both models and observations provide limited support for a significant role of climate change in mid-latitude cold events.
In addition, observed data reveals that, although cold spells still occur, they have become less frequent and less intense over recent decades. Most modeling studies do not consistently reproduce more frequent or severe cold outbreaks. Instead, they often show that the overall warming trend dominates, making cold extremes rarer over time.
This suggests that, if there were a connection between climate change and extreme cold events, the long-term warming trend will still likely lead to fewer, milder cold outbreaks – and that any effect from Arctic amplification would be relatively small.
Have any regions experienced increased cold events?
To help assess the effects of climate change on extreme cold events, Carbon Brief used gridded daily minimum global temperature data from Berkeley Earth to calculate how the temperatures of the coldest 5% of the days of the year have changed since the 1970s.
Minimum daily temperatures reflect the single coldest measurement taken over the course of the day. (While the coldest 5% of days is a somewhat arbitrary number, the results are largely similar for the coldest 10%, 5%, 2%, 1%, or the single coldest day of the year.)
The figure below shows the results for every one-by-one degree latitude-longitude grid cell on the Earth’s land (a size approximately equivalent to 100km by 100km). Grid cells coloured red experienced a decrease in extreme cold days, while those coloured blue had more extreme cold days.
The vast majority of the planet has seen a strong decrease in extreme cold events, with the largest declines seen in high-latitude northern hemisphere regions (which have also experienced the fastest rate of warming overall).
The few regions that have seen an increase in extreme cold events tend to be those with the slowest average rates of warming, including India, South Africa and Antarctica.
In India, this has likely been influenced by rapid increases in air pollution – particularly cooling sulfate aerosols – over this period. Causes of more extreme cold events in Antarctica are less clear, though it is possible that they could be linked to the seasonal loss of ozone layer over the past 50 years.
Another way to assess changes in cold events is to look at the change in the number of days where any hour of the day – that is, the daily minimum temperature – is below freezing (0C, 32F). The map below shows the change in average annual freezing days between 1970 and 2024.
The map shows dramatic shifts in the number of freezing days in much of the high-latitude northern hemisphere, with nearly a month fewer freezing days over the Himalayas, eastern Europe and parts of Canada and the western US over the past 50 years.
(White areas on the graph – such as much of the tropics and subtropics – represent regions of the world where temperatures below freezing almost never occur and thus changes over time cannot be calculated.)
Fewer cold outbreaks in the US
A sizable portion of the academic research on cold outbreaks has been focused on the contiguous US, as it is a region prone to occasional extreme cold conditions caused by intrusions of Arctic air.
The map below shows there has been a warming trend in the coldest days of the year across virtually the entire US over the past 50 years.
This suggests that the effect of Arctic amplification on cold-air patterns is smaller than the strong winter warming trend.
Almost no regions of the US have seen a cooling trend in the 5% coldest days of the year – and higher latitude regions have tended to experience the fastest winter warming.
There has been a slight cooling trend in the coldest days of the year in northern Mexico and slower warming in California, Arizona, southern New Mexico and southern Texas.
Similarly, the figure below examines the change in days where minimum temperatures are below freezing in the US.
It shows that there are, on average, 13 fewer days below freezing each year compared to the 1970s. Or, to put it another way, there is half a month where daily minimum temperatures are no longer cold enough for icy and snowy conditions to occur.
Increasingly rare cold spells
The latest climate models overwhelmingly project that cold extremes will continue to diminish as greenhouse gas concentrations rise.
This means that, even if certain patterns occasionally transport freezing polar air southward, winters on the whole are likely to be milder than in the past.
However, the scientific understanding of precisely how Arctic warming might – or might not – influence mid-latitude weather is still evolving.
Researchers continue to refine models, incorporate better reanalysis data and examine how changes in atmospheric circulation dynamics might play out under different scenarios. Additional data – especially over multiple decades – will help clarify whether the Arctic’s role in mid-latitude cold extremes is significant or overstated.
For now, observations over the past 50 years generally show a world with fewer cold extremes – and projections point toward increasingly rare cold spells in the future.
The post Factcheck: Climate change is not making extreme cold more common appeared first on Carbon Brief.
Factcheck: Climate change is not making extreme cold more common
Climate Change
DeBriefed 15 August 2025: Raging wildfires; Xi’s priorities; Factchecking the Trump climate report
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Blazing heat hits Europe
FANNING THE FLAMES: Wildfires “fanned by a heatwave and strong winds” caused havoc across southern Europe, Reuters reported. It added: “Fire has affected nearly 440,000 hectares (1,700 square miles) in the eurozone so far in 2025, double the average for the same period of the year since 2006.” Extreme heat is “breaking temperature records across Europe”, the Guardian said, with several countries reporting readings of around 40C.
HUMAN TOLL: At least three people have died in the wildfires erupting across Spain, Turkey and Albania, France24 said, adding that the fires have “displaced thousands in Greece and Albania”. Le Monde reported that a child in Italy “died of heatstroke”, while thousands were evacuated from Spain and firefighters “battled three large wildfires” in Portugal.
UK WILDFIRE RISK: The UK saw temperatures as high as 33.4C this week as England “entered its fourth heatwave”, BBC News said. The high heat is causing “nationally significant” water shortfalls, it added, “hitting farms, damaging wildlife and increasing wildfires”. The Daily Mirror noted that these conditions “could last until mid-autumn”. Scientists warn the UK faces possible “firewaves” due to climate change, BBC News also reported.
Around the world
- GRID PRESSURES: Iraq suffered a “near nationwide blackout” as elevated power demand – due to extreme temperatures of around 50C – triggered a transmission line failure, Bloomberg reported.
- ‘DIRE’ DOWN UNDER: The Australian government is keeping a climate risk assessment that contains “dire” implications for the continent “under wraps”, the Australian Financial Review said.
- EXTREME RAINFALL: Mexico City is “seeing one of its heaviest rainy seasons in years”, the Washington Post said. Downpours in the Japanese island of Kyushu “caused flooding and mudslides”, according to Politico. In Kashmir, flash floods killed 56 and left “scores missing”, the Associated Press said.
- SOUTH-SOUTH COOPERATION: China and Brazil agreed to “ensure the success” of COP30 in a recent phone call, Chinese state news agency Xinhua reported.
- PLASTIC ‘DEADLOCK’: Talks on a plastic pollution treaty have failed again at a summit in Geneva, according to the Guardian, with countries “deadlocked” on whether it should include “curbs on production and toxic chemicals”.
15
The number of times by which the most ethnically-diverse areas in England are more likely to experience extreme heat than its “least diverse” areas, according to new analysis by Carbon Brief.
Latest climate research
- As many as 13 minerals critical for low-carbon energy may face shortages under 2C pathways | Nature Climate Change
- A “scoping review” examined the impact of climate change on poor sexual and reproductive health and rights in sub-Saharan Africa | PLOS One
- A UK university cut the carbon footprint of its weekly canteen menu by 31% “without students noticing” | Nature Food
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
Factchecking Trump’s climate report
A report commissioned by the US government to justify rolling back climate regulations contains “at least 100 false or misleading statements”, according to a Carbon Brief factcheck involving dozens of leading climate scientists. The report, compiled in two months by five hand-picked researchers, inaccurately claims that “CO2-induced warming might be less damaging economically than commonly believed” and misleadingly states that “excessively aggressive [emissions] mitigation policies could prove more detrimental than beneficial”80
Spotlight
Does Xi Jinping care about climate change?
This week, Carbon Brief unpacks new research on Chinese president Xi Jinping’s policy priorities.
On this day in 2005, Xi Jinping, a local official in eastern China, made an unplanned speech when touring a small village – a rare occurrence in China’s highly-choreographed political culture.
In it, he observed that “lucid waters and lush mountains are mountains of silver and gold” – that is, the environment cannot be sacrificed for the sake of growth.
(The full text of the speech is not available, although Xi discussed the concept in a brief newspaper column – see below – a few days later.)
In a time where most government officials were laser-focused on delivering economic growth, this message was highly unusual.
Forward-thinking on environment
As a local official in the early 2000s, Xi endorsed the concept of “green GDP”, which integrates the value of natural resources and the environment into GDP calculations.
He also penned a regular newspaper column, 22 of which discussed environmental protection – although “climate change” was never mentioned.
This focus carried over to China’s national agenda when Xi became president.
New research from the Asia Society Policy Institute tracked policies in which Xi is reported by state media to have “personally” taken action.
It found that environmental protection is one of six topics in which he is often said to have directly steered policymaking.
Such policies include guidelines to build a “Beautiful China”, the creation of an environmental protection inspection team and the “three-north shelterbelt” afforestation programme.
“It’s important to know what Xi’s priorities are because the top leader wields outsized influence in the Chinese political system,” Neil Thomas, Asia Society Policy Institute fellow and report co-author, told Carbon Brief.
Local policymakers are “more likely” to invest resources in addressing policies they know have Xi’s attention, to increase their chances for promotion, he added.
What about climate and energy?
However, the research noted, climate and energy policies have not been publicised as bearing Xi’s personal touch.
“I think Xi prioritises environmental protection more than climate change because reducing pollution is an issue of social stability,” Thomas said, noting that “smoggy skies and polluted rivers” were more visible and more likely to trigger civil society pushback than gradual temperature increases.
The paper also said topics might not be linked to Xi personally when they are “too technical” or “politically sensitive”.
For example, Xi’s landmark decision for China to achieve carbon neutrality by 2060 is widely reported as having only been made after climate modelling – facilitated by former climate envoy Xie Zhenhua – showed that this goal was achievable.
Prior to this, Xi had never spoken publicly about carbon neutrality.
Prof Alex Wang, a University of California, Los Angeles professor of law not involved in the research, noted that emphasising Xi’s personal attention may signal “top” political priorities, but not necessarily Xi’s “personal interests”.
By not emphasising climate, he said, Xi may be trying to avoid “pushing the system to overprioritise climate to the exclusion of the other priorities”.
There are other ways to know where climate ranks on the policy agenda, Thomas noted:
“Climate watchers should look at what Xi says, what Xi does and what policies Xi authorises in the name of the ‘central committee’. Is Xi talking more about climate? Is Xi establishing institutions and convening meetings that focus on climate? Is climate becoming a more prominent theme in top-level documents?”
Watch, read, listen
TRUMP EFFECT: The Columbia Energy Exchange podcast examined how pressure from US tariffs could affect India’s clean energy transition.
NAMIBIAN ‘DESTRUCTION’: The National Observer investigated the failure to address “human rights abuses and environmental destruction” claims against a Canadian oil company in Namibia.
‘RED AI’: The Network for the Digital Economy and the Environment studied the state of current research on “Red AI”, or the “negative environmental implications of AI”.
Coming up
- 17 August: Bolivian general elections
- 18-29 August: Preparatory talks on the entry into force of the “High Seas Treaty”, New York
- 18-22 August: Y20 Summit, Johannesburg
- 21 August: Advancing the “Africa clean air programme” through Africa-Asia collaboration, Yokohama
Pick of the jobs
- Lancaster Environment Centre, senior research associate: JUST Centre | Salary: £39,355-£45,413. Location: Lancaster, UK
- Environmental Justice Foundation, communications and media officer, Francophone Africa | Salary: XOF600,000-XOF800,000. Location: Dakar, Senegal
- Politico, energy & climate editor | Salary: Unknown. Location: Brussels, Belgium
- EnviroCatalysts, meteorologist | Salary: Unknown. Location: New Delhi, India
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 15 August 2025: Raging wildfires; Xi’s priorities; Factchecking the Trump climate report appeared first on Carbon Brief.
DeBriefed 15 August 2025: Raging wildfires; Xi’s priorities; Factchecking the Trump climate report
Climate Change
New York Already Denied Permits to These Gas Pipelines. Under Trump, They Could Get Greenlit
The specter of a “gas-for-wind” compromise between the governor and the White House is drawing the ire of residents as a deadline looms.
Hundreds of New Yorkers rallied against new natural gas pipelines in their state as a deadline loomed for the public to comment on a revived proposal to expand the gas pipeline that supplies downstate New York.
New York Already Denied Permits to These Gas Pipelines. Under Trump, They Could Get Greenlit
A “critical assessment” report commissioned by the Trump administration to justify a rollback of US climate regulations contains at least 100 false or misleading statements, according to a Carbon Brief factcheck involving dozens of leading climate scientists.
The report – “A critical review of impacts of greenhouse gas emissions on the US climate” – was published by the US Department of Energy (DoE) on 23 July, just days before the government laid out plans to revoke a scientific finding used as the legal basis for emissions regulation.
The executive summary of the controversial report inaccurately claims that “CO2-induced warming might be less damaging economically than commonly believed”.
It also states misleadingly that “excessively aggressive [emissions] mitigation policies could prove more detrimental than beneficial”.
Compiled in just two months by five “independent” researchers hand-selected by the climate-sceptic US secretary of energy Chris Wright, the document has sparked fierce criticism from climate scientists, who have pointed to factual errors, misrepresentation of research, messy citations and the cherry-picking of data.
Experts have also noted the authors’ track record of promoting views at odds with the mainstream understanding of climate science.
Wright’s department claims the report – which is currently open to public comment as part of a 30-day review – underwent an “internal peer-review period amongst [the] DoE’s scientific research community”.
The report is designed to provide a scientific underpinning to one flank of the Trump administration’s plans to rescind a finding that serves as the legal prerequisite for federal emissions regulation. (The second flank is about legal authority to regulate emissions.)
The “endangerment finding” – enacted by the Obama administration in 2009 – states that six greenhouse gases are contributing to the net-negative impacts of climate change and, thus, put the public in danger.
In a press release on 29 July, the US Environmental Protection Agency said “updated studies and information” set out in the new report would “challenge the assumptions” of the 2009 finding.
Carbon Brief asked a wide range of climate scientists, including those cited in the “critical review” itself, to factcheck the report’s various claims and statements.
The post Factcheck: Trump’s climate report includes more than 100 false or misleading claims appeared first on Carbon Brief.
https://www.carbonbrief.org/factcheck-trumps-climate-report-includes-more-than-100-false-or-misleading-claims/
-
Climate Change2 years ago
Spanish-language misinformation on renewable energy spreads online, report shows
-
Climate Change Videos2 years ago
The toxic gas flares fuelling Nigeria’s climate change – BBC News
-
Greenhouse Gases1 year ago嘉宾来稿：满足中国增长的用电需求 光伏加储能“比新建煤电更实惠”
-
Climate Change1 year ago嘉宾来稿：满足中国增长的用电需求 光伏加储能“比新建煤电更实惠”
-
Carbon Footprint1 year agoUS SEC’s Climate Disclosure Rules Spur Renewed Interest in Carbon Credits
-
Climate Change2 years ago
Why airlines are perfect targets for anti-greenwashing legal action
-
Renewable Energy2 months ago
US Grid Strain, Possible Allete Sale
-
Climate Change2 years ago
Some firms unaware of England’s new single-use plastic ban