The “dangerous humid heat” that engulfed western Africa in mid-February was made 10 times more likely by human-caused climate change, a new rapid attribution study finds.
Throughout February, western Africa was hit by unusually intense heat. Temperatures exceeded 40C in some regions, prompting the Ghanaian and Nigerian meteorological services to issue heat warnings.
The World Weather Attribution (WWA) service have analysed the region’s “heat index” – a measure that incorporates both temperature and humidity, to reflect the physiological impacts of the extreme conditions.
While the average air temperatures in west Africa reached 36C over 11-15 February, the heat index for the same period was about 50C, according to the study.
The study authors find that climate change made the heatwave 10 times more likely and 4C hotter. They warn that if global warming reaches 2C above pre-industrial temperatures, “similar events will occur about once every two years and will become a further 1.2-3.4C hotter”.
There was “very limited” data available on the impacts of this heatwave across west Africa, the study notes. However, the authors told a press briefing that heat is a “silent killer” and that lack of reported impacts does not mean the heatwave was not dangerous.
The report says that “to reduce heat-related morbidity and mortality in southern west Africa, there is an urgent need for improved monitoring and research on the impacts and risks associated with heat waves”.
Early heatwave
Countries across west Africa have been sweltering under unseasonably hot temperatures for weeks.
Wasiu Adeniyi Ibrahim is a meteorologist from the Nigerian Meteorological Agency and a co-author on the study. He told a press briefing that in west Africa, the most severe hot and humid weather of the year is usually recorded during March and April.
However, by February this year, the region was already reporting record-breaking temperatures. This intense heat was driven by an “anomalous high-pressure system over the Sahara region” which “carried hot air towards the coast”, Ibrahim explained.
On 7 February, the Ghanaian capital city of Accra recorded its hottest day in history when temperatures reached 38C.
The finals of the Africa Cup of Nations football tournament were played in Ivory Coast on 11 February. This year, for the first time, the Confederation of African Football included two-minute cooling breaks at the 30th and 75th minutes, with provisions for additional breaks under extreme heat.
The Nigerian Meteorological Agency issued a warning on 13 February after air temperatures hit 41C in the north of the country, stating that the heat could cause conditions including fainting, heat rash, “weakness of the body” and respiratory issues. The agency advised people to stay hydrated, seek shade and stay indoors as much as possible between midday and 4pm.
“Experts warn that the extreme temperatures, amid the epileptic power supply, could trigger diseases, threaten livestock, and lead to death,” the Nigerian newspaper Punch said, reporting on the heat warning.
The WWA adds that, across Nigeria, “doctors reported an increase in patients presenting for heat-related illness” and “people complained of poor sleep due to hot nights”.
The Ghanaian Meteorological Agency released an “urgent public service announcement” on 20 February, advising precautionary measures such as staying hydrated and avoiding direct sun exposure.
As the month progressed, hundreds of regional and national temperature records across the region were broken, including hottest February nights in Ghana, Benin and Togo.
‘Dangerous humid heat’
Extreme heat is particularly dangerous when combined with high humidity. When it is hot, the human body produces sweat to cool itself down. However, as humidity increases, sweating becomes less effective.
To assess the severity of the hot and humid conditions, the study authors analysed the “heat index”. This measure “combines temperature and humidity to reflect how it feels to the human body”, Dr Izidine Pinto – a researcher at the Royal Netherlands Meteorological Institute and co-author on the study – explained to a press briefing.
The study says:
“While the average air temperature in west Africa was above 36C, the heat index for the same period was about 50C, reflecting how a combination of humidity and high temperatures caused dangerous conditions.”
The authors focus on a region of southern west Africa where the heat was the most extreme, including Nigeria, Benin, Togo, Ghana, Ivory Coast, Liberia, Sierra Leone, and small parts of Guinea and Cameroon.
The maps below show the five-day heat index over this region averaged over 11-15 February (left), where purple indicates hotter temperatures, and the difference compared to the 1991-2020 average (right), where red indicates hotter temperatures. The blue boxes in both maps indicate the study region.
Pinto told the press briefing that as there was no meteorological station data available for many of the countries in the study region, the researchers had to “wait for the gridded datasets to be updated and validated for the region” before conducting their analysis. This delayed the release of the study findings, he said.
To put the heatwave into its historical context and determine how unlikely it was, the authors analyse a timeseries of annual maximum five-day heat index over the study region, shown below. Higher bars with darker colours indicate a higher heat index.
The authors find that in today’s climate, this heatwave was a one-in-10 year event.
Attribution
Attribution is a fast-growing field of climate science that aims to identify the “fingerprint” of climate change on extreme-weather events, such as heatwaves and droughts. To conduct attribution studies, scientists use models to compare the world as it is today to a “counterfactual” world without human-caused climate change.
They can also use these models to assess how much more intense or frequent the event would be in an even warmer world.
In this study, the authors investigate the impact of climate change on the maximum five-day heat index in southern west Africa.
They find that global warming made the west African heatwave 4C hotter. They add that if global warming reaches 2C above pre-industrial temperatures, similar events could become a further 1.3-3.4C hotter.
The authors also calculate that climate change made the heatwave 10 times more likely to occur, adding that similar events could occur every other year in a 2C world.
The graphic below illustrates these results. a pink dot indicates the number of years in every 100 that an event like the February heatwave over southern West Africa would be seen at different warming levels.
The square on the left shows a world without climate change, in which such a heatwave would happen less than once every 100 years. The middle square shows that in today’s climate, the heatwave is a one-in-10 year event. And the square on the right shows that in a 2C world, a heatwave of this severity could be expected every other year.
(These findings are yet to be published in a peer-reviewed journal. However, the methods used in the analysis have been published in previous attribution studies.)
Under-reported
West Africa was not the only region to experience record-breaking heat in February 2024.
February 2024 was the world’s hottest February on record, and countries across southern Africa – including Botswana, Namibia, Mozambique, South Africa, Zambia and Zimbabwe – saw temperatures of 4-5C above the February average.
Africa’s record-breaking heat continued into March.
In Johannesburg, South Africa’s largest city, many residents faced several weeks without water. “Authorities in Johannesburg, South Africa’s commercial hub, have blamed the ongoing heatwave for the lack of water in some parts of the city for several weeks,” Daily News reported on 13 March.
On 18 March, the health and education ministries of South Sudan closed its schools, after weather services projected an extreme two-week heatwave with temperatures of up to 45C. Parents were advised to keep all children indoors, and ministries warned that any school found open during the warning period would have its registration withdrawn.
BBC News added:
“Muslims, who make up around 6.2% of the country’s population, have been hit especially hard as many are observing Ramadan – a month of fasting. They are therefore not permitted to drink water or any other liquids to stay hydrated during the day.”
Between March 18-19, at least five countries in Africa, including South Africa and South Sudan, reported record-breaking temperatures.
However, the WWA study says that while the heatwave “potentially affected millions”, there is “very limited” data available about its impacts. As such, it says that very few heat-related impacts were reported by the media and government organisations.
“This, of course, does not mean there are no impacts”, said Maja Vahlberg from the Red Cross Red Crescent Climate Centre, who is a co-author on the study.
In fact, Vahlberg told a press briefing that early-season heatwaves are generally “more impactful than heat waves in the hot season” because “the human body has to very rapidly adjust to extreme temperatures”.
Heatwaves are a “silent killer”, Pinto told the press briefing, warning that “you only see the impacts later”.
The lack of reporting on the impacts of the heatwave “reflects the need to improve awareness of dangerous heat and detection of heat impacts”, the study says.
The post Climate change made west Africa’s ‘dangerous humid heatwave’ 10 times more likely appeared first on Carbon Brief.
Climate change made west Africa’s ‘dangerous humid heatwave’ 10 times more likely
Drought and heatwaves occurring together – known as “compound” events – have “surged” across the world since the early 2000s, a new study shows.
Compound drought and heat events (CDHEs) can have devastating effects, creating the ideal conditions for intense wildfires, such as Australia’s “Black Summer” of 2019-20 where bushfires burned 24m hectares and killed 33 people.
The research, published in Science Advances, finds that the increase in CDHEs is predominantly being driven by events that start with a heatwave.
The global area affected by such “heatwave-led” compound events has more than doubled between 1980-2001 and 2002-23, the study says.
The rapid increase in these events over the last 23 years cannot be explained solely by global warming, the authors note.
Since the late 1990s, feedbacks between the land and the atmosphere have become stronger, making heatwaves more likely to trigger drought conditions, they explain.
One of the study authors tells Carbon Brief that societies must pay greater attention to compound events, which can “cause severe impacts on ecosystems, agriculture and society”.
Compound events
CDHEs are extreme weather events where drought and heatwave conditions occur simultaneously – or shortly after each other – in the same region.
These events are often triggered by large-scale weather patterns, such as “blocking” highs, which can produce “prolonged” hot and dry conditions, according to the study.
Prof Sang-Wook Yeh is one of the study authors and a professor at the Ewha Womans University in South Korea. He tells Carbon Brief:
“When heatwaves and droughts occur together, the two hazards reinforce each other through land-atmosphere interactions. This amplifies surface heating and soil moisture deficits, making compound events more intense and damaging than single hazards.”
CDHEs can begin with either a heatwave or a drought.
The sequence of these extremes is important, the study says, as they have different drivers and impacts.
For example, in a CDHE where the heatwave was the precursor, increased direct sunshine causes more moisture loss from soils and plants, leading to a drought.
Conversely, in an event where the drought was the precursor, the lack of soil moisture means that less of the sun’s energy goes into evaporation and more goes into warming the Earth’s surface. This produces favourable conditions for heatwaves.
The study shows that the majority of CDHEs globally start out as a drought.
In recent years, there has been increasing focus on these events due to the devastating impact they have on agriculture, ecosystems and public health.
In Russia in the summer of 2010, a compound drought-heatwave event – and the associated wildfires – caused the death of nearly 55,000 people, the study notes.
The record-breaking Pacific north-west “heat dome” in 2021 triggered extreme drought conditions that caused “significant declines” in wheat yields, as well as in barley, canola and fruit production in British Columbia and Alberta, Canada, says the study.
Increasing events
To assess how CDHEs are changing, the researchers use daily reanalysis data to identify droughts and heatwaves events. (Reanalysis data combines past observations with climate models to create a historical climate record.) Then, using an algorithm, they analyse how these events overlap in both time and space.
The study covers the period from 1980 to 2023 and the world’s land surface, excluding polar regions where CDHEs are rare.
The research finds that the area of land affected by CDHEs has “increased substantially” since the early 2000s.
Heatwave-led events have been the main contributor to this increase, the study says, with their spatial extent rising 110% between 1980-2001 and 2002-23, compared to a 59% increase for drought-led events.
The map below shows the global distribution of CDHEs over 1980-2023. The charts show the percentage of the land surface affected by a heatwave-led CDHE (red) or a drought-led CDHE (yellow) in a given year (left) and relative increase in each CDHE type (right).
The study finds that CDHEs have occurred most frequently in northern South America, the southern US, eastern Europe, central Africa and south Asia.
Threshold passed
The authors explain that the increase in heatwave-led CDHEs is related to rising global temperatures, but that this does not tell the whole story.
In the earlier 22-year period of 1980-2001, the study finds that the spatial extent of heatwave-led CDHEs rises by 1.6% per 1C of global temperature rise. For the more-recent period of 2022-23, this increases “nearly eightfold” to 13.1%.
The change suggests that the rapid increase in the heatwave-led CDHEs occurred after the global average temperature “surpasse[d] a certain temperature threshold”, the paper says.
This threshold is an absolute global average temperature of 14.3C, the authors estimate (based on an 11-year average), which the world passed around the year 2000.
Investigating the recent surge in heatwave-leading CDHEs further, the researchers find a “regime shift” in land-atmosphere dynamics “toward a persistently intensified state after the late 1990s”.
In other words, the way that drier soils drive higher surface temperatures, and vice versa, is becoming stronger, resulting in more heatwave-led compound events.
Daily data
The research has some advantages over other previous studies, Yeh says. For instance, the new work uses daily estimations of CDHEs, compared to monthly data used in past research. This is “important for capturing the detailed occurrence” of these events, says Yeh.
He adds that another advantage of their study is that it distinguishes the sequence of droughts and heatwaves, which allows them to “better understand the differences” in the characteristics of CDHEs.
Dr Meryem Tanarhte is a climate scientist at the University Hassan II in Morocco, and Dr Ruth Cerezo Mota is a climatologist and a researcher at the National Autonomous University of Mexico. Both scientists, who were not involved in the study, agree that the daily estimations give a clearer picture of how CDHEs are changing.
Cerezo-Mota adds that another major contribution of the study is its global focus. She tells Carbon Brief that in some regions, such as Mexico and Africa, there is a lack of studies on CDHEs:
“Not because the events do not occur, but perhaps because [these regions] do not have all the data or the expertise to do so.”
However, she notes that the reanalysis data used by the study does have limitations with how it represents rainfall in some parts of the world.
Compound impacts
The study notes that if CDHEs continue to intensify – particularly events where heatwaves are the precursors – they could drive declining crop productivity, increased wildfire frequency and severe public health crises.
These impacts could be “much more rapid and severe as global warming continues”, Yeh tells Carbon Brief.
Tanarhte notes that these events can be forecasted up to 10 days ahead in many regions. Furthermore, she says, the strongest impacts can be prevented “through preparedness and adaptation”, including through “water management for agriculture, heatwave mitigation measures and wildfire mitigation”.
The study recommends reassessing current risk management strategies for these compound events. It also suggests incorporating the sequences of drought and heatwaves into compound event analysis frameworks “to enhance climate risk management”.
Cerezo-Mota says that it is clear that the world needs to be prepared for the increased occurrence of these events. She tells Carbon Brief:
“These [risk assessments and strategies] need to be carried out at the local level to understand the complexities of each region.”
The post Heatwaves driving recent ‘surge’ in compound drought and heat extremes appeared first on Carbon Brief.
Heatwaves driving recent ‘surge’ in compound drought and heat extremes
Greenhouse Gases
DeBriefed 6 March 2026: Iran energy crisis | China climate plan | Bristol’s ‘pioneering’ wind turbine
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Energy crisis
ENERGY SPIKE: US-Israeli attacks on Iran and subsequent counterattacks across the Middle East have sent energy prices “soaring”, according to Reuters. The newswire reported that the region “accounts for just under a third of global oil production and almost a fifth of gas”. The Guardian noted that shipping traffic through the strait of Hormuz, which normally ferries 20% of the world’s oil, “all but ground to a halt”. The Financial Times reported that attacks by Iran on Middle East energy facilities – notably in Qatar – triggered the “biggest rise in gas prices since Russia’s full-scale invasion of Ukraine”.
‘RISK’ AND ‘BENEFITS’: Bloomberg reported on increases in diesel prices in Europe and the US, speculating that rising fuel costs could be “a risk for president Donald Trump”. US gas producers are “poised to benefit from the big disruption in global supply”, according to CNBC. Indian government sources told the Economic Times that Russia is prepared to “fulfil India’s energy demands”. China Daily quoted experts who said “China’s energy security remains fundamentally unshaken”, thanks to “emergency stockpiles and a wide array of import channels”.
‘ESSENTIAL’ RENEWABLES: Energy analysts said governments should cut their fossil-fuel reliance by investing in renewables, “rather than just seeking non-Gulf oil and gas suppliers”, reported Climate Home News. This message was echoed by UK business secretary Peter Kyle, who said “doubling down on renewables” was “essential” amid “regional instability”, according to the Daily Telegraph.
China’s climate plan
PEAK COAL?: China has set out its next “five-year plan” at the annual “two sessions” meeting of the National People’s Congress, including its climate strategy out to 2030, according to the Hong Kong-based South China Morning Post. The plan called for China to cut its carbon emissions per unit of gross domestic product (GDP) by 17% from 2026 to 2030, which “may allow for continued increase in emissions given the rate of GDP growth”, reported Reuters. The newswire added that the plan also had targets to reach peak coal in the next five years and replace 30m tonnes per year of coal with renewables.
ACTIVE YET PRUDENT: Bloomberg described the new plan as “cautious”, stating that it “frustrat[es] hopes for tighter policy that would drive the nation to peak carbon emissions well before president Xi Jinping’s 2030 deadline”. Carbon Brief has just published an in-depth analysis of the plan. China Daily reported that the strategy “highlights measures to promote the climate targets of peaking carbon dioxide emissions before 2030”, which China said it would work towards “actively yet prudently”.
Around the world
- EU RULES: The European Commission has proposed new “made in Europe” rules to support domestic low-carbon industries, “against fierce competition from China”, reported Agence France-Presse.