A record 512bn of work hours were lost around the world in 2023 because of the risk of heat exposure, says a new report from the Lancet Countdown on Health and Climate Change.
Agricultural workers in low-income countries were disproportionately affected, the authors say, costing countries around 8% of their GDP in 2023.
The findings are part of the ninth iteration of the annual report, which features indicators of climate change and human health, such as heat mortality, air pollution exposure and how countries are adapting.
The report highlights the many health inequalities in how energy is used around the world. According to the report, the number of deaths caused by fossil fuel-derived air pollution decreased by 7% over 2016-21 – mainly due to wealthy nations phasing out coal.
However, the vast majority of low-income countries still rely heavily on biomass and other “dirty” fuels in their homes. Dr Marina Romanello, lead author and executive director of the Lancel Countdown, added that women and children are usually in charge of sourcing and burning the fuel, making them particularly vulnerable.
The authors also call out governments and fossil fuel companies for “fuelling the fire” through continuing investment into oil and gas assets that are likely to push the world past key warming targets. The study notes that fossil fuel subsidies exceeded national health spending in 2022 for more than 20 countries around the world.
Romanello told journalists her “concern” that governments and companies “keep on promoting fossil fuel expansion, to the detriment of health and survival of people worldwide”.
Extreme heat
The impacts of extreme heat are “insidious”, Prof Ollie Jay, director of the Heat and Health Research Centre at the University of Sydney and author on the report, told a press briefing.
He explained that certain groups of people are more vulnerable to heat – including infants, the elderly, pregnant women and people with pre-existing medical conditions.
In 2023, infants and adults older than 65 faced a new record high of 14 days of heatwaves per person, the report finds. This value exceeds the previous record, set in 2022, by more than 20%.
The combination of a warming and ageing world is putting more people at risk, the report says. For example, in 2023, demographic changes alone would have driven a 65% increase in heat-related deaths among over-65s, compared to the 1990-99 average. The addition of global warming pushes this percentage up to 167% – the highest highest level recorded.
Across the whole population, the authors find that people were exposed to an average of 50 more “health-threatening heat days” in 2023 than they would have been in a world without climate change. (These are defined as days when the daily average temperature exceeds the 84.5th percentile of the 1986-2005 daily regional average.)
Beyond this global average figure, less-developed countries are much more likely to see such health-threatening days. For example, 31 such countries experienced at least 100 more days of health-threatening heat due to climate change.
The map below shows the average number of days with health-threatening temperatures attributable to climate change per year, over 2019-23, by country. Darker colours mean more health-threatening days.
Heat stress is particularly dangerous for outdoors workers, who are often directly exposed to the heat while undertaking manual labour. In 2023, around one-quarter of the world’s population worked outdoors.
The report finds that countries with the lowest human development index (HDI) – a measure of a country’s development – have the highest proportion of outdoors workers, largely due to their reliance on the agricultural sector.
The report measures the number of “potential work hours lost” due to heat exposure, by considering temperature, humidity and “typical metabolic rate of workers in specific economic sectors”.
It finds that heat exposure drove a record high of 512bn potential work hours lost in 2023 – around 1.5 times the 1990-99 average. Approximately two-thirds of this loss was in the agricultural sector, mainly in low and medium HDI countries. In total, the global potential loss of income due to extreme heat reached a record high of $835bn in 2023, the report says.
Wealthy countries were generally the least impacted by heat stress. Very high HDI countries only saw around 41 lost hours per worker due to heat, causing an economic loss of around 1% of their GDP. Meanwhile, low HDI countries lost more than 200 hours per worker, and saw almost an 8% loss in their GDP.
The graph below shows percentage GDP loss due to heat stress in low, medium, high and very high HDI countries, in agriculture (light green), construction (dark green), manufacturing (orange) and services (purple).
This year’s report also introduces a new indicator assessing how night-time heat affects sleep loss. The authors estimate that high night-time temperatures led to 5% more sleep hours lost in 2019-23 than in 1986-2005.
The authors say that air conditioning is an “effective technology for reducing heat exposure”. However, they say that it can also be an example of “maladaptation”, as it is “expensive and energy-intensive, overwhelms energy grids on hot days, and can contribute to greenhouse gas emissions”.
They note that emissions from air conditioning increased by 8% over 2016-21. However, access to the technology is not universal. In 2021, 48% of households in very high HDI countries had air conditioning compared to only 5% of those in low HDI countries.
Malnutrition and disease
The report also unpacks how climate change is exacerbating food insecurity and malnutrition.
It finds that the total proportion of global land area affected by extreme drought for at least one month per year increased from 15% in 1951-60 to 44% in 2013-24.
The authors warn that “the higher frequency of heatwave days and drought months in 2022, compared with 1981-2010, was associated with 151 million more people experiencing moderate or severe food insecurity across 124 countries”.
This year, the authors also introduced a new indicator tracking changes in rainfall events. The authors divide up the world into 80km grid squares and monitor the number of rainfall events that exceed the 99th percentile of 1961-90 rainfall.
Over the last decade, extreme rainfall events increased in more than 61% of grid squares, the report finds. The authors warn that high rainfall can drive an increase in flooding, which can lead to a range of negative health incomes including outbreaks of certain diseases.
For example, Vibrio bacteria in coastal waters can cause “severe” gastrointestinal infections and “life-threatening sepsis”. The study finds that the length of coastlines with suitable conditions for the bacteria reached a new record high of more than 88,000km in 2023 – 32% above the 1990-99 average.
In addition, the total population living within 100km of coastal waters with conditions suitable for Vibrio transmission has reached a record high of 1.42 billion.
The authors also find that the climatic conditions for mosquitoes to transmit dengue, malaria and West Nile virus have increased between 1951-60 and 2014-23 as the world has warmed.
Fossil fuels
On energy use, the study notes that, “given the high greenhouse gas and air pollution emission intensity of coal, its phase-out is crucial to protect people’s health”.
Over 2016-21, very high HDI countries have seen a reduction in the share of energy that comes from coal. (The UK became the first G7 country to phase out coal power in September 2024.)
However, the report highlights that all low HDI countries are still very dependent on coal. Over 2016-21, the share of electricity that comes from coal in low HDI countries increased from less than 1% to 10%.
According to the report, the number of deaths caused by fossil fuel-derived air pollution – specifically, tiny particulate matter known as PM2.5 – decreased by 156,000 over 2016-21 – a drop of 7%. This is mainly due to reduced pollution from coal burning in high and very high HDI countries.
Dr Marina Romanello, the lead author of the report and executive director of the Lancet Countdown, told the press briefing that this an important result as it shows the “enormous potential of coal phase-out to improve health”.
However, the report also warns that biomass burning caused 1.24 million deaths in 2021 – an increase of 135,000 from 2016 levels.
For example, the report finds that 2.3bn people still cook using biomass. In low HDI countries, around 92% of countries use solid biomass for their household energy needs. Conversely, in very high HDI countries, this number is around 10%.
Romanello explained that biomass is “very unreliable, very unstable and particularly polluting”. She added:
“When households rely on biomass, it is often women and children that are in charge of sourcing the fuel, so it also generates disproportionate impacts on these groups.”
The authors also call out fossil fuel companies for “fuelling the fire”. One of the report’s indicators assesses the compatibility of fossil fuel company strategies with the Paris Agreement. It says:
“As of March 2024, the strategies of the 114 largest oil and gas companies have put them on track to exceed their share of greenhouse gas emissions consistent with limiting global heating to 1.5C by 189% in 2040, up from the 173% excess projected in March, 2023.”
The report analyses 86 countries that are collectively responsible for 93% of global CO2 emissions. They find that, in 2022, these countries awarded a record $1.2tn in fossil fuel subsidies. This funding exceeded 10% of national health spending in 47 countries and 100% in 23 countries.
Romanello shared her “concern” with the press briefing that “governments and companies keep fuelling the fire, keep on promoting fossil fuel expansion, to the detriment of health and survival of people worldwide”.
Adaptation
Finally, the report assesses countries’ preparedness for the health impacts of climate change. This section presents a mixed picture.
The report finds that, as of February 2024, fewer than half of the most recent country climate pledges made under the Paris Agreement mentioned a “health keyword”.
However, the report also finds areas of progress. For example, at the end of 2022, only four countries had put forward health national adaptation plans (HNAPs) outlining how they will plan for and adapt to the impacts of climate change on health. Just one year later, this number had jumped up to 40 countries.
Furthermore, the authors find that scientific engagement into the links between climate change and health is increasing. The number of scientific papers investigating the link between climate change and health reached a record high in 2023, with the vast majority of papers focusing on impacts, rather than mitigation or adaptation.
The graph below shows the number of academic papers published each year over 1990-2023 on climate change and health, focused on mitigation (orange), adaptation (green) and impacts (purple).
The report finds that some countries are already implementing successful adaptation measures. For example, it explains that countries with health early warning systems saw a 73% decrease in the number of people killed per extreme weather event between 2000-09 and 2014-23. In countries without such early warning systems, the decrease was only 21%.
The authors note that “the reduction cannot be directly attributed to the implementation of health early warning systems”, but suggest that countries that implement these systems likely have higher “engagement with climate change adaptation efforts”.
The positive news in this report is “not enough to tip the balance” or to “secure a healthy future”, Romanello told the press briefing. However, she said it is “meaningful progress” which can be “built on”.
Dr Jeremy Farrar served as chief scientist of the World Health Organisation, and was previously the director of the Wellcome Trust – the main funding body behind this report. He told journalists at the press briefing that despite the “incredible evidence base” available, the health community “have been too slow to make the case that climate change is a health crisis”.
However, he praised the intersectoral collaboration between health and climate experts, and said he hopes we are “turning a corner” on making sure that climate change is seen as a “health issue”.
The post More than half a trillion hours of work lost in 2023 due to ‘heat exposure’ appeared first on Carbon Brief.
More than half a trillion hours of work lost in 2023 due to ‘heat exposure’
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”.