Of heat stress, health complications
Baboki Kayawe | Tuesday September 23, 2025 12:10
It is early September and only the beginning of summer in Botswana. However, places like Maun have already recorded heights of 36 degrees Celsius. Heatwaves are occurrences that places like Maun have become synonymous with. Maun, the gateway to the pristine inland Okavango Delta, is in the process of being granted city status. The area is a cocktail of both safari businesses and informal entrepreneurship.
Monica Selerilwe, 42, is one of the many street vendors who have had to bear the brunt of the scorching heat as she ekes out a living as a food vendor in the busy Maun taxi rank. It has been a decade now since her food vending business took off.
“Maun is naturally hot, but heat waves are a very recent phenomenon. What we have witnessed in the past three and two years is just out of the ordinary,” says Monica.
She describes the impact on both her health and business as too much. Monica, who has low-blood pressure complications, experiences dizziness, dehydration and sunburns on extremely hot days. The dizziness poses hurdles to work and profitability as she is required to rest even when customers await her services.
“Excessive heat is really bad for my business because foodstuff that is easily perishable like salads, even the mains or starches easily gets bad. That means I make losses when temperatures are skyrocketing high,” she states.
She adds that besides the rest breaks whenever she feels exhausted and dizzy, she constantly drinks water to be hydrated.
Fifty-three (53) year old Tshimologo Morotsi has been a taxi driver in Maun for about four years. He is awfully sensitive to heat pressure. However, he is forced to work under these conditions because it is the only means to bring food on the table.
“My skin gets itchy and irritated during hot days. I try to protect myself by wearing long sleeved shirts. The heat makes me very tired too, and I get excessively sleepy to an extent that I take refuge under a tree shade for about an hour. In the process my business suffers a lot,” he says. During the cool winter period he commences work at 6am. The opposite happens on excessive heat periods as he is only able to start work around 7:30am. The difference greatly impacts his work schedule because profitability is linked to hours worked and the actual time he starts off for duty.
Extreme temperatures, heatwaves and Botswana climatology
Dr Oliver Moses is a climate scientist and senior scholar at the Okavango Research Institute. He notes that extreme temperatures and heat waves are becoming more severe, with studies attesting to this fact. He further states that there is a thin line between heat waves and extreme temperatures, however similarities exist. For heatwaves, temperatures need to be above a certain threshold based on the mean temperature for a prolonged time, while extreme temperature refers to short-lived variations.
“Before heatwaves we need to talk about the mean. “The mean for Maun is currently above 34 degrees Celsius for instance. In climate science we normally look at a 30-year period as a baseline of climatic conditions. As such, heatwaves occur when the mean temperature is surpassed over a period of time,” he says.
He continues: “Let’s say today is 34 degrees Celsius, tomorrow it gets to 42 degrees Celsius, then the next day its drops back to 34 degrees, this then become an extreme temperature occurrence. “This also uses statistical measures, is the temperature below or above the 95 percent interval.”
However, he advances that the key variables in terms of determining heatwaves are frequencies, duration as well as intensity — which have all increased in Maun, and generally across the country.
In 2024, global temperatures were about 1.55 degrees Celsius above the pre-industrial level, reported the World Meteorological Organisation (WMO). This topped the record set in 2023, after 15 consecutive months (June 2023 through August 2024) of temperature records — an unprecedented heat streak, according to NASA.
Dr Moses corroborated the science, adding that generally Botswana and parts of Southern Africa has surpassed the 1.5 degrees Celsius threshold. Specifically, he explains that climatologically the country is divided into North and South, with the north generally hotter to extents similar to those of Kgalagadi.
“In the afternoons, the North gets hot, but Kgalagadi is also a hotspot. Kgalagadi can really get hot as Maun. “The tricky thing is that because of more sand which has properties in that it can absorb and lose temperature, it gets cooler there at night,” he says.
A very important dynamic at play in the state of Botswana’s temperature is the “Botswana High”. According to Dr Moses, this is the main system that has to be mentioned as it is a mid-tropospheric high-pressure system that affects the local climate.
“It is a high-pressure system – and it is strengthening. It is a very key feature that is associated with stable atmosphere. “When it is strong, it keeps the air down, thus sinking it. However, when it weakens, there is upwards movement of air, which is what is desirable. “In short, a strong Botswana High inhibits air movement and has bad implications for cloud formation and rainfall,” he explains.
According to Dr Moses, future predictions are that Earth is heating up, and warmer temperatures are to be expected. If nothing is done the trend is going to remain in the same trajectory and the models are converging. Some of the possible interventions lie in decarbonising the fossil-fuel intensive energy sector and moving towards cleaner sources. He, however, admits that the transition cannot happen overnight.
WHO workplace heat stress and mitigation procedures
In August, the World Health Organisation (WHO) and the WMO published a joint report and guidance highlighting the growing global health challenges posed by extreme heat on workers.
“Heat stress is already harming the health and livelihoods of billions of workers, especially in the most vulnerable communities,” said Dr Jeremy Farrar, WHO Assistant Director-General, Health Promotion, Disease Prevention and Care. “This new guidance offers practical, evidence-based solutions to protect lives, reduce inequality, and build more resilient workforces in a warming world.”
While the report rightfully acknowledges that many workers who are regularly exposed to dangerous heat conditions are already feeling the health impacts of rising temperatures, in particular, manual workers in sectors such as agriculture, construction and fisheries as well as informal sector workers like Monica and Tshimologo are being left out in the lurch.
“Protection of workers from extreme heat is not just a health imperative but an economic necessity,” said WMO Deputy Secretary-General Ko Barrett during the launch of the report.
Unfortunately, as climate change drives more frequent and intense heatwaves, self-employed and small enterprises will have to carry double or triple the burden of excessive heat because unlike their employed counterparts, they do not have the luxury of labour and workplace protective safeguards. This is further exacerbated by the fact that benefits such as sick days off and medical aid coverage are out off-reach for many.
Nonetheless, key findings from the WHO report include that the frequency and intensity of extreme heat events have risen sharply, increasing risks for both outdoor and indoor workers as well as the fact that worker productivity drops by 2–3% for every degree above 20°C. The report further delineated heat related health risks as heatstroke, dehydration, kidney dysfunction, and neurological disorders, “all of which hinder long-term health and economic security”.
Action plans: strategic cold water-vendor outlets for hydration
Some of the recommended actions from the WHO report include designing solutions that are not only effective but also practical, affordable and environmentally sustainable as well as upscaling policy implementation. Embracing innovation by adopting technologies that can help safeguard health while maintaining productivity is yet another endorsement from the report.
It is encouraging that though outside mainstream employment, informal sector workers like Tshimologo and Monica have devised precautionary measures to deal with the heat problem.
Moved by economic pressure, 22-year-old Lefhika Tlotlo set up a filtered water vending outlet around a busy area in one of the oldest malls of Maun. The outlet opened in August 2024. He is, however, not spared from the troubles of working outdoors, though he is sheltered under a small-iron corrugated iron structure.
“I sweat a lot during the day due to this heat and get too exhausted as well to the point that when I get home, I immediately fill a 20 litre bucket and immense myself in it for a long bath,” he says.
Lefhika sells both cold and room temperatures distilled water. He has differentiated his offering such that even the smallest quantity of water is accessible, and at an affordable price of about BWP1 — a small bottle or jug is sold at under a cent (0.075 USD). This is in contrast with what retail outlets have to offer. His intervention is motivated by the sight of extremely thirsty people guzzling bottles of water on the spot. The relief that follows thereafter is unexplainable. His location is also strategic as many people pass there, and the turn up is quite terrific.
“Though economic pressures resulted in this start-up, I find myself offering a solution to the prevailing heat stress. People really get thirsty and all they opt for is cold water,” he adds.
He explains that peak hours for the cold-water business are between 12 noon and 16:00 hours. However, he quickly remarks that when the cold water runs out, room temperature water becomes the alternative as “all people want is water to quench their thirst”. Generally, he sells 600 litres of water per day.
Earth coolling interventions: a solution or technological fantasy?
There is a branch of science hard at work finding “solutions” to excess heat, usually termed “climate interventions”, “carbon management”, “climate systems engineering” among the many labels used. This was explained by Niclas Hällström during a climate journalism training preluding the Africa Climate Summit II in Addis Ababa, Ethiopia recently. He is Director of WhatNext, a Swedish-based platform convening thinking on emerging global social and environmental issues.
In a session titled “Buyer Beware: Rise of False Solution”, Hällström cautioned against dangerous distractions, which he branded false solutions. Moreover, Africa was encouraged to be on the watch out, lest the continent suffers as a battleground of experimentation with these technologies, in addition to worsened impacts of climate change resulting from such interventions.
“If you accept the severity of climate change but are not willing to accept the necessity for systems change and profoundly addressing the underlying root causes, only existentially dangerous techno-fantasies remain as options to square the equation. “The current normalisation of dangerous distractions such as solar geoengineering is likely as dangerous and severe a threat as climate change itself.”
Solar Radiation Modification (SRM) techniques, often referred to as solar geoengineering, attempt to deal with symptoms of climate change by reflecting sunlight away from the earth or allowing more heat back into space. In July this year, the African Ministerial Conference on the Environment (AMCEN) met in Nairobi with SRM at the centre of the conversation. The then weeklong of intense exchanges between the diplomats, scientific, scholarly, research and civil society community was described as a “battlefront” by James Kahongeh of Power Shift Africa, writing in the Daily Nation.
Ultimately, AMCEN rejected the concept of solar geoengineering. A move that is receiving accolades for “good precedence”.
“We reaffirm our unequivocal rejection of any attempt to promote stratospheric aerosol injection or other forms of solar geoengineering technology as unacceptable climate solutions,” a statement from the ministers’ stance read.
Would solar-geoengineering help the situation?
Despite the state of heat pressure Monica and Tshimologo have to endure, they are both sceptical about cooling off interventions promised by stratospheric sulfate aerosol injections, for instance.
Monica wonders what potential harm spraying these sulfate particles would have on the stratosphere and atmospheric layer. “What if this further deteriorates the situation and brings complications to both the stratosphere and earth. I also wonder how long this technology would be used to keep planet Earth cool? Will it be an annual thing or a continuous process for so long as heat stress is still an issue to Earth and mankind?” she asks rhetorically.
Tshimologo questions redirecting ultra-violent lights from the earth too. Quoting scriptures, he says everything has a purpose according to creation.
“If you prevent sunrays from coming down to Earth, you are disturbing the process of creation. In the beginning, in the book of Genesis 1:1 — the Creator knew what He was doing when forming darkness, light, the moon and the sun. “Tempering with spiritual and natural processes is a bad thing,” he says.
Just like Monica and Tshimologo, Dr Moses is also sceptical about creating other problems in the process of attempting to “cool the Earth,” adding that these are just experiments that cannot cover the entire planet. They would also be expensive, he says.
Besides questioning practicability, Dr Moses wondered: “Can these technologies be upscaled? “We don’t know what the consequences would be?”
MAUN, BOTSWANA: There is no winter in Maun. This is a popular phrase one gets to hear once they hit the soils of this northwestern “town” of Botswana. It’s meaning gets more real and much pronounced during the agonizing summer season.
It is early September and only the beginning of summer in Botswana. However, places like Maun have already recorded heights of 36 degrees Celsius. Heatwaves are occurrences that places like Maun have become synonymous with. Maun, the gateway to the pristine inland Okavango Delta, is in the process of being granted city status. The area is a cocktail of both safari businesses and informal entrepreneurship.
Monica Selerilwe, 42, is one of the many street vendors who have had to bear the brunt of the scorching heat as she ekes out a living as a food vendor in the busy Maun taxi rank. It has been a decade now since her food vending business took off.
“Maun is naturally hot, but heat waves are a very recent phenomenon. What we have witnessed in the past three and two years is just out of the ordinary,” says Monica.
She describes the impact on both her health and business as too much. Monica, who has low-blood pressure complications, experiences dizziness, dehydration and sunburns on extremely hot days. The dizziness poses hurdles to work and profitability as she is required to rest even when customers await her services.
“Excessive heat is really bad for my business because foodstuff that is easily perishable like salads, even the mains or starches easily gets bad. That means I make losses when temperatures are skyrocketing high,” she states.
She adds that besides the rest breaks whenever she feels exhausted and dizzy, she constantly drinks water to be hydrated.
Fifty-three (53) year old Tshimologo Morotsi has been a taxi driver in Maun for about four years. He is awfully sensitive to heat pressure. However, he is forced to work under these conditions because it is the only means to bring food on the table.
“My skin gets itchy and irritated during hot days. I try to protect myself by wearing long sleeved shirts. The heat makes me very tired too, and I get excessively sleepy to an extent that I take refuge under a tree shade for about an hour. In the process my business suffers a lot,” he says. During the cool winter period he commences work at 6am. The opposite happens on excessive heat periods as he is only able to start work around 7:30am. The difference greatly impacts his work schedule because profitability is linked to hours worked and the actual time he starts off for duty.
Extreme temperatures, heatwaves and Botswana climatology
Dr Oliver Moses is a climate scientist and senior scholar at the Okavango Research Institute. He notes that extreme temperatures and heat waves are becoming more severe, with studies attesting to this fact. He further states that there is a thin line between heat waves and extreme temperatures, however similarities exist. For heatwaves, temperatures need to be above a certain threshold based on the mean temperature for a prolonged time, while extreme temperature refers to short-lived variations.
“Before heatwaves we need to talk about the mean. “The mean for Maun is currently above 34 degrees Celsius for instance. In climate science we normally look at a 30-year period as a baseline of climatic conditions. As such, heatwaves occur when the mean temperature is surpassed over a period of time,” he says.
He continues: “Let’s say today is 34 degrees Celsius, tomorrow it gets to 42 degrees Celsius, then the next day its drops back to 34 degrees, this then become an extreme temperature occurrence. “This also uses statistical measures, is the temperature below or above the 95 percent interval.”
However, he advances that the key variables in terms of determining heatwaves are frequencies, duration as well as intensity — which have all increased in Maun, and generally across the country.
In 2024, global temperatures were about 1.55 degrees Celsius above the pre-industrial level, reported the World Meteorological Organisation (WMO). This topped the record set in 2023, after 15 consecutive months (June 2023 through August 2024) of temperature records — an unprecedented heat streak, according to NASA.
Dr Moses corroborated the science, adding that generally Botswana and parts of Southern Africa has surpassed the 1.5 degrees Celsius threshold. Specifically, he explains that climatologically the country is divided into North and South, with the north generally hotter to extents similar to those of Kgalagadi.
“In the afternoons, the North gets hot, but Kgalagadi is also a hotspot. Kgalagadi can really get hot as Maun. “The tricky thing is that because of more sand which has properties in that it can absorb and lose temperature, it gets cooler there at night,” he says.
A very important dynamic at play in the state of Botswana’s temperature is the “Botswana High”. According to Dr Moses, this is the main system that has to be mentioned as it is a mid-tropospheric high-pressure system that affects the local climate.
“It is a high-pressure system – and it is strengthening. It is a very key feature that is associated with stable atmosphere. “When it is strong, it keeps the air down, thus sinking it. However, when it weakens, there is upwards movement of air, which is what is desirable. “In short, a strong Botswana High inhibits air movement and has bad implications for cloud formation and rainfall,” he explains.
According to Dr Moses, future predictions are that Earth is heating up, and warmer temperatures are to be expected. If nothing is done the trend is going to remain in the same trajectory and the models are converging. Some of the possible interventions lie in decarbonising the fossil-fuel intensive energy sector and moving towards cleaner sources. He, however, admits that the transition cannot happen overnight.
WHO workplace heat stress and mitigation procedures
In August, the World Health Organisation (WHO) and the WMO published a joint report and guidance highlighting the growing global health challenges posed by extreme heat on workers.
“Heat stress is already harming the health and livelihoods of billions of workers, especially in the most vulnerable communities,” said Dr Jeremy Farrar, WHO Assistant Director-General, Health Promotion, Disease Prevention and Care. “This new guidance offers practical, evidence-based solutions to protect lives, reduce inequality, and build more resilient workforces in a warming world.”
While the report rightfully acknowledges that many workers who are regularly exposed to dangerous heat conditions are already feeling the health impacts of rising temperatures, in particular, manual workers in sectors such as agriculture, construction and fisheries as well as informal sector workers like Monica and Tshimologo are being left out in the lurch.
“Protection of workers from extreme heat is not just a health imperative but an economic necessity,” said WMO Deputy Secretary-General Ko Barrett during the launch of the report.
Unfortunately, as climate change drives more frequent and intense heatwaves, self-employed and small enterprises will have to carry double or triple the burden of excessive heat because unlike their employed counterparts, they do not have the luxury of labour and workplace protective safeguards. This is further exacerbated by the fact that benefits such as sick days off and medical aid coverage are out off-reach for many.
Nonetheless, key findings from the WHO report include that the frequency and intensity of extreme heat events have risen sharply, increasing risks for both outdoor and indoor workers as well as the fact that worker productivity drops by 2–3% for every degree above 20°C. The report further delineated heat related health risks as heatstroke, dehydration, kidney dysfunction, and neurological disorders, “all of which hinder long-term health and economic security”.
Action plans: strategic cold water-vendor outlets for hydration
Some of the recommended actions from the WHO report include designing solutions that are not only effective but also practical, affordable and environmentally sustainable as well as upscaling policy implementation. Embracing innovation by adopting technologies that can help safeguard health while maintaining productivity is yet another endorsement from the report.
It is encouraging that though outside mainstream employment, informal sector workers like Tshimologo and Monica have devised precautionary measures to deal with the heat problem.
Moved by economic pressure, 22-year-old Lefhika Tlotlo set up a filtered water vending outlet around a busy area in one of the oldest malls of Maun. The outlet opened in August 2024. He is, however, not spared from the troubles of working outdoors, though he is sheltered under a small-iron corrugated iron structure.
“I sweat a lot during the day due to this heat and get too exhausted as well to the point that when I get home, I immediately fill a 20 litre bucket and immense myself in it for a long bath,” he says.
Lefhika sells both cold and room temperatures distilled water. He has differentiated his offering such that even the smallest quantity of water is accessible, and at an affordable price of about BWP1 — a small bottle or jug is sold at under a cent (0.075 USD). This is in contrast with what retail outlets have to offer. His intervention is motivated by the sight of extremely thirsty people guzzling bottles of water on the spot. The relief that follows thereafter is unexplainable. His location is also strategic as many people pass there, and the turn up is quite terrific.
“Though economic pressures resulted in this start-up, I find myself offering a solution to the prevailing heat stress. People really get thirsty and all they opt for is cold water,” he adds.
He explains that peak hours for the cold-water business are between 12 noon and 16:00 hours. However, he quickly remarks that when the cold water runs out, room temperature water becomes the alternative as “all people want is water to quench their thirst”. Generally, he sells 600 litres of water per day.
Earth coolling interventions: a solution or technological fantasy?
There is a branch of science hard at work finding “solutions” to excess heat, usually termed “climate interventions”, “carbon management”, “climate systems engineering” among the many labels used. This was explained by Niclas Hällström during a climate journalism training preluding the Africa Climate Summit II in Addis Ababa, Ethiopia recently. He is Director of WhatNext, a Swedish-based platform convening thinking on emerging global social and environmental issues.
In a session titled “Buyer Beware: Rise of False Solution”, Hällström cautioned against dangerous distractions, which he branded false solutions. Moreover, Africa was encouraged to be on the watch out, lest the continent suffers as a battleground of experimentation with these technologies, in addition to worsened impacts of climate change resulting from such interventions.
“If you accept the severity of climate change but are not willing to accept the necessity for systems change and profoundly addressing the underlying root causes, only existentially dangerous techno-fantasies remain as options to square the equation. “The current normalisation of dangerous distractions such as solar geoengineering is likely as dangerous and severe a threat as climate change itself.”
Solar Radiation Modification (SRM) techniques, often referred to as solar geoengineering, attempt to deal with symptoms of climate change by reflecting sunlight away from the earth or allowing more heat back into space. In July this year, the African Ministerial Conference on the Environment (AMCEN) met in Nairobi with SRM at the centre of the conversation. The then weeklong of intense exchanges between the diplomats, scientific, scholarly, research and civil society community was described as a “battlefront” by James Kahongeh of Power Shift Africa, writing in the Daily Nation.
Ultimately, AMCEN rejected the concept of solar geoengineering. A move that is receiving accolades for “good precedence”.
“We reaffirm our unequivocal rejection of any attempt to promote stratospheric aerosol injection or other forms of solar geoengineering technology as unacceptable climate solutions,” a statement from the ministers’ stance read.
Would solar-geoengineering help the situation?
Despite the state of heat pressure Monica and Tshimologo have to endure, they are both sceptical about cooling off interventions promised by stratospheric sulfate aerosol injections, for instance.
Monica wonders what potential harm spraying these sulfate particles would have on the stratosphere and atmospheric layer. “What if this further deteriorates the situation and brings complications to both the stratosphere and earth. I also wonder how long this technology would be used to keep planet Earth cool? Will it be an annual thing or a continuous process for so long as heat stress is still an issue to Earth and mankind?” she asks rhetorically.
Tshimologo questions redirecting ultra-violent lights from the earth too. Quoting scriptures, he says everything has a purpose according to creation.
“If you prevent sunrays from coming down to Earth, you are disturbing the process of creation. In the beginning, in the book of Genesis 1:1 — the Creator knew what He was doing when forming darkness, light, the moon and the sun. “Tempering with spiritual and natural processes is a bad thing,” he says.
Just like Monica and Tshimologo, Dr Moses is also sceptical about creating other problems in the process of attempting to “cool the Earth,” adding that these are just experiments that cannot cover the entire planet. They would also be expensive, he says.
Besides questioning practicability, Dr Moses wondered: “Can these technologies be upscaled? “We don’t know what the consequences would be?”
*Kayawe is a journalist, Voice Over Artist, Media Researcher, 2023 Oxford Climate Journalism Network Fellow and 2023 Southern African Science Service Centre for Climate Change and Adaptive Land Management (SASSCAL). She is also an Mphil Natural Resources Management & Communication Scholarship Recipient, UNDP Climate Change Storytelling Fellow, Africa-China Reporting Fellow 2015, Thomson Reuters Taboo Reporting Fellow 2016, OSISA Media Scholarship Recipient 2014