Africa and the growing problem of heatwaves

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Janny Sikazwe

By Mitchell Mahachi
Janny Sikazwe, a Zambian referee is at the centre of the Africa Cup of Nations controversial match between Mali and Tunisia which ended prematurely twice within five minutes just before the 90th minute mark. This deed has left an indelible mark on African football with some belittling the tournament, others bewildered if not stupefied and the match losers clearly upset. His defence which many have derided as a lame excuse, was that he experienced a heat stroke and heard voices telling him to end the game!

The question, which needs to be answered, is whether climate change could really be behind the referee’s actions to end the match prematurely.  Unconfirmed reports are that the temperature was around 34°C and humidity at 65% on the day in question. What makes it more striking is that after the match was stopped, players are reported to have gone to recover in ice baths!  There was even a water break given to the players to recuperate from the sweltering heat. To borrow from the ghetto youth lingo: “Another thing that will kill us while we stand absent minded is the sun”.

Temperature vs mortality
So diverse are the impacts of climate change that they also permeate into health issues. This instalment looks at the climate change and health nexus particularly the effect of heatwaves. One observation made in recent times is that climate change increases the frequency of heatwaves. The most notable heat wave was that of the 2003 summer in Europe which was regarded as a 500 year event.  With 70 000 fatalities it is reported as the deadliest natural catastrophe in Europe. In studies done in Shangai and New York increased mortalities were recorded from temperatures above 33°C and showed a very strong correlation between temperature and mortality.

However one needs to note that heatwaves are very different in different parts of the world. Harrington and Otto observe that a 2018 heatwave in Canada killed many people when temperatures reached 34°C. Yet such a heat threshold would not even trigger early warning systems in Ahmedabad, since social structures are adapted to temperatures well above 30°C in India. Since heatwave mortality has rarely been reported in sub-Saharan Africa, we do not know the thresholds that result in heat-related mortality. Yet it is this information that is crucial for African societies to adapt appropriately.

Symptoms of a heat stroke
Increased temperatures cause heat stroke which in turn lead to failing of the human circulatory system. The first symptoms are reddening of skin, sweating, dry mucous membranes, headache and vertigo. It is reported that an increase of body core temperature above 41°C can result in death by heart failure. The effect of heat on the human body needs to be understood in the context that the body does not have sensors for individual meteorological parameters hence it is only perceived and observed in the changes of the skin and blood flow. Also the body has its own heat balance which is maintained through heat fluxes to and from the body.

Financial impacts of heatwaves
In a recent study by the International Labour Organisation published in 2019, they note that an increase in heat stress resulting from global warming is projected to lead to global productivity losses equivalent to 80 million full-time jobs in the year 2030. This is equivalent to global economic losses of US$2 400 billion. This is equivalent to the GDP of the whole African continent and one wonders how the impact will be post 2050 when higher temperatures are expected.

Projected temperature outlook
Studies by Dosio (2016) and Valera et al (2020) show that under RCP8.5 the gulf of Guinea, the Horn of Africa, the Arabian peninsula, Angola and the Democratic Republic of Congo are expected to face, every 2 years, heatwaves of lengths between 60 and 120 days. Once every 30 years heatwaves are projected to be longer than 180 days over part of central Africa and the Arabian Peninsula. In addition, it was shown that the total length of heat spells projected to occur normally (ie once every two years) under RCP8,5 may be longer than those occurring once every 30 years under the lower emission scenario.

In comparison, there are only up to 40 days projected to have more than 30 degrees Celsius in Europe per year by 2071 to 2100 when compared to the 1961-1990 period. It must be noted, however, that the IPCC Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (IPCC 2012) claimed a low to medium confidence in the observed change of maximum temperature and heatwave frequency in Africa, mainly due to insufficient evidence and lack of literature.

Heatwaves and African cities
The occurrence of heatwaves is further exacerbated by the urban heat island phenomenon in cities where temperatures are up to 10 degrees higher than in the country side. Currently, around 40% of Africans live in cities, which is a percentage considerably lower than in other areas like the European Union, where 75% of the population lives in urban areas. However, given the population structure and economic structures in most African countries this is set to change drastically.

According to the McKinsey Global Institute, over 500 million Africans live in urban areas and 65 African cities exceed one million population. A megacity is usually defined as a city with a population of more than 10 million people. At present, there are only two megacities in North Africa: Lagos (Nigeria) and Cairo (Egypt). However, the urbanisation rate of Africa is the fastest in the world and the United Nations (UN) projects that there will be more than 30 megacities in Africa by 2050! This places the narrative for heatwaves and climate change vulnerability at the core of the development agenda.

Database gaps
The crux of this article laments at the dearth of data and literature pertaining to heatwaves as hinted above. Given that the body can tolerate temperatures between 10 and 30 degrees Celsius, climate data indicating heatwaves should be regarded as a priority. Given recurrent droughts, heatwaves — past, present and future — are a fact of African life. However, the large body of supporting scientific literature is in stark contrast with the near-absence of reported heatwave events over sub-Saharan Africa in disaster databases. One of the largest databases for extreme weather events the Emergency Events Database (EM DAT) lists no more than two heatwaves in sub-Saharan Africa since the beginning of the 20th century, leading to 71 recorded premature deaths.

In contrast, 83 heatwaves were recorded in Europe over the same timeframe, contributing to more than 140 000 associated deaths. Other inventories of weather-related disasters also reveal a similar trend. Ogunjo et al (2021) aptly summarise this saying, the positive trends of the heatwave in the sub-Saharan region should be a growing concern for public health officials.

Effect of data gaps
Under or a lack of reporting on deaths associated with heatwaves means there is little awareness to the general public that extreme heat can be so deadly. As highlighted earlier, just the heatwave of 2003 killed over 70 000 people in a few days and this is slightly more than half the population of Seke district. It has been observed in general that exposure and vulnerability to extreme weather is often much higher in sub-Saharan Africa than Europe. Therefore, there is likely to be very large numbers of premature deaths from severe heat that have never been registered as such.

One result of the heatwave of 2003 in Europe was the implementation of heat action plans and other measures to minimise risks in the next heat events as well as heat warning systems linked to behaviour.

With more heatwaves predicted for sub-Saharan Africa it would be prudent to start implementing heat action plans designed for the region as well as early warning systems. This is only possible when a robust information database is in place and reporting is done.

What can be done about it?
There are a several ways to reduce heat risk, some are structural like making green roofs out of reflective surfaces, and others behavioural like reminding people to drink more water on hot days and staying out of the sun during the hottest times of the day.

Heat officers?
In a first for Africa, Sierra Leone appointed a heat officer, 34-year-old Eugenia Kargbo to combat rising temperatures and come up with everyday ways to cool the sweltering streets of Freetown. Kargbo is already steering a range of anti-heat initiatives, from tree planting to waste collection and awareness campaigns. Miami, Phoenix and Athens are some of the cities that have engaged heat officers to deal with the threat posed by climate change. This trend is likely to rise in the near future.

African cities have large numbers of informal or slum areas, where there will be specific challenges in dealing with heat. For example, informal houses with corrugated iron roofs get extremely hot during heatwaves. Planting of trees for cover around cities could also help reduce temperatures in cities. Temperatures under tree cover have been observed to be up to over 10 degrees cooler than surrounding areas.

A key aspect of reducing risk is to build public awareness of what to do during heat extremes, supported by good co-ordination between meteorologists, government officials and the media. The second aspect is to have trained medical staff and community workers ready to prevent and respond to heatwaves, backed by interagency emergency response.

There is need for collaborations between local researchers, hospitals and epidemiologists to enable the identification of direct health impacts of extreme heat. Combining this with information gathered from heat-related power outages and transport disruptions could help to improve heatwave identification in sub-Saharan Africa.

In the final analysis, more people need to recognise the dangers of heat on human health and act to set up the systems to prevent heat related deaths. Heatwaves are predictable so there is time to react and save lives, but this requires good planning and co-ordination among actors to ensure this happens. The introduction of early warning systems could increase awareness and accelerate learning about how to best characterise local heat extremes. Without which the vulnerability of Africa to temperature changes will continue to rise and may be difficult to ameliorate later due to rapid and often unplanned urbanisation. Today it was a referee, tomorrow what if a doctor in a theatre under sweltering heat hears the same voices as the referee?

God forbid.