‘Beat heat with cool zones’

Temperatures being recorded in some parts of SA are already close to the limits at which humans can survive

It was a searing 33° C outside Sandile Mqhayi’s shack in Kliptown, Soweto, last week, but inside, it felt even hotter. “It’s like you’re in an oven,” he says. “You can’t breathe.” Mqhayi joined some of his neighbours seeking refuge under a bridge during the punishing heatwave.

“Where we live, it’s an open space. There are no trees and even water is a struggle because we only have a few communal taps. The Jojo tanks aren’t always enough when it’s so hot,” he says.

Heatwaves on the rise

In July, a team of scientists warned that heatwaves in much of the country are:

• Happening more often; • Expected to persist for longer — more than two weeks in rare circumstances; and

• Becoming more intense as the effects of climate change intensify.

Their study, Heatwaves in the Future Warmer Climate of South Africa, described how increases in heatwave frequency and duration may have significant negative effects on human health, economic activities and livelihoods among vulnerable people.

The simulations were performed under the Representative Concentration Pathway 4.5 (moderate greenhouse gas concentration) and 8.5 (high greenhouse gas concentration) emission scenarios.

The team — from the South African Weather Service, the University of the Witwatersrand, the University of Venda and North-west University — described how, under a high greenhouse gas concentration, shortlasting heat waves of an average of three to four days along coastal areas are expected to increase in frequency.

The northwestern part of the country is expected to have the most drastic increase in heatwave occurrences and the central interior, which won’t experience pronounced increases in heatwave frequency, will experience longer heatwaves.

Government’s heat plan

Climate change is the biggest health threat of this century, yet knowledge about it is low in South Africa, says the department of health in its draft national heat health action guidelines released this month.

“Many policymakers and health workers are not even aware that heat is a major public health problem. High temperatures are often seen as something to be tolerated, rather than a major health risk ... In fact, many of the temperatures presently being recorded in South Africa are close to the temperature limits at which humans can survive.”

As extreme heat and heatwaves become more common, educating the public about the risks and actions that need to be taken is a priority.

In the past century, the average global temperature has risen by 1°C, climbing by as much as 2°C in many parts of South Africa.

“If GHG [greenhouse gas] emissions are not reduced, temperatures may increase by more than 4°C over the interior of Southern Africa by 2100, and by more than 6°C over the western, central and northern parts of the country.”

The Northern Cape, North West and Limpopo are expected to have between 20 and 40 very hot days each year, defined as days where the maximum temperature is above 35°C.

The draft guidelines present a package of “practical, feasible, and low-cost interventions” at the individual and local level that can help people adapt to high temperatures.

Heat health warning systems will provide alerts that a period of extreme heat is anticipated based on weather forecasts. Those alerts then feed into the heat-health action plan.

“Within the climate change and health world in South Africa, heat is really becoming one of the prominent things people are focusing on,” says Rebecca Garland, principal researcher in the climate and air quality modelling research group at the Council for Scientific and Industrial Research (CSIR).

“Extreme heat can cause dramatic health impacts and it’s linked to increases in mortality. That’s why we have to take it so seriously,” she says.

The country’s heat burden

The draft guidelines state that health can be affected on isolated days of extreme heat, where temperatures soar above 35°C, or during heatwaves.

“High temperatures, combined with other conditions, give rise to heatwaves that can claim the lives of thousands of people and cause a range of serious health conditions ... During periods of extreme heat the overall mortality rates in South Africa increase considerably, especially deaths from cardiac and respiratory conditions.”

It further explains that mortality related to extreme heat is highest among children under five years and older people. The rates of deaths are highest among people in informal settlements where many people in poor households and groups such as the homeless cannot afford to take measures to reduce their exposure to heat, such as drinking cold water, using electric fans and even finding shaded areas. Low-cost houses and shacks are not resistant to heat.

Air pollution, combined with heat, can exacerbate health problems. “This is concerning as air pollution levels in some cities of South Africa are among the highest worldwide and around a quarter of households in rural areas make use of coal, wood or paraffin for cooking.”

Rising temperatures heighten demand for water and electricity for cooling, which can cause blackouts and clinic visits and hospital admissions can increase “often at rates that overwhelm the capacity of the health system”.

How to tackle extreme heat

Improved “climate smart” urban planning, housing construction and reducing urban heat islands are key, says the draft. Changes to the built environment are especially important for pupils, teachers and health workers who use buildings made from converted shipping containers, which “are especially hot”.

Public shaded areas, shelters or cool rooms are required in each community, it says. “The absence of cooling spaces has major implications for mortality and morbidity in the country,” says Matthew Chersich of Wits University, who has studied the effects of climate change on adolescents.

Jeremy Gibberd, the CSIR chief researcher on sustainable built environments, says social infrastructure such as schools, clinics, and community halls, can be used

as cooling centres for vulnerable people.

South Africa needs “a lot more tree planting, cool community halls and really good, reliable access to water”, he says.

The draft guidelines state that using natural ventilation, electric or solar-powered fans and cooling systems with water sprays, which may also be placed outdoors, can help cool buildings and “painting roofs and walls white increases reflection of sunlight, enhancing cooling”.

Regulatory frameworks and labour standards on heat are required for controlling heat hazards in the workplace. This could include adjusting working hours to start earlier in the day, lengthening break times, creating exterior shaded areas or an indoor “cool space”.

There’s a big economic cost to the high heat, says Gibberd. “Interesting studies in South America have shown how people working outside in sugar cane fields suffer crippling health impacts from not drinking enough water. Their productive life is cut short. If people are forced to work for long periods outside at 35°C plus they don’t drink enough water, we’re going to sit with the same problems.”