/ 21 October 2022

How SA is preparing for the killer heatwaves of the future

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New report warns future heatwaves will lie outside range of human experience. Photo by: VW Pics/Universal Images Group via Getty Images)

When Gillian Maree analysed the results of the Gauteng City-Region Observatory’s (GCRO)  Quality of Life Survey last year, what surprised her the most were the findings on heat.

The survey posed more than 200 questions to 13 616 residents between late 2020 and early last year. In one, they were asked about extreme events — flooding, tremors, fire, heat, wind, lightning, hail, tornados and sinkholes — that they or their household had experienced in the past 12 months and whether these events had caused damage or injury. 

The most prevalent environmental and weather-related extreme events reported were lightning (42% of households), heat (39%) and hailstorms (25%). 

Heat and lightning were consistently high across all the municipalities. 

Maree, a senior researcher, said: “People are experiencing heat far more significantly than we realise. And if we’re expecting the climate to get warmer, we’re already going off quite a high base.

“What makes it [the survey] interesting is that we are asking for people’s perspective of climate change, rather than the scientific explanation for temperature and rainfall.”

The GCRO’s recent map on green carbon compared Johannesburg’s wealthy Sandton suburb to its neighbour, Alexandra township. “If you look at where trees are, it’s in Sandton, not in Alexandra, so in many ways our green infrastructure … reflects the inequalities in our cities,” said Maree. 

The ability to shield oneself from heat was not evenly distributed, she said, with townships and vulnerable areas struggling, as opposed to richer areas with their “leafy green urban forests”.

As the climate changes, extreme heat and heatwaves are becoming more common in South Africa, according to the National Heat Health Action Guidelines, on which the government has now signed off. They aim to help the health sector prepare for the harmful effects of extreme heat.

Climate scientists warn that the number, intensity and duration of heatwaves, defined as unusually high temperatures that last for three or more consecutive days, will rise steeply in the future. 

The guidelines, prepared by the department of health, warn people’s health can be affected on isolated days of extreme heat (maximum temperature >35°C) or during heatwaves. 

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

Heat health warning systems will use weather forecasting to identify when a dangerous temperature level will be exceeded. Warnings then trigger a set of actions, depending on whether the anticipated heat levels are “stressful”, “dangerous to health” or at “the highest level”. Alert messages will be sent to government departments, the media and the public. 

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 greenhouse gas emissions are not reduced, temperatures may increase by more than 4°C over the interior of southern South 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 — where the maximum temperature is above 35°C.

Yet there is “little awareness” among policymakers and the public that heat is a major public health problem, the guidelines said. “Many people see heat as a nuisance to be tolerated, rather than something that can have major negative effects on health. In fact, many of the temperatures presently being recorded in South Africa are close to the temperature limits at which humans can survive.” 

Exposure to extreme heat can cause death by inducing heatstroke, which damages the brain, kidneys and other organs. More commonly, it can increase a person’s chances of succumbing to a heart condition, a stroke or respiratory problems in those already living with chronic conditions.

A warming planet will bring more frequent and severe heatwaves to South Africa, said Willem Landman, a professor of meteorology at the University of Pretoria. Not every heatwave can be attributed to global warming but “things are going to be getting worse than what we’re experiencing currently. That means the number of days with high temperatures will increase and it may also be that the higher temperatures may be extremely high.”

Climate-smart urban planning must become the norm, the guidelines said, noting how public shaded areas, shelters or cool rooms will be required. Heat adaptation plans need to focus on improving urban planning, housing construction, reducing urban heat islands and indoor heat stress. Increasing green spaces and greening is central to all heat-health plans.

The guidelines outline heat-health action plans for all elements of society and services to address heat and heatwaves to protect human health, said Caradee Wright, chief specialist scientist at the South African Medical Research Council’s environment and health research unit.

Scientists and the government need to work together to “ensure we understand how and where people in South Africa will be affected by heat so actions can be taken to help people cope”, Wright said.

Matthew Chersich, a research professor at the Wits Reproductive Health and HIV Institute, who heads the new Heat and Health African Transdisciplinary Centre, said evaporative cooling is a key solution, apart from the built environment. “That’s the cheapest — where you have a water spray and a fan that can allow you to survive another 5°C to 10°C.”

Although heatwaves may be less dramatic than the severe storms, droughts and floods associated with climate change, they are a “silent killer” taking an increasing toll, according to a joint report by the United Nations Office for the Coordination of Humanitarian Affairs, the International Federation of Red Cross and Red Crescent Societies (IFRC) and the Red Cross Red Crescent Climate Centre

Between 2010 and 2019, the IFRC recorded 38 heatwaves accounting for the deaths of more than 70 000 people, making them among the deadliest hazards for that period. 

Projected future death rates from extreme heat are “staggeringly” high and unequal, with people in poorer countries seeing far greater levels of increase, the report said. 

People living in urban poverty, particularly those in informal and off-grid settlements, face a “deadly combination of exposure to higher temperatures, higher vulnerability and lower access to coping mechanisms”. 

During periods of extreme heat, South Africa’s overall mortality rates increase considerably, especially deaths from cardiac and respiratory conditions, the report noted. Mortality is highest among children under five years and older people, state the guidelines. 

“When health systems are inadequately prepared to cope with heat extremes, the most vulnerable can suffer major consequences. These include the elderly, infants and children, pregnant women, outdoor and manual workers, people living in informal settlements, people with mental health conditions, athletes and the poor.” Heat exposure can also cause substantial mental stress and raise levels of violence, including homicide, and possibly suicide and gender-based violence.

Climatologist Coleen Vogel, distinguished professor at Wits University’s Global Change Institute, said her research and that of her students, has shown that cities in South Africa are not geared to tackle extreme heat and heatwaves, “particularly in terms of effective and proactive heat planning – planning before an event and putting in place effective risk reduction practices etc.

“We have to start thinking in a systems way around this, otherwise we really are going to be caught short in the future – what are the connections between energy, water and heatwaves … With Covid-19, we saw how our hospitals were not capacitated for persistent health crises. Can we learn from Covid to be better and more proactively prepared for heatwaves.”