File photo: Kids having a great time at the Ellis Park pool as the heatwave continued. Picture: Bongiwe Mchunu

Johannesburg - When the blistering heatwave struck last month, staff at the Florama old-age home in Roodepoort didn’t take any chances: they brought in extra fans and made sure the home’s nearly 200 residents remained well hydrated.

“No one fainted or became dehydrated, but hell, it was hot,” recalls George Petzel, the manager.

“We spend a lot of time talking about the weather. It’s a concern for us oldies. It’s upsetting when it’s so damn hot,” says the 72-year-old, who “plays a little golf” to cool down.

In the hotter, drier and more humid Joburg of the future, it is the elderly, the sick and the very young who will be most at risk from extreme heat events.

Consider that the City of Joburg’s models suggest that temperatures may increase by about 2.3ºC by the near future (between 2056 and 2065) and by about 4.4ºC in the far future (between 2081 an 2100). It identifies “heatwave-related deaths” and “water demand” as key risks in this warmer future.

Little is known about the health impacts of high temperatures on South Africans, but “there is anecdotal evidence of direct health impacts due to extreme heat – increases in average temperatures and extreme events (such as heatwaves) are projected to induce heat stress, increase morbidity, and result in respiratory and cardiovascular diseases”, according to the South African National Biodiversity Institute.

Vulnerability to heat stress, it points out, depends on health status and socio-economic and environmental factors.

That’s what Dr Rebecca Garland, a senior researcher at the CSIR, is probing: just how does heat stress from rising temperatures affect health?

This may range from feeling uncomfortable, suffering heat stress, or even death from climate change. In the midst of January’s heatwave, Garland and her team were “excited” – heatwaves are rare. The South African Weather Service defines them as three days of maximum temperatures that are 5º higher than the mean maximum for the hottest month.

“Heatwaves are difficult to verify because they don’t happen very regularly, but what is key is the impact on health. We have quite vulnerable populations – a high burden of HIV and Aids and communities without access to water and electricity.

“People in urban, informal settlements, living under a metal roof, the heat bakes them inside… You don’t have access to water, to a park, there aren’t any cooling centres in your area… Air pollution also exacerbates heat stress.”

Early warning systems are crucial, Garland believes.

“We’d like to see that when heat warnings are issued there are emergency plans, heat health plans and advice for communities… buildings open to the public as cooling centres and doctors on alert. We don’t have this in place yet as far as we know.” - Saturday Star