The recent debilitating heatwave linked to the deaths of seven Northern Cape farmworkers is just one indication of what South Africa could experience in the future as more intense, frequent and longer hot spells cause temperatures to soar before summer, warn scientists.
Findings by the South African Medical Research Council (MRC) show those most at risk of heatstroke, other illnesses and death, are children, the elderly, outdoor workers and those with chronic conditions, and that the health effects are related not only to the physical phenomenon of heat, but also the frequency, intensity and duration of heatwaves.
The researchers, who analysed past and future heatwaves using climate models to develop the most effective heat-health warning system for those at risk, said heat reduces the body’s ability to regulate its temperature and keep cool by sweating. As the body becomes too hot, a person may experience heat cramps, heat exhaustion, heatstroke, and even hyperthermia.
They said understanding heatwave characteristics is crucial to the development of heat-health warning systems that could prevent illness or death.
In their analysis the researchers found the longest heatwave event lasted 77 days from 29 October 2015 to 13 January 2016 in North West.
“This could have been the result of record-breaking temperatures caused by one of the strongest El Niño events recorded, occurring during 2015/16, when global surface temperatures and the surface air temperature over South Africa reached record highs with maximum temperatures exceeding 40°C. Anomalies of maximum temperature up to 6°C higher than normal were reported countrywide during October and November 2015, and in December 2015, January and February 2016, as well as March 2016.
“This heatwave had a substantial effect on health, with several hospitalisations due to heat-related illness and even death from heatstroke in North West,” they said.
Thandi Kapwata, a study author and specialist scientist at the MRC environment and health research unit, told TimesLIVE Premium the findings, when looking at climate scenarios, “suggest the number of heatwave events starting before summer is expected to increase”.
And more are expected from the winter months of July and August onwards.
“Temperatures are rising due to climate change, and this has increased the likelihood of severe heatwaves. Projections of future climate scenarios show that these increases in average temperatures will lead to a higher frequency, intensity and duration of heatwaves in the coming years, all of which have serious impacts on the environment and public health as a whole,” she said.
Caradee Wright, chief specialist scientist also based at the SAMRC’s environment and health research unit, said resilience to heatwaves requires more than personal action.
“Education campaigns, climate-proofed housing, access to basic services and financial considerations would all help support resilient coping among South Africans and are urgently required.”
And while there are national heat-health guidelines, these should be activated “to make things happen”.
Kapwata believes heat-health warning systems are an important component of climate change adaptation because they allow the public, medical facilities, homes for the elderly, schools and disaster management teams to prepare.
The Labour Department says employers are expected to conduct risk assessments of workplaces, and when any identified risks change, should introduce mitigating measures, for instance in the recent Kakamas, Northern Cape case, where there was a risk of temperatures rising to 51ºC, and which killed seven labourers.
See more from MedicalBrief archives:
Change in work hours suggested after heat stroke deaths
Extreme heat exacerbating global health risks — UN scientific report
The dire consequences of climate change on SA’s health
Extreme heat exacerbating global health risks — UN scientific report