Study reveals South Africa's weather is becoming more extreme

20th September 2021 By: Donna Slater - Features Deputy Editor and Chief Photographer

South Africa is experiencing more maximum temperature records than expected – a trend which appears to be accelerating, a study by a University of Pretoria (UP) Department of Geography, Geoinformatics and Meteorology PhD student Charlotte McBride shows.

McBride, of the South African Weather Service (SAWS), had her paper, titled “Trends in probabilities of temperature records in the non-stationary climate of South Africa”, published in the International Journal of Climatology.

The paper was co-authored by her supervisor at the SAWS Andries Kruger and co-supervisor UP meteorology associate Professor Liesl Dyson.

This research is in support of other research which is indicating that South Africa is likely to become hotter in the future.

McBride’s research supports the sixth assessment report from the recently published Intergovernmental Panel on Climate Change (IPCC), which indicates that the climate outlook for Africa looks bleak in terms of the increasingly high probability of extreme maximum temperatures and heatwaves projected to occur in the twenty-first century.

“I investigated record-breaking temperature events over South Africa by using weather station data from 25 stations across the country,” she explains.

McBride says daily temperature data for the period between 1951 to 2019 was used, with analyses showing that significantly more records were broken than what was expected to occur over a particular time period.

In addition, her study reveals that in the most recent decade, it was evident that the measured number of maximum temperature records became progressively greater compared to the expected number.

“We thus have evidence that South Africa is not only warming, but that records are being broken more frequently than one would expect,” McBride says.

She says this implies that South Africa’s climate is becoming more extreme. “My research shows that most stations broke more highest daily maximum records than what is expected in a climate that is not under the influence of climate change.”

Nonetheless, even when this influence was taken into account, McBride says there were certain stations that still broke many more high-temperature records. “For example, Pretoria was expected to break an annual average of nine maximum temperature records per year over the past ten years of the study, when taking into account the warming taking place at that station.” However, she says it broke, on average, 15 records a year.

“While future warming is dependent on the amount of future greenhouse-gas emissions, we have already committed our atmosphere to substantial warming in the near- to medium-term,” says McBride. Therefore, she says, it is necessary that climate-sensitive sectors of society prepare themselves for an ever-increasing occurrence of unprecedented record high temperatures, more frequently than what is usually expected.

Meanwhile, the effects of higher temperatures can impact crop yields and contribute to the spread of pests and pathogens, she warns.

From a human health perspective, high temperatures can cause heat-related illnesses, which put certain sectors of the population such as the elderly, young and people with certain pre-existing medical conditions at risk.

Going forward, McBride says, there is a need to address climate change and for governments and the public to play their part in reducing their carbon footprint. “This will include making use of renewable energy sources, saving water, recycling, eating less meat, supporting locally grown produce and supporting tree planting initiatives.”

Her research recommends that policymakers, government departments, non-profit organisations, disaster managers, farmers and developers of infrastructure understand the consequences and risks of the increased frequency of record-breaking temperature events so that their response strategies are more meaningful.

“Farmers might need to review the types of crops or crop varieties they plant to ensure that they are more suited to a warmer climate. Town planners and the construction industry will need to take the warming into account when they plan and construct infrastructure. Health services need to be in a position to respond to increased cases of heat-related illnesses,” says McBride.

This also means, she says, that investment and funding need to be more focused on creating adaptive capacity rather than just responding to disasters. “More thought is needed around how to prepare for climate extremes such as the breaking of high-temperature records rather than waiting for them to occur, then trying to address the consequences.”