Heed the warnings and face the future

Significant increases in temperature of over 2ºC a decade have occurred

THE PART of the map Dr Stephanie Midgley pointed to was filled with a frantic cluster of red triangles pointing upwards: they showed how much hotter Gauteng had become. And they looked like a warning.

“These triangles mean there have been significant increases in temperature, more than 2ºC a decade from 1931 to 2015,” explained Midgley, who has worked on climate change impacts, vulnerability and adaptation for more than 20 years.

“It’s highly significant and all the weather stations in Gauteng have shown this trend. This is more than twice the global rate of temperature increases and higher than the South African mean temperature.”

Midgley and her team are developing a new, updated Gauteng climate change strategy – the last for the province was compiled in 2011 – by looking at climate change trends and projections, risks and vulnerabilities, with a specific focus on adaptation to build resilience and capacity.

She was speaking this week at a workshop convened by the Department of Agriculture and Rural Development on the issue. “In Gauteng, the number of hot days defined as hotter than 35ºC have also been increasing over the same period,” she said.

Climate models showed temperature increases of “very hot days” specifically for the Northern Cape, Limpopo and Gauteng. “In some areas this is as high as 80 to 120 days of these kinds of temperatures – hot, hot days. What’s interesting is that the days of frost will become increasingly rare on the Highveld and probably disappear by the end of the century. This has implications for agriculture.

“Most of the weather stations are saying there are significant and high rates of increases in minimum and maxi mum t emperatures. And if we look at cold nights per annum, the number of warm nights are increasing in Gauteng with large decreases in the number of cold nights… So there are really strong warming increases coming in for Gauteng, and if you look at the other places in the country, those kinds of trends are only seen in the Western Cape and parts of KwaZulu-Natal, so it’s very concerning.”

Gauteng was not isolated from the rest of the country, region or globe, she said. “Whatever happens globally in ter ms of greenhouse gas reductions is going to be critically important in terms of Gauteng.”

Global cl i - mate change trends were affecting Gauteng “in ter ms of food prices, food availability and imports… then for Africa and southern Africa, there are issues around migration, refugees and regional food trade.”

The department said the impacts of climate change were be- ing felt both in the country and at a provincial level and “adapting to these impacts is critical for Gauteng, as it is the most densely populated province with the biggest investments into infrastructure and potential for climate smart agriculture”.

This week, the National Assembly formally approved South Africa’s ratification of the Paris Agreement reached at last year’s 21st Conference of the Parties to the UN Framework Convention on Climate Change.

Climate models showed rainfall variability would increase, but the degree of change could not be predicted confidently. However, studying rainfall patterns in Lesotho was vital for understanding Gauteng’s water future. “Lesotho is critical for us in Gauteng. What happens there filters to what water is available in the Gauteng area.

“Gauteng’s water resources originate to a large degree from Lesotho and it will have its own climate change issues – possibly more or less rainfall. So what happens in Lesotho is going to be of critical importance to that whole water system of transfers from the upper Orange into the Vaal through to Gauteng. It’s not just about rainfall over Gauteng – that’s a minor part of this – it’s actually what’s going to happen to the transfers and evaporation from the big holding dams all along the way.”

Water, said Midgley, was a major issue. “It’s short-sighted to focus on the here and now, this particular drought and the heatwaves – we’ve always had them. It’s about the interaction of stressors. It’s the drought and the heat on top of it. These are new things we haven’t seen before.”