‘There were clear warnings before deadly KZN floods’

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The flooding that struck KwaZulu-Natal in April this year has been described as South Africa’s “deadliest storm on record” and the country’s leaders blamed climate change. But a top climatologist has questioned whether this is strictly accurate.

Francois Engelbrecht, the director of climatology at the University of the Witwatersrand’s Global Change Institute, was speaking at a recent seminar on the role of climate change in the Durban floods.

On 11 and 12 April, a cut-off low pressure system delivered 450mm in some areas in just 48 hours, killing 489 people, destroying 4 000 homes and displacing about 40 000 people.

“How unique was this weather system that caused the flooding and was its presence the result of climate change?” asked Engelbrecht, explaining how cut-off low pressure systems have previously caused comparable events in KwaZulu-Natal.

“On 22 April 2019, the weather pattern is similar, and is also clearly recognisable as a cut-off low,” he said, adding that about 70 people died in the Durban area.

On 27 September 1987, a cut-off low caused floods in Durban, killing 509 people. 

In April 1856, roughly 700mm of rain fell over three days in Durban’s “Great Flood”, he said, adding there was another such event in 1905.

“Cut-off lows have been part of our climatology for as long as we’ve been living here,” he said. “We have about 10 of them every year moving into South Africa’s territory.” 

About two of the 10 cause heavy falls of rain and some form of flooding.

The flooding of September 1987 and April 2019 “should have been clear warnings for us of the amount of rainfall these systems can cause”, he said. “And in April 2019, we saw how vulnerable certain communities are, living in certain areas of KwaZulu-Natal, to these types of rainfall events and the flooding they cause.”

Hard reality

It’s not straightforward to attribute what has happened in Durban in April this year to climate change, he said. “This is an example of an event, a type of weather system that occurs in this region, because of natural variability in the climate system. 

He said the issue to be considered is that people live in vulnerable areas such as KwaZulu-Natal’s steep slopes that become unstable when heavy rainfall saturates the soil.

“The hard reality is there are going to be future cut-off low events bringing heavy falls of rain, with or without climate change.”

He added that as the globe warms, the storm systems that cause flooding in KwaZulu-Natal will bring more rainfall than in previous floods. 

This was in line with the findings of the sixth assessment report of the Intergovernmental Panel on Climate Change (IPCC); that climate change is increasing the intensity and frequency of storm systems worldwide.

Attribution science

Engelbrecht said the results of an attribution study by himself and his colleagues on the role that climate change played in the recent Durban floods is not yet formally published. The team used a new event-attribution model developed at Wits University’s Global Change Institute.

He referred to recent research by World Weather Attribution, which is an international effort to analyse and communicate the possible influence of climate change on extreme weather events. 

Their results showed that the Durban floods have become twice as common because of greenhouse gas emissions and that the event was 4% to 8% heavier than it would have been without climate change. 

Loss and damage 

Elgelbrecht said the fast evolving field of climate change attribution may well become key to inform decisions and policies regarding loss and damage — the destructive effects of climate change that cannot be avoided by mitigation or adaptation.

Attribution science allows scientists to calculate how carbon emissions contributed to specific events such as storms, droughts, heatwaves and floods.

Referring to the recent record-breaking monsoon rainfall in Pakistan, which has left a third of the country underwater, he said: “The prime minister [Shehbaz Sharif] said that what happened in Pakistan will not stay in Pakistan …This is going to be increasingly a global issue

Elgelbrecht asked: “If these weather events can indeed be attributed to climate change, who is responsible for that climate change? Is it fair that a country like Pakistan, who is not a major player in terms of greenhouse gas emissions, that has a very very small historical responsibility for climate change that has occurred today, should suffer these types of losses, without being compensated. By who? 

“By the countries most responsible for this problem of global warming, mainly the large industrial economies of the Global North.”

Loss and damage is a concept of the United Nations Framework Convention on Climate Change, he said. The Paris Agreement reaffirmed the Warsaw International Mechanism for Loss and Damage. This internationally agreed mechanism is the main vehicle through which countries should be able to receive compensation for the losses and damages they incur in a changing climate.

 “At the upcoming COP[27] in Egypt in November, this will be one of the biggest, most controversial aspects of the climate negotiations and often this has been an obstacle in terms of making progress in the negotiations. But after the extreme weather events we’ve seen occurring across the globe since the previous COP, exactly a year ago, I think we can be guaranteed that this will now be centre stage once again in the negotiations.”