Firefighters battle a blaze on Signal Hill in Cape Town. Wildfires are likely to become frequent. Photo: Rodger Bosch/Getty Images
Climate change played a major role in the weather conditions that contributed to the wildfire that raged through Cape Town’s Table Mountain area in April 2021, according to a new study.
The researchers found that climate models suggest that extreme fire weather associated with the Cape Town wildfire “has become 90% more likely in a warmer world”.
The research was conducted by lead author Zhongwei Liu, from the University of Coventry, together with Jonathan Eden, Bastien Dieppois and Matthew Blackett from the University of Coventry, and Stefaan Conradie, a PhD student in climatology from the Climate Systems Analysis Group at the University of Cape Town.
The study described how in April 2021, a devastating wildfire tore through the Table Mountain area. Following a human-induced ignition on the morning of 18 April, worsening weather conditions led to increased fire spread that lasted until the afternoon of 20 April when the fire was eventually extinguished.
Their study, The April 2021 Cape Town Wildfire: Has Anthropogenic Climate Change Altered the Likelihood of Extreme Fire Weather? forms part of a special report of the Bulletin of the American Meteorological Society, which presents assessments of how human-caused climate change may have affected the strength and likelihood of extreme events.
The fire burned across more than 600 hectares of wildland, with its incursion into urban areas resulting in widespread evacuations and several people being admitted to hospital. Up to R1 billion worth of damage to buildings and infrastructure was incurred by the University of Cape Town campus alone and irreplaceable collections in its Jagger Library were destroyed, the study said.
Conradie told UCT News that wildfires are a complex natural phenomenon influenced by various physical, environmental and social factors, of which weather and climate are but a part.
“But weather and climate have a critical influence on when wildfires become dangerous and destructive.”
According to the research, although summer wildfires are common in the Cape Town area, the “rapid spread, spotting behaviour and unprecedented impacts of this fire so late in the fire season”, which is usually considered to run from mid-November to mid-April, “raise important questions about the challenges in responding to changing fire regimes at the wildland-urban interface”.
The study described how the first three weeks of April 2021 were abnormally warm and dry along South Africa’s West Coast, at the southern tip of which Cape Town is situated, with these conditions “highly conducive to wildfire ignition and spread”.
On the day of the 2021 fire, Cape Town experienced the worst autumn fire weather conditions in over 40 years. These weather conditions contributed to the rapid spread of the wildfire, Conradie said. As the researchers analysed weather patterns, they found that the same fire weather conditions as experienced in April 2021 would “very likely” re-occur in the future, he told UCT News.
“Devil’s Peak’s natural vegetation is highly flammable,” he said. “And the invasive species that dominate much of the landscape and that are rapidly regrowing after the fire, tend to burn far more intensely. As has been pointed out with the volume of people moving around the mountain, ignitions are essentially inevitable.
“Couple this with warming and drying weather patterns and the question is when — not if — another big wildfire will threaten the urban fringe around the mountain again. Such fires may exhibit behaviours that have not yet been observed or experienced by firefighters before, making it very challenging to contain the blaze. As the planet warms, this risk is expected to increase,” Conradie said.
The researchers said the results of their analysis complement existing efforts to attribute hydro-climatological extremes around Cape Town, including droughts, and add to the growing set of attribution studies on wildfires and extreme fire weather in different parts of the world.