A recent study indicates that heavy rainfall events in Botswana and South Africa are likely exacerbated by climate change. The flooding from February resulted in numerous casualties and evacuations. Experts highlight the need for resilient infrastructure and improved flood management strategies in urban areas facing rapid development.
Southern Botswana and eastern South Africa experienced unprecedented heavy rainfall from February 16-20, resulting in severe flooding that claimed at least 31 lives and impacted nearly 5,500 individuals in Botswana, necessitating the evacuation of over 2,000 people. A recent study by the World Weather Attribution team, which comprises international climate scientists, indicates that such extreme rainfall events are becoming increasingly likely due to human-induced climate change.
The researchers examined historical weather data and identified a growing trend in intense five-day rainfall events over recent decades. They assessed that occurrences of similar rainfall today are approximately 60% more intense, correlating with a 1.3° Celsius (2.3° Fahrenheit) increase in global temperatures since the preindustrial era, a period marked by significant fossil fuel usage.
However, the researchers faced difficulties in quantifying the specific impact of climate change on the recent flooding event, with inconsistent results emerging from their climate models. Ben Clarke, a co-author and researcher at Imperial College London, explained, “We haven’t been able to quantify the effect, but as the world is warming, we are seeing more extreme rainfall events like this one.”
Joyce Kimutai, another climate scientist at Imperial College, noted the likelihood of increased water retention in a warming climate, leading to more intense rainfall that could overwhelm inadequately maintained drainage systems, particularly in rapidly urbanizing areas. The pressing need for infrastructure upgrades and flood resilience was emphasized for Gaborone, the capital city of Botswana.
Piet Kenabatho, another co-author and environmental science professor at the University of Botswana, underscored the effectiveness of simple nature-based solutions that enhance ground absorption during heavy rainfall events. He pointed out that urbanization has led to the conversion of nearly all green spaces in Gaborone to developed territories.
Despite the benefits of nature-based solutions, Kenabatho stressed the urgent requirement to expand and modernize the outdated stormwater drainage system to effectively manage floodwaters. He suggested strategies like managed aquifer recharge, which have been employed in other African nations, as feasible options for improving flood management in Gaborone and similar regions.
In summary, the heavy rainfall in Botswana illustrates the increasing frequency of extreme weather events linked to climate change. Despite challenges in determining the precise impact of human activities on recent floods, it is clear that infrastructure and urban planning must adapt to these changes. Effective flood management strategies, including the enhancement of drainage systems and nature-based solutions, are necessary to mitigate the risks posed by such events in rapidly urbanizing regions like Gaborone.
Original Source: news.mongabay.com
