Impact of Climate Change on Recent Heavy Rains in Botswana

Heavy rainfall in Botswana and South Africa caused flooding and fatalities. A study by World Weather Attribution determined that such events are more likely due to climate change. Researchers highlighted the need to enhance urban infrastructure to cope with increased rainfall. Effective flood management combines nature-based solutions and upgrades to drainage systems.

From February 16 to 20, southern Botswana and eastern South Africa experienced unusually heavy rainfall, leading to significant flooding that resulted in the deaths of at least 31 individuals. The Botswana government reported that approximately 5,500 people were affected, with over 2,000 requiring evacuation.

A swift evaluation by the World Weather Attribution (WWA) team, consisting of international climate scientists, revealed that such extreme rainfall events are becoming more likely due to human-caused climate change. Historical observations indicated an increasing frequency of severe five-day rainfall events in this region over recent decades.

The study also found that contemporary five-day rainfall events are approximately 60% more intense now, as the global temperature has risen an average of 1.3° Celsius (2.3° Fahrenheit) since preindustrial times, primarily due to fossil fuel use. Despite these findings, the researchers were unable to quantify the exact effect of climate change on the February flooding due to inconsistent results from climate models.

Ben Clarke, a co-author of the report from Imperial College London, noted, “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.” Climate scientist Joyce Kimutai further stated, “Indeed, as our climate continues to warm, it’s understood that this climate is likely to hold more water, and so it’s likely to cause intense rainfall.”

This intensifying climate is expected to strain drainage systems that have not kept pace with increasing populations and rapid urban development. Piet Kenabatho, another report co-author and professor at the University of Botswana, emphasized the urgent need to make cities like Gaborone more flood-resilient, advocating for the improvement of infrastructure.

Kenabatho suggested implementing nature-based solutions to absorb surplus rainfall by restoring vegetation in urbanized areas. However, he cautioned that such measures alone would not suffice. He called for an expansion and enhancement of Gaborone’s outdated stormwater drainage system to efficiently manage floodwaters. He remarked, “Decisions will have to be made as to where some of these waters could be stored.”

He also noted the effectiveness of techniques such as managed aquifer recharge schemes, which direct stormwater into underground aquifers. In summary, Kenabatho asserted that these collaborative efforts are crucial for better flood management in environments like Gaborone.

In conclusion, the severe flooding in Botswana has been linked to climate change and rapid urbanization. The findings underscore the increasing likelihood of extreme weather events and the urgent need for improved flood resilience in urban infrastructure. Effective flood management strategies must incorporate both nature-based solutions and upgrades to existing drainage systems, ensuring preparedness for future climate challenges.

Original Source: news.mongabay.com