Inside Africa: Botswana Swings From El Niño Drought to La Niña Floods

Martin Harvey

Across the third week of February 2025, torrential rain showered over much of Botswana, a country in southern Africa roughly the same size as France. As rivers and dams overflowed, parts of the country were left underwater, with at least 5000 people being affected.

Botswanan authorities confirmed that 9 people had lost their lives to the flooding, including 6 children. Reports say most of them had drowned, or else been crushed under the weight of collapsing homes made of mud. Many who survived the rain were left homeless.  

Kokotsha, a southern town not far from the border with South Africa, saw the highest rainfall in the country at 235mm, while Mogoditshane, a neighborhood of the capital Gaborone, saw 160mm. Across the country, over 50mm of rain was recorded in the space of just 24 hours, with many parts also seeing daily rainfall rise up to between 150mm and 200mm.

Schools were forced to close for the week, and two large commercial centres in Gaborone, the Molapo and Riverwalk Malls, were significantly damaged. One resident said: “I have never seen so much water in my life. The house became a pool of water.”

From one extreme into another.

In the past year, Botswana suffered a severe drought after the rains failed in the rainy season between January and March in 2024. The crop failures and water scarcity led to a food crisis across the country and the rest of southern Africa, with as many as 70 million people in the region exposed to hunger and the risk of starvation. 

Coming out of the ending dry season, when conditions were most strained, farmers hoped for a fruitful rainy season to bring the country back to balance. Botswana usually sees rather low levels of annual precipitation, which is why the rainy season is pivotal in ensuring healthy crop yields across the following year, but it also means the soil is ill adapted to too much rain.

Flooding and heavy rainfall destroys crops, especially in dry countries like Botswana, where the soil isn’t used to absorbing much water. The heavy rainfall of late February has put upcoming crop yields back into question following much crop destruction during the current ploughing season. It means Botswana’s food security concerns continue. 

Unfortunately, this is nothing new for the country. Botswana is being increasingly affected by the Southern Oscillation climate phenomenon, also known as El Niño. The weather pattern occurs when changing trade winds in the pacific impact the temperature regulation of the ocean, which has an effect on what is called the Walker Circulation, i.e. the evaporation and formation of clouds and storms in the pacific.

The El Niño phase occurs when trade winds slow down, forcing warm water to remain in the eastern pacific near the South American Coast. The increased evaporation caused by the warmer ocean creates more rainfall and the risk of cyclones in parts of the Americas and increases the risk of drought in parts of eastern Asia. The ripple effect of an El Niño phase is believed to have caused the rains to fail in Botswana last year, which lead to the drought.

In another extreme phase of the Southern Oscillation, known as La Niña, trade winds accelerate, pushing warm water towards the west of the pacific. This leads to more evaporation and rainfall in the Asian tropics, with an increased risk of tropical cyclones, in turn leaving parts of the central Americas dry.

The ripple effect La Niña has on global weather patterns usually brings more rainfall to southern Africa. Heavy clouds form around Australia and New Zealand and move along the higher latitudes of the southern Indian ocean. This leaves northern East Africa more prone to drought, and heightens the risk of heavy rainfall and cyclones in southern Africa.

La Niña’s frequency has increased recently — between 2020 and 2023, the earth saw La Niña conditions for three consecutive years. But also in the past months, Mayotte, Madagascar, and recently Mozambique have seen multiple devastating cyclones.

The rainfall which caused flooding in Botswana is also believed to be associated with La Niña. In the past decade or so, southern African countries like Botswana, but also Zimbabwe and Mozambique, have been more prone to stronger rainy seasons and subsequent flooding. This year, Botswana’s Department of Meteorological Services had forecasted “persistent La Niña conditions until April 2025”, warning of the potential for more heavy rains.

A study conducted by the World Weather Attribution claims that these weather patterns are not normal for the region. While it found that flooding is common in Gaborone during the rainy season, the study also said the non-stop 5-day heavy rainfall that Botswana saw is “relatively rare”, with a 2%-3% chance of happening in any given year.

Though the results of the study couldn’t “precisely quantify the role of climate change”, the study did find that the severity of the rains correlates to the temperature of the climate, claiming it was “much less likely [to occur] in a colder climate.” The study also found that in a scenario that world temperatures reach 2.6 degrees Celsius, most models they sampled showed that the occurrence of 5-day heavy rainfall incidents would increase.

Though it also mentioned Gaborone’s poor drainage infrastructure and growing population density as factors contributing to the increase of flooding in urban areas of the capital, the study made clear that the emergence of intense rainfall events like this are a potential signal of a consequence of higher global temperatures. It’s unclear by how much, but “human-induced climate change amplified the rainfall leading to flooding in southern Botswana.”

In response to the floods, especially as a result of the six children who drowned, UNICEF has appealed $350,000 for recovery efforts and aid to those most affected. The organisation said “many communities have lost access to safe water, putting them at serious risk of disease.” There are other challenges as well, notably property damage.

Though the Minister for State President Moeti Mohwasa said that “critical infrastructure remains stable, with both electricity and water supply fully restored”, a reality in Botswana is also that many people’s homes are not built to withstand extreme weather conditions. Its why foreign aid is critical in rebuilding the destruction that climate change brings. Especially as a country which contributes 0.02% of global CO2 emissions, in the past year, Botswana has seen much more than its share of the consequences that come with a warming planet.