On Wednesday, the Meteorological Services Department confirmed that the dreaded climate occurrence was already building in the skies above the country and was due to reach its strength by the end of the year, affecting the entire rain season.
El Nino was last at its full strength over the country in 2015/16 when it dried up Gaborone Dam and triggered a water crisis in the capital, while raising temperatures around the country to record highs.
A summary forecast issued by Met Services indicates that:
- There are enhanced probabilities of below-normal rainfall in the country - The eastern parts will be particularly dry - There is an increased risk of drought over some areas - Above normal temperatures are expected over the entire country - Overall, a relatively hot and dry season is expected
Speaking at the launch of the seasonal forecast, Principal Meteorologist, John Stegling, said another climate phenomenon called the Indian Ocean Diapole, was moving into a position where it would likely delay the onset of whatever little rains the country receives.
“The Indian Ocean Diapole, which can affect or suppress early summer rainfall over much of central and eastern Botswana, is currently neutral,” he said. “It is however moving towards positive and when combined with El Nino, the drying effect is usually stronger and more widespread.”
In the last three years, the country experienced the La Nina climate phenomenon, the flipside of the El Nino occurrence. While La Nina is typically associated with bountiful rains in Botswana and the region, rainfall patterns were haphazard and marked by a mid-season dry spell, forcing government to declare droughts for two of the three La Nina years.
Locally, an El Nino event was forecast for the 2018-19 season, but came in much better than forecast.
“El Nino this year is expected to continue throughout the rainfall period with a greater than 95% chance between December 2023 and February 2024,” Stegling said. “This is already a strong El Nino, but we expect it to get even stronger as we move towards December and January.”
According to the Met Services’ forecast, between October and December, rainfall over the eastern and southern parts of the country is expected to be below normal, while rainfall over the north and western parts is expected to be normal to below normal.
Between January and March, rainfall over most parts of the country is expected to be normal to below normal, although rainfall over the extreme eastern parts is expected to be below normal.
Throughout the rain season, temperatures around the country are forecast to be above normal.
The latest forecast also suggests that the troublesome mid-season dry spell that has plagued recent rain seasons, will be even longer this season. Thanks to climate change, in recent years, the period between January and February has tended to suffer from little to no rainfall in most areas, particularly the East and South, accompanied by either heatwaves or above-normal heat.
The result has been that farmers who plant in November watch their crops wilt in January, while those who wait things out and plant in February, find that the time to maturity left until winter means they have to forget about maize and sorghum and opt for ‘fast risers’ or hardier crops such as pulses, beans and legumes, sweet reed, lab lab, melons and others.
The year, the mid-season dry spell lasted 21 days in January before another unexpected 12-day stretch in March, that was a major contributing factor to President Mokgweetsi Masisi’s decision to declare a severe drought for the season.
“For this season, we are going to have frequent dry spells, late onset of rains, more heatwaves and extreme temperatures, with higher possibility of outbreaks of wildfires,” Stegling said.
The Met Services Department has begun its engagements with other stakeholders such as the Ministry of Agriculture to prepare climate sensitive sectors for the forecasts.
