Water levels in Lake Kariba, the world’s largest artificial lake at more than 5 500 sq km, have dropped by six metres in the past three years.

In early March, available water for hydroelectric production at the Kariba dam, which spans the border between Zambia and Zimbabwe, was about 11.5 percent, a slight recovery on the record low in January.

A year earlier, hydro levels at the lake exceeded 42 percent. When running at capacity, the hydroelectric plant produces more than 2.1GW of electricity.

“People see the recent rainfall and the flooding and wonder why the lake isn’t filling up, but what you have to understand is just how huge it is, and how much water has been lost”, said Patrick Siptela, a design engineer with the Zambezi River Authority.

It is now restricted to about a quarter of capacity, leading to frequent power outages across both countries, with many businesses relying on diesel generators for eight hours a day.

About half of Zambia’s total electrical power comes from the Kariba dam, Siptela said. However, this key source of low-carbon power is susceptible to climate-driven impacts in the region. Records dating to 1960 show a warming trend of 0.34C per decade. This suggests the country has warmed by at least 1.7C in 60 years.

In tandem with this strong warming trend, average rainfall in Zambia has fallen by 2.3 percent per decade in the same period.

The nature and timing of rainfall is also changing. After months of severe drought, recent torrential downpours have destroyed crops and infrastructure.

“Some of our roads that have stood the test of time for years are now succumbing. We know the conditions are really extreme”, said Carol Mwape Zulu, the chief climate change officer at Zambia’s Ministry of Lands and Natural Resources.—BBC NEWS.