Lake Victoria in East Africa is the continent’s largest lake and the biggest tropical lake in the world. It spans across Kenya, Uganda and Tanzania, and also supplies water to Rwanda and Burundi. However, Lake Victoria has completely dried up twice in the last 100,000 years. New research published in 2020 predicts that this may happen again.
WHAT DID THE RESEARCH FIND?
A team from the University of Houston in the USA looked at climate models that predict how rainfall and temperature in the region will change in the future. Increased rainfall fills up the lake, whilst higher temperatures cause lake water to evaporate.
The earth’s temperature is rising due to global warming. The team found that if the earth’s temperature continues to rise at its current rate, lake levels are likely to fall. This is because the loss of water due to evaporation is expected to exceed the filling of the lake by rainfall. If the lake levels fall at the rate the team predicts, then the White Nile (a smaller river that leads into the Nile, originating from Lake Victoria) could stop flowing within 10 years. Lake Victoria itself could dry up in as little as 500 years. This agrees with previous research that suggests Lake Victoria is shrinking.
However, these are only predictions, so may not be correct. For example, the model does not consider how human actions will affect the climate in the future. Additionally, some models predict that rainfall in Africa will increase in the next century, and this could lead to a rise in lake levels.
WHAT WOULD THE EFFECTS BE?
Around 30 million people rely on Lake Victoria directly for water. The lake is also a major source of the Nile, which provides water for a further 250 million people. The drying up of Lake Victoria would therefore lead to a loss of water for both drinking and farming. Water from the lake is also used to generate most of Uganda’s electricity in hydroelectric power stations. If water levels in the lake fall then the lake will shrink, meaning port towns around the lake may lose access. This is important as the fishing industry is a major source of income in the area.
WHAT CAN BE DONE?
Increased research will enable scientists to more accurately predict what will happen to Lake Victoria in the future, so that changes can be better prepared for. Tackling global warming will also help to prevent the earth’s temperature rising. This will reduce evaporation of water from the lake. Countries in East Africa and across the world are trying to cut their carbon emissions to reduce global warming. For example, SolarNow, a Ugandan solar energy company, has recently received a big investment from the petrochemical company Shell. Use of solar power instead of fossil fuels for energy helps to reduce carbon emissions.