What phenomenon is leading to extreme water shortages in California and South Africa?

The phenomenon leading to extreme water shortages in California and South Africa is primarily climate change, but there are several contributing factors. Here are the steps to understand this:

1. Climate Change: Climate change is causing shifts in weather patterns, leading to prolonged periods of drought in regions like California and South Africa. This reduces the amount of water available for use.

2. Increased Demand: Both California and South Africa have seen significant population growth and urbanization in recent years. This has increased the demand for water, putting additional strain on already limited supplies.

3. Agriculture: Agriculture consumes a large amount of water. In California, for example, it accounts for about 80% of the state's water use. Inefficient irrigation methods and the cultivation of water-intensive crops can exacerbate water shortages.

4. Infrastructure: Aging and inadequate infrastructure can lead to significant water loss. In South Africa, it's estimated that about 37% of the country's water supply is lost due to leaks in the distribution system.

5. Mismanagement: Poor water management practices can also contribute to water shortages. This includes the over-allocation of water rights, lack of enforcement of water conservation measures, and failure to invest in water-saving technologies and infrastructure.

6. Pollution: Water pollution can reduce the amount of usable water. Industrial activities, agricultural runoff, and inadequate sanitation facilities can all contaminate water supplies, making it unsafe for human use.

In conclusion, while climate change is a significant factor, it's the combination of these issues that is leading to extreme water shortages in California and South Africa.