Conservation, water and population growth

South Africa is water-scarce: our rainfall (about 450 mm a year) is only about half the world average (about 860 mm), and almost all our river water is already being used. Agriculture (irrigation) uses the most water. Water shortages hit poor communities hardest, because they cannot afford tanks or bought water.

• Households: fix leaks and take shorter showers.
• Farmers: use drip irrigation instead of flooding fields.
• Industry: reuse and recycle water inside the factory, and clean waste water before it goes back into rivers.
• An unhealthy river: dead fish, a foul smell and rubbish.
• Alien plants such as black wattle along rivers use lots of water and crowd out others.

Wetlands filter water and reduce floods, but about half of South Africa’s wetlands have already been lost or damaged. A catchment area is the land that drains into one river.

• Tsitsikamma in the Garden Route is Africa’s oldest marine protected area. In marine reserves fish can breed safely and recover.
• Eco-tourism is travel that protects nature and helps locals, with jobs for guides and cooks.
• Overfishing a species until few are left is misuse of a resource.
• Wetlands disappear when they are drained for farms and houses, polluted, or when their water is taken away.
• Case study: iSimangaliso Wetland Park around Lake St Lucia in KwaZulu-Natal is a World Heritage Site with hippos, crocodiles and many birds. It suffers when too much water is taken from the rivers that feed it.
• Caring for a catchment area: keep plants on riverbanks, remove alien plants, don’t dump rubbish or chemicals, and don’t build in wetlands.

For most of history the world’s population grew very slowly: hunger, dirty water and war kept the death rate high. Around 1800 there were about 1 billion people. It took about 125 years to reach 2 billion. After that better medicine, more food and clean water sped up growth, and in 2022 we passed 8 billion.

• War raises deaths and makes people flee.
• China’s one-child policy (1980–2015) limited most families to one child to slow population growth. It has since ended, and families may now have up to three children.
• Some beliefs encourage large families.