Andrew Slaughter and Sukhmani Mantel

Total annual rainfall in Southern Africa does not seem to have changed much over the last century when measurements began.

But it has become more variable: droughts and floods are more frequent than before.

The region’s urban authorities, industries, farmers and other citizens will have to adapt to these conditions.

The experience of other countries may offer useful lessons.

Not all will be applicable, given Southern Africa’s limited financial resources.

For example, Southern African countries cannot afford wasteful expenditure on infrastructure, so we must be sure that our predictions of future water demand and changes in water availability have low uncertainty.

Individual low-income households in Southern Africa cannot afford some of the water-saving technologies used in developed countries.

So it needs to adopt simple, but effective solutions.

Some arid countries have been forced to develop novel technologies and strategies to survive extremely dry conditions.

Australia and Israel, for example, have become more resilient as climate change has brought more frequent droughts.

Two thirds of Israel’s land surface is desert and the remainder is arid.

Yet, the country has found ways to manage water shortages.

Australia, too, has learnt how to cope.

In particular, a drought from 1997 to 2009 forced Melbourne to take drastic measures to conserve water.

Residents changed the way they used water – and that behaviour has persisted.

On average, they still use only a quarter of the water used by the average Californian.

Israel has, over many decades, developed a centralised water management system.

It has invested in continuous technological innovations, improvements in practice and development of long-term management plans.

The country’s infrastructure innovations include a scheme to supply water from the north to all parts of the country, drilling extremely deep wells and seawater desalination plants.

Israel also reuses wastewater and compels people to use water-saving technology.