The Third World Water forum has been told that poor countries lack alert systems for natural catastrophes which often cause thousands of casualties and are set to occur more often due to global warming.

Experts told delegates that new technology would make it possible to forecast weather with greater accuracy, thereby helping the countries most at risk to take precautions which may minimise the consequences of disasters.

By 2025 half the world's population will be living in areas at risk from natural disasters, such as storms in Central America, floods in Asia and droughts in Africa.

The water forum has brought together 8,100 participants from 165 countries to discuss the water and sanitation crisis confronting 2.4 billion people worldwide.