A looming global water crisis and how to avert it is the big talking point at a conference of government ministers and leaders from around the world in Istanbul.The World Water Forum is seeking solutions to growing demand on water resources, and aims to ease tensions between states fighting over rivers, lakes and glaciers. Last week the UN said nearly half of the world’s population will be living in areas of acute water shortage by 2030. Campaigners, who are making their presence felt at the summit, say urgent action is needed now. Security is tight at the conference and clashes broke out as the march neared the venue. The world’s population is expected to rise to around 9 billion by 2050, placing huge demand on already limited fresh-water supplies. Most of the growth will be in developing countries. Water shortages are seen as underlying causes of conflict in several regions. It is feared they will lead to even greater global instability in the future.