By Matt McGrath
Environment reporter, BBC News
Tackling climate change will be one of the major concerns
While global attention has recently focused on energy and food, a global summit this week in Stockholm, Sweden, will tackle the key issue of water.
The World Water Week meeting starts on Sunday and will hear renewed calls to solve growing challenges of sanitation, climate change and drinkable supplies.
Sanitation in particular is one of the most important global issues.
The organisers say lack of adequate sanitation is a scandal that costs the lives of 1.4m children every year.
Investing in this area, say scientists, is the most cost effective health intervention the world could make.
While global concerns about energy and food are real, experts say that tackling key water issues is more fundamental to the world and long-term sustained action is needed urgently.
The 2,500 experts will be considering whether the world will have enough water resources to cope with rising populations.
By 2025, 1.8bn people will be living in regions with absolute water scarcity.
But getting political agreement on how to share or protect water seems to be as far away as ever.
Any discussion on water issues will also have to address climate change.
It is only recently that scientists have been able to work out the impacts of rising temperatures on the water cycle.