Guardian: Countries across the world will have to dramatically increase investment in dams, pipes and other water infrastructure to avoid widespread flooding, drought and disease even before climate change accelerates these problems, experts have warned. Investment needs to be at least doubled from the current level of $80bn (£45.5bn) a year, an international congress was told this week, and one leading authority said spending needed to rise to 1.5% of gross domestic product just “to be able to …