The United Nations has estimated that by 2030 more than half the world's population will live in areas at high risk of water scarcity. But what does this really mean? If you read some newspapers, you could be forgiven for thinking that there is a physical shortage of water that makes "water wars" inevitable. But there are good grounds for scepticism.
Managing increased demand in the context of increased climactic variability presents a huge challenge but if properly addressed, there is more than enough water to go round. Unlike oil, water's unique importance for human and economic development means that dependence on this shared resource generally does more to bring people together than force them apart.
Historically, states sharing river courses have tended to find non-violent ways of resolving disputes and sharing the resource, and the vast majority of conflicts over water have remained confined to the local level. Over the past 50 years, more than 200 water treaties have been successfully negotiated. In a recent interview Secretary of UN-Water Nikhil Chandavarkar stated "that there are many more examples of successful transboundary cooperation than conflict over water."
There are some serious and protracted conflicts, such as in Palestine or Darfur, where access to water is a major focus. However, in most cases, those conflicts are symptomatic of wider conflicts driven by deeper ethnic tensions or historic grievances.
Globally, there are nearly 900 million people who don't have access to basic supplies of safe water and this is first and foremost a question of social justice. The main driver of poor access is an inequity in distribution within countries, communities and households. It's worth repeating that there is more than enough water to go round if shared equitably between all users. But for this to become a reality, we need to support the development of water resource management plans that recognise the legitimate demands of different users - agriculture, industry, households - and ensure that universal access to a basic supply is prioritised as a fundamental human right.
On the rare occasions that poor people get asked to state their own priorities, water is usually top. The impacts of water poverty on child health, girls' education prospects, and women's welfare and livelihoods shouldn't make this a surprise - it is woman and girls who suffer most in terms of collecting water from distant sources, carrying heavy containers for long hours and looking after family members suffering from water related diseases, and stand to benefit most from improved access which is essential in order to reduce maternal and child mortality in developing countries.
Yet access to basic supplies of safe water continues to receive low political and financial priority in developing countries. One way to measure this it to look at international aid flows. Since the mid-1990s, the share of allocable aid for the sector has been contracting and only 30 per cent actually goes to low income countries where the need is greatest.
The world may have made progress towards reaching the Millennium Development Goal (MDG) to halve the proportion of people without access to safe water by 2015 but this is mainly down to rapid improvements in East Asia, particularly China, without which we would still be off-track.
Meanwhile, the MDG target for halving the proportion of people without access to sanitation remains hopelessly off track and, at the current rate of progress, is unlikely to be achieved before 2050. In the meantime, 2.6 billion people have nowhere safe to go to the toilet and, across the world, 4,000 children dies every day from easily preventable diseases caused by unsafe water and poor sanitation.
Sanitation is often characterised as the poor cousin of water, receiving much less attention and much less money. Yet diarrhoea is the second biggest killer of children under five in the developing world and kills more children than Aids, TB and malaria combined. The World Health Organisation has found that when all the benefits of access to sanitation are quantified and added together, every dollar invested brings about at least a $9 return.
Given the scale of the crisis, and the massive potential benefits, why is so little being done? The responsibility lies with both developing country governments and donor governments. But one reason for the continued neglect of sanitation is that the burden of the crisis - in terms of diseases, thwarted educational and economic opportunities - is borne disproportionately by women, children and those in extreme poverty: the people with the least voice in the decision-making process.
This April sees the first ever high leve meeting of the "Sanitation and Water for All" global initiative in Washington, bringing together ministers from North and South. It is an opportunity to reverse decades of political and financial neglect. We expect many heated discussions in the build up to the meeting, but we won't be warring over water, instead we'll be fighting to secure development efforts to date and to stop wider progress on health and education from being undermined for want of two very basic human rights.
Tom Slaymaker is A member of the policy team at WaterAid