Population growth — 9 billion people are likely to inhabit the earth by 2050 — will place increasing demands on global water supplies, especially for agriculture. Expanding urban centres — by mid-century, 70% of the world's population is expected to live in cities — will face declining water supplies and deteriorating water quality. The world's driest regions might face conflicts over water. The spectre of climate change makes future water supplies even more uncertain.

Water scarcity is a global issue. Yet poor people living in rural and peri-urban areas in developing countries will probably suffer the most.

More than 1.2 billion people currently live without access to safe water and some 2.5 billion live without basic sanitation. Some 1.8 million people die each year due to exposure to unsafe water. More than 800 million suffer from hunger and malnutrition due, in part, to limited water supplies. By 2025, more than one-half of all people will be living with water scarcity.

The most recent report of the Intergovernmental Panel on Climate Change (IPCC), published in 2007, concludes that climate change could decrease water availability by some 30% in arid regions, home to 1 billion people. Water supplies stored in glaciers are expected to decline, reducing water availability for another 1 billion people. Crop yields in Asia could fall by 10% by 2020, and more than 130 million Asians might face extreme hunger by 2050. These trends are not new. Yet they are growing worse.

The world has not ignored the chronic global water crisis. Since the 1970s, there has been a series of high-profile international conferences, beginning with the United Nations (UN) Conference on the Human Environment in Stockholm in 1972. Two of the key targets of the UN Millennium Development Goals (MDGs) focus on access to safe drinking water and adequate sanitation. There have also been numerous global water councils and commissions, global assessments and international water forums.

Each ended with a similar set of recommendations. Yet, while they have led to a growing consensus on how to address the problems of water scarcity, these events have failed to ignite action. As a result, little progress has been made in implementing the recommendations or in improving the state of water supplies in developing countries. As knowledge of the causes of the water crisis has grown stronger, the political will for action has grown weaker.

If access to clean water is a 'fundamental human right', as is often declared in international forums, why has progress been so slow in ensuring this right? One reason is inadequate finance. There is a disturbing gap between the urgent rhetoric for improved water quantity and quality, and the amount of money actually being spent on the issue.

So what are the main causes of the global water crisis, and what can be done about it?

Artificially low prices for water services (and sometimes no pricing at all) largely explain water inefficiency, overuse, pollution and degradation. Simply put, free water often causes water to be wasted, especially in agriculture. While water pricing has been advocated for a long time, especially for irrigation, such measures have rarely been enacted.

Governments in developing countries cannot meet the investment demands for water services now, let alone in the future. The private sector will not invest in water-related infrastructure and services unless it can be assured a reasonable return. Yet governments in developing countries continue to resist water pricing, contending that the poor cannot afford to pay.

The fact is that the middle-classes in developing countries often pay low prices for networked water services, while the poor pay high prices for poorer quality water from street vendors. Under the current system, the poor pay more for less.

Substantial financial resources will be needed to meet the challenges posed by water scarcity and inadequate sanitation in the developing world. Where will the money come from? The answer is from many sources: national government budgets, international and bilateral funding, debt relief, private-sector investments and community-level resources. Water pricing will also be crucial.

Money alone, however, will not solve the global water crisis. Neither will technology. Experience shows that policy, institutional and legal reforms will be necessary. Changes in land tenure, enforcement of water rights, more effective water-allocation systems, improved legal and regulatory frameworks and the creation of water-basin management authorities must be integral pieces of the policy-reform puzzle. Providing women's groups, the poor, and youth and community-based groups with opportunities to participate in the decision-making process is also essential.

Water issues cannot be addressed in isolation from other issues such as land degradation, deforestation and ecosystem loss. Reforms linking water, land and people can go a long way towards sustainable water management. Integration is the key. Conserving freshwater ecosystems through better management would help to maintain both the quantity and the quality of water. One promising way to attain these benefits is through payment for environmental services, which is now taking place in Costa Rica and Brazil.

Credit: YVES GELLIE/GAMMA/CAMERA PRESS, LONDON

Knowledge sharing, institutional capacity building and integrating natural resource concerns into economic planning are all essential for the realization of sustainable development, in general, and for effective water management, in particular.

Both governments and the international community can make adequate supplies of clean water available in the developing world. We have enough water to meet our global needs. What we lack are sufficient supplies of political will and the institutional capacity to do the job.