No resource is more fundamental than water to the health and security of people and the environment. Yet the alarm bells are ringing as this finite, yet essential, natural resource comes under increasing pressure from growing demand, poor management and climate change creating a growing global water challenge.

With Rio+20 on the immediate horizon, and a focus on water, energy and food, water will be an issue that world and business leaders are likely to find absorbed into their agendas - and rightly so. Water scarcity and stress is not only an issue of protecting ecosystem and biodiversity, but is also presents a real and present risk to local communities, business and world economies.

Our planet is two thirds covered with water, 97% of that is salt water in the oceans and most of the essential freshwater is locked up in ice-caps, glaciers and deep underground aquifers. Yet the necessity of accessible freshwater is clear to see - it is essential for all human activity, from the food we eat to the clothes we wear; and in the developing world, access to clean water can dramatically change the lives of individuals and transform the livelihoods of whole communities. On a global scale, water has tremendous potential to unlock economic growth if managed properly, as made clear by the findings of a new report published yesterday by HSBC.

The report, 'Exploring the Links Between Water and Economic Growth', commissioned by HSBC, reveals that by 2050, the world's 10 biggest river basins by population are expected to produce a quarter of global GDP - a figure greater than the combined future economies of the US, Japan and Germany - and a sharp increase from a current contribution of a tenth. However, the report also forecasts that by 2050, seven in 10 of those river basins face significant or severe water scarcity without a considerable improvement in water resource management, meaning the forecast economic growth in those river basins may not materialise.

Alongside this report, recent figures from our own Living Planet Report show that the biodiversity in freshwater ecosystems has declined by up to 70% in tropical regions, since 1970, and that already, 2.7 billion people are living in river basins that experience water shortages at least one month a year. These figures show that the effects of poor water management are being felt globally. If we fail to take immediate steps towards a more sustainable freshwater future, then this could grow substantially - it is estimated than almost half the world's population will be living in water scarcity by 2030.

If we are to tackle this water challenge, the time to act is now! Alongside two other NGO partners - WaterAid and Earthwatch- we're proud to be participating in the just-announced HSBC Water Programme - a new $100 million, five-year partnership with HSBC, which aims to tackle water risks in river basins; bring safe water and improved sanitation to over a million people; and raise awareness about the global water challenge.

As part of this programme, we'll help over a thousand businesses and hundred thousand fishers and farmers to promote more efficient use of water in their practices. We'll also be working with governments across the globe to advise on better river basin management which will help to secure water supplies for the future needs of both the human population and the environment.

We'll be working in five basins - the Yangtze, Ganges, Pantanal, Mekong and the African Rift Valley. These basins are home to a combined 1 billion people, some of the world's most endangered species including the finless porpoise and Irrawaddy river dolphin; and, they provide valuable services that support the local and global economy. If you take the Mekong as an example, it supplies 25% of the world's freshwater fish catch and at least 60 million people rely on the river basin to support their livelihoods.

The Yangtze is one of the top 10 rivers highlighted by the research whose contribution to global GDP is set to grow - yet it already provides 30 - 40% of China's GDP. We've worked in the Yangtze with HSBC for the past 10 years - with great success. Our local project with fish farmers has demonstrated how low impact fishing practices can help improve the water quality and local environment, while helping to increase income potential - in one of our projects there was a 30% increase in income.

It is the scaling up of projects such as this and adoption of more efficient management practices by government and business that will help us tackle this water challenge. Through this programme we will encourage greater collaboration by governments and organisations worldwide, to work together to take rapid effective action both in river basins and to bring safe water and sanitation to over a million people.